Operation Manual

Page 29FT-450 OPERATION MANUAL
SHIFT
(
INTERFERENCE REJECTION “SIGNALS WITHIN 3 KHZ”
)
IF Shift allows you to vary the DSP filter passband higher or lower, without changing the pitch of the incoming
signal, so as to reduce or eliminate interference. Because the carrier tuning frequency is not varied, there is no
need to re-tune the operating frequency when eliminating the interference. The total passband tuning range for
the IF Shift system is ±1 kHz.
CONVENIENCE FEATURES
Rotate the
[
SHIFT
]
knob to the left or right to reduce
the interference.
You may observe the position of the passband in the
“SHIFT” indicator of the DSP Graphic Display on the
display.
“SHIFT” Indicator
[
SHIFT
]
knob
[
SHIFT
]
KNOB FULLY COUNTER-CLOCKWISE
[
SHIFT
]
KNOB 12 O
’
CLOCK POSITION
[
SHIFT
]
KNOB FULLY CLOCKWISE
IF
BANDWIDTH
IF
BANDWIDTH
IF
BANDWIDTH
Desired Signal Desired Signal Desired Signal
QRMQRM
-SHI FT+ -SH IFT + -SHI FT +
Referring to Figure “A”, note the depiction of
the IF DSP filter as the thick line, with the
[
SHIFT
]
knob in the 12 o’clock position. In
Figure “B”, an interfering signal has appeared
inside the original passband. In Figure “C”,
you can see the effect of rotating the
[
SHIFT
]
knob to reduce the interference level by mov-
ing the filter passband so that the interfer-
ence is outside of the passband.
A B C