TDA7406T Datasheet, PDF (9/49 Pages) STMicroelectronics – CAR RADIO SIGNAL PROCESSOR

TDA7406T
2 DESCRIPTION OF THE AUDIOPROCESSOR PART
2.1 Input stages
In the basic configuration there is a source-Selector with 8 inputs: one pseudo-differential (CDC), three single
ended stereo (MD, CD, Tape), three single-ended mono (PHONE, NAVI, TIM) plus the “tuner” input. The tuner
input takes the signal from either MPX1 or MPX2/AM pins (through the stereodecoder) see Fig. 1.
2.1.1 Pseudo-differential stereo Input (PD)
The PD input is implemented as a buffered pseudo-differential stereo stage with 100kΩ input-impedance at
each input pin. This input is also configurable as single-ended stereo input (CDC, see pin-out). The common
input-pin, PD- features a fast charge switch to speed up the charge time of external capacitors. This switch is
released the first time the input-selector data-byte (0) is assessed.
2.1.2 Single-ended stereo Inputs, single-ended mono inputs and FM-MPX input
All single ended inputs have an input impedance of 100kΩ. The AM-pin can be connected to the input of the
stereo-decoder in order to use the AM-noiseblanker and AM-High-Cut feature. As input “Tuner” for the input se-
lector either the stereo-decoder output or the AM-pin is selectable.
2.1.3 Mixing Selector
It is possible to enable/disable the mixing feature (ratio 50%) at the outputs stages between whichever input
source and one of the following signals: Beep, Phone, Navigator and Tuner/TIM.
2.1.4 Beep Generator
There are four possible selectable beeping frequencies: 600Hz, 780Hz, 1.56KHz and 2.4KHz.
Figure 1. Input-stages
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