Dsp Tools; Slope Tuning (Ssb/Am); If Shift (Cw) - Kenwood TS-870S Instruction Manual

REJECTING INTERFERENCE
DSP TOOLS
SLOPE TUNING (SSB/AM)
Changing the positions of the LO/WIDTH and HI/SHIFT
controls while in SSB or AM made changes the cut-off
frequencies for the receive pass band. Controlling the
pass band in this way allows you to eliminate adjacent
frequency interference.
Turn the LO/WIDTH contro! clockwise to raise the
high-pass filter cut-off frequency; turn it
counterclockwise to lower the cut-off frequency. This is
effective in removing interference from frequencies
lower than your current operating frequency.
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Turn the H/SHIFT control clockwise to raise the
low-pass filter cut-off frequency; turn it
counterclockwise to jower the cut-off frequency. This is
effective in removing interference from frequencies
higher than your current operating frequency.
Using only these controls, you can eliminate a great
dea of interference on the phone bands. By using both
controls together carefully, you will increase your ability
to pick out weak signals from the interference.
Frequency Selections
LO/WIDTH SSB | 9, 50, 100, 200, 300, 400,
Control | 500, 600, 800, 1000 Hz 200: He
(high-pass
fiter cuett): AM
|, 100, 200, 500 Hz
100 Hz
HUSHIFT ; 1.4, 1.6,1.8,2.0,2.2,24, |
Control | S28) 2'6 2.8, 3.0, 3.4, 4.6, 6.0 kHz 76 KHz
low-pass sy Cutoff), AM | 2.5, 3.0, 4.0, 6.0, 6.0, 7.0 kHz! 6.0 kt
IF SHIFT (CW)
For CW, the center frequency of the filter pass band can
be shifted without changing the current receive
requency. This is an additional method of fighting
adjacent frequency interference. Change the CW
center frequency by adjusting the HI/SHIFT contral.
When the control is adjusted, "SHIFT" and the newly
selected center frequency appears on the Display.
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Be aware that shifting the CW center frequency does
not automatically adjust the receive CW pitch.
Therefore, it is possible to shift the CW pass band such
that the selected CW pitch frequency falls outside the
pass band. Doing this makes the CW signal inaudiole.
Example:
Before adjusting IF Shift:
+ CW oitch: 900 Hz
» IF Shift 800 Hz (center frequency)
+ CW Width: 600 Hz
In this example, the pass band would lie from
500 ~ 1100 Hz (from 300 Hz below the center frequency
of 800 Hz to 300 Hz above the center frequency). Hi the
CW pitch was set for 900 Hz, the signal would be
audible.
After adjusting IF Shift:
* CWoitch: 900 Hz
+ IF Shift: 500 Hz (center frequency)
+ CW Width: 600 Hz
900 Hz pitch 900 Hz pitch
500 800 1100 200 500 800
Now, the pass band would lie from 200 ~ 800 Hz. With
the CW pitch set for 900 Hz, the signal would not be
audible since the pitch frequency is 100 Hz above the
upper edge of the pass bard. In this case, to make the
signal audible, lower the CW pitch frequency by at least
100 Hz.
Freq./ Filler | Frequency Selections | Default
Relationship (Hz) Freq.(Hz)
cw! Center | 400, 450, 500,550, | 800
frequency | 800. 650, 700, 750,
800. 850, 900, 950,
4000
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