CXA1202Q-Z Ver la hoja de datos (PDF) - Sony Semiconductor

Número de pieza

componentes Descripción

Fabricante

CXA1202Q-Z

REC/PB Amplifier for VCR

Sony Semiconductor 

CXA1202Q-Z/CXA1202R

Precautions

1. Do not connect parasite capacitance to REC AMP dumping.

C1

C1

Effect of C2

C2

28

25

Effect of C1

REC AMP

Frequency

2. Do not bring Head AMP input near PB output.

Normally, there is a gain of 67dB between Head Amp input (Pins 29, 30) and RFOUT (Pin 16). During no

signal, the gain is 74dB (as AGC reaches maximum gain). Bringing those closer on the pattern may cause

oscillations in the vicinity of 6 to 7MHz.

3. Use 150kΩ for RF AGC time constant, Resistance

Because a change in this R causes a change in the AGC output level, change the time constant using the

value of capacitance.

4. Watch the time constant of dropout detection.

VCC

R1

DOC TC 15

R2 C

Time constant: t = C × (R1//R2)

C: over 150pF

R2

R1, R2: 5 ×

= 1.2 to 2.0V

R1 + R2

Oscillations may occur unless this condition is satisfied.

5. Take AFM PB output from V RF OUT (Pin 20)

Passing AFM signal through RF AGC causes AGC to reach maximum gain when playing back a virgin tape.

As a result MUTE may not apply to AFM IC (CX20137, CX20037).

6. Adjust tape path by mixing V RE OUT signal and PCM RF OUT signal. In the absence of a signal before

switching, observe the envelope comprising the combination of the VIDEO area and the PCM area by

mixing outputs from V RF OUT (Pin 20) and PCM RF OUT (Pin 8).

RF SWP

V RF OUT

PCM RF OUT

After mixing

– 21 –

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