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Participant syalk1120
Participant
5,576 Views
Registered: ‎05-04-2009

FFT IP core only working at integer clk frequency?

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Does Vertex4 FFT IP core only work at integer clk frequency? At the IP customization,I cann't put in other frational frequency e.g 100.23MHz. Does it mean that FFT IP cann't support the clk frequency with fractional part?

Thanks

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1 Solution

Accepted Solutions
Xilinx Employee
Xilinx Employee
6,043 Views
Registered: ‎11-28-2007

Re: FFT IP core only working at integer clk frequency?

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Any value will be fine. One thing to keep in mind: if you check "Automatically Select" for the FFT implemention architecture, make sure the ratio of the target clock frequency and target data throughput match your actual application as a different ratio may make a tool to pick a different architecture than what you want.

 


@syalk1120 wrote:

jimwu,thanks for your reply.

And there comes another question: Will it be better that Target Clock Frequency is closer to  exact FFT input clk during customizing FFT IP? e.g. if the real input clk for FFT implementation is 212.45MHz,and should I customize the IP for 212MHz or just any random value is okay?Thanks!


 

Cheers,
Jim
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4 Replies
Xilinx Employee
Xilinx Employee
5,551 Views
Registered: ‎11-28-2007

Re: FFT IP core only working at integer clk frequency?

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Target Clock Frequency and Target Data Throughput are only used to automatically select an implementation and to calculate latency. You can connect a clock of any frequency to the clock input of the FFT core for implementation. Keep in mind though that you will get a difference latency if the actual clock frequency is different than the one you specified in CoreGen.

 


@syalk1120 wrote:

Does Vertex4 FFT IP core only work at integer clk frequency? At the IP customization,I cann't put in other frational frequency e.g 100.23MHz. Does it mean that FFT IP cann't support the clk frequency with fractional part?

Thanks


 

Cheers,
Jim
Participant syalk1120
Participant
5,500 Views
Registered: ‎05-04-2009

Re: FFT IP core only working at integer clk frequency?

Jump to solution

jimwu,thanks for your reply.

And there comes another question: Will it be better that Target Clock Frequency is closer to  exact FFT input clk during customizing FFT IP? e.g. if the real input clk for FFT implementation is 212.45MHz,and should I customize the IP for 212MHz or just any random value is okay?Thanks!

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Xilinx Employee
Xilinx Employee
6,044 Views
Registered: ‎11-28-2007

Re: FFT IP core only working at integer clk frequency?

Jump to solution

Any value will be fine. One thing to keep in mind: if you check "Automatically Select" for the FFT implemention architecture, make sure the ratio of the target clock frequency and target data throughput match your actual application as a different ratio may make a tool to pick a different architecture than what you want.

 


@syalk1120 wrote:

jimwu,thanks for your reply.

And there comes another question: Will it be better that Target Clock Frequency is closer to  exact FFT input clk during customizing FFT IP? e.g. if the real input clk for FFT implementation is 212.45MHz,and should I customize the IP for 212MHz or just any random value is okay?Thanks!


 

Cheers,
Jim
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Xilinx Employee
Xilinx Employee
5,185 Views
Registered: ‎08-01-2008

Re: FFT IP core only working at integer clk frequency?

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The only limitation is the clock source and frequency should be less than the maximum frequency supports by the FFT core.

 

Thanks and Regards
Balkrishan
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