Service Manual Part 1

8" 



  

81 111/113)6

 % ' !   

818 111/11#

The incoming signal from the antenna via the PIN switch passes through a band pass

filter to the RF amplifier, Q101. The 50Ω output from the amplifier is coupled to a sec-

ond band pass filter, and these two filters provide the spurious response rejection neces-

sary for the first mixer. An attenuator is provided at the output to allow for fine

adjustment of the front end gain.

The VCO output is fed to the first double balanced mixer via a low pass filter to reduce

harmonic content. The VCO signal is 61.9MHz below the RF signal and the first mixer

output (at 61.9MHz) feeds the first post-mixer buffer, Q103. The output of Q103 feeds a

band pass filter.