Thales NSS 100S-1 Component Maintenance Manual With Illustrated Parts List page 49

(7) AGC Loop
The automatic gain control (AGC) is designed to slave the amplitude of
the A/D converter input signal to a programmable instruction.
An AGC (DAC 0/11) digital signal is generated by the Asic T100 circuit.
It is applied to the input of a digital/analog converter; this converter
delivers the TCAG analog signal applied to the IF amplification stage
which makes it possible to command a gain with a dynamic range of 80 dB
in steps of less than one decibel.
(8) Signal pre-processing
Signal IF is pre-processed by the Asic T100 circuit; its other functions
are:
- Clock reception and generation
- Overflow counter
- Programmable local oscillator
- µp bus interface,
- AGC signal generation.
(a) Signal pre-processing
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COPYRIGHT SEXTANT Avionique 1995
c
The document reference is online, please check the correspondence between the online documentation and the printed version.
COMPONENT MAINTENANCE MANUAL
This function involves performing the following operations:
- Reception of 4 bits ( CAN 0/3) from the A/D converter,
- Sampling of 4 bits and the OVLF overflow bit on the 100 MHz fre-
quency, by the HT100 clock; parallelization on 4 channels,
- Transcoding: saturation and binary coding complemented signed
at 2,
- Transmission of the AGC input signals
- Band pass filtering
- Change of frequency to single side band (output on 7 bits)
- Transcoding of 7 bits to 4X4 bits (ACQ 0/15) and transmission to
the CPU PCB of the pre-processed satellite signal.
C17004
34-57-96
Page 25a
OCT 16/95