TDA7416_11 datasheet(21/37 Pages) STMICROELECTRONICS

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TDA7416

Description of the audio processor part

Doc ID 9837 Rev 2

21/37

4.9

Spectrum analyzer

A fully integrated seven band spectrum analyzer with programmable quality factor is

present in the TDA7416 (Figure 15).

The spectrum analyzer consists of seven band pass filters with rectifier and sample

capacitor which stores the maximum peak signal level since the last read cycle. This

peak signal level can be read by a microprocessor at the SAout-pin. To allow easy

interfacing to an analog port of the microprocessor, the output voltage at this pin is

referred to device ground.

The microprocessor starts a read cycle with the negative going clock edge at the SAclk

input. On the following positive clock edges, the peak signal level for the band pass

filters is subsequently switched to SAout. Each analog output data is valid after the time

tSAdel. A reset of the sample capacitors is induced whenever SAclk remains high for the

time tintres. Note that a proper reset requires the clock signal SAclk to be held at high

potential. Figure 15 shows the block diagram and Figure 16 illustrates the read cycle

timing of the spectrum analyzer.

Figure 15.

Spectrum analyzer block diagram

Figure 16.

Timing spectrum analyzer

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