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kappasm
Joined: 08 Sep 2005
Posts: 3
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 21 Sep 2008 8:33 OFDM switch band ... |
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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.:
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m_pourfathi
Joined: 07 Feb 2008
Posts: 200
Helped: 13
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| 21 Sep 2008 9:22 Re: OFDM switch band ... |
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| Yes you need only the 64 MHz Clock. You should be able to change the bandwidth by changing the sampling period.
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kappasm
Joined: 08 Sep 2005
Posts: 3
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| 21 Sep 2008 9:33 Re: OFDM switch band ... |
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Thanks m_pourfathi,
| Quote: |
You should be able to change the bandwidth by changing the sampling period.
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But how to change the sample time ? Changing the clock scheme ? Do not distort the signal ?
Example:
| Code: |
Band | Clock Scheme | Sample time
----------------------------------------------------
8 MHz | 1010101010101010 | 7/64e6
7 MHz | 1101010100101010 | 8/64e6
6 Mhz | ??? | 7/48e6
5 MHz | ??? | ???
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You can give me an example ?
Kappa.
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