OKI Semiconductor
ML7021
Echo Canceler
FEDL7021-03
Issue Date: Jun. 1, 2005
GENERAL DESCRIPTION
The ML7021 is an improved version of the MSM7602 with the reduced cancelable echo delay
time and additional 2100Hz tone detection function.
The ML7021 is a low-power CMOS 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.
The ML7021 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 ML7021 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 a simplified and efficient echo
canceler configuration.
FEATURES
• Tone disable function
• Cancelable echo delay time:
For a single chip: 8 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:
28-pin plastic SSOP (SSOP28-P-485-0.65-K) (Product name : ML7021MB)
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