MSM7603 Datasheet, PDF (1/20 Pages) OKI electronic componets – Echo Canceler

E2U0064-18-82
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MSM7603/7603B
Echo Canceler
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GENERAL DESCRIPTION
The MSM7603/7603B is an improved version of the MSM7602 with basically the same
configuration, and offers twice the cancelable echo delay time of the MSM7602.
The MSM7603B I/O interface allows switching between m-law PCM and A-law PCM.
The MSM7603/7603B is a low-power CMOS IC device for canceling echo (in an acoustic system
or telephone line) generated in a speech path.
Echo is canceled, in digital signal processing, by estimating the echo path and generating a
pseudo echo signal.
When used as an acoustic echo canceler, the device can cancel the acoustic echo, between the loud
speaker and the microphone, which occur during hands free communication such as on a cellular
phone or a conference system phone.
When used as a line echo canceler, the device can cancel the line echo which returns due to
impedance mismatching in a hybrid.
In addition, a quality conversation is made possible by controlling the level and by preventing
howling through a howling detector, double talk detector, attenuation function and a gain
control function, and by controlling the low level noise by means of a center clipping function.
The use of a single chip codec, such as the MSM7704 (3 V) and MSM7533 (5 V), allows an economic
and efficient echo canceler to be configured.
FEATURES
• Can handle both acoustic and telephone line echoes.
• Switchable between m-law PCM and A-law PCM interfaces. (MSM7603B)
• Cancelable echo delay time:
MSM7603B-003 .............. 55 ms (max.)
• Echo attenuation
: 30 dB (typ.)
• Clock frequency
: 19.2 MHz
17.5 MHz to 20 MHz (when internal sync signal not used)
• Power supply voltage : 2.7 V to 5.5 V
• Package:
28-pin plastic SSOP (SSOP28-P-485-0.65-K) (Product name : MSM7603-003GS-K)
(Product name : MSM7603B-003GS-K)
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