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SQUARE WAVE SIGNALS AND FREQUENCY
R E S P O N S E
Use of a square wave in place of the sine wave will provide
an approximate frequency response of the amplifier
checking the output waveform of the square wave.
ALIGNING THE IF RESPONSE OF FM OR TV
SETS
T o
check the overall response of the intermediate fre-
quency
transformers
of
an
R A N G E (6) should be set to E X T position. Then connect
the output leads of a sweep generator to the mixer and
chassis of the receiver and the sweeep output to the H.
I N P U T of the oscilloscope. Also, connect the oscilloscope
to the test point or output terminal of the limiter of the
FM receiver. This connection may be made by using a
shielded cable with about 1 0 0 k n resistor provided at the
point of
connection
to the receiver.
should be set to the maximum sensitivity while the sweep
generator output level should be set as low as possible. T h e
cable from the sweep generator and other leads from
CO-1506 must be adequately away from the body of the
receiver or must not cross each other to avoid interaction.
Frequency response of amplifier
Gain reduced at high-frequency
2
Gain rises at high-frequency
(3j
Gain reduced at low-frequency
Gain rises at low-frequency
®
With loudness control set ON.
(D
Gain having waving characteristic curve
by
F M
receiver, the
S W E E P
T h e oscilloscope
The above same connections also apply to the response
check of T V receivers for either the video I F or audio IF
response. Use point B for measurements of F M receiver I F
transformers and tracking, and use point A for detector
adjustment.
Sweep generator
T V receiver
Ratio detector
output
Sweep
generator
4 . 5 M H z
T o CO-1506
To the E X T S Y N C / H . I N P U T terminal of CO-1506
Fig. 10 Viewing the SF frequency responses
Square wave output
lOOHz
1 0 . 7 M H z
FM receiver
7 6 - 9 0 M H z
_Detector
joutputl
To CO-1506
I K H z
9
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