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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Summary of Contents for BVH-2000
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