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TDA7540B Datasheet, PDF (65/75 Pages) STMicroelectronics – AM/FM Car Radio Tuner IC with Stereo Decoder and Intelligent Selectivity System (ISS) | |||
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TDA7540B
Appendix
Block Diagram Quality Detection Principle (without overdeviation correction)
Table 51.
Signal
LOW
HIGH
ac
No adjacent channel
Adjacent channel present
ac+
No strong adjacent channel
Adjacent channel higher as ac
sm
Fieldstrength higher as softmute threshold Fieldstrength lower as softmute threshold
dev
dev+
Deviation lower as threshold DWTH
Deviation higher as threshold DWTH
Deviation lower as threshold DTH*DWTH Deviation higher as threshold DTH*DWTH
inton
ISS filter off by logic (wide)
ISS filter on by logic
int80
ISS filter 120kHz (mid)
ISS filter 80kHz (narrow)
Table 52.
Input Signals
ac
ac+
sm
dev
0
0
0
0
0
0
0
1
0
0
0
1
0
0
1
0
0
0
1
1
0
0
1
1
1
0
0
0
1
1
0
0
1
0
0
1
1
1
0
1
1
0
1
0
1
1
1
0
1
0
1
1
1
1
1
1
1
0
1
1
1
1
1
1
dev+
0
0
1
0
0
1
0
0
0
1
0
0
0
0
1
1
inton
0
0
0
1
0
0
1
1
1
1
1
1
1
1
1
1
Mode1
int80
0
0
0
1
0
0
1
1
0
0
1
1
0
0
0
0
Function
wide
wide
wide
narrow
wide
wide
narrow
narrow
mid
mid
narrow
narrow
mid
mid
mid
mid
inton
0
0
0
1
1
0
1
1
1
1
1
1
1
1
1
1
Mode2
int80
0
0
0
1
0
0
0
1
0
1
1
1
0
1
0
1
Function
wide
wide
wide
narrow
mid
wide
mid
narrow
mid
narrow
narrow
narrow
mid
narrow
mid
narrow
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