Operation
Digital Filter
The G90S has a built-in variable digital filter that can continuously adjust the
bandwidth of the filter and improve the anti-interference performance and
selectivity of the radio.
The G90S has two filter adjustment modes: center frequency point mode and
bandwidth mode.
1. Press [Multi-function adjustment knob] in a short time to respectively switch these two filter modes.
2. When the center frequency point mode is selected: The prompt text "Cxxx" appears on the filter icon
("xxx" refers to the center frequency point value) and the green vertical line displays on the orange
trapezoidal center.
3. When the bandwidth mode is selected: The prompt text "Cxxx" appears on the filter icon ("xxx" refers
to the bandwidth value) and the green vertical line displays on the both sides of orange trapezoid.
4. When the center frequency point mode or the bandwidth mode is selected, rotate the [Multi-function
adjustment knob] to adjust corresponding parameters.
Adjustment of the starting and cutoff frequencies of the filter:
1. Press [FUNC] key in a short time to enable the operation of the second function.
2. Respectively press [CMP/F-L] key and [NB/F-H] key and rotate the main knob to adjust the upper and
lower boundaries to form a filter with different bandwidths. Press the [CMP/F-L] key and [NB/F-H] key
again in a short time to display the current set bandwidth value B in the function display area of the screen.
F-L: Adjust the low-end cutoff frequency of the filter
F-H: Adjust the high-end cutoff frequency of the filter
The method to reset the default filter parameters:
1. Press [FUNC] key in a short time to enable the operation of the second function.
2. Long press [CMP/F-L] key or [NB/F-H] key to reset the starting and cutoff frequencies of the filter to
be initial values.
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Properly adjusting the filter parameters can greatly improve the performance of the receiver as well as
its sensitivity and signal to noise ratio.
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In CW mode, the digital filter can be minimized to 50Hz, but there will be obvious kettle effect.
Attention shall be paid to the selection of appropriate bandwidth to gain the best hearing.
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