After IFFT you get a temporal signal which is expected because IFFT transforms
the FFT bins where you placed your QAM symbols into time domain. Now if you use
complex conjugate symbols on your frequency bins you will get a real temporal
signal, however this technique is wasteful. So to efficiently use the available
bins, the complex temporal signal is separated into real and imaginary signal
which, then, can be sent over a cosine and sine carrier or in other words sent
with a phase difference of pi/2.
Amit Pathania
--- On Mon, 11/3/08, Somayeh Mahmoodi wrote:
From: Somayeh Mahmoodi
Subject: Re: [matlab] ofdm simulation
To: m...
Date: Monday, November 3, 2008, 7:47 PM
hi dear,
yes, the output of IFFT is a time varying signal. infact in the output of IFFT
are the samples of time domain signal. if you take for example 128-point IFFT,
after IFFT you get 128 samples of time domain signal.
hope to be useful
--- On Sat, 11/1/08, mohamm1er wrote:
From: mohamm1er
Subject: [matlab] ofdm simulation
To: matlab@yahoogroups. com
Date: Saturday, November 1, 2008, 6:58 PM
hi all
I am simulatin ofdm using matlab,with 16QAM digital modulation.
now my out put from QAM is a complex number.when i apply this to IFFT i
am still getting a complex number(i was hoping to get time varying
signal).
any help
thanks