Page 1
TYPE B4
Including BtA, B4B, B4A/C and B4B/C
INS TRU CTI ON MANUAL
£gag«ra»a»*iK 3fc» • ?4 v -
ADVANCE COMP
ROEBUCK ROAD, HA1
. - T«M m : BUNAUW U tV W
r.
ENTS LIMITED
11% ILFORP, ESSEX
tUtpkooK ATTBNUAlE, ILPORD; :•
Page 2
r f d m u c e
SIGNAL G EN ER AT O R TY PE B 4
(Including fiM: B4B: B4A/C: B4B/C)
T h e Advance Type B4 Signal Generator is available in two versions,
the B4A and B4B, each providing a wide frequency range with accurate
frequency and output voltage calibration.
The frequency ranges are 100 kc/s to 80 Mc/s on B4A, and 30 kc/s to
30 Mc/s on B4B. The accuracy of frequency calibration is ± 1% A
linear scale and vernier are provided to give very close resetting accuracy.
Due to the use of a crystal voltmeter followed by our type A.38 high
frequency resistive attenuator, the output is measured to ± (1 dB + 2%
F.S.D.).
The signal can be modulated internally at 400 c/s from 0 to 80%. Ex
ternal modulation, also O to 80%, may be applied up to 30 kc/s into
the B4A and up to 10 kc/s into the B4B. Both internal and external
modulation depths are monitored.
The instruments are of robust construction and are simple to operate.
Page 3
SPECIFICATION
FREQUENCY
Frequency ranges. .
B4A/C 100 kc/s to 80 Mc/s in 6 ranges. Accuracy ± 1 %
Range A
Range B
Range C
B4B/C 30 kc/s to 30 Mc/s in 6 ranges. Accuracy ± 1 %.
Range A
Range B
Range C
R.F. OUTPUT VOLTAGE Accuracy ± (1 dB + 2% F.S.D.).
100- 300 kc/s. Range D
300-1000 kc/s. Range E
1- 3 Mc/s. Range F
30- 100 kc/s. Range D
100- 300 kc/s. Range E
300-1000 kc/s. Range F
3-10 Mc/s.
10-30 Mc/s.
30-80 Mc/s.
1- 3 Mc/s.
3-10 Mc/s.
10-30 Mc/s.
The output voltage from the 75 ohm attenuator is fed into a
75 ohm transmission line which is terminated with a 75 ohm
dummy aerial pad. The output into 75 ohms is continuously
variable from l^V to lOOmV by means of a 4-step decade
attenuator and a continuously variable control. The signal is
monitored after the variable control to ensure accuracy at high
frequencies.
OUTPUT IMPEDANCE
The output impedance at the end of the unterminated trans
mission line is 75 ohms. When terminated by the Termination
Pad type TP1A supplied with the instrument, three impedance
values are available:—
(1) 37 ohms (with full output).
(2) 10 ohms (with one-tenth indicated output).
(3) A standard dummy aerial (with one-tenth indicated
INTERNAL MODULATION
output).
Frequency 400 c/s ± 10%
Modulation depth 0 to 80%; ± 1 dB ± 2% F.S.D.
EXTERNAL MODULATION
B4A 10 c/s to 30 kc/s, 0 to 80 % for frequencies less than l/30th
of the carrier frequency.
B4B 10 c/s to 10 kc/s, 0 to 80% for frequencies less than l/30th
of the carrier frequency.
Approximately 10% modulation depth per volt input into high
impedance is obtained. The modulation depth is monitored.
Accuracy ± 1 dB.
Page 4
SPECIFICATION
A.F. OUTPUT
R.F. LEAKAGE
ACCESSORIES
This is obtained from the internal modulation oscillator at
approximately 400 c/s. Output is approximately 0 to 10 volts
into 600 ohms.
Good screening and filtering have reduced stray radiation to
less than l^iV.
Each instrument is supplied with the following:—
1 ECC91 Mullard valve (6J6)
I 6SN7GT valve
1 6X5GT valve
1 Pilot lamp, type M,E,S. 11 nim, 6-5 volts
1 Termination and Dummy Aerial Pad, type TP1A
I Shielded R.F. Feeder, complete with plugs, type PL5
1 Shielded A.F. Lead, complete with plug and crocodile
clips, type PL18
I Mains Lead, type PL24
POWER SUPPLY
B4A, B4B: 110, 210, 230, 250 volts 40-100 c/s.
Consumption approximately 25 watts.
A model is also available for 110-125, 140-160, 220 volts
40-100 c/s. and 117 volts 25-60 c/s.
WEIGHT
25 lb (11.4 kg) nett
DIMENSIONS
13 in. x 12$ in. x 1 \ in. (33*0 cm x 31 *4 cm x 18‘4cm)
SPECIFICATION OF TERMINATION PAD TYPE TPIA
Input impedance 75 ohms.
Outputs: 37 ohms at full voltage.
10 ohms giving one-tenth of input voltage.
A standard dummy aerial giving one-tenth of input
voltage.
The TPIA is shown on the circuit diagram.
Page 5
[BAB OHLVj
S?4
-w a
*3«
AAwAA
\AAAr
MAINS
INPUT.
DESCRIPTION
REF.
I5KQ 10%
Rl
33 0K ft 10%
R2
I OK Si 10%
R3
R4
I5K 0 10%
RS
5 6KftlO %
R6
lOKft 10%
l5 K ft 10%
R7
22K ft 10% ^ WATT
22K ft 10% i WATT
R8
R9
22K ft 10% i WATT
RIO
IK I0 Q %
3-3K ftl0%
220 ft 10%
Rl I
RI2
RI3
RI4
RI5
RI7
RI8
RI9
R20
R2I
R22
R23
R24
R25
R26
R27
R28
R29
R30
R3I
R32
R33
IK ft 10%
2200 10%
ON B4A CONNECTION IS STRAIGHT
TO CO IL
22 f t 10% 1 WATT R.M.A.9
IK $ 1 0 % $ WATT R.M.A.9
I0 K Q I 0 % } WATT R .M A .9
330Kg IO% fW A T T R.M .A.9
250K
33 0£
91 £
IK Q
l a5KQ
240 Q
743 ft
743 ft
743 ft
743 0
120ft
91ft
91ft
91 ft
ft
82
5K Q
RESISTOR
| WATT
i WATT
WATT
WATT
WATT
{
i WATT
* WATT
| WATT
t WATT
i WATT
i WATT
* WATT
SEY 003/SER Q .C .
10% i WATT R.M.A.9
NON-INDUCTIVELY WOUN D
POT.
i WATT R.M .A .9
10%
i WATT R.M.A.9
10%
HIGH STABILITY
1!Y?
WATT High Stability
WATT High Stability
WATT High Stability
WATT High Stability
'%
WATT High Stability
V 9
WATT H igh Stability
2A
WATT High Stability
2%
WATT H igh Stability
WATT High Stability
i
PRE-SET POTENTIOMETER
PRE-S
R.M .A.9
R.M .A.9
R.M .A.8
R.M .A.9
R.M.A/9
R.M.A.9
84A ONLY
R.M.A.9
84B ONLY
R.M.A.9
B4B ONLY
R.M.A.9
B4A ONLY
R.M.A.9. B4A
R.M .A.9 B4B
R.M.A.9 B4A
R.M.A.9 B4B
R.M.A.9 B4B
RIO
AAAAA-
A^WSA
RI2
-A 'VW -
f?23
A/W^
R2 A \ fi^5T R2&T R77T
/VVN“ >'W" ■JYV^-' AAA-’'
THE RIGHT IS RESERVED TO ADJUST VALUES OR AMEND THIS CIRCUIT W ITHO UT NOTICE
PART
No.
1177
4408
671
6381
IS2S
671
1177
1271
1271
1271
1175
2736
1272
1175
1272
4419
1175
671
4408
11078
7678
3754
1175
4405
5797
6249
6249
6249
6249
5798
6250
6250
6250
6251
5884
REF.
R34
R35
R36
R37
R38
R39
R40
R4I
R42
R43
R44
R45
R46
DESCRIPTION
RESISTOR
IM ft
2-2M ft
5-I K ri
680K ft
m n
IQOKft
5 I K f t
lOOKft
IK 0
270 f t
100 ft
II 0
390 ft
* WATT
10%
{ WATT
10%
i WATT
* WATT
i WATT
i
* WATT R.M.A.9
i WATT R.M.A.9
a
4 WATT POTENTIOMETER
WATT R.M.A.8
WATT High Stability
I
WATT High Stability
I
WATT High Stability
WATT R.M.A.9
10%
R.M.A.9
R.M.A.9
R.M.A.9
R.M.A.9
R.M.A.9
PART
No.
1171
1180
7496
5024
1171
1270
7496
7628
6911
6896
6106
6414
612
REF.
Cl
C2
C3
C4
C5
C6
C7
C9
CIO
C ll
CI2
CI3
CI4
CI5
CI6
CI7
CI8
CI9
C20
C2I
C22
C23
C24
C25
■F 3-30pF C on cen tric Trimmers
0* t. Paper Tub.
0-MmF
004mF
004mP
0 OImF
00 4 MF
005uf
O'OOlilF 750V. D.C. Moulded Mica.
O OOSuP Moulded Mica
0 005|«P 750V. D.C. Moulded Mica.
__
DESCRIPTION
CAPACITORS
13*5 MpF Variable C ondenser
IdOpF SILVERED MICA
200pF 5% Silvered Mica on B4A
-750pF 5% Silvered Mica on B4B
*330pF 5% Silvered Mica on B4A
uF 350V. D .C .W. Paper Tub.
tp 350V. D.C.W. Paper Tub.
O’CfuF 350V. D.C.W. Paper Tub.
I
0Mr 450V. D.C.W. Electrolytic
350V. D.C.W. Elec. B4A5
lt» F
350V. D.C.W. elec. B4B5
ItliF
350V. D.C .W. Elec. B4A6
32}iF
350V. D.C.W. Elec. B4A5
IftliF
350v. D.C.W . Elec. B4B5
U tf
350v. D.C.W. Elec. B4A6
32uF
Miniature M etallized Paper
Miniature Metallized Paper
Miniature Metallized Paper
M/M 10% Hunts L6/4
Miniature Metallized Paper
Moulded Mica
Moulded Mica
200pF
Miniature M etallized Paper
20% Ceram ic Dlic. B4A
'Z
a©% CERAMIC DISC.
\ w
1
Mica on B4B
Mica on B4A
Mica on B4B
(MLW) H994
B4B ONLY
B4A6
B4A6
ONLY
PART
No.
1620
7368
7492
7493
7577
7489
7579
7488
7578
10770
7491
7491
7491
5921
7014
7014
7014
7014
7014
7014
7485
7485
7485
5803
7485
1524
7131
1524
7131
7493
7850
4274
4274
REF.
Oscillator Coil. 100-300 kc/s B4A
LI
Oscillator Coil. 30-100 kc/s B4B
Oscillator Coil. 300-1000 kc/s B4A
L2
Oscillator Coil. 100-300 kc/s B4B
Oscillator Coil. 1-3 Mc/s B4A
L3
Oscillator Coil. 300-1000 kc/s B4B
Oscillator Coil. 3-10 Mc/s B4A
L4
Oscillator Coil. 1-3 Mc/s B4B
Oscillator Coil. 10-30 Mc/s B4A
L5
Oscillator Coil. 3-10 Mc/s B4B
Oscillator Coil. 30-80 Mc/s B4A
L6
Oscillator Coil. 10-30 Mc/s B4B
R.F. Filter Inductance B4A
L7
R,F. Filter Inductance B4B
R.F. Filter Inductance B4A
L8
R.F. Filter Inductance B4B
L9
L.T. R.F. CHOKE
L.T. R.F. CHOKE
LI0
MAINS R.F. CHOKE
LI I
DUMMY AERIAL INDUCTANCE
LI2
VI
ECC9I (6J6)
6SN7 GT.
V2
V3
6X5GT
Silicon Crystal Rectifier. B.T.H.
XI
Crystal Diode GE. W estinghouse WG5B
X3-6
SIA/D
R.F. Switch
A.C. MODULATION SWITCH
52
Meter Switch DP/DT. Bulgin S270
53
ATTENUATOR SWITCH
54
MAINS SWITCH
55
Pilot Lamp Type MES 11 mm. 6.5v.
PLI
MODULATION TRANSFORMER
TI
MAINS TRANSFORMER
T2
INPUT 110-210-230-250 V.
40-100 cIs on B4A5 & B4B5
INPUT 117V. 25-60 c/s on B4A6
I00mA METER
Ml
DESCRIPTION
Type CS2A
CHR/P
C 4 6 63 • ISSUE, 9
PART
No.
RF 541
RF 551
RF 542
RF 541
RF 543
RF 542
RF 544
RF 543
RF 545
RF 544
RF 545
CI23
CI24
C121
CI23
C95
C95
C83
7034
5873
3150
7110
11538
8332
7382
6846
A29
6718
879
MT3I0
MT309
MT 312
5880
CIRCUIT DIAGRAM T . P I . A
The voltages shown on the circuit diagram
were measured on an " Avo m eter ” model
8 [20,000 ohms per vollt d.c.]
The 3 Mc/s r.f. measurem ent was taken on
the advance “ A dvac" a.c, m illivoltmcter.
All the measurem ents w ere taken with
gen erator set to 3 Mc/s with modulation
switched on and set to a depth of 50%
Page 6
MAINS VOLTAGE
The B4A and B4B are normally despatched with the mains trans
OPERATING
FREQUENCY
former set to operate at 220 to 240V, a.c. (40-100 c/s). For other
supply voltages, withdraw the instrument from its case by unfastening
the fixing screws round the edge of the front panel, unsolder the
lead on the 230-volt tag on the mains transformer, and re-solder it
to the appropriate tapping point.
With the correct mains voltage applied, the instrument can be
switched on. Warming up takes only a few minutes.
Any frequency in the range of the instrument can be selected to an
accuracy of ± 1 % by means of directly calibrated scales and a band
selector switch. A linearly calibrated scale with vernier is also
provided to enable high accuracy of re-setting to be obtained. If a
A
given frequency is to be required on a number of occasions, the
vernier scale reading should be noted, and when re-setting, the
instrument should be set to the reading. Fine frequency adjustment
is easily obtained using the double slow motion drive which gives a
ratio o f 25 : 1. When desired, however, the knob on the main dial
may be used to swing from one end of the band to the other.
R.F. OUTPUT
The r.f. output into a 75 ohm load, or available at the 37 ohm
socket of the terminating pad type TPIA, is variable between ljiV
and lOOmV by means of a continuously variable control and a 5
position 20 dB per step attenuator. The output voltage is monitored
at the input to the attenuator (after the continuously variable control)
by a crystal voltmeter with an open scale. This method avoids the
frequency errors inherent in the continuously variable control.
Page 7
INSTRUCTIONS
To read the output voltage, press the switch marked SET MOD-
CW into the CW position. The output voltage available into a
75 ohm load or at the 37 ohm socket of the TPIA is the product of
the reading of the meter, which is calibrated 0 to 15, and the setting
of the step attenuator marked Xl|iV, XlOfiV, XIOOjiV, XlmV,
XIOmV.
For accurate reading at the higher frequencies the output line must
be correctly terminated, but up to about 5 Mc/s the output voltage
may be doubled with slight error by omitting the termination.
When using the 10 ohm socket or the dummy aerial socket on the
termination pad, the output voltage is one-tenth of the indicated
output.
INTERNAL MODULATION
The signal can be internally modulated from 0 to 80% at 400 c/s.
With the modulation switch set to INT MOD, modulation depth is
varied by the MOD control. The modulation depth is monitored
when the SET MOD-CW switch is set to MOD. Since the modulation
depth is determined by the ratio of modulating voltage to h.t. voltage,
it is advisable to maintain accurately the mains input voltage to the
generator.
EXTERNAL MODULATION
The signal can be modulated from an external source up to 80%,
the acceptable modulation frequencies being 10 c/s to 30 kc/s into the
B4A and 10 c/s to 10 kc/s into the B4B. The upper modulation
frequency is limited to 1 /30th of the carrier frequency. It is desirable
that the mains input voltage is accurately maintained so that the
metering is accurate. The external modulating signal is injected into
the A.F. socket with the modulation switch set to EXT MOD.
Input impedance is high and a d.c. blocking capacitor is incor
porated.
Page 8
AUDIO FREQUENCY OUTPUT
A signal is available at the A.F. socket from the internal 400 c/s
modulating oscillator when the modulating switch is at INT MOD.
Approximately 0 to 10 volts is available into 600 ohms, varied by
the MOD control. This output is taken from the secondary winding
of the modulation transformer and has a low d.c. resistance to
earth.
METER ADJUSTMENT
The monitoring circuits are correctly adjusted before leaving the
factory. If after long use they become inaccurate, they can be
corrected by means of the preset potentiometers provided. These
potentiometers are situated just under the mains transformer.
The most accurate method of adjusting the r.f. metering is by the
use of a calibrated crystal voltmeter with input impedance of 75
ohms, which will indicate 100mV. With lOOmV into the calibrating
meter, the instrument meter reading is adjusted to read 10 (XIOmV)
An alternative is to adjust the metering at a low r.f. frequency,
preferably about 1 Mc/s. The output into a valve voltmeter should
be 200mV when the instrument reads lOOmV.
The modulation depth indication may be adjusted using an oscillo
scope. Care should be taken to avoid errors due to the distortion of
the oscilloscope amplifiers. It may be preferred to use the cathode
ray tube plates directly, obtaining the deflecting voltage by loose
coupling to the tuning capacitor.
Part No. 8347
THE L. & W. PRESS
Page 9
SIGNAL GENERATOR—TYPE MAC
Amendments to Handbook
Page 2 Reference to 75 ohms impedance should read 50 ohms.
Page 2 Reference to 37 ohms impedance should read 25 ohms.
Page 3 Termination Pad type TPIA is replaced by TP1C.
Page 3 RF lead PL5 is replaced by PL43.
Page 3 AF lead PL18 is replaced by PL18/C.
Circuit Diagram R43 is 91 ohms PN.372
R23 is 162 ohms PN.362
R24 is 490 ohms PN.365
R25 is 490 ohms PN.365
R26 is 490 ohms PN.365
R27 is 490 ohms PN.365
R28 is 56 ohms PN.364
R29 is 62 ohms PN.363
R30 is 62 ohms PN.363
R31 is 62 ohms PN.363
R32 is 82 ohms PN.6251
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