FEDL7731-02-04
1
Semiconductor
MSM7731-02
Dual Echo Canceler & Noise Canceler with Dual Codec for Hands-Free
This version: Jan. 2000
Previous version: Jan. 2000
GENERAL DESCRIPTION
The MSM7731 is an IC device developed for portable, handsfree communication with built-in line echo canceler,
acoustic echo canceler, and transmission signal noise canceler. Built-in to the voice signal interface is a linear
CODEC for the analog interface on the acoustic-side, and a linear CODEC for the analog interface on the line-side.
On the line-side, in addition to the analog interface, there is also a
µ-law
PCM/16-bit linear digital interface.
Equipped with gain and mute controls for data transmission and reception, a
µ-law
PCM/16-bit linear digital
interface for memo recording and message output, and transfer clock and sync clock generators for digital
communication, this device is ideally suited for a handsfree system.
FEATURES
• Single 3 V Power Supply Operation (2.7 to 3.6 V)
• Built-in 2-channel (line and acoustic) echo canceler
Echo attenuation
: 35 dB (typ.) for white noise
Cancelable echo delay time :
Line echo canceler + acoustic echo canceler
Acoustic echo canceler only
• Built-in transmission signal noise canceler
Noise attenuation
: 17 dB (typ.) for white noise
40 dB (typ.) for single tone
• Built-in 2-channel CODEC
Synchronous transmission and reception enables full duplex operation
• Built-in analog input gain amp stage (max. gain = 30 dB)
• Analog output configuration : Push-pull drive (can drive a 1.2 kΩ
load
)
• Built-in transmit slope filter
• Digital interface coding formats
: µ-law PCM, 16-bit linear (2's complement)
• Digital interface sync formats
: Normal-sync, short-frame-sync
• Built-in digital transmission clock generators
Sync clock (SYNC)
: 8 kHz output
Transmission clock (BCLK)
: 64 kHz output (µ-law PCM)/128 kHz output (16-bit linear)
• Digital transmission rate
External input
: 64 to 2048 kbps
Internal generation
: 64 kbps (µ-law PCM)/128 kbps (16-bit linear)
• Fixed digital interface sync clock (SYNC) enables automatic power-down
• Master clock frequency
: 19.2 MHz
Compatible with crystal oscillator and crystal
• Low power consumption
Operating mode
: typ. 35 mA (when V
DD
= 3.0 V in a silent mode)
Power down operation
: typ. 0.02 mA (when V
DD
= 3.0 V in a silent mode)
• Control by both the serial microcomputer interface and parallel port is possible
• Transmit/receive mute function, transmit/receive programmable gain setting
• Package
: 64-pin plastic QFP (QFP64-P-1414-0.80-BK)(Product name: MSM7731-02GA)
: Tlined = 27 ms (max.)
Tacoud = 59 ms – Tlined (max.)
: Tacoud = 59 ms (max.)
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