.. _rfft_performance_test:

RFFT 性能测试
==================

概述
------

rfft性能测试主要测试了DSP进行rfft变换的性能

程序设计
------------

软件生成生成几个幅值和相位不同的正弦波并叠加生成一个波形，然后使用rfft变换求出幅频特性数据，几个正弦波如下所示:

- 幅值11，频率8

- 幅值19，频率17

- 幅值13，频率24

硬件设置
------------

无特殊设置

性能优化
------------

- segger已经默认开启O3优化

运行现象
------------

当工程正确运行后，串口终端会输出采样点数，以及幅频特性的数据，以及每一个单元的运行时间，并在最后输出PASS或者ERROR NUM。

串口输出如下所示：


.. code-block:: console

   Rfft demo: 64.
   total times:5133 tick.
   ------------------------------------
   DC component amplitude:5.000004.
   Frequency:8.000000, Amplitude:11.000010.
   Frequency:17.000000, Amplitude:18.999992.
   Frequency:24.000000, Amplitude:13.000002.
   ------------------------------------
   Rfft demo: 128.
   total times:7956 tick.
   ------------------------------------
   DC component amplitude:4.999997.
   Frequency:8.000000, Amplitude:11.000002.
   Frequency:17.000000, Amplitude:18.999996.
   Frequency:24.000000, Amplitude:13.000004.
   ------------------------------------
   Rfft demo: 256.
   total times:25266 tick.
   ------------------------------------
   DC component amplitude:4.999996.
   Frequency:8.000000, Amplitude:11.000001.
   Frequency:17.000000, Amplitude:19.000000.
   Frequency:24.000000, Amplitude:13.000004.
   ------------------------------------
   Rfft demo: 512.
   total times:37868 tick.
   ------------------------------------
   DC component amplitude:4.999998.
   Frequency:8.000000, Amplitude:11.000000.
   Frequency:17.000000, Amplitude:19.000000.
   Frequency:24.000000, Amplitude:13.000000.
   ------------------------------------
   Rfft demo: 1024.
   total times:122305 tick.
   ------------------------------------
   DC component amplitude:4.999998.
   Frequency:8.000000, Amplitude:11.000000.
   Frequency:17.000000, Amplitude:19.000000.
   Frequency:24.000000, Amplitude:13.000000.
   ------------------------------------
   PASS.
   ----------------END--------------------

性能如下表所示：

.. list-table::
   :header-rows: 1

   * - 采样点
     - 64
     - 128
     - 256
     - 512
     - 1024
   * - DSP rfft
     - 5133
     - 7956
     - 25266
     - 37868
     - 122305