I have some questions regarding implementing OFDM in Simulink... I'm using BPSK, thus my output after BPSK would be a complex number. I've splited up the real (16 samples) and imag (16 samples) numbers into 2 matrices. I plan to use IFFT with 64 samples. Except for the DC (sample 1), Nyquist center frequency (sample 32) and the real (13~31) and imag (33~48) samples at both sides of the Nyquist center, i want to pad it with zeros. However, the zero pad block only allows me to pad either from the beginning or from the end. How do i pad between selected rows, ie rows 2~12 and 49~64? This is the image of my OFDM transmitter in Simulink [url=http://img72.imageshack.us/my.php?image=p0io.jpg] [img=http://img72.imageshack.us/img72/4289/p0io.th.jpg][/url]