The lower sideband signal file is useful as a test source as it exists, however I discovered an anomaly that I am trying to track down.
The signal contained in the .wav file is a LSB signal with carrier inserted. I generated the signal utilizing the Matlab modulate.m function. At first I thought the presence of the carrier was a function of the Matlab function. Further testing (including coding my own SSB generation code from first principles) showed a definite presence of an unsuppressed carrier that shouldn't be there. Further investigation has shown the undesired carrier is not present if I generate test tones mathematically. Whenever I input an audio signal either by way of a .wav file or directly from the microphone through the sound card the undesired carrier appears. Inspection of the spectra of the generated signal within Matlab using an FFT shows the same spectral characteristics as displayed in SDRadio. So it seems that the undesired carrier is somehow caused by the sampling associated with the sound-card and/or .wav file. I'm going to try running the audio through a 300Hz to 3kHz BPF before applying it to the modulator to see if I can eliminate the carrier. Once I solve this issue I'll generate some proper LSB, USB, DSB, AM and FM test files. -Ray WB6TPU --- In [email protected], "i2phd" <[EMAIL PROTECTED]> wrote: > > --- In [email protected], "raymonda58" <[EMAIL PROTECTED]> > wrote: > > > > In the WB6TPU folder there is a file labeled ssb_out.wav. This is a > > recording of a 12kHz lower sideband signal with carrier. It was > > recorded with a 44.1kHz sampling rate. > > [...] > > Ray, > > many thanks for that recording, and also for the Matlab script, > which I will surely use for some testings. > I have been able to listen to your voice using another SDR-like > program which I am currently developing, and which has a WAV input > feature. Probably I will use this code also for giving SDRadio the > possibility to work not only live, but also from a WAV file. > > 73 Alberto I2PHD Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/soft_radio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
