E2U0037-28-82
¡ Semiconductor
MSM7602
¡ Semiconductor
Echo Canceler
This version: Aug. 1998
MSM7602
Previous version: Nov. 1996
GENERAL DESCRIPTION
The MSM7602 is an improved version of the MSM7520 with the same basic configuration. The
MSM7602 uses a 19.2 MHz clock frequency to meet PHS, the 3 V power supply (2.7 V to 5.5 V),
and compact packaging. Also, this device adds the howling detecter control pins and main clook
output pins. (See the Appendix)
The MSM7602 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 cancels the acoustic echo between the loud
speaker and the microphone which occurs during hands free communication such as with a
cellular phone or a conference system phone.
When used as a line echo canceler, the device cancels the line echo caused by impedance
mismatching in a hybrid.
In addition, the MSM7602 makes possible a quality conversation by controlling the noise level
and preventing howling with howling detector, double talk detector, attenuation function, and
a gain control function. The devise also controls the low level noise with a center clipping
function.
Further, the MSM7602 I/O interface supports
m-law
PCM . The use of a single chip CODEC, such
as the MSM7566/7704 (3 V) or MSM7543/7533 (5 V), allows an economic and efficient echo
canceler configuration.
FEATURES
• Handles both acoustic echoes and telephone line echoes.
• Cancelable echo delay time:
MSM7602-001 ................. For a single chip: 23 ms (max.)
MSM7602-011 ................. For a cascade connection (can also be used for a single chip)
Master chip: 23 ms (max.)
Slave chip: 31 ms (max.)
Cancelable up to 209 ms (1 master plus 6 slaves)
For a single chip: 23 ms (max.)
• Echo attenuation
: 30 dB (typ.)
• Clock frequency
: 19.2 MHz
External input and internal oscillator circuit are provided.
• Power supply voltage : 2.7 V to 5.5 V
• Package options:
28-pin plastic SSOP (SSOP28-P-485-0.65-K) (Product name : MSM7602-001GS-K)
56-pin plastic QFP
(QFP56-P-910-0.65-2K) (Product name : MSM7602-011GS-2K)
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