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Re: LF: Jason V0.99 with I/Q outputs

To: [email protected]
Subject: Re: LF: Jason V0.99 with I/Q outputs
From: Wolf DL4YHF <[email protected]>
Date: Sat, 15 Jan 2005 14:24:52 +0100
In-reply-to: <[email protected]>
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Hi Alberto,

Thanks for the new version ! The amplitude- and phase adjustment controls work fine, especially because they have an immediate effect on the output while transmitting. A maximum phase error of 0.1° should be good enough for 60 dB suppression of unwanted carrier + sideband, so 0.01° resolution for the control is accurate enough (thinking about the sideband suppression of "commercial" rigs, which are not better).

I found for my prototype phasing exciter, the optimum was exactly the default position (both controls in the center). Only one very little suggestion with minimum prioritiy: Show the slider positions as numeric values (for example, as a positive or negative percentage). This makes it simpler to return to the previous settings just in case something went wrong while tweaking, and one could use the same values in other programs too.

Closely related subject: When building my phasing exciter, I found the "balance" control of my audigy 2 soundcard has a much finer resolution than displayed on the slider control of the "sndvol32" control panel. But the finest increment steps can be realized by selecting the control, and then using the mouse wheel (up and down). You only see something happening on the screen every X-th step, but using an oscilloscope it is obvious that every step has an effect. Furthermore, you may SEE the "balance" control (in sndvol32.exe) exactly centered (on the screen), but in fact it *may* be not. Calibrating the amplitude balance via software would cure this, but only as long as no other program does not restore the soundcard settings (and set the balance control precisely to the center position) .

So much for now, leaving to enjoy the nice WX now ...

73, Wolf DL4YHF .




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