Radio WC6W wrote:
>
>Hello Everyone,
> It's been about a month since I first posted this topic and I thought
>I post an update.
>
> In response to the suggestions I received from my first posting, I've
>added a few features, modes... and a couple K of code.
>
> The unit now generates single tones (with a 2nd output in
>quadrature!), two tones, triple tones, and bandlimited white noise. All
>of these signals can either run continuously or be pulsed at a 50% duty
>cycle -- tentatively 10 cycles of the lowest frequency sine wave
>component or 10 mS for the noise.
>
If you're pulsing the composite signal, it would be important to have a
range of rates to test the effects on power supply regulation. Probably
1Hz, 10Hz and 100Hz would be enough, and 50% duty cycle looks OK to me.
> The two tone & three tone signals are summed digitally and are output
>via a single channel of the CD player DAC. Is there any application
>that would require two individual tones output separately via the R & L
>channels?
>
That depends on how good the IMD of the composite audio signal is. If
signals need to be kept separate for lower IMD, there is always the
possibility of using the two channels and summing externally.
> At the moment I have eight (single, pairs or triples) tone selections
>for each mode -- this could be easily increased to 16 with just a small
>addition to the tables.
>
> I'm still wondering if there are any specific frequencies or
>combinations, beyond those listed in the testing specs in part 2 of the
>FCC rules that are "must haves"?
>
> Always grateful for suggestions!
>
Hope this helps, and we're grateful for the work you're putting in!
73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.com/g3sek
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