CXA2002R datasheet(21/25 Pages) SONY

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CXA2002R

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Description of Operation

Y, chroma, AFM, ATF and PCM signals are input at specified levels so that they are mixed internally to achive

an appropriate current value at the head. The VIDEO path signal (Y + chroma + AFM + ATF) is output to Pin

41 (RECVIDEO) and the PCM path signal (PCM + ATF) to Pin 38 (RECPCM). The Y level is EVR-adjusted at

Pin 8 (YLEVEL) and the low band (chroma, AFM, ATF) level at Pin 5 (LOWLEVEL). The low-band levels of the

video path and the PCM path are interlocked in adjustment.

The VIDEO path signal and the PCM path signal, which underwent recording level adjustment, are switched at

a correct timing, then converted to a current to drive the head.

A feedback dumping circuit is incorporated to inhibit head resonance, and the peaking can be adjusted by EVR

at Pin 26 (REC1CONT), Pin 35 (REC2CONT).

During recording, the output capacitance is about 12pF including that of the head amplifier.

The playback signal from the head is amplified with low noise and high gain. A feedback dumping circuit is

incorporated to inhibit head resonance, and the peaking can be adjusted by external resistors connected to Pin

30 (PBDUMP1), Pin 31 (PBDUMP2).

During playback, the input capacitance is about 20pF including that of the recording amplifier.

This section switches the playback signals of CH1

and CH2 at the correct timing and outputs the

playback VIDEO signal to Pin 14 (MTOUT) and

the playback PCM signal to Pin 16 (PCMOUT). In

the PCM after-recording mode, both playback

VIDEO signal and playback PCM signal are muted

during the PCM recording period.

The middle tune circuit corrects the frequency

response of the playback VIDEO signal.

The center frequency can be adjusted by EVR at

Pin 17 (MTF0), Q at Pin 24 (MTQ) and the boost

at Pin 15 (MTG).

The figure to the right shows the center condition

that sets f0 = 8MHz, Q = 2.5 and the boost = 6dB.

Each control characteristics shown in "Example of

Representative Characteristics" is obtained when

two of them are fixed to the center condition.

<RFAGC>

This circuit inputs the playback Y signal separated from the playback VIDEO signal using an external circuit

and outputs it at a constant level of 410mVp-p. In the PCM after-recording mode, RFAGC gain is kept

unchanged during PCM recording period.

A dropout is detected in the playback Y signal, and a dropout pulse is output. The detection level is optimized

using 224mVp-p input as a reference. If necessary, the detection level can be adjusted by inputting a DC

voltage to Pin 11 (DOCDET). To make this adjustment, input a voltahe proportional to the output voltage of Pin

39 (VREG).

Boost amount

= 6dB

3dB

Center frequency f0 = 8MHz

Q = f0 / (f2 – f1) = 2.5

Frequency

CXA2002R Datasheet(PDF) 21 Page - Sony Corporation

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