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Radio Shack DSP-40
DSP Noise Reduction System
Measured Performance

I connected the DSP-40 to an audio test system and made the following
measurements.

Frequency Response:

  DSP Out Mode	20 - 20000 Hz (-6 dB)

  NR Mode	    -3 dB	   -10 dB	   -30 dB
    Wide	 160 - 3000	 120 - 3200	  60 - 3500	Hz	
    Medium	 160 - 2500	 120 - 2800	  60 - 3100	Hz
    Narrow	 160 - 2000	 120 - 2300	  60 - 2600	Hz

  SSB Mode	    -3 dB	   -10 dB	   -30 dB
    Wide	 160 - 3000	 120 - 3200	  60 - 3500	Hz
    Medium	 500 - 2700	 270 - 2900	 100 - 3200	Hz
    Narrow	 820 - 2000	 520 - 2300	 200 - 2700	Hz

  CW Mode	    -3 dB	   -10 dB	   -25 dB
    Wide	 270 - 1230	 240 - 1280	 180 - 1360	Hz
    Medium	 470 - 1030	 430 - 1070	 360 - 1140	Hz
    Narrow	 600 -  900	 560 -  940	 500 - 1000	Hz


Maximum out-of-band rejection	30 dB (typ)
Notch filter depth (1 kHz)	50 dB


Bill McFadden 1995
billmc@rdrop.com