# Sine wave frequency

Discussion in 'Electronic Design' started by thejim, Dec 11, 2005.

1. ### thejimGuest

I wanted to ask if the sine wave can only have 1 frequency which is
standard or it can take the form of more than 1 frequency.

2. ### Phil AllisonGuest

"thejim"

** A single frequency is a sine wave AND a sinewave is a single frequency.

Look up " simple harmonic motion " .

........... Phil

3. ### MacGuest

The simple answer is that in popular usage a sine wave is only a single
frequency.

But in the real world there is always noise riding on that sine wave, and
possibly other sine waves of smaller amplitude. So if you look at your
sine wave on a spectrum analyzer, you will find that the peak is not a
spike, such as you would see in a purely mathematical Fourier transform,
but is spread out over some frequency range.

You would also see that there are harmonics present. That is to say, there
are components at 2x, or 3x or some higher integer multiple of the
fundamental sine wave frequency.

sci.electronics.basic?

--Mac

4. ### Don LancasterGuest

A sinewave could only have a single frequency if it was on forever.
The switching envelope will otherwise interact with the sinewave itself.

Which is what windowing is all about.

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552

Please visit my GURU's LAIR web site at http://www.tinaja.com

5. ### Paul BurridgeGuest

People here seem to be forgetting it's a *pure* sine wave that
constitutes a single frequency. Any form of ' irregular sine wave'
will contain components of other frequencies and they may not be
apparent from visual examination of the wave on an oscilloscope. Their
presence undeniable, nevertheless.

6. ### MacGuest

True enough. And even if the sine wave did go on forever, you couldn't
measure its spectrum on a spectrum analyzer unless the spectrum analyzer
existed forever, and waited until after the end of time to display its
result.

But the simple answer is still "Yes, a sine wave is a single frequency." ;-)

--Mac

7. ### MacGuest

Which people are you talking about? Maybe there are some posts which have
not appeared on my server yet?

No, I don't see anyone who seems to be forgetting that.

--Mac

8. ### theJackalGuest

Digital communication engineers prefer viewing Sine waves and all
periodic functions in the frequency domain , which actually implies
analyzing their Fourier transforms. Accordingly you can view a Sine
wave as the sum of an infinite number of sinusoids having frequency
components which are integral multiples of the fundamental frequency.

"Go easy on the whisky"

theJackal

9. ### Phil AllisonGuest

"theJackal"

** Huh ??

Better lay off them hallucinogenics - mate.

......... Phil

10. ### theJackalGuest

ha ha You answer to the Op that that he needs to check up Simple
Harmonic motion to understand a Sine wave and now this . oh help my
soul!
You need basic education man ... The "average" engineer knows what
Monsier Joseph Fourier discovered more then 200 years ago
Sine (w*t) = a + (sum of ( bn* Cos n *w* t + phi (n)) The addition
is carried over for n that varies from 1 to infinity.

Phil
"Go easy on the whisky"

theJackal

11. ### Phil AllisonGuest

" The Jackass "

"Phil Allison"

** You are a schizo, fucking IDIOT - Piss Off .!!!!!!!!!!!!

** Absoulute rubbish.

A pure sine wave is a SINGLE frequency.

......... Phil

12. ### theJackalGuest

The two most common elements in the universe are Hydrogen and
stupidity.

Harlan Ellison

"Go easy on the whisky"

theJackal

13. ### Phil AllisonGuest

"theJackal"

** = the wog Jackass.

Must be one of them wannabe terrorist imbeciles.

......... Phil

14. ### theJackalGuest

Keep panting in your bottomless pit wannabe engineer.

"I actually prefer thugs to fools because they sometimes take a
rest"

"Go easy on the whisky"

theJackal

15. ### Phil AllisonGuest

"theJackal"

** Fucking wog psycho.

.......... Phil