arm_cmplx_mag_q31() equivalent in PowerQuad?

[gertvb]

Goeiedag Almal!

Is there a PowerQuad instruction equivalent to the CMSIS-DSP arm_cmplx_mag_q31() function?

Like  PQ_TransformRFFT() is equivalent to the CMSIS-DSP function arm_rfft_q15()

Kind regards

Gert

[xiangjun_rong · Accepted solution]

Hi, Gert Van Biljon,

As you know that the arm_cmplx_mag_q31() function provided by CMSIS platform can compute the power spectrum after FFT.

But I do not think the powerquad library provides the similar function to compute the power spectrum, the powerquad library provides FFT.

After FFT, you can get the real[i]/image[i] array, you can call the matrix product function and addition to compute power spectrum. for example,  after FFT, you get the FFT result FFTResutArrayA, which is 1*512 array for 128 points FFT, clone the FFTResutArrayA to another array FFTResutArrayB, then you can call the matric product function and add the real[i]**2+image[i]**2 yourself.

FFT based on powerquad module

https://www.nxp.com.cn/docs/en/application-note/AN12282.pdf

Hope it can help you

BR

XiangJun Rong