Videotek Tvm-821d Operating instructions

TVM-821D

Serial Digital Component

Monitor/Vectorscope

Service & Instruction Manual

TWO-YEAR LIMITED WARRANTY

Videotek, Inc. warrants that this product is free from defects in materials and workmanship for a period of two years from the

date of purchase, except for CRTs and LCDs, which are warranted for a period of one year. During this warranty period,

Videotek will, at its option, repair or replace defective products at no charge for the parts or labor. Batteries are not covered

in the warranty.

For warranty service or repair, this product must be returned to a service facility designated by Videotek in the original

packing or its equivalent. The purchaser shall insure the product and prepay shipping charges to Videotek, and Videotek

shall insure the product and pay shipping charges to return the product to the purchaser.

The foregoing warranty shall not apply to defects or damage resulting from improper or inadequate maintenance by the

purchaser, connecting the product to incompatible equipment, misuses, operation outside any environmental specification for

the product, improper site preparation or maintenance, or attempts by personnel other than authorized Videotek

representatives to repair or service the product.

No other warranty is expressed or implied. Videotek specifically disclaims the implied warranties of merchantability and

fitness for a particular purpose. The remedies provided by the foregoing warranty are the purchaser's sole and exclusive

remedies. Videotek shall not be liable for any direct, indirect, special, incidental or consequential damages, whether based on

contract, tort, or otherwise.

Printed May 2006

Item #061711 Rev. B

Contents of this publication may not be reproduced in any form without permission of Videotek, Inc.

This instrument, in whole or in part, may be protected by one or more US or foreign patents or patent applications.

Specifications subject to change without notice.

____________________________________________________________________________________________________________

Videotek and the Videotek logo are registered trademarks of Videotek, Inc.

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OPERATOR'S SAFETY SUMMARY

Refer all servicing to qualified service personnel

To maintain and to ensure safe operation, observe the following instructions, symbols and precautions.

1. When the unit is to be permanently cabled, first connect protective ground conductor before making any

other connections.

2. Built-in units should only be operated when properly fitted into the system.

3. For permanently cabled units without built-in fuses, automatic switches or similar protective facilities, the

AC supply line shall be fitted with fuses rated to the units.

4. Before switching on the unit, ensure that the operating voltage set at the unit matches the line voltage.

If a different operating voltage is to be set, use a fuse with appropriate rating.

5. Units of Protection Class I with disconnectable AC supply cable and plug may only be operated from a

power socket with protective ground contact.

a. The protective ground connection should not be made ineffective by an extension cable.

b. Any breaking of the protective ground conductor within or outside of the unit or loosening of the pro-

tective ground connection may cause the unit to become electrically hazardous.

c. The protective ground conductor shall not be interrupted intentionally.

6. Before opening the unit, isolate it from the AC supply.

a. Adjustments and replacement of parts as well as maintenance and repair should be carried out only

by qualified personnel.

b. Observe safety regulations and rules for the prevention of accidents.

c. Use only original parts for replacing parts relevant to safety (e.g. power on/off switches, power trans-

formers or fuses).

7. Operator replaceable fuses may be hazardous live. When replacing fuse, turn unit off by isolating it from

the AC supply.

8. Also observe the additional safety instructions specified in this manual.

Explanation of Symbols Used

Read Operator's Handbook and Service Manual; observe the safety symbols used.

Caution, shock hazard

Protective ground connection

Unit ground

Equipotentiality

Ground

Use of Cleaning Solvents

Cleaning of the equipment with isopropyl alcohol or similar solvents may cause degradation of labels. Use

caution when cleaning so that labels are not removed.

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Table of Contents

Features .......................................................... 7

Specifications ..................................................... 8

Installation Instructions ............................................. 9

Front & Back Panel Controls ......................................... 10

Operating Instructions .............................................. 12

Theory of Operation ................................................ 14

Block Diagram .................................................... 18

Block Diagram for TVM-850 Board ................................... 19

Block Diagram for TVM-851 Board ................................... 20

Performance Check ................................................. 22

Calibration Procedure ............................................... 24

Troubleshooting Procedure .......................................... 25

Interconnection Diagram ............................................ 27

TVM-850 Component Layout ........................................ 30

TVM-850 Board Schematic .......................................... 32

TVM-851 Component Layout ........................................ 46

TVM-851 Board Schematic .......................................... 48

TVM-852 Component Layout ........................................ 57

TVM-852 Board Schematic .......................................... 58

TVM-853 Component Layout ........................................ 62

TVM-853 Board Schematic .......................................... 63

Parts List ......................................................... 65

Exploded View of TVM-821D ........................................ 77

Exploded View of Control Panel Assembly .............................. 78

Exploded View of CRT Ass'y & Connector Panel Ass'y .................... 79

Dimension Drawing of Standard Case SSC-1 ............................ 80

Dimension Drawing of Double Rackmount Case DRC-1 ................... 81

Dimension Drawing of Portable Case PTC-1 ............................ 82

Addendum ........................................................ 83

Features

With 12 bit processing, the technically advanced TVM-821D serial digital waveform monitor/vectorscope for 601 video brings

the most commonly needed functions within quick, easy and affordable reach. With elegance and accuracy, the TVM-821D

was developed with the operator in mind, incorporating a button-per-function concept. Intelligent design philosophy makes

the operation of the TVM-821D intuitively obvious. Unique features include an array of LEDs to continually advise the

operator of the input signal strength, preventing the possibility of system crashes due to weak signals. A second unique

feature is the ability to observe two digital inputs simultaneously. An A and B display (either in parade or overlay) makes

routine tasks such as synchronizing, timing and level setting easy to perform. Other functions include LED alarms to alert

the operator of EDH, EAV and SAV data problems. Add this to Videotek's long history of making high quality test

instruments, the TVM-821D is the perfect test solution for editing, production and post production, broadcast and remote

vehicles.

!Two component serial digital inputs

!Button and knob per function design

!Simple operation

!A/B input "Overlay" mode for easy system timing

!A/B input "Parade" mode for level comparison

!LED alarms for EDH, Gamut and Data errors

!Input EQ display for quick verification of signal integrity

!Analog audio input with X-Y display for gain and phase measurement

!RGB or Y, Cb, Cr display

!525/625 operation - Auto-sensing

!Four memories for fast recall of set-ups

!GPI input for memory recall

!Looping external analog reference input

!GPI output for alarm indication

Specifications

VIDEO

INPUTS : Two 270 Mb/s 4:2:2 serial digital video

CONNECTORS : BNC female

IMPEDANCE : 75 Snominal passive loop through

RETURN LOSS : $18 dB to 270 MHz

LEVEL : 800 mV p-p ± 10%

EQUALIZATION : Automatic equalization for a minimum of

200m of Belden 8281 cable.

ANALOG REFERENCE

INPUT : Composite video or blackburst

CONNECTORS : BNC female

IMPEDANCE : 75 Snominal passive loop through

RETURN LOSS : $40 dB to 5 MHz

SYNC LEVEL : 143 mV to 600 mV

SYNCHRONIZATION REQUIREMENTS

INTERNAL REFERENCE : Derived from serial A or serial B data or

free running internal source

EXTERNAL REFERENCE : External sync will synchronize sweeps

VERTICAL DEFLECTION SYSTEM

FLAT : Y channel to 5 MHz #2% (± 0.2 dB)

Color difference channels to 2.5 MHz #2% (± 0.2 dB)

LOW PASS : 3 dB attenuation at 1 MHz. Low pass response (<

10 kHz) within 1% (± 1 dB) of Flat response

DIFFERENTIATED STEP : For a non-modulated 5 step input with

each step being 140 mV ± 1 %, the spikes produced by the filter are

500 to 700 mV.

The difference between amplitudes will be less than ± 2% of the first

spike's amplitude.

TRANSIENT RESPONSE : Less than 5 mV of preshoot and/or

overshoot at full scale. Flat mode using sin pulse bar signal

PULSE TO BAR RANGE : 0.99:1 to 1.01:1

TILT - FIELD RATE SQUARE WAVE OR VERTICAL WINDOW OR

25 µS PULSE SIGNAL : #1%

VERTICAL MAGNIFICATION : x1 or x5

HORIZONTAL DEFLECTION SYSTEM

FIELD RATE TIMEBASE : Equal to x1, x2 or x3 of the field rate of

applied video or external reference (User selected Parade modes)

LINE RATE TIMEBASE : Equal to x1, x2 or x3 of the H line rate of

applied video or external reference (User selected Parade modes)

SWEEP MAGNIFICATION : x1 or x10

TIMING ACCURACY : 1H, H Mag (0.5 µs/div) ± 2%

2H, H Mag (1 µs/div) ± 2% of 1H Mag

3H, H Mag (1.5 µs/div) ± 2% of 1H Mag

LINEARITY : 2% or less over complete horizontal position range ex-

cluding first and last major division

CALIBRATOR

WAVEFORM MODE FREQUENCY : 100 kHz to 0.1 kHz, synchro-

nizes in H sweep modes providing reference for sweep and magnifier

calibration.

AMPLITUDE : 700 mV ± 0.5%

VECTOR MODE : Provides vector centering dot

MULTIPLE DISPLAY MODE

MEASUREMENT ACCURACY

WAVEFORM OVERLAYS (H MAG) : ± 100 ns - Relative

± 1.5 mV - Relative

VECTOR OVERLAYS : ± 1.5 mV - Relative

AUDIO

INPUTS : Balanced analog audio, AC coupled

CONNECTOR : 15 pin Sub-D

IMPEDANCE : Approximately 20 kS

LEVEL : 0, +4, +8, or +12 dBm internally selectable (factory set

to +4 dBm)

PHASE MATCHING : Less than a trace width separation at 20 kHz

DISPLAYS : Audio may be displayed alone or in any combination

with waveform and/or vector

CONTROL

INPUTS : 4 Contact closure inputs with common return -

Dry Contacts

CONNECTOR : 15 pin Sub-D (Shared with Audio)

CONTACTS : 30V DC max. @ 1A max.

CONTROLS : Each input will cause a system memory to be

recalled. One input per memory

OUTPUTS : 1 Dry Contact Closure consisting of:

1 Normally Open contact

1 Normally Closed contact

1 Common return

CONNECTOR : 15 pin Sub-D (Shared with Audio)

CONTROLS : Contact closure will become energized when an EDH

GAMUT or Data error is detected. Contact will remain energized for

5 seconds.

POWER REQUIREMENTS

POWER INPUT : 115/230V AC 50/60 Hz, nominal

POWER CONSUMPTION : 85 VA maximum

MECHANICAL

DIMENSIONS : Height: 5.25" (13.34 cm)

Width: 8.5" (21.6 cm)

Depth: 17.75" (45.1 cm)

WEIGHT : 12 lb. (15.45 kg)

ENVIRONMENTAL

OPERATING TEMPERATURE : 0Eto 50EC

STORAGE TEMPERATURE : -40Eto 75EC

HUMIDITY : 90% maximum (non condensing)

STANDARD ACCESSORIES

Instruction & Service Manual

15 pin mating "D" connector

Specifications subject to change without notice

Audio Level Switch Position

0 dBm

+4 dBm

+8 dBm

+12 dBm

BOTTOM OF UNIT

FRONT OF UNIT

TVM-851 PC BOARD

AUDIO REF.

LEVEL (SW1)

TRACE ROTATION

POT (R229)

Installation Instructions

POWER REQUIREMENTS

The TVM-821D can be operated at either 115V/60 Hz or 230V/50

Hz. No external selection has to be made in order to change the in-

put voltage. If it becomes necessary to replace the fuse, make

sure to adhere to the proper fuse value.

RACK MOUNTING

The metal cabinet (SSC-1) for the TVM-821D provides the proper

electrical environment for the instrument, limits the handling dam-

age, and reduces dust collection. Two #8-32 screws are provided

to secure the unit into the metal cabinet (they are installed in the

rear of the unit).

COOLING OF THE TVM-821D

The TVM-821D is cooled by an exhaust fan at the rear of the unit.

For proper air circulation, a minimum of 1.75 inches should be

maintained above and below the unit. Care should be taken not to

block the exhaust fan at the rear of the unit.

CUSTOM INSTALLATION

All installations must provide adequate ventilation and mechanical

protection. Top openings should not exceed 0.15 inches in diame-

ter. Other openings should not exceed 0.45 inches in diameter pro-

vided the circuits are at least 0.6 inches from the surface of the en-

closure. All conductive parts must be connected to the frame or

ground.

AUDIO LEVEL SELECTION

An internal rotary switch is provided to select the nominal audio in-

put level. This selection will provide the required attenuation for the

audio display. Factory setting is +4 dBm.

Adjust audio reference level rotary switch (SW1) located on bottom

of TVM-821D (see diagram below). Settings are per following

chart:

TRACE ROTATION

Before installing the unit in its final location, check the trace rota-

tion. The unit, like any other CRT device, is affected by the earth's

magnetic field. The trace might be rotated relative to the etched

graticule, depending upon the position of the instrument. Place the

unit in its final location and use H POS and V POS to position a

horizontal trace relative to the 0 mV line of the graticule. Adjust pot

R229 to align horizontal trace with graticule.

YCbCr

RGB

FIELD

LINE

VEC

WFM

EXT

BOVR

PAR

Y/R

Cb/G

Cr/B

x10

SEL

100 %

VECTORV

GRAT

FOCUS

H. POS

V. POS

CAL VECT FMT

FILTER MEMORY

SAV/EAV STORE

FORMAT VMAG

SWEEP HMAG

DISPLAY AUDIO

REF CHANNEL

INPUT VIEW

TVM-821D

VIDEOTEK

MIN EQ MAX

625

525

REFERENCE

EDH GAMUT DATA

ERROR

INTENSITY

POWER

FRONT VIEW

Front & Back Panel Controls

LEFT CONTROL PANEL

INTENSITY - Knob which controls the brightness of the CRT beam.

GRAT - Knob which controls the brightness of the graticule lights.

FOCUS - Knob which controls the sharpness of the CRT beam.

H. POS - Knob which controls the horizontal position of the wave-

form display.

V. POS - Knob which controls the vertical position of the waveform

display.

VECTOR H - Trimpot which controls the horizontal position of the

vector display.

VECTOR V - Trimpot which controls the vertical position of the

vector display.

RIGHT CONTROL PANEL BUTTONS

INPUT - Selects one or both of the digital video inputs; A, B, or A & B.

VIEW - Selects inputs overlaid or paraded in waveform display.

REF - Selects external reference (nominal reference is selected input

or input A when in A & B mode).

CHANNEL - Selects one or all three of the video components; Y, Cb,

Cr, or Y & Cb & Cr. When in RGB mode the selectable components

are; R, G, B, or R & G & B.

DISPLAY - Selects display as waveform, vector, or waveform &

vector. When in audio mode, both waveform and vector may be dis-

abled resulting in an audio only display.

AUDIO - When selected, audio is added to any of the display modes.

In addition, an audio only display may be achieved by disabling both

waveform and vector using the display button.

SWEEP - Selects between a line-rate and a field-rate waveform

sweep.

HMAG - Toggles waveform horizontal x10 magnification on and off.

FORMAT - Selects between YCbCr (native component format) and

RGB (transcoded component format) waveform displays.

VMAG - Toggles waveform vertical x5 magnification on and off.

SAV/EAV - Enables viewing of SAV and EAV timing signals while in

YCbCr format waveform display.

FILTER - Selects OFF or one of three filters for the waveform display:

lowpass, differential step, or bowtie.

CAL - When selected, the display changes to a single sweep of an in-

ternally generated precision 100 kHz square-wave and a vector cen-

tering dot.

VECT FMT - When selected, the vector display overall amplitude is

reduced by 25% to compensate for the increased amplitude of 100%

saturated color bars.

MEMORY - Each button press cycles through the four available

memory locations. In recall mode, each memory selected changes

the configuration of the unit to match that stored in the memory. If all

four memories are cycled through, the unit will return to it’s original

state. In store mode, initiated by pressing the store button first, the

memory selected will be used to store the current configuration of the

unit. Each memory selected in the store mode will not change the

current configuration of the unit or the configuration stored in the

memory until the store button is pressed again. If all four memories

are cycled through, the store mode will be canceled and the configur-

ation of the unit will be unchanged.

STORE - Enables memory store mode indicated by a flashing SEL

light, otherwise memory recall mode is active. A second press of this

button without any memory locations selected will toggle back to recall

mode. If a memory location was selected while in store mode, a

second press of this button will store the current configuration of the

unit in the selected memory.

All modes are activated by independent button presses, there are no

timed button press sequences required. If a selection is made which

does not pertain to the current display, the selection will still be made

however, the results might not be seen until the corresponding display

is selected.

POWER - Master power on/off switch.

Audio Level Switch Position

0 dBm

+4 dBm

+8 dBm

+12 dBm

EXT. REF.

SERIAL

INPUT A

SERIAL

INPUT B

AUDIO/REMOTE

2.5A 250V

5 x 20mm

INPUT:

115-230V

50-60Hz

70VA MAX

REAR VIEW

Front & Back Panel Controls (cont'd)

INDICATORS

LEDs AT BOTTOM OF FRONT PANEL

EQ A & B - Bar graphs continuously indicate the equalization compen-

sation required for both video inputs. The minimum and maximum

points represent the limits of the compensation range.

ERROR

EDH - Indicates the presence and status of the Error Detection and

Handling (EDH). Green represents a valid EDH calculation and red

represents an EDH error. A blank indicator represents no EDH de-

tected.

GAMUT - Indicates a video signal excursion beyond the RGB limits.

DATA - Indicates missing End of Active Video (EAV) and/or Start of

Active Video (SAV) Timing Reference Signals (TRS) from the se-

lected digital video input.

All error indicators will remain active a minimum of one second after

the occurrence of an error.

REFERENCE 525/625 - Indicates the standard of the reference video;

525 lines or 625 lines.

Y Cb Cr / RGB FORMATS

While in Y Cb Cr format the following applies:

1. Waveform displays video inputs in the native 601 YCbCr format.

2. The CHANNEL button selects between the three components; Y,

Cb, Cr.

3. Vector display is an X-Y representation of the Cb and Cr compo-

nents respectively.

4. Low Pass (LP) and Differential Step (DS) filter the selected Y, Cb,

Cr channels.

5. Bowtie displays a two line sweep of Y-Cb and Y-Cr.

While in RGB format the following applies:

1. Waveform displays video inputs in a transcoded RGB format.

2. The CHANNEL button selects between the three components; R,

G, B.

3. The VIEW SAV/EAV function is disabled while in the RGB format.

4. Vector display is an X-Y representation of the Cb and Cr compo-

nents respectively.

5. Low Pass (LP) and Differential Step (DS) filter the selected R, G,

B channels.

6. Bowtie displays a two line sweep of Y-Cb and Y-Cr.

REAR PANEL

The rear panel of the TVM-821D consists of four digital video input

BNC connectors, two analog video reference input BNC connectors,

a 15-pin audio/GPI connector, an AC power cord connector, and a

fan. Two pairs of BNC connectors labeled SERIAL INPUT A and

SERIAL INPUT B are for passively looping 601 digital video inputs.

There is one pair of BNC connectors for looping an external analog

reference video input.

The 15-pin audio/GPI connector is wired as shown below:

1 -X 9 CONTACT COMMON

2 GND 10 N/C CONTACT

3+X 11GPI#1

4 N/C 12 GPI #2

5-Y 13GPI#3

6 GND 14 GPI #4

7 +Y 15 GPI COMMON

8 N/O CONTACT

PRINTED CIRCUIT BOARD MOUNTED CONTROLS

The audio level rotary switch SW1 is located on the TVM-851 board

(accessible on the bottom of the TVM-821D).

Operating Instructions

INPUT SELECTION

The INPUT button is used to select which of the video inputs are dis-

played on the CRT. There are three possible selections; A only, B

only, and A & B combined. Each press of the INPUT button cycles

through the three available modes.

CHANNEL SELECTION

The CHANNEL button is used to select which of the three compo-

nents is to be displayed as a waveform. There are four possible se-

lections which depend on the format selected. In YCbCr format the

available channels are Y only, Cb only, Cr only, and Y & Cb & Cr com-

bined. In RGB format the available channels are R only, G only, B

only, and R & G & B combined. Each press of the CHANNEL button

cycles through the four available modes.

DISPLAY SELECTION

The DISPLAY button is used to select which of the test displays will

be viewed on the CRT. The number of selections available depends

on the status of audio. If audio is off the available selections are

Waveform (WFM) only, Vector (VEC) only, and WFM & VEC com-

bined. If audio is on the available selections are WFM only, VEC only,

WFM & VEC combined, and audio only. Selecting audio off while

viewing audio only will return the display to WFM only. Each press of

the DISPLAY button cycles through the available modes.

AUDIO SELECTION

The AUDIO button is used the activate the audio lissajous trace. Se-

lecting audio ON will add the audio pattern to any of the displays se-

lected by the DISPLAY button. In addition, while audio is ON an audio

only mode is added to the available display modes accessible by the

DISPLAY button. Each press of the AUDIO button will toggle audio

ON and OFF.

VIEW SELECTION

The VIEW button is used to select between paraded and overlaid

waveforms. Parade means “waveforms displayed next to each other”,

overlay means “waveforms displayed overtop of each other”. The

effect of the VIEW button is dependent on INPUT and CHANNEL

selections and pertains only to the waveform display. Each press of

the VIEW button toggles between parade (PAR) and overlay (OVR)

views.

While only a single input is selected (A or B) the following applies:

1. If only a single channel is selected:

a. The VIEW button has no effect on the appearance since

there is only one waveform to display.

2. If all three channels are selected:

a. In parade view the channels appear next to each other.

b. In overlay view the channels appear overtop of each other.

While both inputs are selected (A & B) the following applies:

1. If only one channel is selected:

a. In parade view the inputs appear next to each other.

b. In overlay view the inputs appear overtop of each other.

2. If all three channels are selected:

a. In parade view the channels appear next to each other and

each channel is an overlay of both inputs.

b. In overlay view the channels and inputs all appear overtop of

each other.

SWEEP SELECTION

The SWEEP button changes the CRT sweep rate between horizontal

(LINE) and vertical (FIELD) rate. Each press of the button toggles be-

tween the two rates.

HMAG SELECTION

The HMAG button multiplies the current sweep rate by a factor of 10.

Each press of the HMAG button toggles the magnification on and off.

The major horizontal divisions on the 0 mV line of the graticule are

calibrated for the three horizontal sweep speeds 1H, 2H, and 3H.

With HMAG off they represent 5.0, 10.0, and 15.0 µS respectively.

With HMAG on they represent 0.5, 1.0, and 1.5 µS respectively.

CAL SELECTION

A precision 100 kHz waveform is provided for verifying vertical gain

and horizontal sweep timing. In addition, a dot is provided which re-

presents the vector origin for vectorscope centering. To select the

calibration mode simply press the CAL button. A second press of the

CAL button will toggle the calibration mode off, returning the display

to the previously selected mode. Selecting the calibration mode will

always force the display into a 1H sweep with the vector origin dot

regardless of the configuration of the unit beforehand.

MEMORY PRESET STORAGE

The TVM-821D allows the storage and retrieval of four complete sets

of front panel configurations. This includes all of the buttons but does

not include any of the knobs or trimmers. The configuration memories

are loaded with default values at the factory.

The default configuration is as follows:

Input A only

Internal reference

WFM only

Line sweep

Format YCbCr

Parade of channels Y, Cb, and Cr

The contents of all four memories may be changed to that of any front

panel configuration. The memories are capacitively backed to pre-

serve the contents in the case of a power failure.

To store a front panel configuration perform the following:

1. Make the desired front panel selections to be stored in the

memory.

2. Press the STORE button, the SEL light should be flashing.

3. Press the MEMORY button repeatedly until the desired memory

location light is flashing.

4. Press the STORE button again, the SEL light should go out and

the MEMORY light should stop blinking.

MEMORY PRESET RECALL

To recall a front panel configuration from a memory location:

1. Verify unit is not in store mode (SEL light is not flashing). If the

SEL light is flashing cancel the store mode by pressing the

MEMORY button repeatedly until the SEL light shuts off. Note: if

the unit is in store mode and a memory location is selected,

pressing the STORE button will overwrite the selected memory lo-

cation.

VIDEOTEK

50˚

40˚

30˚

20˚

10˚

700mV

612.5mV

525mV

350mV

87.5mV

0mV

"K" FACTOR MARKINGS

VECTOR GRATICULE BOX

(GREEN). BOX REPRESENTS

2% OF FULL SCALE VECTOR.

AUDIO PHASE MARKINGS

AUDIO TARGET BOXES

REPRESENTING

0.5 dB AND

1.0 dB AMPLITUDE ERRORS.

AUDIO AND VECTOR

CENTERING BOX.

WAVEFORM MAJOR

GRATICULES SPACED

EVERY 100 mV.

WAVEFORM MINOR

GRATICULES SPACED

EVERY 20 mV.

WAVEFORM MAJOR TIMING DIVISION

SPACED EVERY 5 µS (1H SWEEP).

WAVEFORM MINOR TIMING DIVISION

SPACED EVERY 1 µS (1H SWEEP)

CENTER FOR COLOR

DIFFERENCE CHANNELS.

REFERENCE FOR 75%

COLOR BARS.

Operating Instructions (cont'd)

2. Press the MEMORY button repeatedly until the desired memory

location is selected. Each press of the MEMORY button will recall

a sequential memory location. If the MEMORY button is pressed

after location number four was selected, memory recall will be

disabled and the front panel will return to it’s original state.

3. If any other button is pressed after a memory location has been

recalled, memory recall mode will be canceled because the front

panel will no longer match that stored in the memory location.

POWER-UP RESET

If the CAL button is held in while the power switch is cycled on, the

unit will executea system reset forcing the front panel and all memory

locations to the factory default state (Input A only, Internal reference,

WFM only, Line sweep, Format YCbCr, Parade of channels Y, Cb,

and Cr).

TIMING MEASUREMENTS

(using EAV/SAV markers as illustrated below)

Start of Active Video (SAV) and End of Active Video (EAV) are timing

signals which occur in each line of 601 video (525/625 line). The sig-

nal consist of 4 bytes each and occur just before and after the

samples of active video. These timing signals are normallynot shown

on the CRT when lines of video are displayed (EAV/SAV off). How-

ever, the EAV and SAV markers are useful when determining how

well the active video is centered between these markers. In line rate

sweeps, by pressing the EAV/SAV button to enable this function, the

SAV marker will appear as a large spike at the beginning of each line

of video. The EAV marker be a spike at the end of each line. The

user will then be able to see how active video appears in relationship

to these markers. In addition, when this function is enabled in A and

B input mode, the timing difference between SAV or EAV of each

input can show timing differences between the channels. EAV and

SAV are disabled then in RGB mode.

Theory of Operation

The TVM-821D is a combination waveform monitor and vectorscope.

Its display modesallow waveform and vector displays to be presented

in any combination.

The basic signal flow and control structure of the TVM-821D may be

seen in the interconnection diagram on page 27. The circuitry shown

in the block diagram on page 18 is contained on six different printed

circuit boards. The boards and their primary functions are

1. TVM-850 - converts two channels of component serial digital

video (4:2:2) streams to analog component video. In addition, this

board also houses the microprocessor used to control the

TVM-821D.

2. TVM-851A - contains analog waveform filters, sweep generation

circuitry, and audio processing.

3. TVM-851B - front panel control board. Controls intensity,

graticule, focus, horizontal and vertical position.

4. TVM-852A - this board contains CRT detection amplifier.

5. TVM-852B - graticule light board.

6. TVM-853 board - is the front panel select board, and contains the

contact surfaces for the front panel rubber keys. In addition, this

board contains the front panel LEDs and the vertical and hori-

zontal vector position pots.

The following is a more detailed description of each circuit board's

functions. The sheet number(s) described under each board corre-

sponds with the sheet number in the title block of the schematic for

that board. The schematic section starts on page 30.

TVM-850 BOARD

Sheet 1 & 2 : Both of these schematic pages serve the same func-

tion. Sheet 1 converts digital serial input A to parallel data (10 bit) and

extracts the parallel clock. Sheet 2 performs the same function for

input B. U10 and U24 receive the loop through serial digital data and

extract the 270 MHz clock. Differential clock and data are output from

U10 and U24 to U8 and U26. U8 and U26 deserialize the data and

output 10 bits of parallel data and a 27 MHz clock. U19 is used to

amplify the signal strength indicator from U10 and U24 and buffer the

signals to the micros A/D converter. This signal is used to drive the

unit’s front panel equalization LEDs.

Sheet 3 : Both sets of 10 bit parallel data from the deserializers (U8

and U26) go to U20. U20 is a programmable logic device (PLD). This

device is programmed serially by the microprocessor at power up.

The code for this device is a stored in the units ROM, U21. The pixel

clocks from U8 and U26 are multiplexed, via U14 and U15, along with

an internal 27 MHz crystal clock and are applied to the programmable

device. Each individual pixel clock is also sent into the programmable

devices for internal reference timing.

The PLD device, U20, performs the following functions:

1. Extracts reference timing for input A, input B, or external refer-

ence, or a free-running internal generator.

2. Scans each set of parallel pixel data to determine the beginning

and end of active video, the occurrence of horizontal sync, and

the occurrence of vertical sync.

3. Demultiplexes the data into its component forms (Y, Cb, and Cr).

4. Checks the input (A or B, not both) data for EDH, and Data errors.

5. Provides all timing for real time control of beam and analog

switching. This timing is derived from either input A, input B, the

external analog reference, or is generated as a free running

source inside this logic device.

Sheet 4 : Cb and Cr Data from U20 is sent to Interpolators, U3 and

U4. The interpolators double the effective data for the color difference

channels. This interpolation allows color space conversion of the

video to be done digitally at a 4:4:4 rate in U17.

U5 interpolates all waveform data from a 4x oversampling to 8x in a

12 bit format. The waveforms include Y, Cb, Cr, R, G, B, calibration

pulse and Bowtie.

Sheet 5 and 6 : All symbols on these pages are for a single program-

mable device, U17. This programmable device inputs Y data (4x

oversampling), Cb and Cr data (4x oversampling). The WFM data is

sent to interpolator U5 to increase the data rate to 8x oversampling.

The Cb and Cr data is sent directly to the DACs at a 4x oversampled

rate for vector display. This programmable device performs the

following:

1. Converts YCbCr to RGB.

2. Gamut error detection.

3. Bowtie filter.

4. Waveform multiplexing.

5. 75/100% vector adjustment.

6. Y delay to compensate for CbCr interpolators.

Sheet 7 : Vector DACs. Digital Cb and Cr (4x oversampled) are sent

to the triple DAC, U16. The analog outputs are sent through the

reconstruction filters and buffered for output to the TVM-851 board.

R59 and C45 are used to trim the amplitude and frequency response

of the Cb channel. R64 and C48 are used to trim the amplitude and

frequency response of the Cr channel.

Sheet 8 : WFM DACs. Digital data (Y, Cb, Cr, R, G, B, calibration

pulse, and bowtie), 8x oversampled, is sent to the 12 bit DAC, U6.

The differential output is received by U2, sent through a reconstruction

filter, and is buffered for output to the TVM-851 board. R30 is used

to adjust the WFM amplitude by adjusting the reference voltage to the

DAC. C37 is used to trim the frequency response of the waveforms.

Sheet 9 : CPU and memory: The 68HC11, U30, is used to perform

the following tasks:

1. Loads the programmable logic chips.

2. Controls the front panel LEDs and reads the front panel buttons.

3. Controls waveform, vector, and audio sweeps.

4. Using the built in A/D converter, it reads the amount of input

equalization and displays the equalization on the front panel.

5. Stores and recalls front panel setups. Can recall setups using the

four general purpose inputs.

6. Activates alarm relay during EDH, data, or gamut errors.

The 68HC11 is supervised by U39, a watchdog timer. The watchdog

controls the reset line on the micro and the capacitor backup for the

CPU and external RAM. The watchdog can be disabled by removing

jumper CN2. Two external interrupts to the micro are the Horizontal

and Vertical syncs for the reference video. The Horizonal sync is

gated by U34 prior to going to the XIRQ, a nonmaskable interrupt.

U34 allows the micro to turn off the nonmaskable interrupt while it pro-

grams the programmable logic.

CPU read and write strobe are generated by U34 pins 11 and 6. The

serial port driver U33 is not used in this implementation. U28 is used

to gate the clocks which go to the programmable devices during start

up.

Theory of Operation (cont'd)

Sheet 10 : U32 is used to latch the lower 8 bits of the address from

the multiplexed CPU address/data port. The programmable device,

U23, is used to perform the CPU address decoding. An 8K capacitor

backed-up ram, U29, and a 128K rom, U21, is also used on this

PCBA.

Sheet 11 : Front panel and analog board digital interface. A bidirect-

ional data port is used to send and receive data from the TVM-853

board via U35. U36 sends address lines and data strobes to the front

panel.

U37 and U38 provide drive for the control signals which are sent to

the TVM-851 board. Two signals are received back to U38 from the

TVM-851 board, analog horizontal and vertical sync.

Sheet 12 : CPU ports. U22 is used to access the upper 64K of RAM

in 1K sections. Address bits 12 through 15 are written by the CPU to

this port.

Port U27 is used to configure the programmable logic chips. In addi-

tion, the port for the external error relay is on U27.

Port U31 is a micro input port and is used to read the status of the

programmable logic chips.

Sheet 13 : General Purpose Inputs, Power and Gnd. U25 is used to

detect external contact closures and report them to the micro. Diodes

to power and ground in conjunction with 1K input resistors and shunt

0.1 µF capacitors are used for ESD protection. A closed contact

produces a high signal to the micro.

+5 volts is used to run the digital logic. ± 12 volts are regulated down

to ± 5 volts for use in the analog circuitry. -12 volts or 5 volts can be

used to power the back panel fan using CN4 (5V fan) or CN15 (12V

fan).

TVM-851 BOARD

Sheet 1 : Analog video from the TVM-850 board enters the TVM-851

board via CN7. The signal is buffered by U39 which drives the vertical

deflection selector U30. This switch selects between FLAT or

unfiltered video and LOW PASS and DIFF. STEP filtered video for

waveform displays. When the unit is in vector mode U30 selects

VECY which is the component Cr for the vertical deflection of the

vector display. The output of U30 is connected to a 2x1 switch U29

which chooses between normal and amplified x5 video. The output

of U29 is amplified by U31 before entering the CRT deflection board.

The vertical position of the waveform display is controlled by varying

the offset of U31. The offset voltage for U31 is selected by the

second half of U30 which switches in a summation of the waveform

vertical position voltage and a calibrated offset needed while in x5

amplitude mode.

Sheet 2 : The external reference video enters the TVM-851 board via

CN5 and CN6. U41 buffers the video signal into the sync separator

circuit. U33 is used to low-pass filter the signal resulting in the

elimination of any chroma information. Comparators U40 and U32

and switches U36 form a precision 50% sync level slicing circuit which

extracts a TTL level composite sync signal at pin 14 of U32. A one-

shot U20 is used to eliminate any vertical information resulting in a

horizontal sync signal at TL6. The composite sync is low-pass filtered

by U32 and latched by U19 creating vertical sync.

Sheet 3 : This sheet illustrates the interconnections to the waveform

and vector position controls. CN9 connects the vector vertical and

horizontal position controls. CN11 connects the waveform vertical

and horizontal position controls to the TVM-851 board.

Sheet 4 : The graticule intensity control R64 is connected via CN11

to the graticule lamp driving circuit. The variable voltage created by

R64 is amplified by U1, Q4, Q5, and Q6. This circuit controls the

amount of current flowing through the graticule lamps attached to

CN14.

The beam intensity control R29 and the focus control R98 are buf-

fered by U35 before entering the CRT deflection board. In addition,

a small amount of intensity voltage is added into the focus path via

R167 in order to maintain the focus over the full intensity range. Q10

and Q11 buffer the trace rotation control R229 from the trace rotation

coil connected to CN12.

Sheet 5 : The Cr component VCR is connected to a DC restorer

comprised of U25 and U13. The output of the DC restorer is con-

nected to a 4x1 switch U14. This switch selects between the Cr com-

ponent and the audio vertical component. The output of the switch

enters an all-pass filter which is used to adjust the delay of this signal

to match the timing of the horizontal deflection path. The output of the

all-pass is offset by the front panel vector vertical position control U25

and amplified by U15.

The Cb component VCB is DC restored by U26 and U13. The output

of the DC restorer enters a 4x1 switch U14. This switch selects be-

tween the Cb component and the audio horizontal component. The

output of the switch enters a fixed delay all-pass filter U26. The out-

put of U26 is offset by the front panel vector horizontal position control

U26 and amplified by U27. The output of U27 is connected to a

double isolated switch U34. This switch selects between the output

of U34 and the waveform horizontal deflection ramp. The output of

the switch is amplified by U44 before entering the CRT deflection

board TVM-852.

Sheet 6 : The circuit on this sheet is a precision ramp generator for

the horizontal deflection of the waveform display. Q7 and U5 form a

constant current capacitor charging circuit which provides a linear

ramp. U6 switches the charging current to the proper capacitor for the

selected sweep. C8 is selected for line sweep and C137 is selected

for field sweep. Q3 and Q8 reset the ramp at the end of the sweep by

discharging the associated capacitors. In addition to U6 selecting line

or field sweep, U4 selects different ramp rates depending on what

display mode is selected. If all three components are to be displayed

in a paraded sweep the ramp charging rate has to be three times as

long as that needed for a single line sweep. R212 and R213 are used

to calibrate the line and field rate sweeps respectively. U7 amplifies

the ramp before entering the horizontal magnification amplifier on

sheet 7. The offset of U7 is controlled by U23 and U22. U23 is used

to control the waveform horizontal position. U22 switches in different

offsets needed for each cell of a paraded sweep.

Sheet 7 : The waveform horizontal deflection ramp is amplified byU8

for the HMAG display mode. U9, U10, Q1, and Q2 form a clipping

circuit which limits the amplitude of the amplified ramp. The ramp is

then amplified by U11 before entering a switch U2. This switch

selects between the normal and the amplified ramp for the selected

display mode. The ramp is then amplified by U3 before entering the

deflection switch on sheet 5.

Sheet 8 : U37 and U38 are used to interface the TVM-851 board with

the TVM-850 board. External horizontal and vertical sync are output

to the TVM-850 via U37. Mode selection bits from the CPU are input

to the TVM-851 board via U37 and U38. U24 is a GAL which controls

the operation of this board. The power for this board is connected via

CN13.

Sheet 9 : The differential audio channels are amplified byU42 before

entering attenuators. U43 is a 4x1 switch controlled by SW1 which

selects the available audio amplitude ranges. The outputs of U43 are

amplified by U42 before entering the deflection switches on sheet 5.

K1 is a relay controlled by Q12 which provides the general purpose

output switch closure used to indicate the occurrence of data errors.

Theory of Operation (cont'd)

TVM-852 BOARD

Sheet 1 : Vertical deflection amplifier. The vertical signal enters the

board on CN4 pin 6. The signal passes though the vertical clipper

consisting of Q23, Q24, Q32, and Q31 and their associated capacitors

and resistors. The vertical clipper limits the deflection signals to about

± 2.5V prior to the final vertical amplifier. The purpose of the vertical

clipper is to prevent the vertical deflection amplifier from entering

saturation when driven by large input signals. This helps to increase

the recovery time when signals beyond the scope viewing area are

applied to the input. The clipper is required because the vertical

deflection amplifier takes a relatively long time to recover from an

overdriven condition. Clipping of negative peaks is accomplished by

Q23 and Q24; the threshold is set by R112, R58, D14. When the

deflection signal starts to go more negative than about -2.5V, Q24

starts to turn on, pulling base current through Q23, thereby turning

Q23 on and sourcing current to the junction of R120 and R126 to keep

the voltage at that point from going more negative. Similar action is

performed on positive peaks by Q32, Q31.

The vertical deflection amp takes the deflection signal from the clipper

and amplifies it to peak-to-peak voltages suitable to deflect the CRT

electron beam via the vertical deflection plates. Typically it takes

about 5 volts across the deflection plates to deflect the beam 1 cm on

the screen. The plates are driven differentially for greater voltage

swing and noise immunity. The two vertical deflection plates are

driven by two identical final amplifiers, one being inverted. U6 buffers

the deflection signal and drives one final amplifier, while U4 inverts

the deflection signal and drives the other final amplifier. Since both

final transistor amplifiers are the same, only one will be described.

The final amplifier is made up of Q20, Q19, Q18, Q21 and associated

components. Essentially, it's a classic operational amplifier in the

inverting connection with some enhancements for CRT deflection

drive. Q19 and Q20 are the emitter-coupled differential input stage

with a tail current of about 7 mA set by R118. Q20 base is the

inverting input, while Q19 base is the non-inverting input (grounded for

the closed loop inverting connection). Although the output stage must

be operated from the +100V supplyto allow sufficient swing, Q20 and

Q19 are operated at a Vce of only about 12V (emitters stay at +0.7V);

in this way they can be inexpensive high speed transistors.

The single-ended signal from Q19 collector directly drives the base of

Q21, a common emitter amplifier constant current biased by Q18.

Large signal positive-going output transitions are aided by C36 and

C13 which for a short time allow a relatively large base current for

Q18 (current pass is from +100V through C13, Q18 base, C36, R114,

to -12V). This action increases Q21 collector current, thereby allowing

faster charging of any capacitance on the amplifier output. With this

enhancement, slew rate is dramatically increased in the positive

direction, and the output stage bias current can be reduced (in this

case to about 10 mA) making possible the low power dissipation and

small size of this amplifier. Overall gain is set by the ratio of R55 to

R56, and is about -12 in this instance. R113 pulls about 2.3 mA from

the summing node of the amplifier, biasing the output to about +25V

with no deflection signal. This allows for a swing of about ± 30V at the

output.

Sheet 2 : Horizontal clippers (identical to the vertical clippers; see the

previous description). The horizontal deflection amp is very similar to

the vertical deflection amp, which was described in detail previously.

The important difference is that the horizontal deflection plates must

swing over a larger range of voltages than the vertical plates to get

sufficient beam deflection (for at least two reasons: the horizontal

dimensions of the screen is larger and the horizontal deflection plates

are physically placed in a position where the electron beam is moving

faster, making it more difficult to deflect); fortunately, the bandwidth

requirement is not as stringent so that the higher voltage transistors

required do not have to be as those in the vertical deflection amp.

Also, since the amplifiers are operated from the same +100V supply,

the outputs can be easily biased to the desired +70V output level.

The gain of the final amplifiers in the horizontal deflection amplifier is

greater than the vertical amps so that approximately equal input

signals can deflect the beam horizontally and vertically over the whole

face of the CRT. In the case of the horizontal final amps the gain is

set by the ratio of R38 to R39 for a gain of about -28. Sheet 2 also

depicts the CRT socket.

Sheet 3 : Contains the intensity amplifier, the focus amplifier, the

geometry control, and the astigmatism control for the CRT. The in-

tensity amplifier accepts DC level and boosts it to the amplitude ne-

cessary to drive CRT intensity grid (G1). Its output is then coupled to

the CRT through a clamp circuit which isolates the amplifier from the

high voltage bias on the CRT intensity grid. The intensity voltage is

a 0 to +5V signal proportional to the desired intensity. Then at the

output pin 1 of U2 an intensity signal appears which ranges from

about 0 to -5V with a more negative voltage representing a higher in-

tensity. The blanking signal controls switch U1 to select between the

intensity signal and a fixed blanking voltage of about +0.8V. The re-

sultant intensity signal at U1 pin 14 is then ready to be amplified to the

levels required by CRT.

The intensity amplifier is made up of Q2, Q3, Q4, Q5 and associated

components. It is essentially an op-amp configured as an inverting

amplifier with a gain given by the ratio -R8/R84 (approximately -12).

The differential stage is made of Q5, Q2 and is biased by R80. Cur-

rent source Q3 is an active load for the gain stage Q4, making for

nearly equal rise and fall times from the output, contrasted with the

slow rise times that would characterize a resistively loaded amplifier.

C18 and C20 provide extra drive to Q3 during high speed signal tran-

sitions, thereby enhancing the slew rate of the amplifier. When the

composite intensity signal, ranging from +0.8 to -5V, is passed

through the amplifier, the output range is about -10 to +60V; this is

sufficient to drive the CRT G1 over the range of cut-off to maximum

useful intensity.

Although the peak-to-peak voltage from the output of the intensity

amplifier is sufficient to drive the CRT intensity grid, the signal is not

sitting at the proper DC level to properly bias the grid. The CRT cath-

ode is biased at -2080V and the grid must be more negative than that

to properly control intensity of the electron beam. Therefore, some

sort of interface from the relatively low voltage intensity amp to the

high voltage grid is required. The necessary voltage isolation is

provided by C17, with a working voltage rating of 4000V. AC signals

pass through C17, but a DC reference is required to properly bias G1.

The method used is that of a diode clamp using D3, D4. Biasing is as

follows: -2200V from the power supply is passed through 120V zener

diode D9 to make the -2080V cathode bias voltage. This makes

available a negative grid bias (measured relative to the cathode) of up

to -120V. The most negative grid voltage ever needed (beam cutoff)

is set by R6; the voltage on R6 wiper becomes the DC reference for

the diode clamp circuit. Clamp operation then as follows: when the

intensity signal is blanked, the intensity amplifier output goes to about

-10V. This charges clamp capacitor C17 such that when the intensity

is blanked, the CRT beam is cut off. From there, any AC variations

the intensity signal are coupled directly through C17 to G1. Since the

variations all have to be more positive than blanking level, the clamp

diodes D3, D4 remain biased off, except for during the periodic

blanking periods which also refresh the charge on C17. In this

manner high speed signals are easily coupled to the intensity grid,

and the proper DC bias is maintained. The focus amplifier, similar to

the intensity amplifier, takes the focus signal and amplifies it to the

necessary peak-to peak voltage for driving the CRT focus anode. The

focus signal is a 0 to + 5V signal proportional to the necessary CRT

focus voltage. A similar scheme to the intensity interface is necessary

to couple focus signals to the CRT. U2, an inverting op-amp circuit

with an output pin 7, takes the

Theory of Operation (cont'd)

0 to +5V focus signal shipped from the TVM-851 board and changed

it to a 0 to -5V signal suitable to drive focus amplifier. U1 switches be-

tween the focus voltage and ground, which is selected during blanking

time. The components focus signal is then fed to the focus amplifier

made up of Q6, Q7, Q8, Q9 and associated components. This

amplifier is similar to the previously described intensity amplifier ex-

cept that it is powered off the +150V supply and the gain is higher (-

(R89+R15)/R88= -26.7) to allow the required greater swing in focus

voltage.

Following the focus amplifier is a clamp circuit based on the same

principle as the already described intensity clamp. The difference is

that the focus anode is biased at about -1200 to -1400V. This bias is

established by current source Q1, D5, D6 and associated compon-

ents; the actual DC reference for the clamp is trimmed by R7 to center

the range of focus control.

Geometry and Astigmatism circuits: R23 provides an adjustable volt-

age which is buffered by emitter follower Q10 , filtered by R27, C8,

and sent to the CRT geometry grid (GEOM). R36 is the adjustment

for the astigmatism correction voltage which is buffered by Q14, fil-

tered by R33, C10, and sent to the CRT astig anode (ASTIG).

Sheet 4 : Shows the power supply connection for the board and the

graticule light section of the board.

TVM-853 BOARD

Sheet 1 : An 8 bit bi-directional data with control strobes is used to

interface the TVM-853 board with the TVM-850 board. The data bus

is only driven when the TVM-853 board is addressed by the micro on

the TVM-850 board. The control strobes for the data bus are the read

and write signals, along with the least two significate bits of the

TVM-850 micro’s address bus. U10 is responsible for the address de-

coding by using A1 and the read and write strobes to determine which

of the ICs will be selected. If A1 is low, the LEDs are addressed. If

A1 is high, the switches are being integrated.

The front panel switches are broken into two 8 switch banks. The

micro must write an “FEh” in order to read switch row 1. Row 1 in-

cludes the following pushbuttons: INPUT, REF, DISPLAY, SWEEP,

FORMAT SAV, FILTER, AND CAL. The micro must write an “FDh”

in order to read row 2. Row 2 includes the following pushbuttons:

VIEW, CHANNEL, AUDIO, HMAG, VMAG, STORE, MEMORY, and

VECT FMT. U13 drives the switch data back to the micro on the

TVM-850 board.

Also included on sheet 1 are the vector position pots, R50 (vertical)

and R51 (horizontal) and the power connector.

Sheet 2 : The front panel LEDs are controlled by U11. The micro on

the TVM-850 board writes to various registers on U11 which determ-

ine the state of each LED. U11 scans the LED rows and columns so

that each LED is pulse when on, thereby reducing the total power

consumption of the LEDs. Resistors on the red LEDs are place-

holders in case the red LEDs were too bright. These resistors are not

significant in this design.

TVM-851B

TVM-853

TVM-850

TVM-851A

TVM-852A

AC fuse, filter

and power

switch

AC IN Low Voltage Supply

(+5V,+/-12V) High Voltage Supply

(+8000V, -2150V,

100V, 6.3V AC)

Fan

(12V)

Used to power

all PCBs

-2150V,100V, 6.3V AC

8000V

TVM-852B

Graticule

Lights

CRT

Rotation

Coil

Horiz. &

Vertical

Deflection

Amps

Intensity

Amps

Focus Amp

Analog Mux(s)

Vertical

Horizontal

Rotation

Pot

N.O. and

N.C. Dry

Contact

Blanking

x1 or x5

Vertical

Mag

Vertical

Position

Control

Waveform

Analog

Filters

Vector DC

Restores

Stereo Audio

Analog Input

x1 or x5

Horizontal Mag

Horizontal

Position Control

Ramp

Generator

Alarm Relay

Ext.

Sync External Time

Reference

Audio Left

Audio Right

Timing Control

Microprocessor

Memory

Recalls

Serial A

Serial B

Digital Signal

Processing

(Digital In-

Analog Out)

Vector Centering

Pots

Front Panel

Switches

Front Panel LEDs

Front Panel

Control Knobs

Block Diagram

Interpolate

WFM

by 2x

12 Bit

Digital

to Analog

Converter

10 Bit

Digital

to Analog

Converter

WFM Drive

Cb Drive

Cr Drive

Programmable device which

does the following:

Color space conversion and

Gamut Error;

Waveform selection;

75/100% vector adjustment;

Y delay;

Bowtie filter

Demux

Programmable Device

Mux,

Timing

Extraction,

and EDH &

Data Error

Detection

Deserializer

Cable

EQ/RCVR

Cable

EQ/RCVR

Internal

27 MHz

Clock

Mux

Interpolate

Cb and Cr

by 2x

Analog Board

Interface

Front Panel

Interface

Micro

A/D

E/Q

RS232 Port

Memory

(RAM/ROM)

Watch Dog

and

Battery

EQ to Micro

Serial A

Serial B

Block Diagram for TVM-850 Board

Horizontal

Clipper and

Magnification

Amplifier

Horizontal

Sweep

Generator

Horizontal

Audio/Vector

Selection

Horizontal

Vector

Position and

Gain

Final Horizontal

Selection

Vertical

Audio/Vector

Selection

Waveform Analog Filters,

(Flat, Lowpass,

Differential Step)

CB Vector DC

Restore & Gain

Audio Attenuator

Selection & Gain

Vertical

Vector

Position &

Gain

CR Vector DC

Restore & Gain

Audio Attenuator

Selection & Gain

Vertical

Deflection

Selection

Input Waveform

Amplifier

Analog

Waveform Input

from TVM-850 Bd.

CR Analog

Vector

Audio Y

Input

CB Analog

Vector

Audio X

Input

Timing Signals

from TVM-850 Bd.

Sweep &

Filter

Selection

Control

Digital Signals

from TVM-850 Bd.

Analog Vertical

Deflection Signal

to TVM-852 Board

Analog Horizontal

Deflection Signal

to TVM-852 Board

Analog

Sync

Stripper

Graticule,

Focus, and

Beam

Intensity

Amplifiers

Trace

Rotation

Amplifier

Analog Loop

Through

Reference Signal

Horizontal Sync

to TVM-850 Board

To TVM-852 Board

To Trace Rotation Coil

Block Diagram for TVM-851 Board

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