184.108.40.206. Enabling the Buffered Burst FFT
When the FFT completes the transform of the input block, it asserts the source_valid and outputs the complex transform domain data block in natural order .
Signals source_sop and source_eop indicate the start-of-packet and end-of-packet for the output block data respectively.
- Deassert the system reset.
- Asserts sink_valid to indicate to the FFT function that valid data is available for input. A successful data transfer occurs when both the sink_valid and the sink_ready are asserted.
- Load the first complex data sample into the FFT function and simultaneously asserts sink_sop to indicate the start of the input block.
- On the next clock cycle, sink_sop is deasserted and you must load the following N – 1 complex input data samples in natural order.
- On the last complex data sample, assert sink_eop.
- When you load the input block, the FFT function begins computing the transform on the stored input block. Hold the sink_ready signal high as you can transfer the first few samples of the subsequent frame into the small FIFO at the input. If this FIFO buffer is filled, the FFT deasserts the sink_ready signal. It is not mandatory to transfer samples during sink_ready cycles.