3.6
DEMODULATOR CIRCUIT
Notes:
• Unless otherwise specified in this demod circuit ad-
justments, all measuring points and adjustment parts
are located on the Demod board.
• Unless otherwise specified,set an audio multiplex TV
signal generator as follows;
RF signal : 70 dBµ / 75 Ø , color bar 87.5% modulation.
3.6.1 Input level
•
Signal
(A)
RF signal (Audio: mono 300 Hz)
•
Mode
(B)
Tuner
•
EE
•
Equipment
(C)
Audio level meter
•
Measuring point (D)
IC1501 pin 26
•
EVR mode
(F1)
Jig RCU : Code "57"
•
EVR address
(F2)
A : 20 (Press remote controller "2"
and "0" keys.)
•
Specified value
(G)
500 ± 10 mVrms
•
Adjustment tool
(H)
Jig RCU [PTU94023B]
•
Digit-key remote controller
(1) Set an audio signal mode of the RF signal generator to
mono 300 Hz.
(2) Connect the equipment (C) to the measuring point (D).
(3) Set the VCR to the EVR mode by transmitting the code
(F1) from the Jig RCU.
(4) Set the EVR address to (F2) by pressing the button of
the digit-key remote controller.
(5) Adjust with the channel buttons (+,–) on the VCR (or on
the remote controller) so that the level of the measuring
point (D) becomes the specified value (G).
(6) Release the EVR mode of the VCR by transmitting the
code (F1) from the Jig RCU again. (When the EVR mode
is released, the adjusted data is memorized.)
3.6.2 Stereo VCO
•
Signal
(A)
No signal
•
Mode
(B)
Tuner
•
EE
•
Equipment
(C)
Frequency counter
•
Measuring point (D1)
IC1501 pin 26
•
Short point
(D2)
C1505(–) terminal
•
EVR mode
(F1)
Jig RCU : Code "57"
•
EVR address
(F2)
A : 21 (Press remote controller "2"
and "1" keys.)
•
Specified value
(G)
15.73 ± 0.1 kHz
•
Adjustment tool
(H)
Jig RCU [PTU94023B]
•
Digit-key remote controller
(1) Connect the short wire between the short point (D2) and
the GND (Ground).
(2) Connect the equipment (C) to the measuring point (D1).
3-6
(3) Set the VCR to the EVR mode by transmitting the code
(F1) from the Jig RCU.
(4) Set the EVR address to (F2) by pressing the button of
the digit-key remote controller.
(5) Adjust with the channel buttons (+,–) on the VCR (or on
the remote controller) so that the frequency of the meas-
uring point (D1) becomes the specified value (G).
(6) Release the EVR mode of the VCR by transmitting the
code (F1) from the Jig RCU again. (When the EVR mode
is released, the adjusted data is memorized.)
(7) Disconnect the short wire between the short point (D2)
and the GND (Ground).
3.6.3 Stereo filter
•
Signal
(A)
RF signal (Audio: No signal)
•
Mode
(B)
Tuner
•
EE
•
Equipment
(C)
Oscilloscope
•
Measuring point (D)
IC1501 pin 26
•
EVR mode
(F1)
Jig RCU : Code "57"
•
EVR address
(F2)
A : 22 (Press remote controller "2"
key twice.)
•
Specified value
(G)
Minimum level
•
Adjustment tool
(H)
Jig RCU [PTU94023B]
•
Digit-key remote controller
(1) Set an audio signal mode of the RF signal generator to
no signal.
(2) Connect the equipment (C) to the measuring point (D).
(3) Set the VCR to the EVR mode by transmitting the code
(F1) from the Jig RCU.
(4) Set the EVR address to (F2) by pressing the button of
the digit-key remote controller.
(5) Adjust with the channel buttons (+,–) on the VCR (or on
the remote controller) so that the level of the measuring
point (D) becomes the specified value (G).
(6) Release the EVR mode of the VCR by transmitting the
code (F1) from the Jig RCU again. (When the EVR mode
is released, the adjusted data is memorized.)
3.6.4 Separation - 1
•
Signal
(A)
RF signal
(Audio: L-ch 300 Hz 14% modulated)
•
Mode
(B)
Tuner
•
EE
•
Equipment
(C)
Audio level meter
•
Measuring point (D)
IC1501 pin 26
•
EVR mode
(F1)
Jig RCU : Code "57"
•
EVR address
(F2)
A : 23 (Press remote controller "2"
and "3" keys.)
•
Specified value
(G)
Minimum level
•
Adjustment tool
(H)
Jig RCU [PTU94023B]
•
Digit-key remote controller
(1) Set an audio signal mode of the RF signal generator to
alternate L-ch 300 Hz 14% modulated.
(2) Connect the equipment (C) to the measuring point (D).
(3) Set the VCR to the EVR mode by transmitting the code
(F1) from the Jig RCU.
(4) Set the EVR address to (F2) by pressing the button of
the digit-key remote controller.