[TenTec] Orion II NR Performance Measurements

Bill Tippett btippett at alum.mit.edu
Sun Mar 26 08:58:51 EST 2006


NQ5T:

 >The results are as follows (LCW, 1000Hz spot tone, NR=9)

 >BW=3000Hz: SNNR improves by approx 1dB with NR=9.

         Implies a noise bandwidth of ~2400 Hz.
Simply setting DSP BW = 1800 would improve S/N
by 2.2 dB, and going to 1500 Hz would improve
it by 3.0 dB.  These DSP BW settings require
PBT be set to ~200 Hz for best intelligibility.

 >BW=500Hz:  SNNR degrades by approx 2dB with NR=9.

         Degrades?...strange result!  This
implies a noise bandwidth of ~800 Hz.  Simply
turning DSP BW to 100 (which has an actual BW
of 150 Hz) should **improve** S/N by 5.2 dB.

         The 500 Hz result definitely means
something is not working correctly.

                                 73,  Bill  W4ZV




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