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TK-8100
24
■
IF Amplifier Circuit
The first IF signal is amplified by Q351, and the enters
IC301 (FM processing IC). The signal is heterodyned again
with a second local oscillator signal within IC301 to create a
450kHz second IF signal. The second IF signal is then fed
through a 450kHz ceramic filter (Wide : CF301, Narrow :
CF302) to further eliminate unwanted signals before it is am-
plified and FM detected in IC301.
Item
Rating
Nominal center frequency
49.95MHz
Pass bandwidth
±
5.0kHz or more at 3dB
35dB stop bandwidth
±
20.0kHz or less
Ripple
1.0dB or less
Insertion loss
5.0dB or less
Guaranteed attenuation
80dB or more at fo
±
1MHz
Spurious : 40dB or more within fo
±
1MHz
Terminal impedance
350
Ω
/ 5.5pF
Table 1 Crystal filter (L71-0591-05) : XF351
Item
Rating
Nominal center frequency
450kHz
6dB bandwidth
±
6.0kHz or more
50dB bandwidth
±
12.5kHz or less
Ripple
2.0dB or less
Insertion loss
6.0dB or less
Guaranteed attenuation
35.0dB or more within fo
±
100kHz
Terminal impedance
2.0k
Ω
Table 2 Ceramic filter (L72-0993-05) : CF301
Item
Rating
Nominal center frequency
450kHz
6dB bandwidth
±
4.5kHz or more
50dB bandwidth
±
10.0kHz or less
Ripple
2.0dB or less
Insertion loss
6.0dB or less
Guaranteed attenuation
55.0dB or more within fo
±
100kHz
Terminal impedance
2.0k
Ω
Table 3 Ceramic filter (L72-0959-05) : CF302
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CIRCUIT DESCRIPTION /
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