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-3. Flow of playback Y signal
) playback mode, V-REC signal and REC5V are "L" and PB5V is "H", and the rotary transformer and !C301 are
1 playback mode, and the video head playback a signal from a tape. The playback signal is amplified in the
re-amplifier of PB1-4 and supplied to the selection switch circuit of CH1-4. The switch circuit turns individual
layback signal from CH1-4 into a continuous signal, supplies to 10dB PB AMP in the next step, and outputs
"om pin (41).
he playback signal thus obtained passes through pin (7) of connector AH-BD, is supplied to the buffer of
1410 and divided into two. One is supplied to the playback C signal processing circuit, and the other is sup-
lied either to pin (13) (in SP mode) or to pin (11) (in LP mode) and outputted from pin (16) through the switch
1the !C and 12dB AMP.
hen the high band components are amplified and low band conversion C signal is eliminated in the RF equal-
rer circuit, and the amplitude of FM signal is corrected, then the signal is supplied to pin (17). Then the signal
; outputted from pin (3) and pin (7) for phase correction, phase-corrected in R456, L414, and C446, and sup-
lied to pin (2). Next, the signal is outputted from pin (24) after level control is applied in RF AGC circuit.
M signal thus obtained, whose high band noise components are damped in L403 and C418, is supplied to pin
56) of IC 201. Here the envelope is detected, dropout is detected, and DOC pulse is outputted, as well as the
ignal is sent to LPF and HPF in the IC to respectively become low band component and high band component
upplied to the double limiter.
'he signal through HPF is subject to the first step of the double limiter in the next limiter, then it is mixed with
aid low band components and subject to the second step of the double limiter. The output is demodulated to
'-signal in the demodulator and supplied to the main de-emphasis circuit after FM carrier components are
diminated in sub LPF. The de-emphasis circuit gives the emphasis characteristics in the reverse of those in re-
ording, improves S/N ratio, and supplies the signal to GCA (Gain Control Amplifier) circuit in the next step.
jere, after the Y-signal level is adjusted in R415, it is sent to LPF through the record and playback switch. The
PF has completely the same characteristics as in recording, and eliminates residual high band components,
hen the signal is supplied to the non-linear de-emphasis circuit only in LP mode. In SP mode, the circuit does
10t operate but the signal is outputted from pin (61).
'he Y-signal from pin (61), passing through C416, is inputted in pin (60), clamped, then supplied to the circuit
or obtaining a differential signal between the dropout correction switch and 1H delay signal. Here the switch
s for changing over with 1H delay signal by DOC signal mentioned above in drop-out mode, and it operates
is a video DOC. The Y-signal through the DOC switch is divided into two, one of which is mixed with a signal
imiting the differential signal from above-mentioned
1H delay signal as a line correlative noise reduction
wrocess. The other is outputted from pin (58) to obtain the 1H delay signal, and supplied to pin (6) of IC403.
tere the 1C403 is a CCD delay line with a clock of 2fsc (fsc:4.43 MHz), which clock doubles the fsc output from
| 9in (34) of 1C201 in 1C402, and uses the resultant output. The signal delayed in the CCD delay line is outputted
rom pin (4) of 1C403, passes through the buffer, and delay time of approx. 90 nsec. is added in LPF of L402,
7412 and C413 to obtain delay of 1H. Then the 1H delay signal is adjusted in level, supplied to pin (59) of C201
hrough AMP and buffer of Q402, clamped, then supplied to the dropout correction switch to become a drop-
rut correction signal.
. "he Y-signal that has gone through line correlation noise reduction process is then supplied to the video
>qualizer circuit. The equalizer circuit, which is emitter peaking, corrects the frequency characteristics of the
ayback Y-sighal
by a constant of RLC connected-to-pir
(47): The signals improved-in-S/N-in-the noise cancel—-
'ircuit and supplied to the record and playback switch through the picture quality control circuit.
n EDIT mode set by pin (17), the above line correlation noise reduction operation and picture quality control
" sircuit are turned off, which restrains noise canceling. The playback Y-signal thus obtained, passing through
the record and playback switch, is outputted from pin (40) through the'sub-clamp circuit and AMP the same as
_ IE Y signal. Then it is supplied to pin (1) and (3) of 1C2201, and respectively mixed with playback C signal in pin
| 7) processed in a system separate from playback Y-signal for the viewfinder, and it becomes the playback vid-
20 output signal.
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