mmwave.dsp.ZoomFFT¶

class
mmwave.dsp.ZoomFFT.
ZoomFFT
(low_freq, high_freq, fs, signal=None)¶ This class is an implementation of the Zoom Fast Fourier Transform (ZoomFFT).
The zoom FFT (Fast Fourier Transform) is a signal processing technique used to analyse a portion of a spectrum at high resolution. The steps to apply the zoom FFT to this region are as follows:
 Frequency translate to shift the frequency range of interest down to near 0 Hz (DC)
 Low pass filter to prevent aliasing when subsequently sampled at a lower sample rate
 Resample at a lower rate
 FFT the resampled data (Multiple blocks of data are needed to have an FFT of the same length)
The resulting spectrum will now have a much smaller resolution bandwidth, compared to an FFT of nontranslated data.

compute_fft
()¶ Computes the Fast Fourier Transform (FFT) of the signal.
Returns: A frequencyshifted, unscaled, FFT of the signal. Return type: X (np.ndarray)

compute_zoomfft
(resample_number=None)¶ Computes the Zoom Fast Fourier Transform (ZoomFFT) of the signal.
Parameters: resample_number (int) – The number of samples in the resampled signal. Returns: A frequencyshifted, unscaled, ZoomFFT of the signal. bw_factor (int): Bandwidth factor fftlen (int): Length of the ZoomFFT output Ld (int): for internal use F (int): for internal use Return type: Xd (np.ndarray)

plot_fft
(d=None)¶ Plots the Fast Fourier Transform (FFT) of the signal.
Parameters: d (int) – Sample spacing (inverse of the sampling rate)

plot_zoomfft
(resample_number=None)¶ Plots the Zoom Fast Fourier Transform (ZoomFFT) of the signal.
Parameters: resample_number (int) – The number of samples in the resampled signal.

set_signal
(signal)¶ Sets given signal as a member variable of the class.
e.g. ZoomFFT.create_signal(generate_sinewave(a, b, c) + generate_sinewave(d, e, f))
Parameters: signal (np.ndarray) – Signal to perform the ZoomFFT on

sinewave
(f, length, amplitude=1)¶ Generates a sine wave which could be used as a part of the signal.
Parameters: Returns: Generated sine wave with the given parameters.
Return type: x (np.ndarray)