Description

The Quad ADPCM Transcoder is a low power, CMOS device capable of four encode and four decode functions per frame. Four 64 kbit/s PCM octets are compressed into four 32, 24 or 16 kbit/s ADPCM words, and four 32, 24 or 16 kbit/s ADPCM words are expanded into four 64 kbit/s PCM octets. The 32, 24 and 16 kbit/s ADPCM transcoding algorithms utilized conform to ITU-T Recommendation G.726 (excluding 40 kbit/s), and ANSI T1.303 - 1989.

Features

• Full duplex transcoder with four encode channels and four decode channels

• 32 kb/s, 24 kb/s and 16 kb/s ADPCM coding complying with ITU-T (previously CCITT) G.726 without 40 kb/s), and ANSI T1.303-1989

• Low power operation, 25 mW typical

• Asynchronous 4.096 MHz master clock operation

• SSI and ST-BUS interface options

• Transparent PCM bypass

• Transparent ADPCM bypass

• Linear PCM code

• No microprocessor control required

• Simple interface to Codec devices

• Pin selectable µ−Law or A-Law operation

• Pin selectable ITU-T or signed magnitude PCM coding

• Single 5 volt power supply

Applications

• Pair gain

• Voice mail systems

• Wireless telephony systems