Hi, The attached file contains the results of an experiment in recording signals of short duration. Comments welcomed. Regards, Edgar Moonah, Tasmania. Attachment: signal stretching.zip Description:
Hi Edgar, It would be interesting to compare the spectra with the time- and frequency reassigned spectrogram. It is implemented in Spectrum Lab but needs a bit of tweeking (especially the FFT length)
Hi Wolf, Thank you for your feed back. A copy of the sound file for SRN Strahan is here. https://dl.dropboxusercontent.com/u/101251787/srn.wav Experimenting with the reassigned spectrogram gives this
Interesting experiment. Two sudden ideas... 1- Usually NDB are AM modulated, so you can find a continuous carrier with two keyed sidebands +- about 1000 Hz. Carrier and sidebands are phase correlated
Hello Claudio, Such a program already exists and is called NDBFinder. I have tried it and it works, but it takes time. I still prefer aural copy for the fun of it in a bandwidth of 10 - 20 Hz. 73, Ro
Hi Edgar, Similar results here, not too spectacular for such a strong signal. The signal was very narrow-band filtered so perhaps the reassigned spectrogram looks poorer than it should be (if there w
Hi Wolf, Claudio, and Roelof, Thank you for the feedback. The aim was to lengthen the short cycle signals, not to find them in background noise. The reassigns spectrum method helps as well. Experimen
