TDA7513 datasheet(21/58 Pages) STMICROELECTRONICS

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TDA7513

tTIM = (IRC + 1) / fOSC

tCNT = (CF + 1697) / fIF

(FM mode)

tCNT = (CF + 448) / fIF

(AM mode)

where

tTIM = IF timer cycle time (sampling time)

tCNT = IF counter cycle time

Counting succesful:

tCNT - tERR = tTIM = tCNT + tERR

Count failed:

tTIM > tCNT + tERR

tTIM < tCNT - tERR

where

tERR = discrimination window (controlled by the EW registers)

The IF counter can be started only by inlock information from the PLL, and it is enabled by software

(IFENA).

Adjustment of the Measurement Time and Frequency window

The measurement precision is adjustable by controlling the width of the frequency discrimination window

through control registers EW0 to EW2. The center frequency of the discrimination window is adjustable by

the control register CF0 to CF4. The measurement time per cycle is adjustable by setting the registers

IFS0 - IFS2.

4.4 AUDIO PROCESSOR

Input Multiplexer

CD quasi differential 1

CD quasi differential 2

Stereodecoder input (for both FM and AM signals).

Input stages

The quasi-differential input stages (see figure 4) have been designed to cope with some CD players in the

market having a significant high source impedance which affects strongly the common-mode rejection of

"normal" differential input stages. The additional buffer of the CD input avoids this drawback and offers the

full common-mode rejection even with those CD players. The quasi-differential input can also be used with

normal stereo single-ended output signal sources such as TAPEOUT.

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