45NOTCH, CONT/APFInner Knob (NOTCH)Rotate the inner [NOTCH] knob to adjust the cen-ter frequency of the IF NOTCH filter. Press the[NOTCH] key to turn the IF NOTCH filter ON orOFF.The null position of the IF NOTCH filter can be ob-served on the display.Additionally, the display will show the center fre-quency of the IF NOTCH filter for 0.5 second when-ever the [NOTCH] knob is turned.Press and hold to reset NOTCH, CONTOUR, APF.Outer Knob (CONT/APF)The DSP CONTOUR operation can alter the profileof the passband to partially attenuate an in-bandfrequency component.The CONTOUR operation can be switched ON/OFF with the [CONT] Key.The influence of CONTOUR is depicted graphicallyon the display.If there is interference or noise during CW opera-tion, the APF center frequency is automatically setto the CW PITCH frequency as a “peak filter”, tomake it easier to hear the desired signal.APF operation is switched ON / OFF with the [APF]key.The location of the APF peak frequency is graphi-cally illustrated on the display.When the knob is turned, the center fre-quency of NOTCH, the center frequencyof CONTOUR, or the Peak Frequency shiftwidth of the of the APF will be illustrated onthe display for 0.5 seconds.
