TDA7541 datasheet(30/76 Pages) STMICROELECTRONICS

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Functional description

TDA7541

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“0”: 120 kHz

The bit has only influence if bit BWENA is “1”, or if bit ISSON is “1”

WBON

Weather band enable

“1”: Weather band enable (FMmixer1 is disabled, Wbmixer1enabled, stereo decoder gain

26dB, ISS filter bandwidth 24 kHz,IF2Q=”00”)

“0”: Weather band disable

For weather band enable it is need to set ISSON = “1”

ISSM

ISS filter application mode

“0”: ISS filter application mode1

“1”: ISS filter application mode2

If BWENA is “1” the band width is always switched to ISSBW in case of ISS filter activated

BWDEF

Enable bit ISSBW for ISS filter band with control

“1”: ISS filter is internally controlled, but band width is defined by bit ISSBW

“0”: ISS filter is internally controlled, band width is defined by mode1/2 table

For the internal control two application modes are available (ISSM). The conditions and

settings are described in Table 10 and Table 11.

4.1.4

Block diagram quality detection principle

(without overdeviation correction)

Table 11.

Internal ISS control signals

Signal

Low

High

No adjacent channel

Adjacent channel present

ac+

No strong adjacent channel

Adjacent channel higher as ac

Field strength higher as weak signal mute

threshold

Field strength lower as weak signal mute

threshold

Dev

Deviation lower as threshold DWTH

Deviation higher as threshold DWTH

dev+

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)

TDA7541 数据表(PDF) 30 Page - STMicroelectronics

TDA7541 数据表(HTML) 30 Page - STMicroelectronics

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