Koellner, Guenter DL4MEA schrieb:
>Hello Tobias,
>
>just a question, maybe I am simply missing something from the user manual: How
>do you change Winrad L.O. frequency by, e.g. 25kHz. I only found the method of
>tuning with the mouse wheel, while havign the mouse pointer above the digits
>of the L.O. display. So one can change by 10kHz, but this will be rounded down
>and so no actual change will happen. Maybe I have missed some possibility.
>
>73, Günter
>
>
Hallo Günter !
Assuming you have built a DLL as described in the "Winrad_Extio .pdf".
The procedure is : At WinRad init the DLL is told the LO frequency for
the VFO. This is remembered by the DLL as a local variable. Assume
7050.000 kHz,(VFO has 25 kHz stepwidth). Both WinRad and the DLL know
the LO at this time.
At any time the user changes the LO by any amount, say minus 1 Hz.
WinRad immediately is telling this to the DLL by the function SetHWLO (
parameter : new frequency= 7049999 Hz). The DLL calculates the frequency
difference (between current LO -from Startup- and wanted LO) and "tries"
to change the VFO to that frequency. BUT : The given frequency is not
at a pre-defined step width, so the decision is to change VFO to a
frequency that is AT LEAST one step away from the current LO. ( it may
not just round the frequency to the step-width, but has to obey the
user's wish to change frequency at some amount !!!) The next step in
that direction is 7050000 - 25000 = 7025000. The DLL sets the VFO to
7025.000 and calls the WinRad callback function using (-1,101,....) to
tell a status change. WinRad answeres by calling function GetHWLO of the
DLL. The DLL tells 7025000 as result of the call and WinRad displays
7.025.000 for LO on the screen. (and changes the tuned frequency, too,
by 25000 Hz). This is told back to the DLL by the tunedfrequency
function of the DLL.
That's all. Now both WinRad and the DLL have all informations about
frequencies they need to know. (At the next user input for LO changing
of minus 1 Hz the procedure will start again and would deliver 7000.000
kHz).
The DLL has just to be a little "creative" by interpreting the user's
wishes in accordance to the VFO's features. It at any time has complete
information and control about the frequencies involved and their "history".
73 de dg3lv Tobias
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