OKI Semiconductor

FEDL7021-03

Issue Date: Jun. 1, 2005

ML7021

Echo Canceler

1

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)