msm7708-02 Oki Semiconductor, msm7708-02 Datasheet - Page 24

• Manufacturer Part Number: msm7708-02
• Description: Serial Register Interface Adpcm Codec For Telephone Recording
• Manufacturer: Oki Semiconductor

¡ Semiconductor
(3) CR2 (PCM CODEC Operation Mode Settings and Transmit/Receive Gain Adjustment)
The above gain settings table shows the transmit/receive voice signal gain settings and the
transmit side gain settings for DTMF tones and other tones. Tone signal transmission is enabled
by CR4 - B6 (discussed later), and the gain setting is set to the levels shown below.
For example, if the transmit gain set value is set to +8 dB (B7, B6, B5, B4) = (0, 1, 0, 0), then the
following tones appear at the PCMSO pin.
However, the gain of the receive side tone and the gain of the side tones (path from transmit side
to receive side) are set by the CR3 register.
CR2
Initial value
B7
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
DTMF tones (low group): ................................. –16 dBm0
DTMF tones (high group) and other tones: ... –14 dBm0
DTMF tones (low group): ................................. –8 dBm0
DTMF tones (high group) and other tones: ... –6 dBm0
B6
0
1
0
0
1
1
1
1
0
0
0
0
1
1
1
1
B7, B6, B5, B4: .... Transmit side signal gain adjustment (refer to Table 2)
B3, B2, B1, B0: .... Receive side signal gain adjustment (refer to Table 2)
B5
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
GAIN3
B7
TX
0
B4
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Table 2 Transmit/Receive Gain Settings
Transmit Side Gain
GAIN2
B6
TX
0
–16 dB
–14 dB
–12 dB
–10 dB
+10 dB
+12 dB
+14 dB
–8 dB
–6 dB
–4 dB
–2 dB
+2 dB
+4 dB
+6 dB
+8 dB
0 dB
GAIN1
B5
TX
0
GAIN0
B4
B3
TX
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
B2
0
1
0
0
1
1
1
1
0
0
0
0
1
1
1
1
GAIN3
B3
RX
0
B1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
GAIN2
B0
B2
RX
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
Receive Side Gain
GAIN1
B1
RX
0
MSM7708-02
–16 dB
–14 dB
–12 dB
–10 dB
+10 dB
+12 dB
+14 dB
–8 dB
–6 dB
–4 dB
–2 dB
+2 dB
+4 dB
+6 dB
+8 dB
0 dB
GAIN0
24/38
B0
RX
0