energized, two 10-db T-pads are inserted
c e n t e r frequency of 10.7 mc, and a low-
in series between the output of the mixer
output impedance cathode follower, V211
s t a g e and the input to interstage trans-
which supplies driving power to the audio
f o r m e r T205. The second T-pad consists
a n d meter detectors within detector and
of resistors R3 (which is common to both
e l e c t r o m e t e r assembly A201. The band-
t h e first and second T-pad), R2, and R1.
width of the if. amplifier circuit is 80 kc
T h e if. signal has a path of continuity
through the movable contacts of relays K2
a. Interstate Transformer T205
and K1 (both in their energized conditions)
(fig. 25). The attenuated if. signal at con-
t o the two series-connected T-pads. The
nector J2 on if. step attenuator AT201 is
output signal at connector J2 is, therefore,
d c coupled, through resistor R250 to the
20 db smaller in amplitude than the circuit
p r i m a r y winding of T205. The signal is
c o n d i t i o n s present before energizing the
stepped up in amplitude by T205 secondary
two relays, K2 and K1.
winding, which is tuned to 10.7 mc when
t h i s winding is resonated with the paral-
40. If. Amplifier, Detailed Analysis
lel-connected capacitor C265. Resistor
(fig. 25 and 26)
R247 loads the secondary winding. The if.
T h e if. amplifier subassembly houses
s i g n a l is coupled from the secondary of
i n t e r s t a t e transformer T205, four ampli-
T205, through C266, to the grid of first if.
f i e r s V207 through V210 operating at a
a m p l i f i e r V207.
Figure 26. Tuning unit 2, if. amplifiers V209 and V210, schematic diagram.