TDA7406 Datasheet, PDF (16/64 Pages) STMicroelectronics – Car radio signal processor

Description of the audioprocessor part
4
Description of the audioprocessor part
TDA7406
4.1
4.1.1
4.1.2
4.1.3
4.1.4
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 Figure 3.
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.
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 selector either the stereo-decoder output or the AM-pin
is selectable.
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.
Beep Generator
There are four possible selectable beeping frequencies: 600Hz, 780Hz, 1.56KHz and
2.4KHz.
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