MSM7731-02 OKI [OKI electronic componets], MSM7731-02 Datasheet - Page 35

• Manufacturer Part Number: MSM7731-02
• Description: Dual Echo Canceler & Noise Canceler with Dual Codec for Hands-Free
• Manufacturer: OKI [OKI electronic componets]

B1
B0
1 Semiconductor
Attenuator control
This bit selects the attenuation of the ATT function to prevent howling by means of attenuators (ATTsA,
ATTrA) provided in the RinA input and SoutA output of the acoustic echo canceler.
If input is only to RinA, the ATT for SoutA (ATTsA) is activated. If input is only to SinA, or if there is
input to both SinA and RinA, the ATT for RinA input (ATTrA) is activated. The ATT value of each
attenuator is approximately 6 dB or 12 dB. This function is valid when the ATHR pin is in the normal
mode. Because this bit is read in synchronization with the rising edge of the SYNC signal, hold the data
in the bit for 250 µs or longer.
This bit is internally ORed with the AATT pin.
Gain controller control
This bit turns ON or OFF the gain control function to control the RinA input level and prevent howling
by means of a gain controller (GainA) provided in the RinA input of the acoustic echo canceler.
The gain controller adjusts the RIN input level when it is –10 dBm0 or above, and it has the control
range of 0 to –8.5 dB. This function is valid when the ATHR pin is in the normal mode. Because this bit
is read in synchronization with the rising edge of the SYNC signal, hold the data in the bit for 250 µs or
longer.
This bit is internally ORed with the AGC pin.
1: ATT 12 dB
1: GC OFF
0: ATT 6 dB
0: GC ON
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