Yaesu FT dx 1200 Operating Manual

Also see for FT DX 1200: Operation manual Operating manual Operating manual

Page 45FT D X 1200 O PERA T ING M ANUALconvenience featuresreceiver operAtion (Front end block diAgrAM)The FTDX1200 includes a wide range of special features to suppress the many types of interference that may be encoun-tered on the HF bands. However, real world interference conditions are constantly changing, so optimum setting of thecontrols is somewhat of an art, requiring familiarity with the types of interference and the subtle effects of some of thecontrols. Therefore, the following information is provided as a general guideline for typical situations, and a startingpoint for your own experimentation.The FTDX 1200 interference-fighting circuitry begins in its “RF” stages, and continues throughout the entire receiversection. FTDX 1200 allows configuration of the features described below.R. FLT (IF Roofing Filters)Three Roofing filters, of 15 kHz, 6 kHz, and 3 kHzbandwidths, are provided in the First IF, right after thefirst mixer. These filters are automatically selected toprovide narrow-band selectivity to protect the followingIF and DSP stages. The automatically selected filter maybe manually changed by the operator, if desired, for spe-cial operating circumstances.CONTOUR FilterThe DSP Contour filter has the unique ability to pro-vide either a null or a peak in tunable segments of thereceiver passband. You may suppress interference andexcessive frequency components on an incoming signal,or you may peak those tunable frequency segments. Thelevel of the null or peak, and the bandwidth, over whichit is applied, are adjustable via the Menu.IF SHIFTThe passband center frequency of the IF DSP filter maybe moved up or down by adjusting this control.IF WIDTHThe width of the IF DSP filtering may be adjusted usingthis control.IF NOTCHThe IF Notch filter is a high-Q notch filter that can elim-inate, or significantly reduce an interfering carrier.DNF (Digital Notch filter)When multiple interfering carriers are encountered dur-ing reception, the Digital Notch Filter can significantlyreduce the level of these signals.DNR (Digital Noise Reduction)The DSP’s Digital Noise Reduction (DNR) feature uti-lizes 15 different mathematical algorithms to analyzeand suppress different noise profiles encountered on theHF/50 MHz bands. Choose the selection that providesthe best noise suppression, and allows the signal to riseup out of the noise.AGCThe AGC system is highly adaptable to changing signaland fading characteristics, making reception possibleunder the most difficult conditions.Front end block diAgrAM