[TenTec] UCW and LCW

Sinisa Hristov shristov at ptt.yu
Fri Nov 3 14:34:49 EST 2006


Ron Morell wrote:
 
> As a practical matter it seems to completely eliminate some
> interfering signals when I change from UCW to LCW.


Ron, could you, please, try it again,
taking care about following:

  a) exactly the same BW is used on both UCW and LCW
     (BW can be altered by pressing LCW/UCW);

  b) PBT = 0;

  c) the roofing filter used is significantly wider than BW,
     i.e. 1 kHz filter with 400 Hz BW.

Under above conditions there should be no change in inteference level,
no matter what the inteference frequency is. This follows from the
symmetry of filter's response - Orion's DSP filters are very accurately
symmetrical.

Some asymmetry may be introduced by roofing filters, 
but nevertheless for interference reduction one should
rely on reducing BW, and not on UCW/LCW switching.


73,

Sinisa  YT1NT, VE3EA




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