Re: LF: VLF exciter / signal generation in Spectrum Lab

["Markus Vester" <markusvester@aol.com>]

Wolf, Graham,

 

thanks Wolf for the interesting hint regarding the AudioIO.dll, I will need to look at it in detail.

 

Up to now I have mostly used the free version Virtual Audio Cable 3.12 http://software.muzychenko.net/eng/vac3.htm . I found it surprisingly simple to set up. The limitations are that it won't run with Windows 7 or 8, and that there is no audio reformatting, which means that channel number and samplerate of sink and source need to be the same. The latter may actually be an advantage, because the lack of resampling may help to avoid subtle frequency instabilities and glitches in the interpolation process.

 

For WSPR-X which requires a different samplerate, I have also used the stone-age analog routing from DAC to ADC through the Windows mixer, eg by the "stereo mix" input slider. This circumvents VAC-3 audio formatting issues, but usually requires a second physical soundcard in addition to the one which is feeding SpecLab in the first place.

 

Best 73,

Markus (DF6NM)

From: wolf_dl4yhf

Sent: Sunday, December 29, 2013 2:25 PM

To: rsgb_lf_group@blacksheep.org

Subject: Re: LF: VLF exciter / signal generation in Spectrum Lab

Hello Graham,

Am 29.12.2013 14:04, schrieb Graham:

Wolf,

 

Q How to  configure  SL  as audio  frequency   changer ?  

 

say   1500 Hz to  8 KHz , or , 8100 to  8200   etc

 

how is the  set  up  ?

The easiest way is using the 'narrowband filter', which can also shift frequencies.
Start by selecting 'Quick Settings' in the menu, then 'Other amateur radio modes', 'Narrow CW filter with adjustable xyz'. You can see the filter's passband on the main frequency scale, along with the 'zero beat' indicator similar to a web sdr. Grab the passband widh the mouse and move it to the 'source' frequency range. Alternatively, enter the frequency shift in numeric form on the filter control panel. Details:

http://www.qsl.net/dl4yhf/speclab/filters.htm#filter_controls_on_main_freq_scale

 

 

will SL  appeared as a  sound  source  ?

It can, but unfortunately only as an ASIO device. Microsoft's ever-changing driver model is so utterly complex that I gave up writing my own 'multimedia driver'. Also I didn't feel like re-inventing the wheel for XP, Vista, Win7, Win8, and whatever-comes-next...  :o)  Thus the easiest (??) method would be to use Virtual Audio Cable.

The more complex (but VAC-less) way, if ASIO is supported by the audio-receiving application, is decribed in the 'Audio I/O' manual:

http://www.qsl.net/dl4yhf/AudioIO/AudioIO_Manual.pdf

The relevant chapter would be "Installation of in_AudioIO.dll as an ASIO device".



Now back to the soldering iron..

73,  Wolf .