TDA7406 datasheet(42/64 Pages) STMICROELECTRONICS

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Functional description of the multipath-detector

TDA7406

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Functional description of the multipath-detector

Using the Multipath-Detector the audible effects of a multipath condition can be minimized.

A multipath-condition is detected by rectifying the spectrum around 19kHz in the

fieldstrength signal. An external capacitor is used to define the attack- and decay-times for

the Stereoblend (see block diagram, fig. 32). Due to the very small charge currents this

capacitor should be a low leakage current type (e.g ceramic). Using this configuration an

adaptation to the user's requirement is possible without effecting the “normal” fieldstrength

input (LEVEL) for the stereodecoder. This application is given in fig. 28. Another (internal)

time constant is used to control the 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 30.

Block diagram of the Multipath-Detector

TDA7406 Datasheet(PDF) 42 Page - STMicroelectronics