# how the fourier transfom actually used in elactronics

Discussion in 'General Electronics Chat' started by vead, Dec 11, 2013.

Nov 24, 2011
701
11
I am having problem to understand Fourier transform in practical way
I have done some work to understand Fourier transform
in communication signal can be represent in term of time and frequency

Time domain- curve of amplitude over time axis
example
I have 5volt amplitude signal that start with t=-1 and end with t=1
function f(x)= x limit -t to +t
f(x)=5 -1 to +1

frequency domain- curve of amplitude over frequency axis
I have 5volt amplitude signal that start with f=-3 hz and end with =3hz
function f(x)= x limit -fz to + fz
f(x)=5 -3 to +3

transform - convert one domain to another domain with no loss of information
frequency domain<> timedomain

can anyone tell me how to use fourier transform in practical way

2. ### blah2222 Well-Known Member

May 3, 2010
571
36
It can be very useful when you begin to look at system design, more specifically filter design. The ability to create systems that selectively pass certain signals at certain frequencies while they block signals at other frequencies.

The Fourier Transform is a tool that can be used to display useful frequency information of signals and frequency properties of systems.

The time domain of signals makes it very difficult to pick out frequency information, especially when there are multiple frequencies involved and at different amplitudes.

3. ### ramancini8 Active Member

Jul 18, 2012
461
129
When you want to amplify a complex waveform you need to know the highest frequency component (and its amplitude) to insure selection of an amplifier with the correct BW. The fourier transform does this for you.

4. ### crutschow Expert

Mar 14, 2008
16,174
4,318
The Fourier transform can be used whenever you want to know the frequency content of an arbitrary signal which is important if you want to process the signal. The Fast Fourier Transform (FFT) is commonly used by oscilloscopes and computers for this purpose.

Nov 24, 2011
701
11
thanks
Time domain- curve of amplitude over time axis
example
I have 5volt amplitude signal that start with t=-1 and end with t=1
function f(x)= x limit -t to +t
f(x)=5 -1 to +1

frequency domain- curve of amplitude over frequency axis
I have 5volt amplitude signal that start with f=-3 hz and end with =3hz
function f(x)= x limit -fz to + fz
f(x)=5 -3 to +3
please anyone tell me the relation between function , time limit,frequency limit, sin
why these used in signal analyses