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RE: [linrad] Frequency reported incorrectly
- Subject: RE: [linrad] Frequency reported incorrectly
- From: Leif Asbrink <leif.asbrink@xxxxxxxxxxxxxxxxxxxx
- Date: Tue, 28 Oct 2003 23:36:37 +0100
> Please refer to the screenshot at
> Somehow, the frequency reported along the top of the screen is
> much to high. What you are looking at is about 7 hours of
> standard frequency station WWV at 5 MHz ending at about 13:00 UTC
> this morning. The receiver is set such that the main carrier
> going into the sound card is at about 600 Hz. Linrad reprorts a
> frequency of about 89438 Hz. What am I doing wrong? I am
> sampling at 44100 Hz.
You have entered 2.5 MHz into the frequency control box.
I do not know what hardware you use, direct conversion
or a conventional radio with filters.
What you observe is F=2489438 Hz.
I suggest you enter 0.0 into the frequency control box.
With a conventional radio you then get the signal at
about 600 Hz. With direct conversion the scale will
not go from -22050 to +22050, it will be shifted and
go from 0 to 44100 with 600 Hz audio at 21450 or at
22650 depending on the phase relation.
The idea is that you should supply the routines to control
your own hardware and to get the frequency scale correct.
The default routines fit the WSE converters.
Read about this in USERS_HWARE
> By the way, note the effect of the solar flare at about 11:00 UTC
> . The signal at 89478 is a reference at 5.000040 MHz derived
> from a GPS disciplined oscillator.
The baseband waterfall can be run at much higher resolution
simultaneously at very low cpu load if you are interested.
Leif / SM5BSZ