Yamaha CT-7000 Service Manual page 12

CT-7000
2. Phase Comparison and Detection Section
19kHz
a. The pilot signal, a composite signal neces­
sary for phase comparison and detection, is selected
by
the band pass filter composed of the circuit
from the I' terminal to point@
19kHz
b. This selected
1
Tr and fed to points
and Tr3 respectively. To these transistors the
square wave from the oscillation section points
and ® are also fed.
c. In this way the phase comparison and detection
circuit is formed, and output Vc' and Vd' can be
( I )
2-1. T o detect the waveform in chart
ing to chart 4 and chart 5 (previous page),
10-a. Output at (d) when chart 4 is added to Tr2.
1
0-b. Output at (c) when chart 5 is added to Tr3.
At the same time, these also show the outputs at point
@
(in the condition seen in chart
is set to Tr3, also show the output at the point
(@
in chart 10- when chart 5 set to Tr2.
a � � . �� + a '
.
/ .
10
pilot signal is amplified by
© and (Q), connected to Tr2
19kHz
CHART 8
9
above accord­
1 - l
0 ® when chart 4
@
.
.;;:. /:
/
10
CHART
obtained. Since the
ing Tr2 and Tr3 are in opposite phase, Vc' and
Vd' are activated alternately. This phenomenon is
then amplified by the differential amplifier formed
of Tr4 and Tr5.
d. The phase relations between the pilot signal and
the signals at points
tential at points
G)
The figure to the left shows the point ®input
waveform. The one on the right shows that for
@
point .
2-2. To detect the waveform in chart
chart 6 and chart 7 shown on the previous page:
11-d.
Output at (d) when chart 6 is added to Tr2.
11-d.
Output at (o) when chart 7 is added to Tr3.
At the same time, these also show the outputs at point
@
(in the condition seen in chart
is set to Tr3, also show the output at the point
11-@
in chart when chart 7 set to Tr2.
19kHz
square wave signals driv­
(D
®,
and as well as the po­
@
@
and , are shown below:
CHART 9
9
above using
11-@l
when chart 6
+
CHART
(d)
11