How to change bandwidth and sample time in OFDM ?

[kappasm]

Hi,

I have implemented a system OFDM 2K with band of 8 MHz, style DVB-T. Using a system clock of 64 MHz everything works perfectly. Now I should be able to decrease the band OFDM to 7/6/5 MHz using the same 64 MHz clock. To get the bandwidth of 8 MHz in 2K (1705 active portant), simply clock output data from a IFFT at period of 7/64e6 = 109.375 nS.

In that way or with that technique can reduce the clock out for obtain 7/6/5 MHz of band ? Without necessarily changing the clock 64 MHz ?

Any idea ?

Thanks.

Kappa.:

 

[m_pourfathi]

Re: OFDM switch band ...

Yes you need only the 64 MHz Clock. You should be able to change the bandwidth by changing the sampling period.

 

[kappasm]

Re: OFDM switch band ...

Thanks m_pourfathi,

You should be able to change the bandwidth by changing the sampling period.

But how to change the sample time ? Changing the clock scheme ? Do not distort the signal ?

Example:

Band     |     Clock Scheme    |  Sample time
----------------------------------------------------
8 MHz    | 1010101010101010    | 7/64e6
7 MHz    | 1101010100101010    | 8/64e6
6 Mhz    | ???                 | 7/48e6
5 MHz    | ???                 | ???

You can give me an example ?

Kappa.