Yaesu FT-450D Operation Manual

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Page 30 FT-450D OPERATION MANUALReferring to Figure “B”, this is default band-width.By rotating the [DSP/SEL] knob to the left,the bandwidth will narrow (see Figure “A”),while rotation of the [DSP/SEL] knob to theright, as depicted in Figure “C”, will widen thebandwidth.The default bandwidths, and total bandwidthadjustment range, will vary according to theoperating mode:SSB Mode: 1.8 kHz / 2.4 kHz / 3.0 kHz(Nominal: 2.4 kHz).CW Mode: 300 Hz / 500 Hz / 2.4 kHz(Nominal: 2.4 kHz).DATA Mode:300 Hz / 2.4 kHz / 3.0 kHz(Nominal: 2.4 kHz).AM Mode: 3.0 kHz / 6.0 kHz / 9.0 kHz(Nominal: 6.0 kHz).FM Mode: 2.5 kHz / 5.0 kHz(Nominal: 5.0 kHz).A B CWIDTH (I NTERFERENCE R EJECTION “S IGNALS WITHIN 3 KHZ ”)The IF Width tuning system allows you to vary the width of the DSP IF passband with three steps (FM: twosteps), so as to eliminate interference. Moreover, the bandwidth may actually be expanded from its defaultsetting, should you wish to enhance incoming signal fidelity when interference on the band is low.CONVENIENCE F EATURES1. Press the [DSP] button several times to set the“>” icon to the “WIDTH” indicator of the DSPGraphic Display on the display, to enable adjust-ment of the bandwidth by the [DSP/SEL] knob.2. Rotate the [DSP/SEL] knob to adjust the band-width. Counter-clockwise rotation reduces thebandwidth, while clockwise rotation increases thebandwidth.“WIDTH” Indicator[DSP] button[DSP/SEL] knobUsing IF Shift and Width TogetherThe IF Shift and Variable IF Width featurestogether form a very effective interference-fighting filtering system.For example, in Figure “A” you can see howinterference has appeared both on the highand low sides of the desired signal. By rotat-ing the [DSP/SEL](WIDTH) knob, as shownin Figure “B”, the interference from one sidecan be eliminated, and by re-positioning the[SHIFT] knob (Figure “C”), the interferenceon the opposite side can be removed, with-out re-introducing the interference previouslyeliminated in Figure “B”.Advice: For best interference reduction, theWidth and Shift features are the primary toolsyou should use. After narrowing the bandwidth(Width) and/or adjusting the center of thepassband (Shift), the Contour control mayalso yield additional signal-enhancement ben-efits on the net residual bandwidth. What’smore, the IF Notch Filter (see the next sec-tion) may also be utilized, in conjunction withthe three other filter systems, to significantadvantage.A B CIFBANDWIDTHIFBANDWIDTHIFBANDWIDTHIFBANDWIDTHIFBANDWIDTHIFBANDWIDTHDesired Signal Desired Signal Desired SignalQRMQRMQRMQRMQRMQRM