Philips PM 5125 User manual

1
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PHILIPS
GENERATOR
PM
5125
5445
O51
25031
9499 450
04411
31511/1103
Manual.

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

3
Contents
GENERAL
I.
Introduction
II.
Technical
data
III.
Accessories
IV.
Description of the block
diagram
5
6
10'
10 ;
DIRECTIONS
FOR USE
V.
Installation
17
VI. Controls,
terminals and their functions
18
VII.
Operation
20
SERVICE
DATA
VIII. Circuit
description 23
IX. Gaining
access to parts
2ff
X.
Survey of
adjusting
elements 3p
XI.
Checking and adjusting
32
XII. Fault fi
nding
37
XIII.
Lists of parts
38
XIV.
Information
concerning the
modular
system and optional
accessories
4$
A.
General
4g
B.
Coupling accessories
50
C.
Coupling
instructions
S9 ,

4
List of
figures
Typical frequency
response curve
6
2
Typical
distortion curve
7
3
Block diagram
13
4
Rear view
18
5
Controls and
terminals
19
6
Load diagram
20
7
Adjustment of
distortion
22
8
Simplified
diagram of the
oscillator
23
9
Voltage
diagram
24
10
Thermis[or circuit
25
I I Stand
assembly
28
12 Left-hand
view indicating the
adjusting
elements
31
13 Right-hand
view indicating the
adjusting
elements
31
14 Front
view
indicating
the
mechanical
components
39
IS Stand
assembly
indicating
the
mechanical
components
40
16
Rear view indicating the
mechanical
components
40
17A Top
view
indicating
the mechanical
components 41
17B Bottom
view indicating the mechanical
components
41
l8
Coupling kit
52
19 Cover kit
52
20 Stand assembly
55
2l Rack -mounting, exploded view
57
22 Coupling two modular units, exploded view
23
Printed wiring board of
the
oscillator
GO
24 Printed
wiring
board
of
the squarer and the
amplifier
61
25 Printed
wiring board of
the power supply
62
26 Printed
wiring
board
of
the
meter
circuit
63
27 Circuit
diagram of
the oscillator
65
28 Circuit
diagram of
the
squarer,
the
amplifier and the
meter
circuit
72
29 Circuit diagram
of
the power supply
79
30
Overall diagram
86
[ I
L J
L
i

1
.S.4f.'~i ...
. ... .
A Y ~
& ~..
ar;EASY
MlII~e9~i'sWJivZn
5
GENERAL
Introduction
0
The generator PM 5125
provides
stable and accurate sine and square
wave
signals in the frequency range from
10
Hz, up to l MHz.
The
midbank frequency response is lint within 0.1 dB. The settling
time
(bounce) is very short.
The frequency may be varied
in
steps
of
one decade and continuously:
The following two outputs are provided:
-
one output
with an
impedance
of 600 4.
The output voltage may he
varied
continuously up
to
l0 V (open
circuit)
as
well as in
four
accurate
steps of 20 dB.
- one
low impedance output. The
output voltage may be
varied
Conti-, ;
nuously up to 10 V.
Both
outputs are
switched simultaneously to
sine wave
or to square wave.
The output
voltage is monitored
by means
of
a
built-in voltmeterL ,
The generator frequency may be synchronised by means of an external'
signal.

6
Technical data
i ]
0
Data
expressed in numerical values
as tolerances are
guaranteed by the
factory. r
The
other numerical values are
for information only and
indicate the f`
characteristics of an average instrument. The
maximum
ambient
tem-
perature is
45 ° C. r
A. FREQUENCY
Range
10 Hz... 1 MHz
in fi
ve
overlapping subranges i
Inaccuracy at 20 ° C
100 Hz — 100 kHz: < 3% `
10 Hz — I
MHz:
~
5%
l
1E9
t
z05
Frequency variations at mains
variations off 10%
Temperature
coefficient
.0<
.oa i
az
of
1
~
~ ~
l
-ol
oz
negligible
0.015%
per
°C
at 5 kHz
sF
ro
earm
s
F
.dl~[,I~o~
OA
~-
WN:
IOOHx IkHz
Fig. 1.
Typicaljrequency response curve
AFH[
100MHz IMN[
F AE
OUE NCY _
M45066

Long
term drift
Short
term drift
B.
OUTPUT SIGNALS
1. Sine wave signal
Frequency
response
(See
Fig. 1)
Total harmonic
distortion
(See
Fig. 2)
ID
05
08
0.7
0. 6
0.5
O.L
0.3
0.1
0,1
0.05%
in 7 hours at 5
kHz after a
warming up'
period of 20 minutes
and at constant ambient.
temperature and mains
voltage
0.005%
in 10 minutes at 5
kHz after
a
warming ;
up period
of 20 minutes and at
constant ambient
temperature
and mains voltage
I00 Hz - 100
kHz:
Hat
within ~_ 0.1
dB
referred
to
5
kHz
l0 Hz - I
MHz:
fl at
within ~ 0.2
dB
referred to 5
kHz
10 Hz -
100 kHz:
c3
° io
at 600
kHz
<
1 °o
SPECIFICA
iION
IOHx 100Hz
IMHz
IONHz
Fig. 2.
Typrca!
distortion
curve
t
OOk Hz
IMHx
FRE~VENCV
-►
MA6066A

J
s
I
Y '
2. Square wave signal
Rise and fall time
Wave-Ibnn
aberration
C. O
UT PU"1'S
I.
600 4
Maximum amplitude
Output impedance
Attenuation
continuous
in steps
Hum and noise
2. LOW ""/
,a
Maximum
amplitude
Output impedance
Minimum resistive load
Maximum capacitive
load
Attenuation, continuous
100
nanoseconds
above 5
kHz
3
"/„
10 V~,,,, (for
sine
wave) or 10
V,,,,
(for
square
wave),
open
circuit
5
V r ,,,,, (for
sine wave)
or
5
V,,,,
(for syuare
wave)
into
600
S2
600 4
40 d6 linear (for sine wave)
26 dB linear (for square wave)
3 ~
20 dB (inaccuracy: 0.2
dB/s[epatSkHz)
60
dB down
a[
maximum
setting
of the
continuous attenuator
10 V~,,,, ((or
sine
wave) or
10 V„~
(for
square
wave)into 600 O
16 f2
for
sine wave
10 52 for square wave
6(1(1
52
SO pF
> 40 dB linear (for sine wave)
26
dB linear (for
square
wave)
Hum and noise ~
60 dB down
at
maximum
setting of the
continuous attenuator
Note: Both
outputs may
he
loaded simultaneously with 600 n
each, with only a
slight
deterioration of performance.
Both
outputs
are switched
simultaneously to
the sine
wave voltage
or to [he
syuare wave voltage by means of
waveform selector mo t,/~.

D.
OUTPUT METER
Indication
Scales
Inaccuracy
E.
SYNCHRONISATION
Range
Required input voltage
Maximum
input
DC voltage
Input
impedance
F. POWER SUPPLY
The meter
is
switched
simultaneously by means
of
the
waveform selector to
indicate:
a. the sine
wave output voltage
r.ms, open
circuit,
or
b.
the square wave output
voltage p -p,
open
circuit.
0—lOV
0-16dBm
<
5/ of full scale
deflection
max.
7%
{-
2% of
set
frequency with a negligible deteriora-
tion of
performance ,,
40
mV r ,,,„ per
%hold
j- I S V
100 kS2
Supply voltage I IS V or 230 V _~ IS"/„
Frequency 50 — 100 Hz
Power consumption 28 W
G. MECHANICAL DATA
Dimensions
Weight
3
module
cabinet (see
chapter XIV)
5
kg (I I Ibs)

,~
Accessories
Manual
Optional accessories
Coupling
kit PM
9500.
® [ ~
-
A
selection of
5 different
cover kits PM 9502... PM 9506.
-
Rack -mounting
kit PM 9510
for mounting a 6
-module
cabinet into
a
19" rack.
-
Extension
test board 4822 466 10165
for
carrying out measurements r
on the
plug-in
printed
wiring
boards
while
the instrument is
in ■`
operation.
The
description and
ordering information of
these
accessories are given
in chapter XIV
of
this
manual.
Description of
the
block diagram
(See
Fig.
3)
This instrument contains aphase-shift
oscillator, an
amplifier, a squarer,
a
voltmeter,
two attenuators
and
a double
power supply.
r
OSCILLATOR
The phase -shift oscillator consists
of
three
unity
gain amplifier stages.
The fi rst two amplifier stages give each
aphase-shift
of 90° for the
oscillating frequency and the third
amplifier stage gives
aphase-shift
of
180°.
The
output signal of the third amplifier
stage is fed
back to the
input
of
the fi rst amplifier stage.
The amplifier stages are coupled by means
of impedance
converters
(emitter followers).
The
unny loop gain is
maintained by
means of a
thermistor,
which is a r'
part
of
the collector impedance of the third
amplifier
stage.
FREQ.
Hz(SK3, Rlr - Rlrt) ~('
The frequency
of
the oscillator may
be
varied
continuously by
means
of
the double potentiometer
Rlt - Rl~t
and in steps
of one
decade by
means of the switch
SK3. r
l ,,,

SYNC. IN (BU3)
The frequency
of the oscillator may be
synchronised by means of an
external source
connected [o the terminal BU3.
WAVEFORM SELECTOR 'Z,/
(SK2)
The sine wave
generated in the oscillator is
applied either to the amplifier
(via the
continuous attenuator R2r)
or to
the
squarer by means of the
selector switch
SK2.
In
position
~
of SK2
the
sine wave signal is
amplified and then fed
to
the output
terminal LOW
Zo (BU1), to the step attenuator
SK4 and to
the meter M1, which monitors
the
output
voltage at BUI.
In position 2,
of SK2
the
squarer converts the sine wave
signal into a
square wave
signal; then
the
square wave signal is also
applied
to the
terminal LOW Zo (BU l), tothe step
attenuator SK4and to the meter M,1.
AMPLfTUDE (R2r — R2rr) ~~
The amplitude of the output
signala[the[erminals
LOW
Zo (BUI) and
600 4 (BU4) may be
varied continuously by means of the double
poten-
tiometer
AMPLITUDE
(R2r —
R2tt),
STEP ATTENUATOR (SK4)
The
amplitude
of
the output signal at the
terminal 600 S2 (BU4) m4y
also be varied
in
steps
of 20 d6 by means of the
attenuator switch SK4.

(3
SK3
FREOUENCV
RANGE
SELECTOR
1 AMPLIFIER AMPLIFIER
T522
PHASE
SH/F
i
90 °
T525
PHASE SHIFT
90 °
SVN C. IN
Q
BU3
3
AMPLIFIER
R1 Z -R1II
GANGED
CONTINUOUS
FREQUENCY
CONTROL
T528-29
PHASE
SH/F!
!80 °
AMPLITUDE
~
CONTROL
T530-T53L R<6
oscl«aroR
OUTPUT
STAGE
T532
ti
SQ
UARER
SCRMITT
TRIGGER
T
561---63
1
OUTPUT
STAGE
T S6< - 65
R
2 I _R2II
GANGED
CONTINUOUS AT TEN UATOR
AMP,'_
ICIER
~'
T581-BG
OUTPUT
STAGE
T 585-86
SK2 WAVE
FORM
SELECTOR
STEP
ATTEN
UATOR
SK4
8U4
60071
BU1
LOW Z°
M A
5045
Fig. 3.
Block diagram

17
DIRECTIONS FOR USE
Installation
For coupling two or more
modular units refer to
chapter
XIV.
A.
ADJUSTMENT
TO
THE LOCAL MAINS VOLTAGE (See Fig.
4)
The instrument may be
adjusted to a mains
voltage
of 100... 130 V or
200... 260
V
by means
of switch SK12 on the rear panel.
Incase of a mains voltage of
100...
130
V,
the
fuse VLI rated at 250 mA
(delayed action) should
be
replaced by a
fuse
with
a
500 mA-rating
(delayed
action).
B.
EARTHING
(See Figs. 4 and 5)
The
instrument should be earthed
in conformity with the local safety
regulations. This can
be
done:
a, via the
supplied
3
-core mains cable,
b. via the
earthing terminal BU12, marked ~, on the rear panel,
c. via
[he earthing terminal BU6, marked
1,
on the
front panel.
NOTE: For operation
as
a
single unit connect BU6 to BU7
The units of the modular
system
have
asemi-floating circuit so that the
circuit need to be earthed at one point
only when several units are coupled
together.
Earth currents which
may
give
rise
to
hum are thus avoided.
The
terminals BU6 and BU12
are connected
to
the metal frame of the
cabinet.
The
signal earth is connected
directly
of
the terminals BU2,
BUS and BU7, marked -~-, and to the cabinet via a
100 kit resistor.
This provides the following output
possibilities:
- output from a circuit which is earthed by
linking BU7 (1)
to
BU6
(1)
-
output from a circuit which is earthed via
other
coupled modules
or
via
auxiliary equipment.

is
Controls,
termincls and their functions
(See Figs.
4
and 5)
POWER ON (SK1, LAI)
Frequency
dial
(RI)
FREQ. Hz (SK3)
AMPLITUDE
(R2)
dB-attenuator
(SK4)
Waveform selector ~,/~ (SK2)
Output
terminal LOW
Zo
(BUl)
Fig. 4.
Rear view
CD12
SK12
VLl
On/off
switch with neon indicator
Continuous
frequency
control
Frequency control in steps. The output frequency
given in Hz is equal to the product
of
the
setting
of
SK3
and the setting of RI.
Continuous
control of the amplitude at
both
output
terminals BUl and BU4.
Switch for setting the
attenuation of
the
ampli-
tude at
terminal BU4 in four steps
of 20 dB, viz:
—60
dB, —40 dB, —20 dB
and
0
dB.
Switch for selecting the output
waveform at the
terminals BU1 and
BU4.
The
output voltage at
this terminal may be
varied
continuously by means of R2.
The output impedance
is l0 S2
for
the
square wave
and 16 f2
for
the sine
wave.
CD11
MA67B3
f~
~ J
C 1
[~
J
~J
~J
l~` ]
J
C)
C1
~1

19.
Output
terminal 600 S2
(BU4)
SYNC. IN (BU3)
Signal earth
(BU2, BUS,
BU7)
Chassis
earth
(BU6, front panel)
(BU12, rear panel)
SK12,
rear panel
CDI1, rear panel
CD12,
rear panel
R1
BU3
BUS
The
output voltage at
this
terminal may be'
varied continuously by
means of R2
and in steps
of 20
dB
by
means of
SK4.
The output
impedance is 600
S2.
Input terminal
for the
external synchronisation'
signal.
Terminals to
which the signal
earth is connected
Earthing terminals
connected to
Che metal frame`
of
the cabinet.
The
signal
earth and the
chassis
earth
may be
connected by
linking BU6 to
BU7. Also refer to
chapter V —B.
Mains
voltage
selector
Mains input
terminal
Mains
output
terminal
SK3
R2
Fig. S. Contro/s and terminals
LAi
SKl
SK4
BU6
MA6281
Mt
BU1
SK2
BU2
BU4
BU7

20
Operation
A.
CONNECTING THE LOAD (See
Figs. 5 and 6)
— Connect the load to the
terminal "600 S2" (BU4) or to
the terminal
LOW
Zo (BU I).
— The resistive load
connected to the terminal LOW Zo (BUI)
should
be at least 600 !Z. The capacitive
load connected to the
same terminal
should not exceed 50
pF.
— The load connected
to
the
terminal 600
n
(BU4) may
be
very low.
— Both output terminals
may
be
loaded simultaneously, with
a slight
deterioration of the performance
(as indicated in chapter
II
"TECHNICAL
DATA"), in accordance with Fig. 6 and the table below.
TABLE OF
LOADS
Nornea/
minimum
(oad
impedance (Maximum
rurrenr /~ - /7
mA)
Absofure minimum
/oad
impedance (Maximum
current
/t
=-
23
mAJ
R a =
o0
R a
=600 S2
R6
= 00
Rp -= 600 !7
Rp
=approaching
0
S2
Rp .=
approaching
0 S2
R a -- 600 S2
Rp ---- 600 S2
R a = 400 S2
R a — 600 n
R a -- 1200 n
It=I I
+I2=mox.25mA ~
r.m,s.
P -
P
Fig. 6. Load diagram
MA5043
a
r
l
r
r
t
r
l
r

21
B. SWITCHING
ON
-
Switch on the instrument by means of the switch POWER
ON (SKI).
The
indicator LAI should then light up.
-
Wai[
for
20
minutes before proceeding with the following, if ,a stable
output
frequency or
voltage
is required.
C. SELECTING THE
FREQUENCY
1. -Select the frequency range by means
of
the
switch
"FREQ. Hz"
(SK3).
- Adjust
the
desired
frequency
within
the selected
range by
means
of
the
frequency dial
(Rlr - Rln).
2. -
if
synchronisation of
the generator frequency is requited; then
apply
an external signal
to the terminals SYNC. IN (BU3 and BU5).
This
signal
should have an
amplitude
of 40 mV per
peccent of
required hold. For the initial set-up
make sure that the generator
frequency corresponds to
the frequency of the
external
signal;
D.
SELECTING THE
OUTPUT VOLTAGE
- Select the waveform of
the output voltage by means of
the
'switch
-
Set the attenuator switch "—dB" (SK4)
to
position 0.
- Adjust the amplitude of
the output voltage at the terminals "LOW Zo"
(BUl) and "600 S2" (BU4)
continuously by
means
of the attenuator
"AMPLITUDE"
(R2), as indicated
by the
meter
ML
- Adjust
the amplitude
of
the output voltage at the terminal "6p0 S2"
(BU4) in
steps
of
20
dB
by means of the attenuator switch
"-dB"
(SK4).
Notes
1.
The meter M1
indicates the output voltage at the
terminal
"LOW
Zo".
When no
load is connected to the terminal "600 S2", then
the
output
voltage at
this
terminal
is equal to the indication of M I divided by
a
factor:
- 1
in
position 0 dB of
the
switch "—dB" (SK4)
- 10 in position
—20 dB of
the
switch "---dB" (SK4)
- 100 in position
—40
dB
of the switch "—dB" (SK4)
- 1000 in position
—60 dB of
the switch
"—d6" (SK4).
When a
600
S2
-load is connected
to the terminal
"600 Sl", then
the
output
voltage at this terminal
is halved.

22
The top
scale of
the
meter M 1 is
calibrated for:
—
RMS
values in the case
of
sine
wave
operation
—
peak
to
peak values in the case
of square wave
operation.
The
bottom
scale
of MI indicates the
output variations
in dBm
(0 dBm 1
mW
into
600 n (0.775
V)).
2.
When
the
waveform selector ~,/~ is
in position 2„ it is recommended
to screen the
output
at
the
terminal
"600
S2" for
optimum waveform
in the case that
the attenuator
"—dB" is
set
to its lowest
position
(-60 dB).
3.
The
trimming
potentiometer R45 (see Fig. 12)
controls the
distortion
and
the
settling time.
A lower
distortion
and
a higher
settling
time
are obtained
when R45
is
turned anti -clockwise.
A
higher distortion and a
lower settling time are
obtained, when R45
is turned
clockwise.
(see Fig.
7)
i,<
ID
09
OH
07
0.
6
0.
5
0<
03
0.2
0.1
0
IO Nz
Rt,S MAXIMUM
R46 NORMAL
R<5 MINIMUM
SPECIFICATION
IOOMx IM
Mx
Fig. 7. Adjustmen( ojdistortion
IOkNz IOOk Nz
IM
Nz
FRED
UENLV
MA5613A

23
SERVICE DATA
Circuit
description
A. OSCILLATOR
(See
Figs. 8, 9,
10
and 27)
The sine wave
oscillator used in this instrument is a phase -shift oscillator
consisting mainly
of
three
amplifier stages TS22, TS25 and TS29, which'
are coupled by
means
of
the emitter
followers TS23—TS24, TS26—TS27
and TS30—TS21
respectively.
Two
identical frequency
control
circuits have
been used. The fi
rst
one
is connected
between the collector and the emitter
of
TS22
and consists,
of the capacitors
C21...C27 and the resistors R24 —Rh —R25. The second
one
is
connected
between
the
collector and the emitter of T525 and
consists of the capacitors
C28...C34 and
the
resistors R30—Rlrr—R31.
These
networks provide each aphase-shift
of 90°
at
the
oscillation
frequency, f o .
.,a~
Fig.
8. Simplified diagram of the oscillator

In
Fig. 9 the phase
relationship between the voltages at the
different
points of the
oscillator has been
drawn.
This fi gure shows that the
phase -shift
between the input of the fi rst
amplifier
stage TS22 and the
output of the
fi
rst
frequency control circuit is 90°;
thus
the phase -shift
between V, and
Vy
is
90°. The same applies to the
second amplifier
stage
TS25
and the second
frequency control circuit; thus the phase -shift
between V s
and V s is 90'.
The
phase -shift due
to the third
amplifier
stage TS29 is
180'';
thus the
phase -shift
between V S
and
V 6 is 180°. The total phase -shift is
then
90°
-}
90° }- 180" _= 360°.
Consequently, the input voltage V, and the
output
voltage V 6 are
in
phase.
The
frequency is changed in steps of one
decade by switching the capa-
citors C21...C27 and
C28...C34 in steps by means of SK3. Continuous
frequency control
(ratio
1
10)
is
effected by means
of
the double
potentiometer Rlt --
Rltt
The output
amplitude may be adjusted
with R40 and R42. The
thermistor
R44 keeps
the output amplitude constant. R42
is adjusted in such a way
that
Rs
(see
Fig. 10)
becomes complementary to the
differential resistance
of R44. Hence
n
V total
becomes zero.
pl
The diodes GR21--GR22 introduce a
controlled amount
of non-linear
distortion, which results
in
a
shorter settling time of the
sine wave
when
switching over to the lowest frequency range.
The current
through
GR21—GR22 may be adjusted
with
R45.
V t V fi
V4
V 2 V 5
V3
Frg. 9. Voltage
diagram