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565hilowcut [2007/05/20 19:43]
127.0.0.1 external edit
565hilowcut [2012/02/22 10:05] (current)
n1eu
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 ====== Orion Hi Cut / Low Cut Explained ====== ====== Orion Hi Cut / Low Cut Explained ======
-**From the Ten-Tec Reflector January 5, 2004**+**W4PA in 2004:**
  
 I'll try to explain Hi Cut / Lo Cut succinctly: I'll try to explain Hi Cut / Lo Cut succinctly:
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 The PBT and BW values are supposed to update on screen graphics and text - unfortunately compounding the confusion is a bug that is present when HI CUT is adjusted. ​ LO CUT shows the adjustment of PBT and BW values simultaneously,​ while HI CUT only shows the BW update, not the PBT value. This needs to be corrected. The PBT and BW values are supposed to update on screen graphics and text - unfortunately compounding the confusion is a bug that is present when HI CUT is adjusted. ​ LO CUT shows the adjustment of PBT and BW values simultaneously,​ while HI CUT only shows the BW update, not the PBT value. This needs to be corrected.
  
-Scott RobbinsW4PA+ 
 +---- 
 + 
 +**John Henry in 2012:** 
 + 
 +PBT allows the operator to move the signal down the slope of the filter to get away from interference. 
 + 
 +High cut only narrows the top half of the DSP filter and there is no need to change PBT because the signal is not being moved inside the filter pass band. So on Hi Cut only the narrowing of the high end of the filter is shown. 
 + 
 +On low cut it is necessary to move the signal with PBT to keep it centered inside the filter pass band. PBT and the band width on the display change because this is actually what is occurring with the filter. As low cut is moved not only is the low end of the filter being narrowed but the signal is constantly being moved by the PBT to keep it centered in the filter pass band. 
 + 
 +If you do watch when you change HiCutyou will see that the top limit of the filter moves and the bottom limit does not move. 
 +If you do watch when you change LoCut,you will see the low end of the filter move, and whereas the top end moves a tad, if you continue to move the low cut, you will see that the top is relatively the same. Shuffling a little up/down but basically close to the same point. 
 + 
 +It may be confusing a bit to see lo cut also adjusting PBT, but that is actually part of what is happening to keep the passband the same. 

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