CT-7000
12
STEREO/MONO DRIVE AND STEREO INDICATOR
CIRCUIT
This circuit receives stereo
FM
signals strong enough
for stereo reception. When the
PLL
circuit is phase
Operation
1. The composite signal is fed from the
I
1
terminal
and undergoes a high cut due to R1, C1 and C2. It is
added to the 19kHz 90° phase shifter composed of
Tr1, R2 and C3. In this way the 19kHz pilot signal
leads by 90° and is amplified at Tr2 (only during
stereo broadcast reception, of course).
2. At the same time, the
PLL
circuit
D
terminal out
put (7) enters via
I
2
and the phase detector Tr3 is
operated by Tr4.
3. Using the phase difference between the pilot signal
and signal, Fig. 7 to see the potential at point� (i.e.,
the phase detector output, the following points be
come clear.
See chart 14.
The o peration to the detector when the
PLL
circuit
is phase locked is shown by the chart 15.
At this
time the phase difference is zero, and maximum posi
tive output is obtained.
4. The potential change is integrated by R3 and R4,
and when it is more than 0.25V, Tr5 goes on and Tr7
goes off, which switches Tr8 on. In this way the
multiplex demodulator begins to operate and at the
same time the stereo indicator lamp lights, driven by
Tr9.
However, if the station display signal is not received
via 13, i.e., if the strength of the received signal
is bel ow the muting level, the base of Tr8 will be
grounded through 02, keeping it off and keeping the
stereo indicator lamp from lighting. The multiplex
demodulator will also fail to be activated.
locked the demodulator operates and the stereo indi
cator lamp lights, which is this circuit's function.
Содержание CT-7000
Страница 1: ......
Страница 2: ...YAMAHA Hi Fi STEREO SERVICE MANUAL FM STEREO TUNER MODEL CT 7000 Printed in Japan 10 74 ...
Страница 4: ...CT 7000 EXTERNAL VIEW FRONT PANEL 1 REAR PANEL U S CANADIAN MODELS REAR PANEL EUROPEAN MODEL 2 ...
Страница 19: ...CT 7000 Photo 14 Photo 15 DIAL MECHANISM 17 ...
Страница 25: ...CT 7000 MPX CIRCUIT BOARD NA06483 23 ...
Страница 26: ...CT 7000 CONTROL CIRCUIT BOARD NA06484 24 ...
Страница 27: ...CT 7000 SWITCH CIRCUIT BOARD NA06487 POWER CIRCUIT BOARD NA06485 25 ...
Страница 29: ......
Страница 31: ...CT 7000 PARTS LIST FRONT VIEW INTERNAL VIEW 31 ...
Страница 32: ...CT 7000 INTERNAL VIEW EXPLODED VIEW 24 32 ...
Страница 33: ...CT 7000 INTERNAL VIEW INTERNAL VIEW BOTTOM 33 CT 7000 INTERNAL VIEW INTERNAL VIEW BOTTOM 33 ...
Страница 34: ...CT 7000 EXPLODED VIEW BACK VIEW EUROPEAN MODEL BACK VIEW 34 ...
Страница 42: ...Printed in Japan 10 74 m 1887 YAMAHA NIPPON GAKKI CO LTO HAMAMATSU JAPAN ...