STV8203 ST Microelectronics, STV8203 Datasheet - Page 14

• Manufacturer Part Number: STV8203
• Description: MULTISTANDARD TV SOUND DEMODULATOR
• Manufacturer: ST Microelectronics

STV8203
PROGRAMMING THE DEVICE (continued)
3 - Register Description
3.1 - Registers Not Controlled By Autostandard (except some mentioned bits)
PRE-FM (Prescale FM Level)
Address
Type
Reset
FM PRESCALE : 00000
Sets the reference level for an FM signal. Note, this is also dependant on the PLL programming. For
example, with default settings for the PLL, an FM deviation of 27kHz will result in a signal 17dB below full
scale before de-emphasis. At 1kHz, the internal de-emphasisgain is 14dB giving a level of -3dB. Full scale
output from the DAC is 2V
PRE-NICAM (Prescale NICAM Level)
Address
Type
Reset
NICAM PRESCALE : 00000
Sets the reference level for a NICAM signal. For example, a full scale NICAM signal at 1kHz would be
received at -12dB before de-emphasis. Internal de-emphasis gain at this frequency is 9dB so for 1V
pre-nicam should be set to -3dB.
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bit 7
bit 7
0
0
: 02
: R/W
: 0001 1101
: 03
: R/W
: 0001 1101
bit 6
bit 6
0
0
01100
10100
(step size = 1dB, range = 12dB in 2’s complement)
01100
10100
(step size = 1dB, range = 12dB in 2’s complement)
RMS
+12dB
-12dB
bit 5
corresponding to 0dB. and so for 1V
bit 5
0dB
0
0
+12dB
-12dB
0dB
bit 4
bit 4
bit 3
bit 3
NICAM PRESCALE
FM PRESCALE
RMS
bit 2
bit 2
, PRE-FM should be set to -3dB.
bit 1
bit 1
bit 0
bit 0
RMS
,