DESCRIPTION OF THE AUDIOPROCESSOR

PART

Programmable Input Matrix

The programmable input matrix of the TDA7461N

offers several possibilities to adapt the audioproc-

essor to the desired application. In to the stand-

ard application we have:

CD quasi differential

Cassette stereo

Phone differential

AM mono

Stereodecoder input.

The input matrix can be configured by only 2 bits:

bits 3 and 4 of subaddress 0. Basically the bit of

subaddress 13 is fixed by the application and has

to be programmed only once at the startup of the

IC.

For many configurations the two bits are also

fixed during one application (e.g. the standard ap-

plication) and a change of the input source can

be done by loading the first three bits of subad-

dress 0.

In other configurations for some sources a pro-

gramming of bit 3 and 4 of subaddress 0 is nec-

essary in addition to the three source selection

bits. In every case only the subaddress 0 has to

be changed to switch from one source to another.

The following picture shows the input and source

programming flow:

TDA7461

CD QD

CD FD

APPL. 2

APPL. 1

APPL. 3

APPL. 5

APPL. 4

APPL. 6

CD QD

CASSETTE

FM STD

AM MONO

PHONE (D)

CD QD

CASSETTE

FM STD

AM STEREO

PHONE (SE)

CD QD

CASSETTE

FM STD

AM STD

PHONE (D)

CD FD

CASSETTE

FM STD

AM MONO

PHONE (SE)

CD FD

CASSETTE

FM STD

AM STEREO

CD FD

CASSETTE

FM STD

AM STD

PHONE (SE)

D97AU632B

Figure 1. Input Configuration Tree

Note: in AMSTD configuration the AM mono signal is lead through the FM stereodecoder part to use its additional filters and high-cut function.

TDA7461N

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