4-12. Input Highpass Filter.
The 455 Receiver input circuitry includes a highpass filter that is designed to prevent high level
video signals at the bottom of the baseband from overloading sensitive sections of the receiver. In
applications where video is present on the baseband, this filter should always be strapped IN.
In applications without video, where the entire baseband is dedicated to subcarriers, the filter
should be jumpered in the OUT position. The input highpass filter selection is made with
P8. P8 is located directly in front of the Baseband Loop-Thru OUT connector at the rear center
of the circuit board. The jumper positions (looking from the front of the unit) are:
Figure 4.1 P8 Settings for High Pass Filter IN
Figure 4.1 P8 Settings for High Pass Filter OUT
455 Operation Manual
Page 33
6/23/98
P8
J3
J2
J1 J4
OUT
IN
OUT
IN
P8
J3
J2
J1 J4
OUT
IN
OUT
IN
