https://github.com/r9y9/constantq.jl

A fast constant-q transform in Julia
https://github.com/r9y9/constantq.jl

Last synced: 16 days ago
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A fast constant-q transform in Julia

• Host: GitHub
• URL: https://github.com/r9y9/constantq.jl
• Owner: r9y9
• License: other
• Created: 2015-05-01T17:08:41.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2024-07-07T08:23:38.000Z (4 months ago)
• Last Synced: 2024-07-07T09:39:22.723Z (4 months ago)
• Language: Julia
• Homepage:
• Size: 499 KB
• Stars: 10
• Watchers: 4
• Forks: 4
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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README

        
# ConstantQ

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[![License](http://img.shields.io/badge/license-MIT-brightgreen.svg?style=flat)](LICENSE.md)

A fast constant-q transform in Julia

![](examples/constant-q-spectrogram.png)

## High-level interface

```julia

X, timeaxis, freqaxis = cqt(x, fs)

```

where `x` is a input monoral signal and fs is its sampling frequency.

## Low-level interface

```julia

# Define geometrically-spaced frequency range to analyze

freq = GeometricFrequency(min=55, max=fs/2, bins=24)

# Create spectral kernel matrix

K = speckernel(Float64, fs, freq)

# Compute constant-q spectrogram

hopsize = convert(Int, round(fs * 0.005)) # 5ms hopsize

X, timeaxis, freqaxis = cqt(x, fs, K, hopsize=hopsize)

```

## References

- J. C. Brown and M. S. Puckette, "An efficient algorithm for the calculation of a constant Q transform," J. Acoust. Soc. Amer., vol. 92, no. 5, pp. 2698–2701, 1992.

- J. C. Brown. "Calculation of a constant Q spectral transform," Journal of the Acoustical Society of America,, 89(1): 425–434, 1991.