Specifications

4-15. Receiver Emphasis Type. - The emphasis type selection controls the de-emphasis
used only when the expander is switched out. The expander includes its own emphasis
system that cannot be modified. Emphasis selection for the "A" channel is made with jumper
block P4, and for the "B" channel with P5. The jumper positions (looking from the front of the
unit) are:
P4 or P5
75 uS
J.17
J.17
75 uS
P4 or P5
75 uS
J.17
J.17
75 uS
75µS CCITT J.17
4-16. Input Highpass Filter. - The 450 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 common to both channels, and is made with P8. The jumper positions (looking
from the front of the unit) are:
OUT
P8
IN
HPF
OUT
IN
OUT
P8
IN
HPF
OUT
IN
Highpass Highpass
Filter IN Filter OUT
450 Operation Manual Rev A Page 32 8/26/99