On Sun, Oct 2, 2016 at 2:40 PM, Cinaed Simson <cinaed.sim...@gmail.com> wrote:
> On 10/01/2016 04:46 PM, Juan Antonio wrote: > > Hello, someone would know how to calculate the impulse response of a > > COFDM, DVB-T channel with an SDR device? > > > > Thank you in advance > > > > > > _______________________________________________ > > Discuss-gnuradio mailing list > > Discuss-gnuradio@gnu.org > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > An inverse DFT on a sinc function in the frequency domain yields a sine > function in the time domain. And a DFT on the sine function in the time > domain yields a sinc function in the frequency domain. > No, the DFT of a sine function is an impulse. More formally, a Dirac delta function. The sinc function is the result of a truncated sine wave where the sine wave is multiplied by a square wave. The DFT of a square wave is a sinc, so with a truncated sine wave in the time domain, you are convolving a sinc with a delta function in the frequency domain. Tom > I presume the "C" in COFDM means to chop up the bandwidth into carriers > such that the sinc function in one channel hits nulls in the other > channels. > > Piece of cake in theory. > > There's a gr-dvbt project on github > > https://github.com/BogdanDIA/gr-dvbt > > I don't know anything about it - I don't even know if it works. > > -- Cinaed >
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