Krohn-Hite 35 User manual

Model 35
170Hz to 25.6MHz, 24dB/Octave
Butterworth Tunable Active
Plug-In Filter Card
Operating Manual

Service and Warranty
Krohn-Hite Instruments are designed and manufactured in accordance with sound
engineering practices and should give long trouble-free service under normal operating
conditions. If your instrument fails to provide satisfactory service and you are unable to
locate the source of trouble, contact our Service Department at [phone], giving all
the information available concerning the failure.
DO NOT return the instrument without our written or verbal authorization to do so. After
contacting us, we will issue a Return Authorization Number which should be referenced on
the packing slip and purchase order. In most cases, we will be able to supply you with the
information necessary to repair the instrument, avoiding any transportation problems and
costs. When it becomes necessary to return the instrument to the factory, kindly pack it
carefully and ship it to us prepaid.
All Krohn-Hite products are warranted against defective materials and workmanship. This
warranty applies for a period of one year from the date of delivery to the Original Purchaser.
Any instrument that is found within the one year warranty period not to meet these
standards, will be repaired or replaced. This warranty does not apply to electron tubes,
fuses or batteries. No other warranty is expressed or implied.
Krohn-Hite Corporation reserves the right to make design changes at any time without
incurring any obligation to incorporate these changes in instruments previously purchased.
Modifications to this instrument must not be made without the written consent of an
authorized employee of Krohn-Hite Corporation.

MODEL 35
170Hz to 25.6MHz
LOW-PASS BUTTERWORTH
PLUG-IN FILTER CARD
OPERATING AND MAINTENANCE
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PLUG-IN FILTER CARDS
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I..FL..I KRCHN-HITE
~ COFlPOFl.A.TION
255 Bodwell Street, Avon, MA 02322-9987
Tel: [phone]; Fax: [phone]

Table of Contents Model 35
Table of Contents
1.0 GENERAL DESCRIPTION 1-1
1.1
INTRODUCTION 1-1
1.2 SPECIFICATIONS 1-1
1.2.1 Filter Ch ar ac te rist ics 1-1
1.2.2 Input 1-1
1.2.3 Output 1-2
1.2.4 General 1-2
2.0 OPERATION 2-1
2.1 INTRODUCTION 2-1
2.2 TURN-ON PROCEDURE 2-1
2.3
SELF-TEST fEATURE 2-1
2.4 JUMPER SETTINGS FOR FRONT AND REAR PANEL OPERATION 2-2
2.5 FRONT PANEL CONTROLS AND DISPLAY 2-2
2.5.1 Data Keys 2-2
2.5.2 [MODE] Key 2-2
2.5.3 [TYPE] Key 2-2
2.5.4 Channel 2-2
2 .5.5 Gain Set 2-2
2.5.6 Input Overload 2-2
2.5.7 Output Overload 2-2
2.5.g ICE] Clear Entry Key 2-3
2.5.9 lALL CHANNEL] Key 2-3
2.5.10 Input Ohms (Labeled White) 2-3
3.0 I£EE-488 STn (GPID) PROGRAMMING 3-1
3.1 INTRODUCTION 3-1
3.2 FILTER TYPE 3-1
3.3 MODE OF OPERATION " 3-1
3.4 DEVICE CLEAR 3-1
4.0 INCOMING ACCEPTANCE 4-1
4.1 INTRODUCTION 4-1
4.2 TEST EQUlPMENT REQUIRED 4-1
4.3 INITIAL SETTINGS 4-1
4.4 DC OUTPUT LEVEL CHECKS 4-1
4.5 GAIN ACCURACY CHECK 4-2
4.6 DISTORTION CHECK 4-2
4.7 SQUAREWAVE RISE AND FALL TIME CHECK 4-2
4.8 FREQUENCY CALIBRATION CHECK 4-2
4.9 WIDEBAND NOISF CH ECK 4-3
4.10 STOPBAND ATTENUATION CHE CK 4-3

Model 35 Table of Contents
ii

Table of Contents Model 35
Model 35 Plug-In Filter Card
iii

Moclel35 Section 1 - General Description
SECTION 1
GENERAL DESCRIPTION
1.1 INTRODUCTION
The Model 35 is a low-pass, Butterworth (maximally flat) filler card, used in the Models 3905B and 3916B
mainframes, providing 24GB/octave rolloffwith a minimum
stopband attenuation of up to lOOdB. The Model
35 covers the frequency range of 170Hz to 25.6MHz with 2Vzdigits of resolution.
The filter card has selectable AC or DC couplingand selectable 1M or 50 ohm impedance. Programmable input
gains
of up to 20dB and output gains of up to 26dB are standard.
The Mode135 also has the capability to be configured in an Amplifier By-Pass mode to operate as an amplifier,
by-passing
the filter. This gives the user the ability to amplify without filtering when so desired.
The Model 35 is one of many Krohn-Hite filter cards used in conjunction with two GPIB programmable
mainframes; the 3 1/2' high Model 3905B (5 plug-in cardchassis) or the Model 3916B (16 plug-in card chassis).
1.2 SPECIFICATIONS
1.2.1 FILTER CHARACTERISTICS
Filter Type: 4-Pole, Butterworth, Low-Pass.
Tunable
Cutoff Frequency Range: 170Hz (0 25.6MHz .
Frequency Response:
FreQuency Range Resolution
170Hz \0 2.56kHz 10Hz
2,6kHz to 25.6kHz 100Hz
26kHz to 256kHz 1kHz
260kHz to 2,56MHz 10kHz
2.6MHz \0 25.6MHz 100kHz
Cutoff Frequency Accuracy: ±2% to 2.56MHz, =5% to 25.6MHz.
Attenuation Slope: 24dB/Octave.
Stopband Attenuation: 100dB to 1MHz, 80dB at 1 OM Hz,70dB at 30MHz, 60dB at 50MHz, 50dB to lOOMHz.
Amplified Bypass
Mode Bandwidth: >50MHz..
Amplified Bypass Mode
Rise and Fall Time: <7ns with OdB input gain 6dB output gain, < IOns with +20dB
input or output gain. <5% ringing or overshoot.
1.2.2
INPUT
Input/Output Coupling: AC or DC. AC coupling cutoff is approximately 16Hz at the input and 10Hz at the
output with a 50Q termination. Note that the internal 50Q input termination is before the AC coupling.
Input Impedance: Selectable 1MQ or 50Q, =2%, shunted by 45pF.
Passband Response: =O.2dB up to 2.56MHz, =0.5dB to 25.6MHz.
Input Gain (Pre-Filter): OdB, + lOdB, +2OdB =O.ldB.
Maximum Input Signal: = 1.5V peak with OdB input gain, reduced in proportion to input gain selected.
Input DC Blocking Voltage: 200V Note that the internal input termination is before the AC coupling and can
only tolerate 7Vrms when ON.
1-1

Section 1 - General Description Model 35
Maximum Input Without Damage: 12Vrmswith input terminator OFF, 7Vrms with input terminator ON.
1.2.3 OUTPUT
Maxim um Ou tpu t Signal: ±3V peak open cireuit, ± 1.5V peak in to 50Q.
Output Gain (Post-Filter): (kiB,HidE, + 2Ck:iB, +26dB, ± 0.1dB.
Output Impedance: SOQ, ±2%.
Distortion (lVrms sinewave): >-6O<1B belowsignal up to 100kHz (0.1%).All harmonics below 50dB to 1MHz;
below 40dB above 1 MHz.
Output DC Offset: Adjustable to Zero.
Output DC Offset Drift: ±0.5mVtC referred to input.
Noise
Spectral Density (10kHz to l00MHz referred to input): Below-128dBmlHz into 50 ohms. This translates
into a wideband noise power or voltage for a 30MHz BW of below -5 3dBm or O.50mVrms referred to input.
Spurious Signals: Below --80dBm to 65MHz ; below -75dBm to l00MHz. Referred to input, represented in
voltage form: 22J.lV and 40.uV respectively.
1.2.4 GENERAL
Input/Output Connectors : BNe.
Power:8 watts.
Weight 1.75 lbs, (.8kg) net.
Operating Temperature: O°C to 50°e.
Specifications apply at 25°C ±10°C,
Specifications subject to
change without notice.
NOTE: The Model 35filter card must be used with the Model 39058 or 39168 mainframes.
1-2

Model 35 Section 2 - Operation
SECTION 2
OPERATION
2.1 INTRODUCTION
The Model 35 low-pass filter card covers the frequency range from 170Hz to 25.6MHz. It is one of a series of
filter cards available for the 5 plug-in card mainframe, Model 3905B or the 16 plug-in card mainframe , Model
3916B mainframe. All filter
parameters are programmablevia the mainframes front panel or remotely over the
IEEE-488 (GPIB) bus. For detailed information of the front panel controls and remote programming. refer to
Section 2
and 3 of the Model 3905N/3916B mainframe's Operating and Maintenance Manual. Section 2.4 of
this manual briefly describes the operation of the principal front panel controls and data key operation.
2.2 TURN-ON PROCEDURE
a. The line voltage range of the Model 3905B/3916B mainframe has been preset at the factory for either 115V
or 230V operation. This range switch is located internally if a line voltage change isrequired. Check to see
that a fuse with the correct rating is in the fuse receptacle.
b.
Make certain that the POWER switch on the front panel of the unit is in the OFF position.
c. Plug
the line cord into the unit first, then into an ac outlet.
CAUTION
.. :.':.... ':'.' .,.;. ',:.
For safetypurposes, the line cord must be connected to a grounded
3-t enninal ac outlet. Because of 'potentiallydangerous voltages thai
exist within the mainframe, the covers should be removed only by
qualifiedpersonnel.
d. If the Model 3905B/3916B is remotely programmed via the IE EE-488 (GPIB) bus, connect the bus cable
to
the rear panel 24 position "D" connector at this time. Programming information is provided in Section 3
of the Model 3905B/3916B Operating and Maintenance Manual, with additional information in Section 3
of this manual.
e. The POWER switch is a toggle type, located on the front panel of the Model 3905B/3916B. After
familiarizi ng yourselfwith the self-test feat ure described next, turn-on the Model 3905B/3916B.
2.3 SELF·TEST FEATURE
When tur ned 0 n, the Model 3905B/3916B mieroproccssor pcrftirrnsa Scif -Tcs t routine whereby the en tire RAM
and ROM operation is verified. During the test, the front panel L EDs and display will light up sequentially.
If there is a malfunction in the microprocessor, such as a defective RAM or ROM. the sequence will stop and
the word "bAd" will appear in the display, followed by a number from 1 to 3. Refer to Section 7.6, Digital Circuit
Maintenance, to find which
RAM or ROM isdefective; otherwise, when the Self -Test program is complete , the
Model 3905B/3916B will return to the last set-up prior to turning off the unit.
The Model 3905B/3916B is now ready to be programmed for operation.
2-1

Section 2 - Operation Model 35
2.4 JUMPER SETIINGS FOR FRONT AND REAR PANEL OPERATION
Toachieve clean high frequency signal performance from the rear panel input and output ENCs, it is necessary
to disconnect
the cabling connecting the front panel ENCs by moving the two jumpers on jumper blocks J201
(for input) and J517
(for output) shown in Figure 2.1 below. The Model 35 filter cards are shipped with the
jumpers set with front panel BNG; active.
REAR ONLY
FRONT &
REAR
INPUT
OUTPUT
, -, r
~
, <,
~
~
<,
-REAR ONLY
G[ID
-
[]I]]
0 ~0 El 0 FRONT &
-/
<,
-0 r
~
, -0 0 REAR
/
~
-,
<,
Figure 2.1 Front and Rear panel Jumper Blocks
2.5 FRONT PANEL CONTROLS AND DISPLAY
2.5.1 DATA
KEYS
Data entry keyboard controls, [0]-[9] and [.],and associated 4digitdisplay set the numericvalue of the parameter
selected. I fa cutofffreg uency of 1.5 kHz isreguired, press the [1]l-][5] data keys, then press [Kl LO] and [FREQJ
parameter keys. The cutoff frequency will be indicated in the 4 digit display.
2.5.2 [MODE} KEY
Indicates the mode of operation in the channel displayed, alternating between low-pass, "L.P." and amplifier
by-pass,
"GAin", which disconnects the filter.
2.5.3 [TYPE] KEY
Displays "bu.", indicating Butterworth filter.
2.5.4 CHANNEL
The two channel controls [ft][ ~ ] and associated display, increment or decrement the channel setting. When
held , the Model 3905B/3916B willcycle through all the channe ls continuously.
2.5.5 GAIN SET
Input and OutpuL gain is controlled by the two GAIN SET controls [ft][ ~ ] and associated two digit displays.
Input gain is selectable to OdB, lOdB or 2OdB. Output gain is selectable to OdB, 6dB, 20dB or 26dB.
2.5.6 INPUT OVERLOAD
With OdB Input gain, the input overload indicator will turn on at approximately ± 1.6V peak. At lOdE,
approximately ±O.5V peak. At 20dB, approximately ::to.16V peak.
2.5.7 OUTPUT OVERLOAD
The output overload indicator will light at approximately ±3.2V peak output with the output not terminated,
or ± 1.6V peak output with the output terminated, for all gain settings except OdB output gain. For OdB output
gain the values are 1/2.