Ed et al, It seems to me that this thread is growing into a mountain and as a whole is providing a lot of individuals with the opportunity of allowing themselves to get more confused on this, oops excuse me, these subjects. Let's try to separate these subjects and maybe put some order to this seeming small cell of chaos and put this thread to rest. HARMONICS: The fundamental frequency is the first harmonic of a particular fundamental frequency (i.e., 1xfundamental frequency). Harmonics then usually start with the 2nd harmonic (2xfundamental) of the fundamental and go up from there (3rd=3x, 4th=4x, etc.). This is assuming that sub-harmonics and the fundamental waveshape characteristics are not significant issues. This is how it was taught in school and also how I've applied it since. It has worked well. As for DC, we all know that its frequency component is zero(0). So, assigning a frequency designation to it is ludicrous in the practical sense. F0: As for f0, this scheme was never intentioned to be an indicator of any frequency, particularly a frequency fundamental. Many communication systems text books, for example, try to make it simple to illustrate and describe relationships between 2 or more frequencies and by doing so utilize f0, f1, fn accordingly. OK, sometimes in these texts f0 sometimes equates to a fundamental frequency but this is purely coincidence. So, we can plainly see that some people are mixing these two methods together and getting something slightly slippery. Metaphorically speaking, don't each of us have to sift through the chaff to get to the wheat? And after all, is this f0 subject just a simple matter of semantics anyway. Just some humble opinions of mine that I thought might serve some useful purpose pertinent to this thread. Best regards, Ron Pickard [email protected] ______________________________ Reply Separator _________________________________ Subject: Re: Harmonics Author: <[email protected]> at INTERNET List-Post: [email protected] Date: 4/23/99 12:51 PM
Jeff: If the Fundamental is the First Harmonic, and should be written as F1 (and subse ent harmonics F2 and F3 being double and triple the Fundamental frequency), then 0, or the Zeroth Harmonic (being zero times the F1) is always zero Hz (aka DC). That sounds mathematically consistent. However, I have seen, countless times, the use of F0 to represent the fundamenta frequency of a signal. For instance, a frequency step from F0 to F0 + 1 MHz. Or asin a sweep from 20% below F0 to 20% above F0. Are we just looking at two different sides of the same elephant? Ed ------------------------ From: Jeff Chambers <[email protected]> Subject: Re: Harmonics Date: Fri, 23 Apr 1999 19:41:52 +0100 To: Gary McInturff <[email protected]>, "'[email protected]'" <[email protected]>, Robert Macy <[email protected]>, Scott Douglas <[email protected] > Cc: [email protected] > I don't think anybody's said this yet. Fo is used to signify the dc > component of the waveform. If a square wave switches from 0 to 5V, with a > 50% duty cycle, Fo = 2.5V. F1 is the fundamental (1GHz in your example), F2 > the second harmonic etc. The term 'first harmonic' is really a bit > confusing, and 'the fundamental' is better. > > Jeff Chambers > > ------------------------------------------------------------- > Dr Jeff Chambers > Westbay Technology Ltd > Suppliers of EMC Design Software > Tel: +44 1229 869 108 > Fax: +44 1229 869 108 > http://www.emcnet.com/westbay > [email protected] > > Main St > Baycliff > Ulverston > Cumbria LA12 9RN > England > ------------------------------------------------------------- > -----Original Message----- > From: Gary McInturff <[email protected]> > To: '[email protected]' <[email protected]>; Robert Macy > <[email protected]>; Scott Douglas <[email protected]> > Cc: [email protected] <[email protected]> > Date: 23 April 1999 18:07 > Subject: RE: Harmonics > > > >Jeeez, if we follow the convention of the harmonic being the being written > >as FX (and the fundamental F0) where the subscript is some integer which > >represents an harmonic and we include 0 as an integer, which is an integer > >by definition, then the fundamental or F0 is Fundamental times 0 or O > >Hertz, for all frequencies. The first harmonic must then be what we > >traditionally call the fundamental. The first harmonic, F1 then is the > >Fundamental times 1 and both the fundamental and the first harmonic are the > >same. > > By way of example. I choose 1 GHz (because it gives me heartburn in > >my equipment) > > The fundamental F0 = 1 Ghz times 0 = 0 Ghz. > > The first harmonic F1 = 1 Ghz times 1 = 1 Ghz > > Life sort of gets back to normal as we hit the second fundamental, > >but again that depends on which side of the argument which started all of > >this, you believe. > > The second harmonic F2 = 1 Ghz times 2 = 2 Ghz. Ad infinitum > >and ad nausium. > > > > Take care (but don't write back I will be off playing golf in > >California for the next week yea wooooo!) > > Gary > > > > > ---------------End of Original Message----------------- -------------------------- Ed Price [email protected] Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 List-Post: [email protected] Date: 04/23/1999 Time: 12:51:20 Military & Avionics EMC Services Our Specialty Also Environmental / Metrology / Reliability -------------------------- --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators). --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
