Philips SPENDEX 40 Maintenance Manual page 20

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4.4.6 Vocoder program memory
This program memory (32,768 x 8 bit) contains the firmware for the
vocoder controller.
4 . 4 . 7 Vo c o d e r d a t a m e m o r y
The vocoder data memory consists of a 2048 x 8 bit memory. The
vocoder controller uses this memory for the temporary storage of
data. Part of the data memory, the analysis part, is used for the
storage of frames on the transmitting side. Another part, the
synthesis part, is used for the storage of frames on the receiving
side.
4 . 4 . 8 Vo c o d e r a d d r e s s d e c o d e r
This address decoder takes care of the addressing of the various I/O'
and memory locations within the vocoder.
4 . 4 . 9 T i m i n g c i r c u i t
The timing circuit generates several timing signals for the control
of the various circuits within the vocoder.
4 . 4 . 1 0 M a s t e r c l o c k s i g n a l g e n e r a t o r
The master clock signal generator produces clock signals of 8192 kHz,
4096 kHz, 2048 kHz and 512 kHz. The clock signals control various
circuits within the vocoder. The 4096 kHz clock signal also controls
the comsec controller on the controller board and the key generators
on the key generator board.
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