msm7617 Oki Semiconductor, msm7617 Datasheet - Page 25

• Manufacturer Part Number: msm7617
• Description: 2-channel Echo Canceler
• Manufacturer: Oki Semiconductor

¡ Semiconductor
NOTES ON USE
1. Set echo return loss (E. R. L) to be attenuated. If the echo return loss is set to be amplified, the
2. Set RIN input so that there is not excessive input (above 0 dBm0) from the PCM CODEC. Echo
3. Applying the tone signals to this echo canceler will decrease echo attenuation.
4. For changes in the echo path (retransmit, circuit switching during transmission, and so on),
5. If a clock is not input after power is applied, then the internal circuits will not stabilize,
6. Always reset after power is applied or power-down is released.
7. When the device is used as an acoustic echo canceler, equipment noise and environment noise
echo cannot be canceled. (Refer to the "E. R. L vs Echo Attenuation" characteristic graph.)
When the echo return loss is amplified, adjust the input level to be attenuated by setting the
mode with the SA pin. If the level from the SA pin is too low by setting the mode with the SA
pin, then amplify the output level by setting the mode with the SG pin.
cancellation is not possible with excessive input. (Refer to the "RIN vs Echo Attenuation"
characteristic graph.)
Recommended input levels are –10 to –20 dBm0. If there is a possibility of excessive input,
then set GC mode or 6LR mode with the RGC pins.
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 each time.
possibly damaging the device.
When power is applied, set the PWDWN pin to "H" and input the basic clock.
If the device is put into PWDWN immediately after power has been applied, be sure to input
10 or more clocks of the basic clock before setting to the power down mode.
For power-on reset operation, an external oscillator may require a certain setting time after
powered on. Allow 10 ms for a reset time after the oscillator has settled.
from the microphone amp may be amplified, and echo attenuation may be below 30 dB.
MSM7617
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