Digital Voice Systems VC-20-ATC-10B Especificações descarregar pdf (Página 9)

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 3

2.0 GENERAL DESCRIPTION

2.1 Overview

The FAA20 is a 4” x 5” embedded card designed to provide DVSI 4.8 kbps

AMBE+ Vocoder functionality. The card is based on the TMS320C5416

Digital Signal Processor (DSP) manufactured by Texas Instrument. Figure

1 is a photograph of the FAA20.

Figure 1: FAA20 Vocoder Board

The voice interfaces for the FAA20 include the PCM serial audio and

compressed nibble interface (available on the DIN connector) as well as an

analog voice interface (available on computer audio jacks). Voice data can

also be transferred (in ASCII format) over the FAA20 RS-232 serial ports.

The FAA20 was designed as a VC20 upgrade. The VC20 is an embedded

board available from DVSI that implements the original floating point

version of the AMBE+ vocoder algorithm. After the release of the VC20,

DVSI developed a fixed point version of the algorithm that has bit exact

properties, i.e. a known input voice vector generates a known output vector.

The FAA20 was produced to use this updated algorithm within NEXCOM

prototyping equipment and to more easily support truncated timing mode.

DB9F

Connector

(COM2)

DIN

Connector

DB9F

Connector

(COM1)

Audio

Connectors

Switches

LEDs

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Digital Voice Systems VC-20-ATC-10B Especificações Página 9