Circuit Operating Descriptions
14-44
Samsung Electronics
5) PB AMP
The diagram to the left is the playback amp and the gain input/output are as
follows.
Av = 1 +
The playback characteristic of VHS format can be satisfied by using Z
1
, Z
2
in
the above equation.
PB amp gain should be designed to be approximately 45dB (1KHz).
Z
1
Z
2
INPUT
PB AMP
OUTPUT
Fig. 14-27 PB Amp
Z
2
Z
1
Z
2
Z
1
~
~
6) REC AMP
The diagram to the left is REC AMP. The amp gain is approximately 14dB.
R
1
and R
2
that determine the gain is located inside the IC.
It is uniform and independent to frequency. Frequency characteristics should
be considered when designing rec amp. The REC amp should be the opposite
to playback characteristics.
OUTPUT
PB AMP
INPUT
R
1
R
2
Fig. 14-28 REC Amp
7) OSC (Oscillation)
Oscillation frequency is 70KHz. It’s size is approximately 45Vp-p. it operates on recoed mode. It is supplied to
audio erase head and full erase head used to erase already recorded signals.
Also, it conducts “AM (Amplitude Modulation)” using oscillation signals.
8) BIAS Control
Oscillation coil is used in oscillation Bias. Coil output changes according to the impedance of F/E, A/E and
R/P head connected to the coil.
9) 60KHz HPF
There must be standard signal for bias control and that signal uses HPF only to obtain oscillation signal that
comes through R/P head.
10) S/W
The switch opens when recording, shorts during playback and exterior transister is used.
Summary of Contents for DVD-VR320/XEF
Page 32: ...5 22 Disassembly and Reassembly Samsung Electronics MEMO ...
Page 68: ...Troubleshooting 6 36 Samsung Electronics MEMO ...
Page 76: ...Exploded View and Parts List 7 8 Samsung Electronics MEMO ...
Page 216: ...Circuit Operating Descriptions Samsung Electronics 14 17 Fig 14 12 IC601 Block Diagram ...
Page 249: ...Circuit Operating Descriptions 14 50 Samsung Electronics MEMO ...
