next up previous contents
Next: Synchronization symbol Up: ADSL Modulation Methods Previous: Nyquist frequency

Modulation by the inverse discrete Fourier transform (IDFT)

The modulating transform defines the relationship between 512 real values and the

for k = 0 to 511.

The encoder and scaler, see figure gif, generate only 255 complex values of (plus zero at dc, and one real value if the Nyquist frequency is used). In order to generate real values of these values shall be augmented so that the vector has Hermitian symmetry.

Kimmo K. Saarela
Mon Mar 6 12:47:27 EET 1995