Sony BVH-2000, Руководство по эксплуатации и обслуживанию

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5-3-6. BE-02
Board
BE-02 configured the touowmz
Audio Bias/Erase Oscillator
• Video/CTL Erase Oscillator (Stationary Head)
• Audio Erase Amplifier
• CTL Bias Amplifier
• Crosstalk
Canceller Controller
• Bias Timing Controller
master is 14.31818 and the
frequency of 198.9 kHz, produced by dividing the master
frequency by 72, is used as the bias and erase signals. Also, in
order to prevent accidental erasure when the power is switched
on, the timing
of the oscillation start is controlled by the
POWER ON RESET signal from the PS board. The generated
signal is to the audio erase head through the
amplifiers various channels on board.
onto
board,
3. Video/CTL Erase Oscillator (Stationary Head)
This circuit is composed of an astable multivibrator with an
oscillation frequency of 118 kHz. When the VTR placed in the
assemble mode.the video CTL tracks erased. As
audio oscillation
controlled from
baord.
BVH-2000( U/C)/PS/PM
BVH-2180(U/C)/PS/PM
The circuit for and
description is confined the AUDIO-I channel.
IC10l is a Miller Integrator which controls the slope of the erase
signal's rise and fall. The erase signal is supplied to IC3-13 as a
square wave which becomes a sine wave in the resonance circuit
configured
by LV4/CI08, and it is supplied to the erase head
through buffer QIOI to QI04.
Muting
controlled the
before
5. CTL Bias Amplifier
The circuitry of this amplifier is configured in the same way as
that of the audio erase amplifier although the time of the rise
and fall of the ramp waves generated by Miller Integrator IC9
differs.
The Ax CANCEL signal, which serves as the control signal
the crosstalk canceller, is produced by inverting the logic of the
Ax REC signal from the LG· board. The timing at which the
crosstalk canceller is set off is delayed by an amount of time
equivalent
to the fall of the audio bias.
Bias
The BE-03
Ax REC controlled
AUDIO SIGNAL SYSTEM
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