[TenTec] 100 Hz DSP CW filter response with Orion I V2.056

[Barry Gross]

When I measure the audio response, I find that the width at -6dB is 107hz
and at -60dB it's 298hz

Spectrum taken shown at http://n1eu.com/100hz_v2056.gif

73, Barry N1EU

On 3/11/06, Sinisa Hristov <shristov at ptt.yu> wrote:
>
> The following 100 Hz DSP CW filter response was measured
> with a calibrated signal fed directly to ADC input on A7 board.
>
> 156 Hz width at -6 dB
> 378 Hz width at -40 dB  (sidelobe peak)
> 512 Hz width at -49 dB  (sidelobe peak)
> 660 Hz width at -56 dB  (sidelobe peak)
> 796 Hz width at -62 dB  (sidelobe peak)
> 463 Hz width at -67 dB  (sidelobe peak)
> 1072 Hz width at -70 dB  (sidelobe peak)
> 1210 Hz width at -75 dB  (sidelobe peak)
>
> Both S meter and AGC respond happily to sidelobes as measured.
> The response is essentially the same as with V1 firmware.
>
> V2 apparently introduces an additional audio filter preventing
> sidelobes from being heard, which may be useful in some circumstances,
> although many would not call it "real" selectivity as the AGC is
> still being keyed by strong signals more than half a kHz away.
>
> Selectivity measurements by spectral analysis of the audio response
> to white noise will show combined selectivity of IF and audio filters.
>
> I wouldn't consider this a bug.
> It is an "unpublished feature", although somewhat misleading one.
>
>
> 73,
>
> Sinisa  YT1NT, VE3EA
>
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