Steve Eddy said:
...do not recall saying individual electrons move with infinite velocity....infact, i have implied, by providing a relevant reference, that they move very slowly indeed!!!!very...very..slowly........have you good folk lost track...of reason?......sophistic misrepresentation....
...this 'electromagnetic wave propagation' nonsense is about cause and effect....radio waves...(remember transmitters??), are a special case of such....but just because a circuit can be persuaded to generate such does not mean this is the means by which electrons drift...kapitsch? phew.
.......profound nonsense...
....wakey wakey....
Dave said:
Hi dave ....group delay is defined as the rate of change of phase shift with angular frequency, d(theta)/d(omega)........in other words another way of describing phase shift ....
...took it as given that at the frequencies of interest such group delay is effectively non-existent....
...see
http://glossary.its.bldrdoc.gov/fs-1037/dir-017/_2508.htm
and..
http://ccrma-www.stanford.edu/~jos/filters/Group_Delay.html
...hope this helps...cheers
hope this helps...........
Group delay is the slope of the phase shift. It is very measurable over the audio range for such things as speakers and crossover filters. It also effects the impulse response. It is easily measured over the unity gain intercept bandwidth for an amplifier.
http://www.linkwitzlab.com/frontiers.htm#F
I am mystified at you giving exact definitions and links for the topics under discussion, and then ignoring their relevance and actual magnitudes. Terms like "another way of describing" and "is effectively non-existent" hardly demonstrates any feel for what these definitions really mean. Links from a search engine and quotes from text books hardly show much insight into the subjects. In other words, no, it doesn't help.
P.S. Its nonexistent not non-existent. If you are published much, they don't pay your editor near enough money for that much work.
http://www.m-w.com/
http://www.stthomas.edu/mgmtctr/Newsletter/email_tips.htm
mikek said:
Group delay is the slope of the phase shift. It is very measurable over the audio range for such things as speakers and crossover filters. It also effects the impulse response. It is easily measured over the unity gain intercept bandwidth for an amplifier.
http://www.linkwitzlab.com/frontiers.htm#F
I am mystified at you giving exact definitions and links for the topics under discussion, and then ignoring their relevance and actual magnitudes. Terms like "another way of describing" and "is effectively non-existent" hardly demonstrates any feel for what these definitions really mean. Links from a search engine and quotes from text books hardly show much insight into the subjects. In other words, no, it doesn't help.
P.S. Its nonexistent not non-existent. If you are published much, they don't pay your editor near enough money for that much work.
http://www.m-w.com/
http://www.stthomas.edu/mgmtctr/Newsletter/email_tips.htm
Congrats! But you don’t get $200:
Duhh ??? It is describing the derivative of phase against frequency. From acoustical perspective there is a correlation between the shape of the group delay curve and what you actually hear: Peaks in the group delay curve correspondents to “pitchy” sound at the same frequencies of the peaks in the curve. In other words it tells something about ringing.
No, not interesting at all if you are not stating the frequencies of interest at all and a particular audio device. But it appears to me that you never build a loudspeaker system yourself or implemented a parametric equaliser for instance.
Seen no arguments, what is not here can’t be lost.
Again, back to earth please.
Pjotr said:
Congrats! But you don’t get $200:
Duhh ??? It is describing the derivative of phase against frequency. From acoustical perspective there is a correlation between the shape of the group delay curve and what you actually hear: Peaks in the group delay curve correspondents to “pitchy” sound at the same frequencies of the peaks in the curve. In other words it tells something about ringing.
No, not interesting at all if you are not stating the frequencies of interest at all and a particular audio device. But it appears to me that you never build a loudspeaker system yourself or implemented a parametric equaliser for instance.
Seen no arguments, what is not here can’t be lost.
Again, back to earth please.
...so you do'nt think group delay is a function of phase shift?.....'pitchy sound'=more subjective stuff....tells you precisely nothing about ringing...which has more to do with the Q of your circuit than group delay...duh...
Re: hope this helps...........
...perhaps i could have been clearer...group delay is a function of phase shift.....does that make the whole more intuitive??
....'easily measured over the unity gain bandwidth of he amp'...which is of course not the bandwidth 'of interest' i was referring to...unless by some miracle you are able to hear sound at ultrasonic freqs.?
...'easily measured over the unity gain bandwidth of the amp'...that was never in dispute....and is as obvious as saying phase shift is measurable over the unity gain bandwith of the amp....
...and no...group delay is not 'the slope of the phase shift'....since you wish to demonstrate a penchant for precision, i suggest you get your definitions right before patronising anyone else...
...and this extremely silly notion that in the average audio frquency power amp. with feedback, (3db bandwidth~2hz~200khz), the impulse response will be significantly impaired by phase shift,...or indeed group delay is hilarious!!
...the impulse response of a power amplifier is invariably going to be swamped in practical use, (i.e:connected to 'speaker..?), by ringing courtesy of the output inductor resonating with transducer capacitance.....
.......the point i have been trying to make was made by D. Self a while a go, and i qoute:
' NO LINEAR CIRCUIT CAN INTRODUCE A PURE TIME DELAY; THE OUTPUT MUST BEGIN TO RESPOND AT OUNCE, EVEN IF IT TAKES A LONG TIME TO COMPLETE ITS RESPONSE.
IN THE TYPICAL AMPLIFIER THE DOMINANT POLE CAPACITOR INTRODUCES A 90 DEGREE PHASE SHIFT BETWEEN INPUT PAIR AND OUTPUT AT ALL BUT THE LOWEST AUDIO FREQUENCIES, BUT THIS IS NOT A TRUE TIME DELAY.
THE PHRASE DELAYED FEEDBACK IS OFTEN USED TO DESCRIBE THIS SITUATION, AND IT IS A WRETCHEDLY INACCURATE TERM; IF YOU REALLY DELAY THE FEEDBACK TO A POWER AMPLIFIER, (WHICH CAN ONLY BE DONE BY ADDING A TIME CONSTANt TO THE FEEDBACK NETWORK RATHER THAN THE FOWARD PATH), IT WILL QUICKLY TURN INTO THE PROVERBIAL POWER OSCILLATOR AS SURE AS NIGHT FOLLOWS DAY.'
....as for my english spelling skills,....get a life...you sound like Donald Rumsfeld,...all the vices of an american, with non of the virtues....
P.S As for dictionary link, we do'nt use Websters here in the UK, where we speak the real thing...
Fred Dieckmann said:
...perhaps i could have been clearer...group delay is a function of phase shift.....does that make the whole more intuitive??
....'easily measured over the unity gain bandwidth of he amp'...which is of course not the bandwidth 'of interest' i was referring to...unless by some miracle you are able to hear sound at ultrasonic freqs.?
...'easily measured over the unity gain bandwidth of the amp'...that was never in dispute....and is as obvious as saying phase shift is measurable over the unity gain bandwith of the amp....
...and no...group delay is not 'the slope of the phase shift'....since you wish to demonstrate a penchant for precision, i suggest you get your definitions right before patronising anyone else...
...and this extremely silly notion that in the average audio frquency power amp. with feedback, (3db bandwidth~2hz~200khz), the impulse response will be significantly impaired by phase shift,...or indeed group delay is hilarious!!
...the impulse response of a power amplifier is invariably going to be swamped in practical use, (i.e:connected to 'speaker..?), by ringing courtesy of the output inductor resonating with transducer capacitance.....
.......the point i have been trying to make was made by D. Self a while a go, and i qoute:
' NO LINEAR CIRCUIT CAN INTRODUCE A PURE TIME DELAY; THE OUTPUT MUST BEGIN TO RESPOND AT OUNCE, EVEN IF IT TAKES A LONG TIME TO COMPLETE ITS RESPONSE.
IN THE TYPICAL AMPLIFIER THE DOMINANT POLE CAPACITOR INTRODUCES A 90 DEGREE PHASE SHIFT BETWEEN INPUT PAIR AND OUTPUT AT ALL BUT THE LOWEST AUDIO FREQUENCIES, BUT THIS IS NOT A TRUE TIME DELAY.
THE PHRASE DELAYED FEEDBACK IS OFTEN USED TO DESCRIBE THIS SITUATION, AND IT IS A WRETCHEDLY INACCURATE TERM; IF YOU REALLY DELAY THE FEEDBACK TO A POWER AMPLIFIER, (WHICH CAN ONLY BE DONE BY ADDING A TIME CONSTANt TO THE FEEDBACK NETWORK RATHER THAN THE FOWARD PATH), IT WILL QUICKLY TURN INTO THE PROVERBIAL POWER OSCILLATOR AS SURE AS NIGHT FOLLOWS DAY.'
....as for my english spelling skills,....get a life...you sound like Donald Rumsfeld,...all the vices of an american, with non of the virtues....
P.S As for dictionary link, we do'nt use Websters here in the UK, where we speak the real thing...
..to continue..fred.
....its quite obvious that the word delay in the phrase group delay, is causing you some difficulty......this has nothing to do with signals arriving at the end af an audio amp. say a fortnight after they are applied to its input......to reiterate group delay is rate of change of phase shift with frequency.....do not imbue it with subjectively derived new-age holistic connotations beyond this simple...elementary definition...please.
cheers.
....its quite obvious that the word delay in the phrase group delay, is causing you some difficulty......this has nothing to do with signals arriving at the end af an audio amp. say a fortnight after they are applied to its input......to reiterate group delay is rate of change of phase shift with frequency.....do not imbue it with subjectively derived new-age holistic connotations beyond this simple...elementary definition...please.
cheers.
Re: Re: hope this helps...........
Perhaps you need to revisit your first year college mathematics as well. The slope of a curve at a particular point is defined as the slope of the tangent line to the curve at that point. Geometrically, the derivative of a function at a point is described by the slope of curve representing that function. The slope of the change phase divided by the change in frequency seems a valid description to me, but you will surly go in search of further semantic flaws. Perhaps you should have been a lawyer.
http://troi.cc.rochester.edu/~renz/Calcrev_files/frame.htm
I don't know where all these presumptions about the bandwidth and impulse response of audio power amplifies come from. The phase margin and group delay are useful in amplifier design. Particularly into reactive loads. Many amplifiers don't use output inductors. Those that do usually have a damping resistor across it. Even an amplifier with a first order pole has an output impedance that is inductive unless an output network is used. I don't what "the average amplifier" means, but plenty have dominant above the lowest audio frequency. Perhaps if you didn't limit yourself to analysis of Mr. Self's designs you will see all kinds of exceptions to the "average amplifier " generalization. Sorry that you fee that way about Mr. Rumsfeld. I have the greatest respect for Tony Blair but I won't get bogged down in political discussions here. Feel free to use the Oxford dictionary. I would think that someone demanding such precession from others in there post. You abuse of grammar, syntax, punctuation, and spelling; brings to mind post by the average 14 year old in a chat room. Do you refuse to write with literacy or you unable?
While you have your dictionary of choice out, check on the following:
freqs
patronising
bandwith
do'nt
qoute
english
american
mikek said:
...perhaps i could have been clearer...group delay is a function of phase shift.....does that make the whole more intuitive??
....'easily measured over the unity gain bandwidth of he amp'...which is of course not the bandwidth 'of interest' i was referring to...unless by some miracle you are able to hear sound at ultrasonic freqs.?
...'easily measured over the unity gain bandwidth of the amp'...that was never in dispute....and is as obvious as saying phase shift is measurable over the unity gain bandwith of the amp....
...and no...group delay is not 'the slope of the phase shift'....since you wish to demonstrate a penchant for precision, i suggest you get your definitions right before patronising anyone else...
...and this extremely silly notion that in the average audio frquency power amp. with feedback, (3db bandwidth~2hz~200khz), the impulse response will be significantly impaired by phase shift,...or indeed group delay is hilarious!!
...the impulse response of a power amplifier is invariably going to be swamped in practical use, (i.e:connected to 'speaker..?), by ringing courtesy of the output inductor resonating with transducer capacitance.....
.......the point i have been trying to make was made by D. Self a while a go, and i qoute:
' NO LINEAR CIRCUIT CAN INTRODUCE A PURE TIME DELAY; THE OUTPUT MUST BEGIN TO RESPOND AT OUNCE, EVEN IF IT TAKES A LONG TIME TO COMPLETE ITS RESPONSE.
IN THE TYPICAL AMPLIFIER THE DOMINANT POLE CAPACITOR INTRODUCES A 90 DEGREE PHASE SHIFT BETWEEN INPUT PAIR AND OUTPUT AT ALL BUT THE LOWEST AUDIO FREQUENCIES, BUT THIS IS NOT A TRUE TIME DELAY.
THE PHRASE DELAYED FEEDBACK IS OFTEN USED TO DESCRIBE THIS SITUATION, AND IT IS A WRETCHEDLY INACCURATE TERM; IF YOU REALLY DELAY THE FEEDBACK TO A POWER AMPLIFIER, (WHICH CAN ONLY BE DONE BY ADDING A TIME CONSTANt TO THE FEEDBACK NETWORK RATHER THAN THE FOWARD PATH), IT WILL QUICKLY TURN INTO THE PROVERBIAL POWER OSCILLATOR AS SURE AS NIGHT FOLLOWS DAY.'
....as for my english spelling skills,....get a life...you sound like Donald Rumsfeld,...all the vices of an american, with non of the virtues....
P.S As for dictionary link, we do'nt use Websters here in the UK, where we speak the real thing...
Perhaps you need to revisit your first year college mathematics as well. The slope of a curve at a particular point is defined as the slope of the tangent line to the curve at that point. Geometrically, the derivative of a function at a point is described by the slope of curve representing that function. The slope of the change phase divided by the change in frequency seems a valid description to me, but you will surly go in search of further semantic flaws. Perhaps you should have been a lawyer.
http://troi.cc.rochester.edu/~renz/Calcrev_files/frame.htm
I don't know where all these presumptions about the bandwidth and impulse response of audio power amplifies come from. The phase margin and group delay are useful in amplifier design. Particularly into reactive loads. Many amplifiers don't use output inductors. Those that do usually have a damping resistor across it. Even an amplifier with a first order pole has an output impedance that is inductive unless an output network is used. I don't what "the average amplifier" means, but plenty have dominant above the lowest audio frequency. Perhaps if you didn't limit yourself to analysis of Mr. Self's designs you will see all kinds of exceptions to the "average amplifier " generalization. Sorry that you fee that way about Mr. Rumsfeld. I have the greatest respect for Tony Blair but I won't get bogged down in political discussions here. Feel free to use the Oxford dictionary. I would think that someone demanding such precession from others in there post. You abuse of grammar, syntax, punctuation, and spelling; brings to mind post by the average 14 year old in a chat room. Do you refuse to write with literacy or you unable?
While you have your dictionary of choice out, check on the following:
freqs
patronising
bandwith
do'nt
qoute
english
american
Re: Re: Re: hope this helps...........
...my dear....dear....dear....fred........ ....if you you are going to differentiate something, its got to be with respect to something else....
......lets give this a rest fred...really...you are getting hot under the collar...not good for your health.......cheers.
...OH...and feel has an 'l' at the end of it....
AND ,moreover, its 'precision', and not' preccesion'...
Fred Dieckmann said:
...my dear....dear....dear....fred........ ....if you you are going to differentiate something, its got to be with respect to something else.... ......lets give this a rest fred...really...you are getting hot under the collar...not good for your health.......cheers.
...OH...and feel has an 'l' at the end of it....
AND ,moreover, its 'precision', and not' preccesion'...
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