Philips PM 6650 User manual

PHILIPS en
COUNTER/TIMER 512 MHz/ins PM 6650
9446 066 50...1
Operating Manual
740215/1/01 9499 460 06011

IMPORTANT
In correspondence concerning this instrument, please quote the type number and the serial number as given on
the type plate on the rear of the instrument.
© N.V. PHILIPS’ GLOEILAMPENFABRIEKEN — EINDHOVEN — THE NETHERLANDS — 1974
Printed in Sweden / Be-Te Tryck i Solna AB

CONTENTS
GENERAL INFORMATION
|. Introduction
ll. Cabinets and blank panels
Ill. Technical data
IV. Accessories, options and sub-units
V. Block diagram description
DIRECTION FOR USE
VI. Installation
1. Cabinets
2. Sub-unit installation
3. Installing BCD output unit PM 9684 and
remote control unit PM 9685
4. Installing D/A converter PM 9687
5. Installing oven-enclosed oscillator
PM 9680 A and PM 9681
6. Mains voltage conversion and rear
panel fuse
7. Internal fuses
8. Earthing
Vil. Controls, indicators and connectors
VIll. Operation
1. General information
2. Measurements
12
16
16
16
16
16
16
16
16
16
18
26
26
28
LIST OF FIGURES
Il-1.. Bench cabinet, 4/6 rack sizes
II-2. 19” cabinet, 6/6 rack size
Il-3. PM 6650 with cabinet PM 9716 A and blank
panel PM 9722
IV-1. Rear panel PM 9664 for interconnection of
counter and sub-unit
1V-2. PM9680A, or PM 9681, crystal oscillator
in proportionally controlled oven
1V-3. PM 9684, BCD output unit
1V-4. PM 9685, remote control unit
1V-5. PM 9687, digital to analogue converter
V-1. Simplified block diagram
VI-1. Installing the PM 6650 in bench cabinet
VI-2._ Mounting the brackets for rack installation
VI-3. 19” cabinet provided with rear panel
PM 9664
VI-4. Inputs for optional cards
VI-5. Plugging in BCD output unit PM 9684
VI-6. Plugging in remote control unit PM 9685
VI-7. Plugging in DAC PM 9687
VI-8. Mounting optional oscillator PM 9680 A or
PM 9681
VI-9. Internal fuses
VIl-1. Front panel controls and connectors
Vll-2.. Rear panel controls and connectors
Internal switches and connectors
Measurement error vs frequency and
period, PM 6650 A and E
Measurement error vs frequency and
period, PM 6650 B.
11
11
27
27

Il. INTRODUCTION
The PM 6650 can perform CW frequency, burst fre-
quency, ratio, totalize, single period, period average,
time interval and time interval average measurements.
The frequency range is 512 MHz and the accuracy at
time interval measurement is 1 ns.
The three models PM 6650 A, B and E are identical
except the stability of the clock oscillator used.
Each model features two direct-gated input channels
A and C for frequency measurement, and a third input
B for time interval or ratio measurement or external
ll. CABINETS AND BLANK PANELS
The PM 6650 is supplied without cabinet. The counter
can be placed either in a bench cabinet or in a 19”
cabinet.
PM 9714 A
Bench cabinet (4/6 rack size) including handle, feet,
tilting bracket and skin plate covers.
PEM 5037
Figure IIl-1._ Bench cabinet, 4/6 rack sizes
GENERAL INFORMATION
gating of channel A. The inputs have selectable 1 MQ
and 50-Q impedance. The nine-digit planar display has
leading zero blanking and switchable memory.
The PM 6650 can be used as bench equipment or in an
automatic test system using the options available.
Typical applications are time domain measurements
such as frequency, period time, pulse duration, phase
difference.
Pulsed carriers can be measured directly using the
burst mode.
PM 9716A
19” cabinet (6/6 rack size) including grips, feet, tilting
bracket, skin plate covers and cable cover with 2
angular brackets for 19” rackmounting.
19” cabinet, 6/6 rack size
Figure II-2.
PM 9721
Blank panel to cover 1/6 empty space.
PM 9722
Blank panel to cover 2/6 empty space when the
PM 6650 is placed in PM 9716 A cabinet and no sub-
unit is used.

Ill. TECHNICAL DATA
Properties expressed in numerical values with statement of tolerances are guaranteed. Numerical values without
tolerances are intended for information purposes only and indicate the properties of an average instrument. The
numerical values hold good for the nominal mains voltage.
A. MEASUREMENTS
Frequency
Range
Mode
Gate times
Accuracy
Inputs
Display
Period
Range
Frequency counted
Resolution
Accuracy
Input
Display
Period Average
Range
Frequency counted
Periods averaged (N)
Resolution
Accuracy
Input
Display
Time Interval
Range
Frequency counted
Resolution
Time interval repetition rate
Accuracy
Inputs
Display
DC... 512 MHz
normal. frequency or burst frequency
100 ns ... 100 s (in decade steps)
+1 count + time base accuracy
channel A (DC ... 160 MHz)
channel C (5 MHz .. . 512 MHz)
kHz, MHz and GHz, decimal point automatically positioned
DC... 10 MHz
100 MHz... 1 Hz (in decade steps)
10ns...18
+1 count + time base accuracy = trigger error *
channel A
us, ms and s, decimal point automatically positioned
DC...10 MHz
100 MHz
1... 108 (in decade steps)
10 ns
N
+1 count + time base accuracy + trigger error */N
channel A
ns or us, decimal point automatically positioned
40 ns... 10? s (approx. 31 years)
100 MHz... 1 Hz (in decade steps)
10ns...1is
max. 10 MHz
+1 count + time base accuracy + trigger error **
Channels A and B; can be common or separate
us, ms and s, decimal point automatically positioned
* trigger error is <+3 10° for sine wave signals at specified sensitivity with signal to noise ratio of 240 dB
** trigger error is <
signal slope (V/ns) se

Time Interval Average
Range
Minimum time from stop to start
Frequency counted
Time intervals averaged (N)
Time interval repetition rate
Resolution
Accuracy
Inputs
Display
f
Multiple Ratio (Ratio = -N)
Frequency range
Input A (higher frequency)
Input B (lower frequency)
Multiplier (N)
Accuracy
Display
Count A (totalizing)
Range
Pulse repetition rate
Pulse resolution
Count accumulation
Mode
Input
Display
: fA
Scaling Cy )
Range
Frequency range
Input
Output
Display
Check
100 ps...10s
50 ns
100 MHz
1... 108 (in decade steps)
max. 10 MHz
10 ns
N
+1ns + time base accuracy + —
VN
Channels A and B; can be common or separate
ns and us, decimal point automatically positioned
DC ... 160 MHz
DC ... 10 MHz
1... 107 (in decade steps)
trigger error * of fB
N
dimensionless, decimal point automatically positioned
+1 count of fA +
109
DC... 160 MHz
2.5 ns minimum pulse width
during only the first start/stop event or during repetitive start/stop
events
start/stop by manual gate control or Count A gated by channel B
channel A
Dimensionless
scaling factor selectable from 1... 10% (in decade steps)
DC... 10 MHz
channel A
same as time base output
Dimensionless
100 MHz counted during selected gate time. Functional test of logic circuits.
Display test
Functional test of all the decimal points, the measuring unit annunciators and the character segments.
Sub-unit
In the position “SUB-UNIT” the PM 6650 is programmed to accept sub-units such as the automatic microwave con-
verter, prescaler etc.
10 ns + trigger error **

B. INPUT CHARACTERISTICS
Input Channels A and B (not prescaled)
‘Frequency range
DC coupled
AC coupled
Pulse resolution
Sensitivity
sine wave
peak
Impedance
Trigger window
Dynamic input voltage range
Coupling
Attenuation
Trigger slope
Trigger level
Trigger level monitor
Channel Inputs
Overload protection
Connector
Input Channel C (not prescaled)
Frequency range
Sensitivity
Impedance
Attenuation
AM modulation tolerance
Coupling
Level indication
Overload protection
Connector
External Reference Input
Frequency range
Impedance
Sensitivity
Coupling
Overload protection
Connector
DC ... 160 MHz
30 Hz... 160 MHz
2.5 ns minimum pulse width
50 mMVims Or 500 MVims
150 mV,.p or 1.5 Vp-p
1 MQ//25 pF or 50 Q
About 80 mV hysteresis which is virtually eliminated in the TIME
INTERVAL modes
+3 V added to set trigger level voltage times attenuator setting
AC or DC
x 1 or x 10
+ or —
Preset
to
centre
triggering
0
V
or
variable
between
—3V...
+3V
times
attenuator
setting
Set trigger voltages available on miniature jacks (at front) and
BNC (at rear)
Channel A and B; can be common or separate
230 Vims < 400 Hz or 300 Va, in 1 MQ positions
12 Vims in the 50 Q and in 1 MQ position for frequencies 2 1 MHz
BNC
5 MHz... 512 MHz
10 MVims
50 Q, nominal
automatic by AGC max 62 dB
99 % at modulation frequencies < 5 kHz
50 % at modulation frequencies 5 kHz — 10 kHz
30 % at modulation frequencies > 10 kHz
AC
LED indicates sufficient signal level for correct triggering
12 Vims
BNC
0.1 — 10 MHz
1 kQ//50 pF
500 mMVims
AC
12 Vims
BNC

C. OUTPUT CHARACTERISTICS
Trigger level output
Range —3V...43V
Impedance 4 kQ in 0 V position
Overload protection short circuit proof to earth
Connector miniature jacks (at the front)
BNC (at the rear)
Gate monitor (“GATE OPEN”)
Provides Z-modulation output for observation of the measured interval.
Amplitude approx. +0.4 V, when the gate is closed
approx. +5 V, when the gate is open
Impedance approx. 200 Q
Delay
internal
delay
between
the
signal
inputs
and
the
trigger
monitor
output
is approx. 50
ns
Overload protection short circuit proof to earth
Connector BNC
Time base out
Frequency 100 MHz... 0.01 Hz (in decade steps)
Amplitude 500 mV,.p into 50 Q
Impedance approx. 100 2
Overload protection short circuit proof to earth
Non-interrupted signal is available if the display time control is in “HOLD” position and in the functions: “FRE-
QUENCY’, “PERIOD”, “TIME INTERVAL” and “CHECK”.
10 MHz out
Amplitude 1 Vims into 1 kQ
Impedance approx. 200 Q
Overload protection short circuit proof to earth
Connector BNC

10
D. GENERAL CHARACTERISTICS
Display
Read out
Memory
Display time
Reset
Unit annunciators
9 digit planar display
Leading zero blanking
10 mm high 7-segment numerals
Decimal point indication
Switchable ON/OFF on front panel
50 ms ...5s or infinite (HOLD) -
Minimum externally controlled display time 3 ms
Pushing RESET button resets counter to zero
ns, ws, ms, kHz, MHz, GHz and NO-GO by read only memory pro-
gramming
Gate lamp LED indicates when the main gate is open and counting takes place
Osc LED indicates, when power cord is connected, that oven-enclosed
oscillator is on for initial stabilization
Remote LED indicates when the instrument is remotely controlled. Remote
control overrides manual control
Time base
Stability at 10 %
T t 0
Version Oscillator Ageing rate | eer variation of Warm-up
| — stability ; i
| mains voltage time
PM 6650 B TCXO += 1>10-7/month £1x10-8/°C avg. +1x10° None
PM 6650 A PM 9680 A + 1.59/24 h* = 5x 10-19/°C avg. = 110-10 we
PM 6650 E PM 9681 +5>x10-19/24 h * =5>x10-19/°C avg. = 1x 10-10 ia
* Average, after 72 hours continuous operation
** Less than 7 minutes to within = 10-7
Supply
Voltage
Consumption
Temperature range
Operating range
Storage range
Dimensions
Width
Height
Depth
Weight
115 V or 230 V £15 %, 50... 400 Hz
40 W (without any options and sub-units)
75 W (including PM 6634 and options)
5 W (in stand-by)
0... +45°C
—40... +70°C
Table top 19” rack mount
Cabinet PM 9714 A Cabinet PM 9716 A
305 mm 445 mm
132 mm 132 mm
404 mm 445 mm (incl. handles)
9.5 kg 11.5 kg

11
IV. ACCESSORIES, OPTIONS AND SUB-UNITS
tll
1. Standard accessories supplied with the instrument
1 mains cable
1 manual
1 Allen wrench
2. Options, sub-units and accessories to be ordered
separately
2.1. Oven-enclosed oscillators
PM 9680A option for model PM 6650 B
PM 9681 option for models PM 6650 A and
PM 6650 B
2.2. Data peripherals
PM 9684 BCD output unit
PM 9685 Remote control unit
PM 9686 Bus system interface
~— PM 9687 D/A Converter
2.3. Sub-units
PM 6632 Pre-scaler, 810 MHz
PM 6633 Pre-amplifier
PM 6634 Microwave converter, 12.6 GHz
PM 6636 Pre-scaler, 1 GHz
Figure IV-1._ Rear panel PM 9664 for interconnection
of counter and sub-unit
Figure IV-2. PM 9680 A, or PM 9681, crystal
oscillator in proportionally controlled
oven
2.4.
2.5.
2.6.
27.
Input interface accessories
PM 9351 Passive measuring probe 10 MQ//11 pF
220 MHz, attenuation 10x
PM 9353‘ FET probe, 1 MQ//3.5 pF, 220 MHz
PM 9346 Power supply for PM 9353
PM 9584 Resistive mixing piece, 50 Q, 3 BNC
sockets
PM 9665 _ _Low-pass filter with 3 BNC inputs:
< 50 kHz, < 500 kHz, < 5 MHz.
Coaxial cables
PM 9074 50 Q, BNC to BNC, length 1 m.
PM 9588 = Set of 50 O cables, BNC to BNC:
5 cables, length 20.7 cm
4 cables, length 40.5 cm
3 cables, length 60.3 cm
3 cables, length 198.6 cm
Mains cable
PM 9011 3-core detachable mains cable.
Cabinets and blank panels (refer to chapter II for
full details)
PM 9664 Rear panel for cabinet PM 9716 A
PM 9714A Bench cabinet, 4/6 rack size
PM 9716A 19” cabinet, 6/6 rack size
PM 9721 Blank panel, 1/6 rack size
PM 9722 Blank panel, 2/6 rack size
Figure IV-3. PM 9684, BCD output unit
Figure IV-4. PM 9685, remote control unit
Figure IV-5. PM 9687, digital to analogue converter

12
V. BLOCK DIAGRAM DESCRIPTION
1. Input channels A and B
The PM 6650 has two identical input channels A and
B, consisting of input conditioning circuits operated
with front panel controls ATT., COUPLING, and
SLOPE. An amplifier and trigger circuit shapes the
signal which is routed to the Function Selector. The
desired triggering level can be set with front panel
control LEVEL and is accessible at output LEVEL OUT
at the front and rear panels.
2. Input channel C
Channels C contains an automatic gain control circuit
which keeps the output signal at an optimum level
independent of the input amplitude. This signal is also
fed to the Function Selector.
3. 10 MHz clock oscillator
The internal 10 MHz clock signal is fed through the
external/internal selector circuit to the Function Selec-
tor. If an external clock is used, the internal clock is
disconnected.
4. Function Selector
In general, two signals are routed to the Function
Selector: the input signal from channels A, B, or C,
and the clock signal. One of the signals is used to
control the main gate. The first pulse of the control
signal will open the gate allowing the other signal to
pass through until the next pulse of the control signal
is closing the gate. The information from the last
counting interval is stored in the memories during the
new counting interval.
When the main gate is closed, the control circuits
generates a transfer pulse enabling the new informa-
tion to pass on to the display. After the set display
time, the decade counters are reset and a new meas-
urement can start.
At time interval measurement, the start signal applied
to channel A and the stop signal applied at channel B
control the main gate via the Function Selector. The
10 MHz clock signal is multiplied to 100 MHz and
counted during the start to stop interval.
5. Frequency dividers
At frequency measurement, the clock signal is scaled
in the frequency dividers as determined by the TIME
BASE switch. The scaled signal controls the main gate
and the input signal applied to channel A or C is
counted during the set gate time interval.
At period measurement, the signal from input A con-
trols the main gate directly. The clock signal is multi-
plied to 100 MHz and is scaled in the frequency
dividers. The scaling factor is set with the MULTIPLIER
switch. The scaled signal is then counted during an
interval determined. by the input A signal.
In period averaging situations, the A signal is scaled
in the frequency dividers and used to control the main
gate. The 10 MHz clock signal is multiplied to 100
MHz and counted during an interval determined by the
scaled input signal.
6. Decade counters, memories and display
The fastest HF decade provides the most significant
digit to the memories and the TTL decades the remain-
ing digits in parallel form. The memories are shift
registers which convert the parallel information into
serial form for the decoder drivers and the display.
7. Time interval average synchronizer
The synchronizer provides bursts of clock pulses
which are counted during a time determined by the
MULTIPLIER switch. The number of clock pulses within
each burst corresponds to the average time interval
between signals A and B. The MULTIPLIER setting
represents the number of averagings selected.
A detailed description is given in the Service Manual.

16
VI. INSTALLATION
1. Cabinets
Two types of cabinets are available for the PM 6650:
— a bench cabinet (4/6 rack size)
—a 19” cabinet (6/6 rack size)
Refer to chapter II for full details.
1.1. Bench cabinet
Proceed as follows to fit counter in cabinet (refer to
fig. VI-1):
— Loosen Allen screws “A”.
— Press knurled part of quick-release cams “B” so
that they hinge out.
— Slide counter into cabinet, press release cams and
tighten screws “A”.
1.2. 19” cabinet
— Remove rear plastic cover.
— Fit the dark grey plastic rails to cross-bars located
at 4/6 distance from left-hand side of cabinet (refer
to fig. VI-2).
— Mount rear panel PM 9664 with four screws A (fig.
VI-3).
— Slide counter into cabinet, press and secure release
cams.
NOTE: If no sub-unit is used, the empty compartment
can be covered by blank panel PM 9722 (2/6
rack size) or two blank panels PM 9721 (1/6
rack size).
1.3. Rack installation
The rear plastic cover of the 19” cabinet contains two
angular brackets for rack mounting.
Refer to fig. VI-2 and proceed as follows:
— Remove four screws 1.
— Slightly lift side plates at front and remove plastic
plates 2.
— Mount angular brackets in the place of the plastic
plates.
— Refit side plates and secure with screws 1.
— Remove feet 3.
— Remove tilting bracket and two pivot brackets.
2. Sub-unit installation
2.1. The desired sub-unit is installed in the 2/6 com-
partment of the 19” cabinet. The sub-unit is connected
to the PM 6650 via rear panel PM 9664 and a front
panel coaxial cable.
Proceed as follows:
— Switch off power.
— Push sub-unit into compartment until front panel is
flush with counter.
— Press and secure release cam.
— Interconnect sub-unit output and relevant input of
PM 6650 using a coaxial cable (refer to operating
instruction of sub-unit).
3. Installing BCD output unit PM 9684 and remote
control unit PM 9685
3.1. BCD output unit PM 9684 (refer to fig. VI-4 and
fig. VI-5).
— Remove rear cover plate A.
— Plug unit into connector C.
— Secure unit to rear panel with the two screws sup-
plied.
3.2. Remote control unit PM 9685 (refer to fig. VI-4 and
fig. VI-6).
— Remove rear plate B.
— Plug unit into connector D.
— Secure unit to rear panel with the two screws sup-
plied.
4. Installing D/A converter PM 9687
— Remove reer cover plate A (fig. VI-4).
— Plug unit into connector C (fig. VI-7).
— Secure unit to rear panel with the two screws sup-
plied.
5. Installing oven-enclosed oscillators PM 9680 A or
PM 9681
5.1. Model PM 6650 B can be equipped with optional
oscillator PM 9680 A or the ultra-stable type PM 9681
(refer to chapter I! for full details).
The PM 9681 can also be installed in model PM 6650 A.
5.2. Proceed as follows (refer to fig. VI-8):
— Unplug TCXO.
— Fasten oscillator box to left-hand side wall with the
four screws supplied.
— Connect coaxial cable to connector BU616 and
supply leads to earth and +12V.
— Let the PM6650 warm up for at least 7 minutes
before measuring.
6. Mains voltage conversion and rear panel fuse
The PM 6650 can be adapted to two mains voltage
ranges as shown in table VI-1. The mains voltage
selector (refer to fig. Vil-2) is operated with a screw-
driver inserted in the switch slot.
At delivery the PM 6650 is set to 230 V and provided
with a 0.5 A slow-blow fuse in the rear panel fuse-
holder (refer to fig. VIl-2). Be sure to change fuse to
1 A, slow-blow, if 115 V range is selected!
Mains voltage : ; marking
range slide switch visible
200...260V downwards 115V_ 0.5 A slow-blow
100...130 V_ upwards 230 V 1A slow-blow
Mains frequency range is 50 Hz to 400 Hz.
fuse
7. Internal fuses
Two more fuses protecting the power supply are ac-
cessible inside the PM 6650 on unit U6. Refer to fig.
VI-9. Both fuses are 2 A, normal.
Refer to the Service Manual to isolate fault causing
fuses to blow.
8. Earthing
The local safety regulations prescribe how the PM 6650
should be earthed. Two ways are possible:
a) via the 3-core mains cable plugged into an outlet
with protective earth contact.
b) via the protective earth terminal on the rear panel
(fig. VII-2).
NOTE: Use only one of these alternatives, otherwise
hum may occur.

|
Q trigger
lamp
A AMP
Display
trigger | :
@) tri
vat lone decoder drivers
B AMP &
.
cS
|
Memories
a
oT
FUNCTION feontrol
selector | |
AGC |
C 100 MHz due GATE decade decades
x10
EXT. STD AMP
reset
Frequency
Control
dividers circuits |transfer
reset
10 MHz
| |
clock | |
DISPLAY TIME
TIME BASE /
Figure
V-1._
Simplified
block
diagram
MULTIPLIER

17
PM 6650 programmable counter/timer 512 MHz/‘ins
‘DISPLAY TIME
= osc
‘WWE BASE
15 3
@ ©@®
Figure VI-1.
DF 2
3 a |
plastic guide rails
Figure VI-2. Mounting the brackets for rack
installation
Figure VI-7._ Plugging in DAC PM 9687
19” cabinet provided with rear panel Figure VI-3.
PM 9664
ravens
sya
tomers pes
® ©
Figure VI-8. Mounting optional oscillator PM 9680 A
or PM 9681
Figure VI-4. Inputs for optional cards
/
Fuses, 2A, normal
©
Figure VI-5. Plugging in BCD output unit PM 9684 Figure VI-9. Internal fuses

18
Vil. CONTROLS, INDICATORS AND CONNECTORS
Figure VII-1
e START/STOP
& GATED BY B
a POWER ON/OFF
Sets display time between 0.05 s to 5 s. Infinite display time when knob is
pulled to HOLD position.
Resets decade counters and display to zero. Starts new measurement when
released.
When button is depressed, measurement information is stored until next
measurement cycle is completed. Released button makes display follow
decade counters continuously.
Allows counter to measure burst signals in mode FREQ. A or FREQ. C.
With FUNCTION switch set to COUNT A, manual control of main gate in
totalize mode. When MEMORY switch is depressed, reset of decade coun-
ters occurs after STOP plus set display time; new counting starts from zero.
When MEMORY is released, counting is cumulative.
In the COUNT A mode, the signal at INPUT A can be gated by signal at
INPUT B. When MEMORY switch is depressed, reset of decade counters
occurs after set display time when gating pulse ends. When MEMORY is
released, counting is cumulative.
Secondary power switch. Turns d.c. voltages of circuitry on/off. A.C. volt-
ages and oven-enclosed oscillator supply present when counter is con-
nected to mains.
Sets trigger level of channel A to +3 V or +30 V when the ATT switch is
set to x10. Level is preset to zero when knob is pulled.
Provides 10x attenuation of signal at INPUT A.
Selector for AC or DC coupled input.
Enables triggering either on positive or negative slope of input signal.
Sets 1 MQ input impedance of channels A and B.
Sets 50Q input impedance of channels A and B.
Separates inputs A and B.
Connects A signal also to B channel. If selected, 502 input impedance is
maintained.

19
Operation mode selector. Blue text corresponds to blue text at TIME BASE/
MULTIPLIER switch.
Positions:
SUB-UNIT
COUNT A
RATIO A/B
PERIOD A
PERIOD AVG A
TL. ATOB
T.l. AVG ATOB
FREQ. A
FREQ. C
CHECK
DISPLAY TEST
Matches counter to sub-unit used.
Sets counter to totalize or scaling mode (see also con-
trols 5 “and 6). Signal applied to INPUT A is scaled by a
factor 1 to 10? as set with MULTIPLIER switch. Scaled
signal available at rear TIME BASE OUT connector. Fre-
quency range in totalize mode 0 to 160 MHz, in scaling
mode 0 to 10 MHz.
Used when measuring ratio of frequency A (0 to 160 MHz)
applied at INPUT A to frequency B (0 to 10 MHz) applied
at INPUT B.
Sets counter to measure single period applied at INPUT
A. Desired resolution 10 ns to 1 s is set with TIME BASE
switch. Frequency range 0 to 10 MHz.
Sets counter to measure period of signal applied at
INPUT A. MULTIPLIER switch sets number of periods (1
to 108) to be averaged. Frequency range 0 to 10 MHz.
Sets counter to measure time interval A to B, with start
signal at INPUT A and stop signal at INPUT B. TIME BASE
switch sets counted frequency (100 MHz to 1 Hz). Input
range is 40 ns to 10? s. Inputs A and B can be common
or separated. A deadtime of = 50 ns between interval is
required.
Sets counter to measure average interval A to B, with
start signal at INPUT A and stop signal at INPUT B. Input
range is 100 ps to 10 s, repetition rate 10 MHz. MULTI-
PLIER switch sets number of intervals to be averaged
(1 to 108). A dead-time of 2 50 ns between intervals is
required.
Sets counter to measure frequency of signal applied to
INPUT A. TIME BASE switch sets suitable gate time (100
ns to 100 s). See also 20. INPUT A.
Sets counter to measure frequency of signal applied to
INPUT C. TIME BASE switch sets suitable gate time (100
ns to 100 s). See also 18. INPUT C.
Used for self-check of internal logic circuits.
Counter displays 100 MHz (derived from internal oscil-
lator) during gate time set with TIME BASE switch.
Used to check function of decimal points, measuring unit
display and character segments. Each step up to 1 s of
TIME BASE/MULTIPLIER switch provides one functional
test.

20
(17) TIME BASE/MULTIPLIER
FUNCTION:
SUB-UNIT
COUNT A
RATIO A/B
PERIOD A
PERIOD AVG A
T.1.ATOB
T.. AVG ATOB
FREQ. A and FREQ. C
CHECK
DISPLAY TEST
Function depends on set operating mode:
TIME BASE/MULTIPLIER:
Depends on sub-unit used.
Refer to relevant operating manual.
Sets scaling factor 1 to 10° for signal applied at INPUT A and
available at rear TIME BASE OUT connector.
Sets multiplying factor 1 to 107.
Selects scaling factor for internal or external oscillator
signal.
Sets number of periods to be averaged.
Selects scaling factor for internal or external oscillator
signal.
Sets number of time intervals to be averaged.
Selects gate time.
Selects gate time.
Selects 8 functional tests (cw rotation from 10 ns) of decimal
points, unit display and character segments.
——-

Rear panel switch and connectors
230 V
115 V
21
Input connector for channel C. Frequency range is 5 to 512 MHz, sensi-
tivity 10 mMV,.,.. Input impedance is 50 Q; AGC circuit provides automatic
attenuation. Maximum input voltage is 12 Vrms.
Light:emitting diode turns on when input level is sufficient for correct trig-
gering.
Input connector for channel A. Frequency range is 0 to 160 MHz when DC
coupled, 30 Hz to 160 MHz when AC coupled. Impedance can be set to 1 MQ
shunted by 25 pF or to 50 Q.
Dynamic range is +3 V compared to set trigger level times attenuator set-
ting. Trigger level is available at front panel miniature jacks and BNC con-
nectors at rear panel. Maximum input voltage is 230 V,»; or 230 V dic. at
1 MQ, and 12 V_.. at 50 .
Same as 20. Input A but accepts also gating signal for channel A in totalize
mode.
Light-emitting diode turns on during 100 ms when triggering level is passed.
Provides set triggering voltage from channel A.
Light-emitting diode turns on when mains cable is connected to mains.
Indicates that oven-enclosed oscillator circuits are connected to supply
voltage.
Light-emitting diode indicates when main gate is open (on) and closed (off).
Light-emitting diode turns on when counter is programmed externally via
remote control unit, e.g. option PM 9685.
Unit annunciator indicates measuring unit. “No go” is indicated at impos-
sible combinations of control settings.
Figure VIlI-2
Mains voltage selector.
Mains input.
Sub-unit connector. Fits connector of rear panel PM 9664 in 19” cabinet
PM 9716 A.
Output signal depends on operating mode set with FUNCTION switch:
COUNT A: Scaled signal. Scaling factor set with MULTIPLIER switch.
PERIOD A
or
T.l. ATO B: Output signal 100 MHz to 0.01 Hz.
CHECK: 100 MHz signal gated by set TIME BASE (DISPLAY TIME control
pulled).
Amplitude is 500 mV,, in 50 Q; source impedance approx. 100 Q, DC
coupled.

22
@ 10 mz our
® TRIGG. LEVEL OUT
34) EXT STD 1 OR 10 MHz
35) GATE OPEN
26)
37)
Internal switches and connectors
38 ] INT.STD/EXT.STD
39) 10 MHz STD/1 MHz STD
40)
oO
2)
Provides internal oscillator signal even if external standard frequency is
used. Amplitude is 1 V;ms in 1 kQ and source impedance approx. 200 2, DC
coupled.
Provides trigger level of channel A. Amplitude is +3 V to —3 V as set with
front panel control LEVEL A. Impedance is 4 kQ.
Set level equals measured value independent of load.
Accepts external frequency standard. Internal switch of unit 4 can be set to
match counter to 1 MHz or 10 MHz standards. 10 MHz must be used if time
resolution better than 1 us is required. 100 kHz signal can be applied but
correct position of decimal point must then be calculated. Impedance is
1 kQ shunted by 50 pF, AC coupled. Sensitivity is 500 mV;,; and maximum
input voltage 12 Vins.
Provides signal when main gate is open. Can be used as a Z-modulation
signal in single period, single time interval and frequency burst operating
modes. Amplitude is approx. +04 V when main gate is closed and approx.
+5 V when main gate is open.
Impedance is 200 Q. Delay from input A to GATE OPEN is about 50 ns.
Clamp for protective ground.
Fuse holder.
Figure VII-3
Sets counter to operate with internal or external clock oscillator.
Sets counter to accept 10 MHz or 1 MHz external clock frequency.
Input connector for 10 MHz signal from optional oscillator PM 9680 A or
PM 9681.
Connector for optional remote control unit PM 9685.
Connector for optional BCD output unit PM 9684 or digital to analogue
converter PM 9687.

—
Figure VII-3.
Internal switches and connectors
23