Yaesu FT-991 Operating Manual

Also see for FT-991: Manual Manual Operating manual Reference book Instruction manual

Page 39FT-991 O PERA T ING M ANUALIF BANDWIDTHDesired Signal Desired Signal Desired SignalQRMQRMIF BANDWIDTH IF BANDWIDTHMULTI MULTI MULTIinTerferenCe reJeCTioniF ShiFt operAtion (SSb/cw/rtty/pkt ModeS)IF SHIFT allows you to move the DSP filter passband higher or lower, without changing the pitch of the incoming sig-nal, and thus reduces or eliminates interference. Because the carrier tuning frequency is not varied, there is no need tore-tune the operating frequency to eliminate the interference. The total passband tuning range for the IF SHIFT systemis ±1 kHz.1. Touch [SHIFT] displayed by pressing the F(M-LIST) button repeatedly to reduce the interference.A dvice :The display will show the shift value of the IFSHIFT whenever [SHIFT] on the LCD is touched.Referring to Figure “A”, note the depiction of theIF DSP filter as the thick line, with MULTI knobin the 12 o’clock position. In Figure “B”, an in-terfering signal has appeared inside the originalpassband. In Figure “C”, you can see the effectof rotating the MULTI knob. The interferencelevel is reduced by moving the filter passband sothat the interference is outside of the passband.A B CF(M-LIST) Button