Trev, I have tried to make some recordings of these signals, first as a wave and then converting to MP3. I have to do this because of the size of wave recordings.. However, I have encountered some problems, first, the sound card or chip in computers are intended for music and I am trying to record frequencies which are at the very end of scale. Secondly, I have tried several computers all of which have a AVC automatic volume control built in. Unfortunately this completely distorts the signal and the important variations which appear on the oscilloscope plot are lost. I need to try another method of approach.
On Sunday, March 2, 2014 9:15:41 AM UTC, John Dawes wrote: > > The attached Hum traces were taken on March 1 9.30 pm. > The undulations came in batches which lasted a bout 5 minutes. These were > separated by spaces of erratic levels which lasted about 15 minutes. > Whether these variations are accidental or deliberate and man made is > still open to question. > However, as one may see from the time scale, the period of these > undulations is in the same frequency range as that used by the human brain > which may explain some of the strange effects experienced by Hum sufferers. > > -- You received this message because you are subscribed to the Google Groups "Hum Sufferers" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/hum-sufferers. For more options, visit https://groups.google.com/d/optout.
