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Product(s)

Obsolete

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13/34

TDA7407D

tion even with those CD players.

The output of the Cd stage is permanently available of the Cd out-pins

6.1.3 AutoZero

In order to reduce the number of pins there is no AC coupling between the In-Gain and the following stage,

so that any offset generated by or before the In-Gain stage would be transferred or even amplified to the

output.

To avoid that effect a special offset cancellation stage called AutoZero is implemented.

This stage is located before the volume-block to eliminate all offsets generated by the Stereodecoder, the

Input Stage and the In-Gain (Please notice that externally generated offsets, e.g. generated through the

leakage current of the coupling capacitors, are not cancelled).

The auto-zeroing is started every time the DATA-BYTE 0 is selected and takes a time of max. 0.3ms. To

avoid audible clicks the audioprocessor is muted before the volume stage during this time.

6.1.4 AutoZero Remain

In some cases, for example if the

useful to start a new AutoZero action because no new source is selected and an undesired mute would

appear at the outputs. For such applications the TDA7407D could be switched in the "Auto Zero Remain

mode" (Bit 6 of the subaddress byte). If this bit is set to high, the DATABYTE 0 could be loaded without

invoking the AutoZero and the old adjustment value remains.

6.1.5 Multiplexer Output

The output signal of the Input Multiplexer is available at separate pins (please see the Blockdiagram). This

signal represents the input signal amplifier by the In Gain stage and is also going into the Mixer stage.

6.1.6 Softmute

ized in a special S shaped curve to mute slow in the critical regions (see figure 9).

Figure 8. Input Stages

15K

15K

100K

CD+

CD-

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+

-

27K

28K

PHONE-

27K

28K

+

-

D98AU854D

100K

100K

100K

STEREODECODER

IN GAIN

CASSETTE

AM

MPX

1

1

100K

Obsolete

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Product(s)