12 REJECTING INTERFERENCE
NOTCH FILTER (SSB) | MANUAL BEAT CANCEL (ALL MODES) |
Auto Notch filter automatically locates and attenuates any single interfering tone within the receive pass band. This function operates digitally at the IF filter level, hence it can affect your
Receive pass band
Interfering tones
Desired signal
BeforeAfter
Press [A.N./ LEVEL] to toggle the Auto Notch Filter ON and OFF.
•“A.N.” appears when the function is ON.
•The interfering beat signals are notched out.
If the interfering beat signals change the tone frequency randomly, you can adjust the Auto Notch level.
Press [FUNC], [A.N./ LEVEL] to access the Auto Notch level adjustment, then turn the MULTI/ CH control to select the level from FIX, and 1 to 4.
Level 1 is the slowest beat tone tracking speed and Level 4 is the fastest. FIX terminates the beat tone tracking. Adjust this pamameter manually to remove the beat signal if necessary.
AUTO BEAT CANCEL (SSB/ AM)
Auto Beat Cancel uses an adaptive filter and attenuates more than one cyclic interference within the receive pass band. The adaptive filter changes its characteristics according to the nature of the signal being received at any given moment. You can use automatic Beat Cancel when in SSB or AM mode.
Receive pass band
Interfering tones
Desired signal
BeforeAfter
Press [B.C./ MANUAL] to toggle between the Auto Beat Cancel ON and OFF.
•“B. C.” appears when the function is ON.
Press [FUNC], [B.C./ MANUAL], then turn the MANUAL BC control to select the single Beat Cancel frequency manually. You can select the beat cancel frequency from approx. 300Hz to 3000 Hz by turning the control. Turn the control clockwise to select a higher frequency and counterclockwise to select a lower frequency.
Since the DSP Beat Cancel processes the incoming signals at the AF stage, strong beat signals may control the AGC, then weaken the target signal level. In this case, use the Auto Notch Filter instead, to remove the beat signal from the IF passband filter.
Note: While adjusting the MANUAL BC control, the transceiver clicks. This is not a malfunction.
NOISE REDUCTION
(N.R. 1: ALL MODES, N.R. 2: SSB/ CW/ FSK/ AM)
This transceiver provides two types of Noise Reduction functions (1 and 2) for reducing random noise which interferes with the desired signal. Trying them both is the easiest way to judge which function works more effectively under the current conditions. Normally, select Noise Reduction 1 (Line Enhanced) in SSB mode and Noise Reduction 2 (SPAC) in CW mode.
Press [N.R./ LEVEL] to toggle between Noise Reduction 1, Noise Reduction 2, and OFF.
•“
” or “
” appears, depending on which function is selected.
■Setting the N.R. 1 Level Adjustment
The Noise Reduction 1 (Line Enhanced Method) uses an adaptive filter to reduce the noise element from the received signals. When the S/N ratio is reasonably good in SSB, using N.R. 1 will improve the S/N further.
While N.R. 1 is ON, you can further adjust the noise reduction level by pressing [FUNC], [N.R./ LEVEL], then turn the MULTI/ CH control to select the level from 1 to 9 or AUTO. The default is AUTO.
■Setting the N.R. 2 Time Constant
You can change the correlation time for Noise Reduction 2 (SPAC). When in SSB mode, select the correlation time that allows you to hear signals with more clarity. When receiving CW, it is best to select the longest correlation time that allows reliable reception. The longer the correlation time, the better the S/N ratio.
When N.R. 2 is ON, press [FUNC],
[N.R./ LEVEL], then turn the MULTI/ CH control to select the correlation time from 2 ms to 20 ms. The default is 20 ms.
Note:
◆Using Noise Reduction 2 in SSB mode may lower the clarity of signals or induce pulse noise, depending on the conditions.
•If desired, you can manually control the beat cancel frequency.
◆Only Noise Reduction 1 is available for the
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