DRP3510 datasheet(6/30 Pages) ETC

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DRX 3960A

ADVANCE INFORMATION

Micronas

1.3. Analog TV Application

The Digital Receiver Front-end DRX 3960A is able to

replace a conventional IF IC including several SAWs.

Nevertheless, quasi split sound processing is per-

formed with standard specific internal filtering and

group delay equalizing.

The input signal of the DRX 3960A is the TV IF with its

carrier at:

– 38.9 MHz (B/G, D/K, I, L, and M/N in multistandard

applications)

– 32.9 MHz (L’)

– 45.75 MHz (M/N in single standard applications)

– other frequencies are also programmable

– 36.125 MHz (DVB-C or DVB-T in further versions)

These signals are available from conventional tuners.

For pre-filtering, one 8-MHz channel SAW filter must

be used, e.g. the Epcos X6966M. Nevertheless, the

entire multistandard processing is performed. The pre-

filter limits the signal bandwidth to 8 MHz and sup-

presses major parts of the adjacent channels.

After the desired standard information is transferred

into the DRX 3960A, the following standard specific

procedures are performed:

– Adjacent channel suppression

– Carrier locking including AFC information genera-

tion

– Nyquist slope adjustment

– Video/sound splitting

– Video AGC, including delayed tuner AGC

– Group delay post distortion

– Video and sound frequency shaping

– Video demodulation

– Second SIF generation and AGC

Similar to conventional analog front-ends, the tuner

gain is controlled by the DRX 3960A. New AGC algo-

rithms have been implemented for superior level track-

ing for both positive and negative video modulation.

The demodulated CVBS signal and the second sound

IF (SIF) are available as analog output signals.

If an FM radio channel is transferred to the IF inputs,

down-mixed by means of a standard TV tuner, it can

preselected and

further down-mixed by the

DRX 3960A. Thus, a succeeding sound demodulator,

e.g. the MSP, will be able to demodulate that channel.

The DRX 3960A operates with its own quartz or with

appropriate external clocks, e.g.:

– 13.5, 20.25, 27 MHz from an employed video IC

– 1, 4 MHz from the tuner

Fig. 1–2: Multistandard video and sound IF processing with DRX 3960A

Tuner

DRX 3960A

VPC/VCT

MSP

SAW

Delayed Tuner AGC

CVBS

2nd SIF

I2C

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