Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

How many bits will be used for my input of FFT design in OFDM?

Status
Not open for further replies.

siva_7517

Full Member level 2
Joined
Jan 16, 2006
Messages
138
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,296
Activity points
2,401
HI,

I am designing a FFT catered for OFDM application. My spec for the fft will 16-point design in radix-4. The problem is i am not sure how many bits will be used for my input of FFT. Can i asume the value that are going in is from -1 to 1? So, I can represent this value with 16 bit.
 

FFT design in OFDM

Hi
It depends on your ADC accuracy and wanted accuracy in that system.
 

Re: FFT design in OFDM

Please use a good test enviroment which monitors the wordlenght and clipping effects of you choice.

You model typical a fixed point in matlab instead of [-1..1] range. There are some libs which accelarate this tuning with C. The wordlenght for a specific S/N contribution of the FFT increase to the middle and then decrease again. If you make hardware reuse of a fixed lenght cell you have to design it for the middle stage execution. Allow seldom clipping if you use clipping in the logic. If you set the S/N be 2 bits better than the ADC you need about 5-6 bits more than the ADC.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top