Icom IC-751A - Notch Filter Operation; Filter Switch Operation; Rit;^Itx Operation

7-8
NOTCH
FILTER OPERATION
CONTROL
NOTCH
SWITCH
7-9
FILTER SWITCH
OPERATION
-FILTER
SWITCH
7
-10
RIT/^TX
OPERATION
•
RIT OPERATION
This circuit
provides
high
attenuation
at
one
particular
frequency
in
the IF
passband.
It may
be
used
to
reduce
or
eliminate
interfering
heterodyne
signals
that fall
within
the
passband
of
the
receiver.
1)
Push
the NOTCH
FILTER
SWITCH
to the
ON
position (IN).
2)
Adjust
the NOTCH
FILTER
CONTROL
to
minimize
inter-
ference.
I
NOTCH FILTER
CHARACTERISTIC
This switch selects the different
combinations of
the internal receive
filters.
FILTER
SWITCH
SSB
CW/RTTY
*1
CW/RTTY
NARROW
AM FM
OUT
2.3kHz
*2
500Hz
500/250HZ
*4
8kHz 15kHz
IN
2.6kHz
*3
2.3kHz
500/250HZ
*5
3kHz
15kHz
*1
: ON
NARROW or RTTY NARROW mode requires either
an
optonal FL-52A or FL-53A narrow
filter.
*2,
*3:
Internal preset switch
S4
on the MAIN unit
reverses
these
narrow and wide filters:
FILTER SWITCH OUT:
2.3kHz
FILTER SWITCH
IN
:
500Hz
*4,
*5:
Internal preset switch
S3
on the MAIN unit reverses these
wide
and narrow filters:
FILTER SWITCH OUT:
3kHz
FILTER
SWITCH
IN :
8kHz
By
using the RIT circuit, it is
possible
to
shift the receive
frequency
up
to
9.9kHz
to either side of the
transmit frequency without
mov-
ing the transmit frequency. This
is. useful for
fine tuning stations
which
call
off frequency
or
for compensating
for frequency
drift.
1)
Push
RIT SWITCH to turn ON
the
RIT.
Receive : 14.267.8MHz
Transmit: 14.267.8MHz
"RIT"
displays.
USB
f~
RIT
1 P f, 1 R
n n n 1
/.
L
LI /.
LI
VfO A
LI. LI LI
1
1)
Push the RIT SWITCH
once
to
turn the RIT
circuit ON. The
letters “RIT" and the
amount of shift are
displayed.
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36
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