Philips PM 3342 User manual

PHILIPS
WiIUDi
PM
334
OUAI
T0.ACE
Y
AMPI
PM 3342 DUAL TRACE
UNIT
9499 440 04911
21 869
2 02 03

3
IMPORTANT
In correspondence
concerning this
apparatus, please
quote the type number
and the serial number
as given on
the type
plate at the
rear
of the
apparatus.

4
Contents
GENERAL
INFORMATION
XI. Checking and adjusting
26
I. Introduction 7
II. Technical data 7
A. General
information 26
III.
Description of
the
block
diagram 9
B. DC
balance
26
C. Levels of channels A
and
B
27
DIRECTIONS FOR USE
D.
Sensitivity of channels
A
and B
27
E.
AC -DC
switch; CHECK
ZERO 27
IV. Installation 11
F.
Square -wave response 27
V.
Controls and
their functions
13
G. Frequency response curve 29
VI. Applications 15
H. Defection
and shift 29
A. Amplitude measurements 15
B. Differential measurements 15
J.
Input attenuators
29
C. Phase measurements
16 K. Blocking of channels A
and
B
30
D.
Single time -base
16
L. Rejection factor 30
M.
Triggering
30
SERVICE NOTES
N.
Cho
in
pp~ g
31
VII.
Block diagram
17 O. Alternate 31
VIII. Vertical amplifier 23
XII. Parts lists 32
IX. Switching control -circuits
24
A. Mechanical
33
X.
Trigger amplifier
25
B. Electrical 34

5
List of figures
Fig. Page
1 Block diagram
9
2 Front view with
indication of controls and
connections
12
3
Block diagram (detailed)
19
4 Typical waveforms
22
5 Display
22
6 Right-hand view
26
7 TU-5
pulser
28
8 Left-hand
view
28
9
Measuring
probe,
directly
earthed
29
10 Input RC
standardiser
30
ll
Amplifier, channel A
38
12
Amplifier, channel B
39
13 Dual -trace unit
40
14 Output
amplifier
40
15
Trigger amplifier
41
16 Drift
compensator
41
17
Attenuator,
channel A
44
18
Attenuator, channel B
48
19
Trigger
-amplifier
circuit
52
20
Dual -trace circuit
56
21 Y
-amplifier
circuit
61

z
GENERAL INFORMATION
Introduction
0
The PM
3342
is a
dual
-trace
plug-in unit for
the
Y -
channel
of the PM 3330.
The unit contains
two
identical
amplifiers with an
electronic switch,
by
means of
which two signals can
be
compared
in
amplitude and
in
phase.
Technical
data
Note: Properties,
expressed
in numerical
values with
statement
of
tolerances are guaranteed by
the
factory. Numerical
values without tolerances
are
intended
for
information purposes only
and
indicate the properties
of an
average apparatus.
Input circuit
input
input
impedance
input
maximum
permissible
d.c. voltage
in
the a.c. position
Measuring probe
type
input
attenuation
permissible voltage
Amplifier
deflection coefficient
Moreover,
the sum and
the difference of two
input
signals can be displayed.
Trigger
of the
time base
occurs
at choice on one of
the
two input signals or on
the combined signal.
The
amplifier
data
apply
to channel A as well as
to
channel B.
adjustable AC or DC;
push-button for checking
the zero
level
1 MS2//15pF
BNC
400 V
PM 9331 A/10
10 MS2//8 pF
1 :
10,
tol.:
3%
1,OOOVpeak
adjustable to 10 calibrated values: 10,20, 50 mV/cm etc.,
up
to
10
V/cm; tolerance: 3%
continuous attenuator 1 :
3
(non
-calibrated)
bandwith D.C.:
0-50
Mc/s
A.C.:
1.6
c/s — 50 Mc/s
rise
-time 7 ns
rise time
of unit by itself: 5 ns
overshoot < 2%
rejection factor
>_ 100 x
for
frequencies <
1
Mc/s
in
position D.C. provided that the
amplifiers
are adjusted
to identical deflection -coefficients
maximum
common
mode input
signal corresponding
to
10
cm trace height
magnification
3
times useful screen
height,
symmetrical
round the centre
of
the
screen
for
frequencies up to
10
Mc/s.
The top of a
signal,
which is magnified at maximum, can be displayed
with
the
shift control.

8
polarity
phase difference
between both channels
Switching possibilities
externally
chopped
voltage
required
repetition frequency
rise time
input
capacitance
Trigger
mode
trace height required
in positions
DC,
LF
and
HF
in position AUT.
in positions
TV
LINE
and
TV FRAME
Mechanical data
reversible
not measurable
on the screen
1.
channel A
2.
channel B
3. channels A and B chopped; frequency 500 kc/s
or
20 kc/s
(internal
selection facility)
4. channels A
and
B alternately
5. channels
A
and
B
added
6. channels
A
and
B externally
chopped
symmetrical
square -wave voltage:
minimum, 1 V P
_p,
maximum, 20 V p
_ p
100 kc/s
1-100 ns
70 pF
A, B or A -~ B (in position "ADDED" only)
3 mm
for
frequencies up to
10
Mc/s
2 cm
for
frequencies up to
20
Mc/s
1 cm for frequencies up to 1 Mc/s
2 cm
dimension
width 15 cm
height 17.5 cm
length 29 cm (knobs
and
plug
included)
weight
3 kg
Accessories
1 Manual
Optional: 2 Measuring probes PM9331A/10

9
Description o f the block diagram
Channels A and B each consist of an
input circuit
in
which
the
"AC
-DC"
switch
and the step
attenuator
are
included., and
an amplifier which
containsthe V/cm
continuous
attenuator,
the
SHIFT control
and
the
polarity switch, see
Fig. 1.
The switching of
these
channels occurs
at the output
of
these
amplifiers, after which
the combined
signal
is
applied to
an
output
amplifier.
The
switching
circuit consists
of
a blocking
oscillator
A
0
CHECK
V/cm
A C
ZEORO
~DC
20 kHz
r - ~
I...i
i
500 kHz ~T'
MODE
A • t --
B •
CHOPPED •
ALTERNATE •
ADDED •
EXT.-CHOPPED
O
B
O AC~
DC
r --
b
DCBAL
Z
MOD
1
PM
3330
BLOCKING
OSCILLATOR
CATH
FOLL.
AMPLIFIER
and
a
bi-stable
multivibrator,
which
supplies the
switching
voltage. The trigger
voltage
for
the basic
oscilloscope is
taken
from
one
of
the channels via a
selector
switch.
A trigger
amplifier amplifies this
voltage, so that
the
trigger -
signal
and the
Y
-input
signal
have identical
amplitudes.
In position "ADDED"
of the "MODE" selector,
the
trigger
signal is directly taken from
the output
ampli-
fi
er.
NORMAL
INVERT
V'cm
CONT
I '
~ I SHIFT
b
GAIN
TRIGG
r
TRIGGER
AMPLIFIER
MULTIVIBRATOR
1
ELECTR.
SW
TCH
DCBAL
4
L_-
CHECK
ZERO
V
/ /CSR \
Fig. 1. Block
diagram
CATH
FOLL.
GAIN
V/cm
CONT
I
SHIFT
AMPLIFIER
NORMAL
INVERT
PEM
2633
I
FINAL —~
I Y-AMPL.
I
— ~1
I
POS. I
ADDED]
TRIGGER
O
I
PRE-AMPL.
STAGE

11
DIRECTIONS FOR USE
Installation
The
PM 3342 shculd
be plugged into the left
plug-in
compartment (Y -UNIT) of basic
oscilloscope
PM
3330.
Switching -on
is effected with the mains switch of the
basic
oscilloscope.
Approximately 10 minutes
after
switching -on,
the
unit has
reached its
operating
temperature and meets
the
technical
data.
When
using
the PM 3342, the switch
on
the
rear side
of
the
basic
oscilloscope should be set to
position
"MULTI -TRACE CHOPPER".

12
DN~tIDS
PM
334
DUAL
iRA~
SK8
,.-=.. ~ ate,,.. ~
SK6
S K 9 ---~
SK
10
Fig.
2.
Front view with indication of controls and connections

13
Controls and their functions
(Fig. 2) O
MODE selector SKS
~
~
~ i ~
~
~ ~ i i i i
~~
~~` ~~`
~ `~
~~
Trigger mode selector SK6
Input circuit
The
working mode
of
the
unit
can
be selected
with the
six -position
mode
selector.
channel A is
switched in,
channel B is out
of action
channel B is switched
in,
channel A is out
of action
CHOPPED
both
channels
are
switched in. The
volt-
ages
applied to
sockets
A
and
B
are
elec-
tronically switched.
The
frequency
in
which the
channels are
switched,
can
be
adjusted to
20 kc/s
or 500 kc/s
with switch
SK 11, located
on
aprinted-wiring board
at the
right-hand
side of the
unit.
"ALTER-
channels A and
B
are
alternately
dis-
NATE"
played.
Switching
occurs
during the
fl yback of
the time
-base voltage.
"ADDED" the
voltages at the
output
of both
ampli-
fiers
Aand Bare
added.
Dependent
on
the
position of the
polarity
switches, the
sum or the
difference
of
the
input
signals
is
applied to the
Y
-amplifier of the
basic
oscilloscope.
"EXT. The
channels are
switched
with a voltage,
CHOPPED
the
frequency of
which is
equal
to
that of
BU3" the
voltage
applied to
socket
"EXT.
CHOPPED".
TRIGG
A The
trigger
signal is
equal
to the
voltage
applied to
socket
A.
B
The
trigger
signal
is
equal to the voltage
applied to socket
B.
When
the
MODE
selector
is
in
position
"ADDED",
the
"TRIGG."
switch is out
of action.
In that case the
trigger signal is
taken from the
output
amplifier.
AC
-DC Via
this switch, the
input socket
is con -
switch nected to
the
V/cm switch.
In
the
DC-
(SK3;
SK9)
position,
the entire
input
signal
is fed to
the
V/cm
switch; in
the
AC
-position, the
DC
-component is blocked.