MSM7620 データシートの表示（PDF） - Oki Electric Industry

部品番号

コンポーネント説明

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MSM7620

Echo Canceler

Oki Electric Industry 

¡ Semiconductor

MSM7620

NOTES ON USE

1. Set echo return loss (ERL) to be attenuated. If the echo return loss is set to be

amplified, the echo can not be eliminated.

Refer to the characteristics diagram for ERL vs. echo attenuation quantity.

2. Set the level of the analog input so that the PCM CODEC does not overflow.

3. The recommended input level is –10 to –20 dBm0. Refer to the characteristics

diagram for the RIN input level vs. echo attenuation quantity.

4. Applying the tone signal to this echo canceler will decrease echo attenuation. If the

tone signal is input to the SIN pin during the time that a signal is input to the RIN

pin, this echo cancceler operates faultily.

A signal must be input to either the RIN pin or the SIN pin. The ADP or HCL pin

must be driven at "H" if the tone signal is input to the SIN pin during the time that

a signal is input to the RIN pin.

5. For changes in the echo path (retransmit, circuit switching during transmission, and

so on), convergence may be difficult.

Perform a reset to make it converge.

If the state of the echo path changes after a reset, convergence may again be difficult.

In cases such as a change in the echo path, perform a reset when possible.

6. When turning the power ON, set the PWDWN pin to "1" and input the basic clock

simultaneouly with power ON.

If powering down immediately after power ON, be sure first input 10 or more clocks

of the basic clock.

7. After powering ON, be sure to reset.

8. After the power down pin is changed to a "1" from a "0", be sure to reset.

9. If this canceler is used to cancel acoustic echoes, an echo attenuation may be less

than 30 dB.

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