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Fig. 14. Al ternately damping and adjusting the primary and secondary circuits
2. 3.3.2.2. R F and oscillator circuits
- Connect the indicator according to F ig, 14
- Connect the h.f. generator to the f.m. aerial input via impedance transformer PM 953 7
- Set the volume contro l o f the receiver to minimum
- Set the receiver to f.m. ( V H F)
-
Adjust the pointer to the mark on the dial given in the
- Set the receiver and the h.f. generator to the frequency ind icated in the tuning table of the receiver
-
Adjust the cores ot the h.f. and oscillator circuits to m aximum deflection
mentioned in the tuning table.
2.3.3.3. Checking and adjusting at TV sets
2. 3.3.3.1. G eneral
The i.f. a mplifier of a TV'set must meet several requirements:
- the
band-pass curve should have
in
which the low frequencies have the advantage with respect to
This i mplies, a mong others', that the carrier of the picture signal has to be attenuated by a factor 2 ( Fig. 15).
-
The sound carrier must be attenuated too : in
receivers 200 times (f3).
-
finally, complete suppression must t a ke p lace of the
the i mage carrier in the adjacent lower channel (f5).
f5 f3
Fig. 15. Idealiz ed band-pass curve of the i. f. amplif i e r of a TV set
v .
,
,
-
.
,
�
+
+
RF
OUT
MA 8296
tuning
a
correcting effect on the
frequency
inter-carrier receivers
sound
carrier in the adjacent higher channel (f4) and of
f1
MA8212
'
'
table
of the
receiver-documentation
of the
indicator
in
response curve
of
the transmitter
the
high frequencies.
12 to 20 times (f2), in separated
A f
A f1
=-
2
A f2 = -
--
12+20
A f
A f3=
--
200
A f4
A f5 = --
=
ft.
21
INDICATOR
(eg PM 2.03)
the
sequence
signal,
carrier
A f
--
A f
800
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