Jerry Avins wrote:> Jani Huhtanen wrote: >> Jerry Avins wrote: >> >>> Jani Huhtanen wrote: >>> >>> ... >>> >>>> Phase shift, in general, does not imply time shift. Only if the phase >>>> shift is _not_ a constant as a function of frequency, it implies time >>>> shift. Inverter is an example where phase shift does not imply time >>>> shift ;) >>> wt + phi = wt', where t' = t + phi/w. If phi is the phase shift, phi/w >>> is the time shift. If an inverter is an example of phase shift, does the >>> phase lead, or lag? >>> >>> Jerry >> >> By those definitions, I don't know. I thought that by time shift you >> meant group delay as you were also talking about transients. I'm not sure >> how "your" time shift relates to transients in question, however, IMO >> group delay would explain the transient behaviour intuitively (i.e., >> inverter does not delay nor advance the signal as the phase shift is 180' >> for all w). >Firstly, I have a feeling that I have somehow completely missed your point. Just to make sure, is this discussion purely on theoretic basis, or do the "problems" arise only when an analog inverter is actually implemented? I assume that this is a theoretic discussion ;)> 180 degrees lead, or 180 degrees lead? If inverted twice, is that 360 > degrees?Why would it matter? If I would have to answer that I would say that both, 180' and -180', but also any phase of form 360'*n+180'. And if inverted twice it would be just n*360'. By you definition of a timeshift it seems as if 370' phase shift would cause larger timeshift than 10'. Perhaps this is true for a sinusoid (however the results are identical), but it certainly does not tell that the delay would be more than in case of 10'. In general, single sinusoid of a more complex waveform does not carry information by which one could say anything about how much signal has been delayed.> An inverter works just fine with non-periodic waveforms, but > phase is a hard concept to force upon them.As far as I care, phase is a property of *a* sinusoid. More complex waveforms -periodic or not- are composed (or can be composed) of sinusoids. I don't force a concept of phase upon any other waveform (at least in the context of Fourier theory).> > Jerry-- Jani Huhtanen Tampere University of Technology, Pori
How does an inverter affect phase?
Started by ●June 15, 2006
Reply by ●June 19, 20062006-06-19
Reply by ●June 19, 20062006-06-19
Jerry Avins wrote:> Jani Huhtanen wrote: >> Jerry Avins wrote: >> >>> Jani Huhtanen wrote: >>> >>> ... >>> >>>> Phase shift, in general, does not imply time shift. Only if the phase >>>> shift is _not_ a constant as a function of frequency, it implies time >>>> shift. Inverter is an example where phase shift does not imply time >>>> shift ;) >>> wt + phi = wt', where t' = t + phi/w. If phi is the phase shift, phi/w >>> is the time shift. If an inverter is an example of phase shift, does the >>> phase lead, or lag? >>> >>> Jerry >> >> By those definitions, I don't know. I thought that by time shift you >> meant group delay as you were also talking about transients. I'm not sure >> how "your" time shift relates to transients in question, however, IMO >> group delay would explain the transient behaviour intuitively (i.e., >> inverter does not delay nor advance the signal as the phase shift is 180' >> for all w). >Firstly, I have a feeling that I have somehow completely missed your point. Just to make sure, is this discussion purely on theoretic basis, or do the "problems" arise only when an analog inverter is actually implemented? I assume that this is a theoretic discussion ;)> 180 degrees lead, or 180 degrees lead? If inverted twice, is that 360 > degrees?Why would it matter? If I would have to answer that I would say that both, 180' and -180', but also any phase of form 360'*n+180'. And if inverted twice it would be just n*360'. By you definition of a timeshift it seems as if 370' phase shift would cause larger timeshift than 10'. Perhaps this is true for a sinusoid (however the results are identical), but it certainly does not tell that the delay would be more than in case of 10'. In general, single sinusoid of a more complex waveform does not carry information by which one could say anything about how much signal has been delayed.> An inverter works just fine with non-periodic waveforms, but > phase is a hard concept to force upon them.As far as I care, phase is a property of *a* sinusoid. More complex waveforms -periodic or not- are composed (or can be composed) of sinusoids. I don't force a concept of phase upon any other waveform (at least in the context of Fourier theory).> > Jerry-- Jani Huhtanen Tampere University of Technology, Pori
Reply by ●June 19, 20062006-06-19
Jerry Avins wrote:> Jani Huhtanen wrote: >> Jerry Avins wrote: >> >>> Jani Huhtanen wrote: >>> >>> ... >>> >>>> Phase shift, in general, does not imply time shift. Only if the phase >>>> shift is _not_ a constant as a function of frequency, it implies time >>>> shift. Inverter is an example where phase shift does not imply time >>>> shift ;) >>> wt + phi = wt', where t' = t + phi/w. If phi is the phase shift, phi/w >>> is the time shift. If an inverter is an example of phase shift, does the >>> phase lead, or lag? >>> >>> Jerry >> >> By those definitions, I don't know. I thought that by time shift you >> meant group delay as you were also talking about transients. I'm not sure >> how "your" time shift relates to transients in question, however, IMO >> group delay would explain the transient behaviour intuitively (i.e., >> inverter does not delay nor advance the signal as the phase shift is 180' >> for all w). >Firstly, I have a feeling that I have somehow completely missed your point. Just to make sure, is this discussion purely on theoretic basis, or do the "problems" arise only when an analog inverter is actually implemented? I assume that this is a theoretic discussion ;)> 180 degrees lead, or 180 degrees lead? If inverted twice, is that 360 > degrees?Why would it matter? If I would have to answer that I would say that both, 180' and -180', but also any phase of form 360'*n+180'. And if inverted twice it would be just n*360'. By you definition of a timeshift it seems as if 370' phase shift would cause larger timeshift than 10'. Perhaps this is true for a sinusoid (however the results are identical), but it certainly does not tell that the delay would be more than in case of 10'. In general, single sinusoid of a more complex waveform does not carry information by which one could say anything about how much signal has been delayed.> An inverter works just fine with non-periodic waveforms, but > phase is a hard concept to force upon them.As far as I care, phase is a property of *a* sinusoid. More complex waveforms -periodic or not- are composed (or can be composed) of sinusoids. I don't force a concept of phase upon any other waveform (at least in the context of Fourier theory).> > Jerry-- Jani Huhtanen Tampere University of Technology, Pori
Reply by ●June 19, 20062006-06-19
Jerry Avins wrote:> Jani Huhtanen wrote: >> Jerry Avins wrote: >> >>> Jani Huhtanen wrote: >>> >>> ... >>> >>>> Phase shift, in general, does not imply time shift. Only if the phase >>>> shift is _not_ a constant as a function of frequency, it implies time >>>> shift. Inverter is an example where phase shift does not imply time >>>> shift ;) >>> wt + phi = wt', where t' = t + phi/w. If phi is the phase shift, phi/w >>> is the time shift. If an inverter is an example of phase shift, does the >>> phase lead, or lag? >>> >>> Jerry >> >> By those definitions, I don't know. I thought that by time shift you >> meant group delay as you were also talking about transients. I'm not sure >> how "your" time shift relates to transients in question, however, IMO >> group delay would explain the transient behaviour intuitively (i.e., >> inverter does not delay nor advance the signal as the phase shift is 180' >> for all w). >Firstly, I have a feeling that I have somehow completely missed your point. Just to make sure, is this discussion purely on theoretic basis, or do the "problems" arise only when an analog inverter is actually implemented? I assume that this is a theoretic discussion ;)> 180 degrees lead, or 180 degrees lead? If inverted twice, is that 360 > degrees?Why would it matter? If I would have to answer that I would say that both, 180' and -180', but also any phase of form 360'*n+180'. And if inverted twice it would be just n*360'. By you definition of a timeshift it seems as if 370' phase shift would cause larger timeshift than 10'. Perhaps this is true for a sinusoid (however the results are identical), but it certainly does not tell that the delay would be more than in case of 10'. In general, single sinusoid of a more complex waveform does not carry information by which one could say anything about how much signal has been delayed.> An inverter works just fine with non-periodic waveforms, but > phase is a hard concept to force upon them.As far as I care, phase is a property of *a* sinusoid. More complex waveforms -periodic or not- are composed (or can be composed) of sinusoids. I don't force a concept of phase upon any other waveform (at least in the context of Fourier theory).> > Jerry-- Jani Huhtanen Tampere University of Technology, Pori
Reply by ●June 19, 20062006-06-19
Jerry Avins wrote:> Jani Huhtanen wrote: >> Jerry Avins wrote: >> >>> Jani Huhtanen wrote: >>> >>> ... >>> >>>> Phase shift, in general, does not imply time shift. Only if the phase >>>> shift is _not_ a constant as a function of frequency, it implies time >>>> shift. Inverter is an example where phase shift does not imply time >>>> shift ;) >>> wt + phi = wt', where t' = t + phi/w. If phi is the phase shift, phi/w >>> is the time shift. If an inverter is an example of phase shift, does the >>> phase lead, or lag? >>> >>> Jerry >> >> By those definitions, I don't know. I thought that by time shift you >> meant group delay as you were also talking about transients. I'm not sure >> how "your" time shift relates to transients in question, however, IMO >> group delay would explain the transient behaviour intuitively (i.e., >> inverter does not delay nor advance the signal as the phase shift is 180' >> for all w). >Firstly, I have a feeling that I have somehow completely missed your point. Just to make sure, is this discussion purely on theoretic basis, or do the "problems" arise only when an analog inverter is actually implemented? I assume that this is a theoretic discussion ;)> 180 degrees lead, or 180 degrees lead? If inverted twice, is that 360 > degrees?Why would it matter? If I would have to answer that I would say that both, 180' and -180', but also any phase of form 360'*n+180'. And if inverted twice it would be just n*360'. By you definition of a timeshift it seems as if 370' phase shift would cause larger timeshift than 10'. Perhaps this is true for a sinusoid (however the results are identical), but it certainly does not tell that the delay would be more than in case of 10'. In general, single sinusoid of a more complex waveform does not carry information by which one could say anything about how much signal has been delayed.> An inverter works just fine with non-periodic waveforms, but > phase is a hard concept to force upon them.As far as I care, phase is a property of *a* sinusoid. More complex waveforms -periodic or not- are composed (or can be composed) of sinusoids. I don't force a concept of phase upon any other waveform (at least in the context of Fourier theory).> > Jerry-- Jani Huhtanen Tampere University of Technology, Pori
Reply by ●June 19, 20062006-06-19
Jerry Avins wrote:> Jani Huhtanen wrote: >> Jerry Avins wrote: >> >>> Jani Huhtanen wrote: >>> >>> ... >>> >>>> Phase shift, in general, does not imply time shift. Only if the phase >>>> shift is _not_ a constant as a function of frequency, it implies time >>>> shift. Inverter is an example where phase shift does not imply time >>>> shift ;) >>> wt + phi = wt', where t' = t + phi/w. If phi is the phase shift, phi/w >>> is the time shift. If an inverter is an example of phase shift, does the >>> phase lead, or lag? >>> >>> Jerry >> >> By those definitions, I don't know. I thought that by time shift you >> meant group delay as you were also talking about transients. I'm not sure >> how "your" time shift relates to transients in question, however, IMO >> group delay would explain the transient behaviour intuitively (i.e., >> inverter does not delay nor advance the signal as the phase shift is 180' >> for all w). >Firstly, I have a feeling that I have somehow completely missed your point. Just to make sure, is this discussion purely on theoretic basis, or do the "problems" arise only when an analog inverter is actually implemented? I assume that this is a theoretic discussion ;)> 180 degrees lead, or 180 degrees lead? If inverted twice, is that 360 > degrees?Why would it matter? If I would have to answer that I would say that both, 180' and -180', but also any phase of form 360'*n+180'. And if inverted twice it would be just n*360'. By you definition of a timeshift it seems as if 370' phase shift would cause larger timeshift than 10'. Perhaps this is true for a sinusoid (however the results are identical), but it certainly does not tell that the delay would be more than in case of 10'. In general, single sinusoid of a more complex waveform does not carry information by which one could say anything about how much signal has been delayed.> An inverter works just fine with non-periodic waveforms, but > phase is a hard concept to force upon them.As far as I care, phase is a property of *a* sinusoid. More complex waveforms -periodic or not- are composed (or can be composed) of sinusoids. I don't force a concept of phase upon any other waveform (at least in the context of Fourier theory).> > Jerry-- Jani Huhtanen Tampere University of Technology, Pori
Reply by ●June 19, 20062006-06-19
Jerry Avins wrote:> Jani Huhtanen wrote: >> Jerry Avins wrote: >> >>> Jani Huhtanen wrote: >>> >>> ... >>> >>>> Phase shift, in general, does not imply time shift. Only if the phase >>>> shift is _not_ a constant as a function of frequency, it implies time >>>> shift. Inverter is an example where phase shift does not imply time >>>> shift ;) >>> wt + phi = wt', where t' = t + phi/w. If phi is the phase shift, phi/w >>> is the time shift. If an inverter is an example of phase shift, does the >>> phase lead, or lag? >>> >>> Jerry >> >> By those definitions, I don't know. I thought that by time shift you >> meant group delay as you were also talking about transients. I'm not sure >> how "your" time shift relates to transients in question, however, IMO >> group delay would explain the transient behaviour intuitively (i.e., >> inverter does not delay nor advance the signal as the phase shift is 180' >> for all w). >Firstly, I have a feeling that I have somehow completely missed your point. Just to make sure, is this discussion purely on theoretic basis, or do the "problems" arise only when an analog inverter is actually implemented? I assume that this is a theoretic discussion ;)> 180 degrees lead, or 180 degrees lead? If inverted twice, is that 360 > degrees?Why would it matter? If I would have to answer that I would say that both, 180' and -180', but also any phase of form 360'*n+180'. And if inverted twice it would be just n*360'. By you definition of a timeshift it seems as if 370' phase shift would cause larger timeshift than 10'. Perhaps this is true for a sinusoid (however the results are identical), but it certainly does not tell that the delay would be more than in case of 10'. In general, single sinusoid of a more complex waveform does not carry information by which one could say anything about how much signal has been delayed.> An inverter works just fine with non-periodic waveforms, but > phase is a hard concept to force upon them.As far as I care, phase is a property of *a* sinusoid. More complex waveforms -periodic or not- are composed (or can be composed) of sinusoids. I don't force a concept of phase upon any other waveform (at least in the context of Fourier theory).> > Jerry-- Jani Huhtanen Tampere University of Technology, Pori
Reply by ●June 19, 20062006-06-19
Jerry Avins wrote:> Jani Huhtanen wrote: >> Jerry Avins wrote: >> >>> Jani Huhtanen wrote: >>> >>> ... >>> >>>> Phase shift, in general, does not imply time shift. Only if the phase >>>> shift is _not_ a constant as a function of frequency, it implies time >>>> shift. Inverter is an example where phase shift does not imply time >>>> shift ;) >>> wt + phi = wt', where t' = t + phi/w. If phi is the phase shift, phi/w >>> is the time shift. If an inverter is an example of phase shift, does the >>> phase lead, or lag? >>> >>> Jerry >> >> By those definitions, I don't know. I thought that by time shift you >> meant group delay as you were also talking about transients. I'm not sure >> how "your" time shift relates to transients in question, however, IMO >> group delay would explain the transient behaviour intuitively (i.e., >> inverter does not delay nor advance the signal as the phase shift is 180' >> for all w). >Firstly, I have a feeling that I have somehow completely missed your point. Just to make sure, is this discussion purely on theoretic basis, or do the "problems" arise only when an analog inverter is actually implemented? I assume that this is a theoretic discussion ;)> 180 degrees lead, or 180 degrees lead? If inverted twice, is that 360 > degrees?Why would it matter? If I would have to answer that I would say that both, 180' and -180', but also any phase of form 360'*n+180'. And if inverted twice it would be just n*360'. By you definition of a timeshift it seems as if 370' phase shift would cause larger timeshift than 10'. Perhaps this is true for a sinusoid (however the results are identical), but it certainly does not tell that the delay would be more than in case of 10'. In general, single sinusoid of a more complex waveform does not carry information by which one could say anything about how much signal has been delayed.> An inverter works just fine with non-periodic waveforms, but > phase is a hard concept to force upon them.As far as I care, phase is a property of *a* sinusoid. More complex waveforms -periodic or not- are composed (or can be composed) of sinusoids. I don't force a concept of phase upon any other waveform (at least in the context of Fourier theory).> > Jerry-- Jani Huhtanen Tampere University of Technology, Pori
Reply by ●June 19, 20062006-06-19
Jerry Avins wrote:> Jani Huhtanen wrote: >> Jerry Avins wrote: >> >>> Jani Huhtanen wrote: >>> >>> ... >>> >>>> Phase shift, in general, does not imply time shift. Only if the phase >>>> shift is _not_ a constant as a function of frequency, it implies time >>>> shift. Inverter is an example where phase shift does not imply time >>>> shift ;) >>> wt + phi = wt', where t' = t + phi/w. If phi is the phase shift, phi/w >>> is the time shift. If an inverter is an example of phase shift, does the >>> phase lead, or lag? >>> >>> Jerry >> >> By those definitions, I don't know. I thought that by time shift you >> meant group delay as you were also talking about transients. I'm not sure >> how "your" time shift relates to transients in question, however, IMO >> group delay would explain the transient behaviour intuitively (i.e., >> inverter does not delay nor advance the signal as the phase shift is 180' >> for all w). >Firstly, I have a feeling that I have somehow completely missed your point. Just to make sure, is this discussion purely on theoretic basis, or do the "problems" arise only when an analog inverter is actually implemented? I assume that this is a theoretic discussion ;)> 180 degrees lead, or 180 degrees lead? If inverted twice, is that 360 > degrees?Why would it matter? If I would have to answer that I would say that both, 180' and -180', but also any phase of form 360'*n+180'. And if inverted twice it would be just n*360'. By you definition of a timeshift it seems as if 370' phase shift would cause larger timeshift than 10'. Perhaps this is true for a sinusoid (however the results are identical), but it certainly does not tell that the delay would be more than in case of 10'. In general, single sinusoid of a more complex waveform does not carry information by which one could say anything about how much signal has been delayed.> An inverter works just fine with non-periodic waveforms, but > phase is a hard concept to force upon them.As far as I care, phase is a property of *a* sinusoid. More complex waveforms -periodic or not- are composed (or can be composed) of sinusoids. I don't force a concept of phase upon any other waveform (at least in the context of Fourier theory).> > Jerry-- Jani Huhtanen Tampere University of Technology, Pori
Reply by ●June 19, 20062006-06-19
Jerry Avins wrote:> Oli Filth wrote: >> Jerry Avins said the following on 19/06/2006 16:13: >>> Oli Filth wrote: >>> >>> ... >>> >>>> As for Jerry's example, let's suppose we had two components: >>>> >>>> x(t) = sin(w_1 t + phi) + sin(w_2 t + phi) >>>> >>>> We cannot transform this to x'(t') as we could for the >>>> single-frequency example. >>> >>> Sure we can. sin[w_1(t + phi/w_1)] + sin[w_2(t + phi/w_2)] >> >> >> t' = ??? > > t_1' = t + phi/w_1 t_2' = t + phi/w_2 Naturally, equal phase shifts > at different frequencies implies different time shifts. > > Show me a phase shifting scheme that inverts at DC, and I'll agree that > inversion and phase shift are equal. Until then, stick with Wikipedia. > > JerryDigital or analog? Convolve with -1 (or modulate, same operation). Or more complex, convolve with [0 -5 10 -10 5 -1]. Both have phase shift of 180' at DC, but latter only has the 180' shift on a certain band around DC while former has a constant phase shift. Of course just flipping the signs of the coefficients would make the phase shift 0'. -- Jani Huhtanen Tampere University of Technology, Pori
