INTERFERENCE REJECTION(SIGNALS WITHIN 3KHZ)

IF NOTCH FILTER OPERATION (SSB/CW/RTTY/PKT/AM MODES)

The IF Notch filter is a highly-effective system that allows you to slice out an interfering beat note or other carrier signal from inside the receiver passband.

1.Press the [NOTCH] button. The Notch characteristic will appear in the display to confirm that the Notch filter is engaged.

2.Initially, rough adjustment of the center frequency of the IF Notch Filter is adjusted using the outer [COARSE] knob; thereafter, fine tuning of the Notch frequency is adjusted using the inner [FINE] knob.

3.To switch the IF Notch filter off, press the [NOTCH] button once more. The Notch notation will turn off, confirming that the IF Notch filter is no longer operat- ing.

ADVICE:

￿The IF Notch filter affects the Main band (VFO-A) only.

￿You may observe the graphically-depicted peak (maxi- mum null) position of the IF Notch Filter in the NOTCH indicator on the display.

￿The width of the IF Notch null may be adjusted using Menu item “092 rdSP NOTCH W.” Both “Wide” and “Narrow” selections are available, with “Narrow” pro- viding the least disruption of the “desired” signal.

￿When the optional DMU-2000Data Management Unit is connected, the effect of the IF Notch filter may be observed on the Audio Scope (on the “Oscilloscope” page). The Notch will be observed as a “dip” in the noise platform observed. What’s more, the “Waterfall” display may be used to observe the effect of the IF Notch filter, which will appear as a white area in the colored background area. The tuning rate for the IF Notch is somewhat slow while you adjust the [FINE] knob, so the use of the Waterfall display to confirm proper adjustment is highly recommended.

NOTCH Indicator

[NOTCH] Button

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[NOTCH] Knob

The performance of the IF Notch filter is shown in Figure “A,” where the effect of rotation of the [NOTCH] knobs is depicted. In Figure “B,” you can see the notching effect of the IF Notch filter as you rotate the [NOTCH] knobs to eliminate the incoming interference.

A

B

Desired Signal

Desired Signal

QRM

QRM

(Heterodyne)

(Heterodyne)

IF

IF

BANDWIDTH

BANDWIDTH

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FT-2000 OPERATING MANUAL