Equipment information

Marconi TF 2002B Generator
Model TF 2002B
Date 1979
Category Measurement instruments
Group Generator
Description Signal Generator

The TF 2002B gives high quality a. m. outputs from 10 kHz to 88 MHz and f. 
m. outputs between 100 kHz and 88 MHz. It has very high frequency 
discrimination which, coupled with the good stability reached soon after 
switching on, makes it particularly suitable for setting up and adjusting crystal 
controlled receivers where the channel spacing is small and the i. f. pass 
band must have an accurate absolute setting. Another feature is the low 
leakage which will be found of advantage for tests on receivers that have an 
internal ferrite rod aerial.
Permeability tuning of the Oscillator and output filter modules enables the 
complete range to be covered in only eight bands. The hand calibrated near-
logarithmic tuning scale is displayed in a continuous zig-zag pattern, with 
scales running alternately left and right. This cuts out much of the tedium 
usually associated with tuning about the band-change frequencies. Above 
100 kHz (carrier frequency) direct reading incremental tuning gives high 
discrimination. Frequency control can also be achieved by externally applied 
d. c. or by the use of Digital Synchronizer TF 2170B.
Crystal check points are available at intervals of 1 MHz, 100 kHz or 10 kHz. 
Subsidiary check points can be switched in at 1 kHz relative to each of the 
main points. The dial of the incremental control can be adjusted to high 
accuracy against the crystal check points by means of two independent 
trimmer controls.
Up to 1 V p. d. can be obtained with 100% modulation over all the range and 
up to 2 V p. d. is available with c. w. or f. m. outputs. Output is controlled by 
cam operated 20 dB and 1 dB step attenuators with voltage and dB 
calibration in terms of p. d. across a 50 Î2 load or of source e. m. f. ; 
interpolation between
attenuator steps is provided by the carrier level control and meter. Automatic 
level control holds the output constant against frequency or range changing.

An auxiliary unmodulated output is available for driving a Counter or the 
Digital Synchronizer TF 2170B.

Internal a. m. up to 100% is produced by a continuously tuned low distortion 
Oscillator covering a frequency range 20 Hz to 20 kHz. This means that the 
Generator can be used for r. f., i. f. and a. f. response measurements on a 
receiver with no additional equipment other than a receiver output meter. 
The Oscillator output is available for external use at terminals situated at the 
rear of the instrument. Envelope negative feedback ensures a good 
modulation quality up to at least 80%, and modulation depth is independent 
of both carrier tuning and carrier level.
The continuously variable a.f. Oscillator also provides frequency modulation, 
and deviation is indicated directly on the modulation meter. Three ranges of 
deviation are provided for each carrier range above 200 kHz.

External frequency control terminals can be used to provide dynamic sweep 
measurements (with or without internal AM), FSK, phase modulation or digital 
f. m.
External amplitude control terminals can be used for level control 
programming or modulation at a very low frequency without phase shift.

Silicon devices are used throughout and emphasis has been placed on 
accessibility despite the compact structure and thorough screening. The 
instrument has three major horizontal sections; the centre one containing the 
oscillators and other circuits can be withdrawn and operated without 
electrical disconnection.

These manuals are available for the above equipment:

Manual Type Service and User Manual Marconi-11689-Manual-Page-1-Picture
Pages 139
Size 11.04 Mbytes (11571631 Bytes)
Language english
Date 01 May 1979
Quality Scanned document, all readable.
Upload date
MD5 9b97e1217043640891d2ca88691d67bb
Downloads 53 since 06 January 2019

1.1	Features  ... 	10


2.1	Introduction  ... 11

2.2	Controls and connectors (supply and

tuning  ... 	11

2.4	Controls and connectors (rear panel)	11

2.5	Fuses  ... 11

2.6	AC supply cable  ... 11

2.7	Battery operation ... 	18

2.12	Setting output  ... 	29

2.19	General notes on connecting Oscilloscope

for dynamic displays  ... 	

Decibel conversion tables  ... 	35 Simplified block diagram  ... 43

4.1	Introduction  ... 	45

4.4	Preliminary checks  ... 51

4.5	Test equipment  ... 51

4.6	Circuit performance  ... 51


5.1	Introduction  ... 56

5.2	Fault finding  ... 56

5.3	Additional information  ... 	67

Index to units • • • • • • • • ■ • • •	81


Circuit notes  ...  ______101

Fig. 7.18 Power unit and regulators .,.	101

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