Filter
Top Products
26
Interference
Interference
Target signal
Interference
Interference
Target signal
Low-cut
Hi-cut
Fig. 20: Slope tune in action
●
RX DSP filters
In SSB, AM and FM modes, you can independently set high- and low-cut frequencies for the AF
filters to suit operating conditions (slope tune).
Fig. 20 illustrates how slope tune works. When there are interfering signals in proximity to the
target signal, you can use a high-cut filter and a low-cut filter to remove the signals above and
below the target.
In SSB mode, installing the optional SSB narrow filter results in even better interference reduction.
In AM mode if you select NAR, RX is possible using this SSB IF filter.
Listed below are the cutoff frequencies (unit: Hz) that can be chosen; default values are shown in
bold.
SSB/FM
Low-cut
0 50
100
200 300 400 500 600 700 800 900 1000
Hi-cut
1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000
3400
4000 5000
AM
Low-cut
0
100
200 500
Hi-cut
2500
3000
4000 5000
In CW and FSK modes, the AF filters function as a VBT, changing bandwidth without altering the
center frequency. In CW mode, the center frequency is coupled to the CW pitch, whereas in FSK
mode it is determined by the FSK tone and FSK shift frequencies.
Fig. 21 shows how it is possible during CW operations to extract a target signal from surrounding
interference by changing the AF filter bandwidth (WIDTH).