TDA7540B datasheet(28/75 Pages) STMICROELECTRONICS

номер детали	TDA7540B

подробное описание детали	AM/FM Car Radio Tuner IC with Stereo Decoder and Intelligent Selectivity System (ISS)

PDF	75 Pages

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производитель	STMICROELECTRONICS [STMicroelectronics]

домашняя страница	http://www.st.com

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Functional description

TDA7540B

28/75

Stereoblend control

The stereoblend control block converts the internal LEVEL-voltage into a demodulator

compatible analog signal, which is used to control the channel separation between 0dB and

the maximum separation. Internally this control range has a fixed upper limit, which is the

internal reference voltage V

REF1. The lower limit can be programmed between 29 and 58% of

VREF1 in 4% steps (see fig.6).

To adjust the external LEVEL-voltage to the internal range two values must be defined: the

LEVEL gain L

G and VSBL. To adjust the voltage where the full channel separation is reached

(VST) the LEVEL gain L

G has to be defined. The following equation can be used to estimate

the gain:

LG = VREF1/FSU@full stereo

The MONO-voltage VMO (0dB channel separation) can be chosen selecting VSBL.

Figure 6.

Relation between internal and external level-voltagees and setup of stereoblend

The stereo blend function can be switched ON/OFF using bit Addr25<d2>. Please note that

in AM it must be switched in forced mono!

Highcut control

The highcut control set-up is similar to the stereoblend control set-up: the starting point

VHCH can be set with 2 bits to be 42, 50, 58 or 66% of VREF1 whereas the range can be set

to be 11, 18.3, 25.7 or 33% of VHCH (see fig. 7).

TDA7540B датащи(PDF) 28 Page - STMicroelectronics