Digital Voice Systems VC-20-ATC-10B Especificaciones descargar pdf (Pagina 25)

FAA20 Embedded NEXCOM Vocoder

Board Manual

This manual has been prepared for the Federal Aviation Administration.

FA100-00107 (March 2004) – Rev 1.0.0 Page 19

5.1.4 TEST Mode

The TEST mode supports FAA20 integration testing. It is especially

designed to allow back-to-back FAA20 unit connection (requires adapter

board). In this mode, the most of the automatic external vocoder controls

are disabled to allow manual control of these items. Specifically, the

following vocoder signal conductors are ignored: VAD, GO, TMRX.

5.2 Interfaces

5.2.1 AUD Interface

There are two physical connections to the audio interface: a DIN

connection and a jack connection. These signals are internally wired

together. If the DIN connector is used as the primary connection interface,

the audio jack can still be used to monitor audio signals.

5.2.2 PCM Interface

The digital PCM interface supports serial, time division multiplexed (TDM)

transmission of digital voice data. A common clock, SCLK, is used for both

data transmission and reception. Frame synchronization signal, FSX and

FSR, enable the transmission and reception of a digital data word,

respectively. Figure 6 provides a signal timing diagram.

Figure 6: PCM Interface Timing Diagram

The SPRDY signal is a vestige of the VC20 digital PCM interface. While

the VC20 required PCM signals to be tri-stated until the unit is ready, the

SCLK

FSX

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

FSR

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

SPRDY

Data clocked out with rising edge of SCLK

FSX sampled on falling edge of SCLK

Data

sampled on falling

edge of SCLK

FSX sampled on falling edge of SCLK

SPRDY is al

ways high

1 2 ... 20 21 22 23 24 25 26 27 28 29 30 ... 108 109

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Digital Voice Systems VC-20-ATC-10B Especificaciones Pagina 25