
TCM4400E
GSM/DCS BASEBAND AND VOICE A/D
AND D/A RF INTERFACE CIRCUIT
SLWS082A – JULY 1999 – REVISED MARCH 2000
52
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
PRINCIPLES OF OPERATION
Table 18. Uplink PGA Gain
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1
0
1
1
1
–11 dB
1
1
0
0
0
–10 dB
1
1
1
0
0
0
1
1
1
–9 dB
–7 dB
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1
1
0
1
0
–8 dB
1
0
0
0
1
1
0
1
1
1
–1 dB
1 dB
0
0
1
1
0
0 dB
0
1
0
0
0
2 dB
0
0
1
1
0
0
6 dB
1
0
0
0
1
7 dB
1
0
0
0
1
1
0
0
0
8 dB
10 dB
1
0
0
1
1
9 dB
1
voiceband downlink control register
The values in the voiceband downlink control register bit positions control the audio power level in the downlink
path. Earphone volume is set (three bits VOLCTL0 –VOLCTL2) and PGA gain is set from –6 dB to 6 dB in 1
dB steps. This is shown in Table 19.
Table 19. Voiceband Downlink Control Register
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VDLON:
Power on of the downlink path of the audio codec
VBCTL2: VOICEBAND DOWNLINK CONTROL REGISTER
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ADDRESS: 11
R/W
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R/W
VDLAUX
VDLEAR
VOLCTL2
VOLCTL1
VOLCTL0
VDLG3
VDLG2
R/W
VDLG1
VDLG0
R/W
VDLON
0
<–ACCESS TYPE
1
0
1
1
1 / 0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
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VDLEAR:
Enables the earphone amplifier if the VDLON bit is 1
VDLAUX:
Enables the auxiliary output amplifier if the VDLON bit is 1
VGLG (0–3) 1 dB:
Gain of the voice-downlink programmable gain amplifier (–6 dB to 6 dB in 1-dB steps);
see Table 20.