TDA7406T datasheet(33/49 Pages) STMICROELECTRONICS

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TDA7406T

Highcut through the multipath detector

Selecting the “internal influence” in the configuration byte the Stereo-Blend and/or the Highcut is automatically

invoked during a multipath condition according to the voltage appearing at the MP_OUT-pin.

Figure 28. Block diagram of the Multipath-Detector

QUALITY DETECTOR

The TDA7406T offers a quality detector output which gives a voltage representing the FM-reception conditions.

To calculate this voltage the MPX-noise and the multipath-detector output are summed according to the follow-

ing formula:

VQual = 1.6 (VNoise-0.8 V)+ a (REF5V-VMpout).

The noise-signal is the PEAK-signal without additional influences (see noiseblanker description). The factor 'a'

can by programmed from 0.7 to 1.15. The output is a low impedance output able to drive external circuitry as

well as simply fed to an AD-converter for RDS applications.

8TESTMODE

During the Testmode, which can be activated by setting bit I2 of the subaddress byte and bit D1 of the stereo-

decoder testing-byte, several internal signals are available at the FD2R+ pin. During this mode the input resis-

tance of 100kOhm is disconnected from the pin. The internal signals available are shown in the Data-byte

specification

TDA7406T 数据表(PDF) 33 Page - STMicroelectronics