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Chirp Z-transform

Project description

Chirp Z-Transform (CZT)

PyPI version

From Wikipedia:

The chirp Z-transform (CZT) is a generalization of the discrete Fourier transform (DFT). While the DFT samples the Z plane at uniformly-spaced points along the unit circle, the chirp Z-transform samples along spiral arcs in the Z-plane, corresponding to straight lines in the S plane. The DFT, real DFT, and zoom DFT can be calculated as special cases of the CZT.

Getting Started

You can install the CZT package using pip:

# to install the latest release (from PyPI)
pip install czt

# to install the latest version (from GitHub)
git clone
cd CZT
pip install -e .

# to install dependencies for examples
pip install -e .[examples]


Consider the following time-domain signal:

This is an exponentially decaying sine wave with some distortion from higher-order frequencies. We can convert this signal to the frequency-domain to investigate the frequency content using the Chirp Z-Transform (CZT):

Note that the CZT also allows us to calculate the frequency response over an arbitrary frequency range:

We can see that the signal has frequency components at 1 kHz, 2.5 kHz and 3.5 kHz. To remove the distortion and isolate the 1 kHz signal, we can apply a simple window in the frequency-domain:

Finally, we can use the Inverse Chirp Z-Transform (ICZT) to transform back to the time domain:

As we can see, we were able to remove the higher-order frequencies that were distorting our 1 kHz signal.

You can find this example and others in the examples/ directory.


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czt-0.0.7.tar.gz (7.3 kB view hashes)

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