STV8206 Datasheet, PDF (49/97 Pages) STMicroelectronics – Multistandard TV Audio Processor and Digital Sound Demodulator

STV82x6
Register List
Bit Name
SQTH1[7:0]
Reset
Function
00111100
The squelch detector measures the level of high frequency noise (> 40 kHz) and compares it to
the threshold level (SQTH). If the level is below this value, the S/N of the FM signal is
considered to be acceptable. Values are given for FM with standard deviation.
SQTH S/N (dB)
FAh
0
77h
10
3Ch
15 (Default)
23h
20
19h
25
CAROFFSET1
Channel 1 DCO Carrier Offset Compensation
Address (hex): 22h
Type: R/W
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
CAROFFSET1[7:0] (S)
Bit 2
Bit 1
Bit 0
Bit Name
Reset
Function
CAROFFSET1[7:0]
00000000
This value is used correct the carrier frequency offset of the incoming IF signal. Automatic
frequency control in FM mode can be implemented by registers FM_DCR and FM_DCL.
A DCO frequency offset (in two’s complement format) is added to the pre-programming value
by AUTOTSD in the CARFQ1 registers (corresponding to the standard IF carrier frequency).
The programmable carrier offset ranges from -192 kHz to +190.5 kHz with a resolution of
1.5 kHz.
For standard FM deviation, the value displays by FM_DCL can be directly loaded in
CAROFFSET1 to exactly compensate the carrier offset on Channel 1
9.7 Demodulator Channel 2
IAGCR
Channel 2 Internal AGC Reference for QPSK
Address (hex): 25h
Type: R/W
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
IAGC_REF[7:0]
Bit 2
Bit 1
Bit 0
Bit Name
IAGC_REF[7:0]
Reset
Function
10001000 Sets the mean value of the internal AGC, used for QPSK demodulation. The default setting
corresponds to half full scale amplitude at the baseband PLL input.
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