# Time-domain to frequency domain

1. Jul 7, 2012

### justwild

How will the graph of a sine wave (plotted against time axis) of a particular frequency look like if the same is plotted against frequency???

2. Jul 7, 2012

### mathman

Single sine wave frequency domain graph is a delta function at the frequency of the sine wave.

3. Jul 7, 2012

### justwild

Do you mean that there will be single thin line rising upto 1 corresponding to that frequency only?

4. Jul 7, 2012

### davenn

from a practical point of view, for an example of this your could compare 2 different pieces if test equip used for measuring/displaying a signal
An Oscilloscope gives a time domain view ... the y ( vertical ) axis is amplitude
the x axis is time .... you will see the signal ( frequency ) displayed as a series of cycles on the screen

A Spectrum Analyser gives a frequency domain view .... again you have y axis as amplitude, but in the x axis is frequency, there is only that single vertical line representing that frequency

Dave

5. Jul 9, 2012

### PlanckShift

There is a second delta function at the negative frequency. In addition, there's a phase shift of \pi/2.