TS-5700
CIRCUIT DESCRIPTION
•
Noise Blanker Circuits
The 8.83MHz IF signal generated by the second
mixer is input to IF amplifier 011: 3SK131, passes
through buffer amplifier 09: RU201, and amplified by
noise amplifier 0800, 0802, and 0804: 2SC2714,
passes through buffer amplifier 0806: 2SC2714, and
noise-detected by 0800: MA716. This signal switches
0805 and 0807 to control 075 and 015. It changes
the source potential of the IF amplifier 011 and blanks
noise.
•
AGC Circuit
The part of the IF signal amplified by IC15: KCD11 is
envelope-detected for the AGC to control the AGC volt
age. The AGC voltage is applied to the first and second
amplifiers in IC15, the first IF amplifier 012: 3SK131,
and the second IF amplifier 011: 3SK131. The time
c o n s t a n t i s changed by a n a l o g s w i t c h IC4:
BU4066BCFV.
1 1
0
0
00
a::
R43
2nd IF
L802
O'>
0
00
a::
Fig. 7 Noise blanker circuits
RBK