Marconi TF 2002AS Generator
Producent:
Model:
TF 2002AS
Data:
1971
Kategoria:
Grupa:
Opis:
Signal Generator

Informacja

FEATURES This all transistorized signal Generator gives high quality a.m. outputs from 10 kHz to 72 MHz; f. m. outputs are provided between 100 kHz and 72 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 of note is the low leakage which will be found of advantage for tests on receivers that have an internal ferrite rod aerial. The instrument is rugged yet compact in design and is fitted with a removable lid to protect the front panel, and to provide stowage for the Accessories. Permeability tuning of the Oscillator and output modules provides the low impedance required by the transistor circuitry and 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, which 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. Carrier shifts can also be produced by externally applied d. c. 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 standardized against the crystal check points by means of two independent trimmer controls. The whole system can provide a degree of scale expansion equivalent to a total scale length of over 3/4 of a mile. Up to 2 V source e. m. f. can be obtained with 100% modulation over most of the range. 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 fi 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 such purposes as driving a Counter to monitor the signal Generator frequency. Internal a. m. up to 100% is produced by a continuously timed Oscillator covering the audio band. This means that the Generator can be used for comprehensive 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 thé 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 Oscillator provides frequency modulation, and deviation is monitored directly on the modulation meter. Three ranges of deviation are provided for each carrier range above 100 kHz. External frequency control terminals can be used to provide external frequency shift, phase modulation or, with the aid of a phase discriminator, phase locking of the carrier for maximum stability. External amplitude control terminals can be used for level control or programming and very low frequency modulation without phase shift. 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 output circuits can be withdrawn and operated via an extension lead.

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Serwis i User Manual
Typ ręczny:
Serwis i User Manual
Strony:
84
Rozmiar:
3.63 Mbytes (3810078 Bytes)
Język:
english
Rewizja:
Ręczny ID:
Data:
1971 08 01
Jakość:
Skanowany dokument, czytając częściowo źle, nie częściowo czytelny.
Data przesłania:
2019 01 06
MD5:
5df94cfca78439edc6fe086b0cf6e9e9
Pobrane:
397

Informacja

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