I tend to agree with Tom as continuous tones are not representative of speech. I would think that ringing is involved, it is due to group delay and happens on transients. But I am not knowledgeable enough to elaborate further.
Jean-Claude PJ2BVU --- In [email protected], "Tom Holden" <[EMAIL PROTECTED]> wrote: > > I could not hear a difference on my notebook's poor sound system that would allow me to pick out which was which but I don't think we would hear any anyway on a simple steady-state signal such as this. It's a poor example. Group delay distortion is more discernable on transients and more complex waveforms. > > Why do finer multi-driver speaker systems attempt to time-align the drivers? Why do telecommunications systems control group delay on speech channels? Why is group delay controlled in analog television systems, in digital transmission systems? Because it can be a discernible and objectionable distortion if it's large enough and the signal or information is susceptible to it. But group delay does not generate new components in the signal - it just shifts them around in time. New waveform but the component frequencies and amplitudes are unchanged. > > I agree that the assertion misstates the nature of group delay distortion. > > Tom VE3MEO > > ----- Original Message ----- > From: i2phd > To: [email protected] > Sent: Friday, February 02, 2007 7:10 PM > Subject: [soft_radio] Re: Tecnical discussion > > > --- In [email protected], "in3otd" <claudio.girardi@> wrote: > > > > Maybe someone on the group who is less programming impaired than me > > could synthetically generate an SSB signal demodulated with different > > phase shifts to see if the differences can be heard... > > > > Best regards, > > > > Claudio, IN3OTD > > > > Claudio, > > no need to program anything to hear (or to not hear...) the > differences between two sounds with components of different phases. > > I generated with Adobe Audition a sound file with a 800 Hz tone, > summed with its second harmonic at 1600 Hz, which had 0 degrees of > phase difference at time 0 (arbitrarily chosen). > > Then I did the same, but now the phase difference at time 0 was 90 > degrees. > > I prepared a simple Web page where it is possible to see the two > waveforms (quite different one from the other) and to hear them. > To my ears they sound _exactly_ the same. The page is at > http://sundry.i2phd.com/phase.html > > This means that the following assertion probably is not valid : > > 5) If we put a multiple monochromatic signal in a system with flat > response, linear amplitude response and NOT flat group delay, > will the signal be distorted ? > > YES .NEW SIGNALS (DISTORTION )WILL BE CREATED FROM THE GROUP DELAY > BEING NOT FLAT ,LIKE WHEN THERE IS ONLY NON LINEAR AMPLITUDE > RESPONSE . > > 73 Alberto I2PHD > > > > > > [Non-text portions of this message have been removed] >
