MT9125 Datasheet, PDF (1/16 Pages) Mitel Networks Corporation – CMOS Dual ADPCM Transcoder

CMOS MT9125
®
Dual ADPCM Transcoder
Preliminary Information
Features
• Dual channel full duplex transcoder
• 32 kbit/s and 24 kbit/s ADPCM coding,
• compatible to G.721 & and G.723 (1988) and
ANSI T1.303-1989
• Low power operation, total 25mW typical
• Asynchronous 4.096 MHz master clock
operation
• Transparent ADPCM bypass capability
• Serial interface for both PCM and ADPCM data
streams
• ST-BUS interface supported
• Pin selected µ-law or A-law operation
• Pin selected CCITT or sign-magnitude PCM
coding
• Single 5 volt power supply
• Optional reset value (CCITT Table 3/G.721)
capability
Applications
• Pair gain
• Voice mail systems
• Wireless set base stations
ISSUE 3
Ordering Information
August 1993
MT9125AE
MT9125AP
24 Pin Plastic DIP
28 Pin PLCC
-40 to +85°C
Description
The Dual-channel ADPCM transcoder is a low
power, CMOS device capable of two encoder
functions and two decoder functions. Two 64 kbit/s
PCM channels are compressed into two 32 kbit/s
ADPCM channels, and two 32 kbit/s ADPCM
channels are expanded into two 64 kbit/s PCM
channels. The 32 kbit/s ADPCM transcoding
algorithm utilized conforms to CCITT Recom-
mendation G.721 and ANSI T1.303-1989. The
device also supports a 24 kbit/s (three bit word)
algorithm (CCITT/G.723).
Switching, on-the-fly, between 32 kbit/s and 24
kbit/s, is possible by toggling the appropriate Mode
Select (MS1-MS4) control pins.
C2o
BCLK
F0i
MCLK
ENS
ADPCMi
ADPCMo
ENA
Timing
ST-BUS
Converter
ADPCM
I/O
Transcoder 1
Transcoder 2
PCM
I/O
Control Decode
EN1
EN2
DSTo
DSTi
ENB1
ENB2
VDD VSS PWRDN IC
MS1 MS2 A/µ FORMAT MS3 MS4
Figure 1 - Functional Block Diagram
8-17