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Spectrum

Source: R/spectrum-wrapper.R
Spectrum.Rd

Praat Spectrum object with direct C++ module binding (complex FFT spectrum). Spectrum objects represent frequency-domain representations of sounds. Uses a shared dispatch table for minimal memory per object.

Arguments

.xptr

Not for direct use. External pointer to the underlying C++ Spectrum object; set internally when a method returns a new Spectrum.

Value

A Spectrum object with methods for frequency-domain spectral analysis.

Query methods

  • get_lowest_frequency() - lowest frequency (Hz)

  • get_highest_frequency() - highest frequency (Hz)

  • get_number_of_bins() - number of frequency bins

  • get_frequency_step() - frequency step (Hz)

  • get_real_value_in_bin(bin) - real part at a bin

  • get_imaginary_value_in_bin(bin) - imaginary part at a bin

  • get_frequency_from_bin(bin) - frequency for a bin number

  • get_bin_from_frequency(freq) - bin number for a frequency

  • get_band_density(fmin, fmax) - power density in a band (Pa²/Hz²)

  • get_band_energy(fmin, fmax) - energy in a band (Pa²·s)

  • get_centre_of_gravity(power = 2.0) - spectral center of gravity

  • get_standard_deviation(power = 2.0) - spectral standard deviation

  • get_skewness(power = 2.0) - spectral skewness

  • get_kurtosis(power = 2.0) - spectral kurtosis

  • get_central_moment(moment, power = 2.0) - central moment

Modification methods

  • pass_hann_band(fmin, fmax, smooth = 100) - apply a Hann band-pass filter

  • stop_hann_band(fmin, fmax, smooth = 100) - apply a Hann band-stop filter

  • cepstral_smoothing(bandwidth) - smooth using the cepstral method

Transform methods

  • to_sound() - convert to Sound (inverse FFT)

  • to_ltas(bandwidth) - convert to long-term average spectrum

  • to_spectrogram(...) - convert to Spectrogram

  • to_excitation(erb_density) - convert to Excitation (auditory representation)

Export methods

  • as_matrix() - export as a numeric matrix (real + imaginary)

  • as_data_frame() - export as a data.frame (freq, real, imag, power)

  • save(path) - save to a file

See also

Sound, Spectrogram, Ltas, PowerCepstrum

Examples

sound <- Sound$create_tone(duration = 0.5, frequency = 440, sampling_rate =
 44100)
spectrum <- sound$to_spectrum(fast = FALSE)
cog <- spectrum$get_centre_of_gravity(power = 2.0)
energy <- spectrum$get_band_energy(fmin = 400, fmax = 500)

# Create a spectrum from a recording read from disk
sound <- Sound(system.file("extdata", "test.wav", package = "pladdrr"))
spectrum <- sound$to_spectrum(fast = TRUE)
spec_df <- spectrum$as_data_frame()