STV0042 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'STV0042' PDF : 24 Pages View PDF
STV0042A
CONTROL REGISTERS (continued)
Register 5 : FM Deviation Selection
4
3
2
1
0
Selected Nominal Carrier Modulation
Bit 5 = 0
Bit 5 = 1
0
0
0
0
0
Do not use cal : do not use = 0.3373V offset on VCO
0
0
0
0
1
Do not use cal : do not use = 0.3053V offset on VCO
0
0
0
1
0
Do not use cal : do not use = 0.2763V offset on VCO
0
0
0
1
1
Cal. set. (2V) calibration setting (1V offset on VCO)
0
0
1
0
0
592kHz
296kHz modulation
0
0
1
0
1
534kHz
267kHz modulation
0
0
1
1
0
484kHz
242kHz
0
0
1
1
1
436kHz
218kHz
0
1
0
0
0
396kHz
198kHz
0
1
0
0
1
358kHz
179kHz
0
1
0
1
0
322kHz
161kHz
0
1
0
1
1
292kHz
146kHz
0
1
1
0
0
266kHz
133kHz
0
1
1
0
1
240kHz
120kHz
0
1
1
1
0
218kHz
109kHz
0
1
1
1
1
196kHz
98.3kHz
1
0
0
0
0
179kHz
89.7kHz
1
0
0
0
1
161kHz
80.9kHz
1
0
0
1
0
146kHz
73.1kHz
1
0
0
1
1
122kHz
66.0kHz
1
0
1
0
0
120kHz
60.0kHz
1
0
1
0
1
109kHz
54.4kHz = default power up state
1
0
1
1
0
98kHz
49.1kHz
1
0
1
1
1
89kHz
44.3kHz
1
1
0
0
0
78kHz
39.8kHz
1
1
0
0
1
71kHz
35.9kHz
1
1
0
1
0
65kHz
32.4kHz
1
1
0
1
1
58kHz
29.1kHz
1
1
1
0
0
53kHz
26.7kHz
1
1
1
0
1
48.6kHz
24.3kHz
1
1
1
1
0
43.8kHz
21.9kHz
1
1
1
1
1
39.6kHz
19.7kHz
Example : Default power up state 54.4kHz ⇒ ±54.4kHz.
Register 1
Bit <7>
0
0
1
1
Register 3
Bit <3>
0
1
0
1
Video Deemphasis/22kHz
Deemphasis 1 (default)
Deemphasis 1 + 22kHz (Pin 13)
Deemphasis 2
Deemphasis 2
FM DEMODULATION SOFTWARE ROUTINE
With the STV0042A circuit, for each channel, three
steps are required to acheive a FM demodulation :
- 1st step :To set the demodulation parameters :
• FM deviation selection,
• Subcarrier frequency selection.
- 2nd step : To implement a waiting loop to check
the actual VCO frequency.
- 3rd step :To close the demodulationphase locked
loop (PLL).
Refering to the FM demodulation block diagram
(page 12), the frequency synthesis block is com-
mon to both channels (left and right) ; consequently
two completesequenceshave to be done one after
the other when demodulating stereo pairs.
Detailed Description
Conventions :
- R = Stands for Register
- B = Stands for Bit
Example : R05 B2 = Register 05, Bit 2
For clarity, the explanations are based on the fol-
lowing example : stereo pair 7.02MHz/L
7.20MHz/R, deviation ±50kHz max.
20/24
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