in DSP what do U mean by a 'Freq Component'... ...does it mean a "pure Sine Wave" OR "Any waveform with that many Zero Crossings"....? ..Thanks in advance, Shakes_ck
Hi, in DSP what do U mean by a 'Freq Component'...
Started by ●November 30, 2006
Reply by ●November 30, 20062006-11-30
shakes_ck wrote:> in DSP what do U mean by a 'Freq Component'... > ...does it mean a "pure Sine Wave" OR "Any waveform with that many Zero > Crossings"....?Pure sine wave. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●November 30, 20062006-11-30
Jerry Avins wrote:> shakes_ck wrote: > >> in DSP what do U mean by a 'Freq Component'... >> ...does it mean a "pure Sine Wave" OR "Any waveform with that many Zero >> Crossings"....? > > > Pure sine wave. >It comes from Fourier's work. He showed that any signal can be expressed as the sum of different sinusoidal signals. Whenever one of these stands out we call it a "component" or "frequency component". The zero crossings in a repetitive signal are often related to the component frequencies, but sometimes the relationship can be obscure. For the most part it's a different thing. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Posting from Google? See http://cfaj.freeshell.org/google/ "Applied Control Theory for Embedded Systems" came out in April. See details at http://www.wescottdesign.com/actfes/actfes.html
Reply by ●November 30, 20062006-11-30
On 30 Nov., 14:50, Jerry Avins <j...@ieee.org> wrote:> shakes_ck wrote: > > in DSP what do U mean by a 'Freq Component'... > > ...does it mean a "pure Sine Wave" OR "Any waveform with that many Zero > > Crossings"....? > > Pure sine wave.So a rectangular pulse, for example, has no frequency components?
Reply by ●November 30, 20062006-11-30
Andor wrote:> > On 30 Nov., 14:50, Jerry Avins <j...@ieee.org> wrote: >> shakes_ck wrote: >>> in DSP what do U mean by a 'Freq Component'... >>> ...does it mean a "pure Sine Wave" OR "Any waveform with that many Zero >>> Crossings"....? >> Pure sine wave. > > So a rectangular pulse, for example, has no frequency components?It has many. A pure sine has only one. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●November 30, 20062006-11-30
Andor wrote:> So a rectangular pulse, for example, has no frequency components?A rectangular pulse has infinitely many frequency components. The Fourier transform of a rectangular pulse is a sinc function, which is defined on all real numbers. It is zero on countably many points (all integers), but the real numbers are uncountable, so sinc is nonzero on infinitely many points, meaning it has an infinite number of frequency components. Jason
Reply by ●November 30, 20062006-11-30
cincydsp@gmail.com wrote:> Andor wrote: >> So a rectangular pulse, for example, has no frequency components? > > A rectangular pulse has infinitely many frequency components. The > Fourier transform of a rectangular pulse is a sinc function, which is > defined on all real numbers. It is zero on countably many points (all > integers), but the real numbers are uncountable, so sinc is nonzero on > infinitely many points, meaning it has an infinite number of frequency > components.He knows that. He intended his question to be a counterexample to my curt statement. I contended that it was not. Andor and I may soon be flinging definitions at ten paces, but we agree on what these things *are*. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●November 30, 20062006-11-30
On Thu, 30 Nov 2006 11:13:30 -0500, Jerry Avins <jya@ieee.org> wrote:>cincydsp@gmail.com wrote: >> Andor wrote: >>> So a rectangular pulse, for example, has no frequency components? >> >> A rectangular pulse has infinitely many frequency components. The >> Fourier transform of a rectangular pulse is a sinc function, which is >> defined on all real numbers. It is zero on countably many points (all >> integers), but the real numbers are uncountable, so sinc is nonzero on >> infinitely many points, meaning it has an infinite number of frequency >> components. > >He knows that. He intended his question to be a counterexample to my >curt statement. I contended that it was not. Andor and I may soon be >flinging definitions at ten paces, but we agree on what these things *are*. > >JerryJason's answer was still pretty good, though. I was impressed that he captured some concepts pretty clearly and concisely there. Eric Jacobsen Minister of Algorithms, Intel Corp. My opinions may not be Intel's opinions. http://www.ericjacobsen.org
Reply by ●November 30, 20062006-11-30
Eric Jacobsen wrote:> On Thu, 30 Nov 2006 11:13:30 -0500, Jerry Avins <jya@ieee.org> wrote: > >> cincydsp@gmail.com wrote: >>> Andor wrote: >>>> So a rectangular pulse, for example, has no frequency components? >>> A rectangular pulse has infinitely many frequency components. The >>> Fourier transform of a rectangular pulse is a sinc function, which is >>> defined on all real numbers. It is zero on countably many points (all >>> integers), but the real numbers are uncountable, so sinc is nonzero on >>> infinitely many points, meaning it has an infinite number of frequency >>> components. >> He knows that. He intended his question to be a counterexample to my >> curt statement. I contended that it was not. Andor and I may soon be >> flinging definitions at ten paces, but we agree on what these things *are*. >> >> Jerry > > Jason's answer was still pretty good, though. I was impressed that he > captured some concepts pretty clearly and concisely there.Yes. If I seemed to squelch him, I apologize to him. I intended only to give Jason some background into the dynamics of this group. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●November 30, 20062006-11-30
shakes_ck skrev:> in DSP what do U mean by a 'Freq Component'... > ...does it mean a "pure Sine Wave" OR "Any waveform with that many Zero > Crossings"....?It's a somewhat sloppy term, that most of the time means "sinusoidal", in the sense "sine wave", but which also can mean "spectrum coefficient". Rune
