spec

Functions

int main(int argc, char *argv[])

spec [ option ] [ infile ]

-l int
- FFT length \((2 \le L)\)
-m int
- order of numerator coefficients \((0 \le M < L)\)
-n int
- order of denominator coefficients \((0 \le N < L)\)
-z str
- filename of double-type numerator coefficients
-p str
- filename of double-type denominator coefficients
-e double
- small value added to power spectrum
-E double
- relative floor in decibels
-o int
- output format
  - 0 amplitude spectrum in dB
  - 1 log amplitude spectrum
  - 2 amplitude spectrum
  - 3 power spectrum
infile str
- double-type data sequence
stdout
- double-type spectrum

The below example performs spectral analysis. To prevent \(log(0)\), a small value is add to power spectrum using -e option.

frame -l 400 data.d | window -l 400 -L 512 | spec -l 512 -e 1e-6 > data.sp

Instead a relative floor value of spectrum can be set using -E option.

spec -E -30 data.d2 > data.sp

Parameters:

argc – [in] Number of arguments.
argv – [in] Argument vector.

Returns:

0 on success, 1 on failure.

See also

fftr phase grpdelay glogsp grlogsp

class WaveformToSpectrum

Convert waveform to spectrum.

The input is the \(L\)-length waveform signals:

\[ \begin{array}{cccc} x(0), & x(1), & \ldots, & x(L-1). \end{array} \]

The output is the \((N/2+1)\)-length spectrum and takes one of the following forms.

Type 0:

\[ \begin{array}{cccc} 20 \log_{10}|H(0)|, & 20 \log_{10}|H(1)|, & \ldots, & 20 \log_{10}|H(N/2)|. \end{array} \]

Type 1:

\[ \begin{array}{cccc} \ln|H(0)|, & \ln|H(1)|, & \ldots, & \ln|H(N/2)|. \end{array} \]

Type 2:

\[ \begin{array}{cccc} |H(0)|, & |H(1)|, & \ldots, & |H(N/2)|. \end{array} \]

Type 3:

\[ \begin{array}{cccc} |H(0)|^2, & |H(1)|^2, & \ldots, & |H(N/2)|^2, \end{array} \]

where \(N\) is the FFT length.

Public Functions

WaveformToSpectrum(int frame_length, int fft_length, SpectrumToSpectrum::InputOutputFormats output_format, double epsilon = 0.0, double relative_floor_in_decibels = sptk::kMin)

Parameters:

frame_length – [in] Frame length, \(L\).
fft_length – [in] FFT length, \(N\).
output_format – [in] Output format.
epsilon – [in] Small value added to power spectrum.
relative_floor_in_decibels – [in] Relative floor in decibels.

inline int GetFrameLength() const

Returns:: Frame length.

inline int GetFftLength() const

Returns:: FFT length.

inline SpectrumToSpectrum::InputOutputFormats GetOutputFormat() const

Returns:: Output format.

inline double GetEpsilon() const

Returns:: Epsilon.

inline double GetRelativeFloorInDecibels() const

Returns:: Relative floor.

inline bool IsValid() const

Returns:: True if this object is valid.

bool Run(const std::vector<double> &waveform, std::vector<double> *spectrum, WaveformToSpectrum::Buffer *buffer) const

Parameters:

waveform – [in] \(L\)-length waveform signals.
spectrum – [out] \((N/2+1)\)-length spectrum.
buffer – [out] Buffer.

Returns:

True on success, false on failure.

class Buffer: Buffer for WaveformToSpectrum class.

class FilterCoefficientsToSpectrum

Convert filter coefficients to spectrum.

The input is the \(M\)-th order numerator coefficients and the \(N\)-th order denominator coefficients:

\[\begin{split} \begin{array}{cccc} b(0), & b(1), & \ldots, & b(M), \\ K, & a(1), & \ldots, & a(N). \end{array} \end{split}\]

The output is the \((L/2+1)\)-length spectrum and takes one of the following forms.

Type 0:

\[ \begin{array}{cccc} 20 \log_{10}|H(0)|, & 20 \log_{10}|H(1)|, & \ldots, & 20 \log_{10}|H(L/2)|. \end{array} \]

Type 1:

\[ \begin{array}{cccc} \ln|H(0)|, & \ln|H(1)|, & \ldots, & \ln|H(L/2)|. \end{array} \]

Type 2:

\[ \begin{array}{cccc} |H(0)|, & |H(1)|, & \ldots, & |H(L/2)|. \end{array} \]

Type 3:

\[ \begin{array}{cccc} |H(0)|^2, & |H(1)|^2, & \ldots, & |H(L/2)|^2, \end{array} \]

where \(L\) is the FFT length.

Public Functions

FilterCoefficientsToSpectrum(int num_numerator_order, int num_denominator_order, int fft_length, SpectrumToSpectrum::InputOutputFormats output_format, double epsilon, double relative_floor_in_decibels)

Parameters:

num_numerator_order – [in] Order of numerator coefficients, \(M\).
num_denominator_order – [in] Order of denominator coefficients, \(N\).
fft_length – [in] FFT length, \(L\).
output_format – [in] Output format.
epsilon – [in] Small value added to power spectrum.
relative_floor_in_decibels – [in] Relative floor in decibels.

inline int GetNumNumeratorOrder() const

Returns:: Order of numerator coefficients.

inline int GetNumDenominatorOrder() const

Returns:: Order of denominator coefficients.

inline int GetFftLength() const

Returns:: FFT length.

inline SpectrumToSpectrum::InputOutputFormats GetOutputFormat() const

Returns:: Output format.

inline double GetEpsilon() const

Returns:: Epsilon.

inline double GetRelativeFloorInDecibels() const

Returns:: Relative floor.

inline bool IsValid() const

Returns:: True if this object is valid.

bool Run(const std::vector<double> &numerator_coefficients, const std::vector<double> &denominator_coefficients, std::vector<double> *spectrum, FilterCoefficientsToSpectrum::Buffer *buffer) const

Parameters:

numerator_coefficients – [in] \(M\)-th order coefficients.
denominator_coefficients – [in] \(N\)-th order coefficients.
spectrum – [out] \((L/2+1)\)-length spectrum.
buffer – [out] Buffer.

Returns:

True on success, false on failure.

class Buffer: Buffer for FilterCoefficientsToSpectrum class.

class SpectrumToSpectrum

Convert spectrum to spectrum.

The input and output are the \((N/2+1)\)-length spectrum and take one of the following forms.

Type 0:

\[ \begin{array}{cccc} 20 \log_{10}|H(0)|, & 20 \log_{10}|H(1)|, & \ldots, & 20 \log_{10}|H(N/2)|. \end{array} \]

Type 1:

\[ \begin{array}{cccc} \ln|H(0)|, & \ln|H(1)|, & \ldots, & \ln|H(N/2)|. \end{array} \]

Type 2:

\[ \begin{array}{cccc} |H(0)|, & |H(1)|, & \ldots, & |H(N/2)|. \end{array} \]

Type 3:

\[ \begin{array}{cccc} |H(0)|^2, & |H(1)|^2, & \ldots, & |H(N/2)|^2, \end{array} \]

where \(N\) is the FFT length.

Public Types

enum InputOutputFormats

Input and output format.

Values:

enumerator kLogAmplitudeSpectrumInDecibels

enumerator kLogAmplitudeSpectrum

enumerator kAmplitudeSpectrum

enumerator kPowerSpectrum

enumerator kNumInputOutputFormats

Public Functions

SpectrumToSpectrum(int fft_length, InputOutputFormats input_format, InputOutputFormats output_format, double epsilon = 0.0, double relative_floor_in_decibels = sptk::kMin)

Parameters:

fft_length – [in] FFT length, \(N\).
input_format – [in] Input format.
output_format – [in] Output format.
epsilon – [in] Small value added to power spectrum.
relative_floor_in_decibels – [in] Relative floor in decibels.

inline int GetFftLength() const

Returns:: FFT length.

inline InputOutputFormats GetInputFormat() const

Returns:: Input format.

inline InputOutputFormats GetOutputFormat() const

Returns:: Output format.

inline double GetEpsilon() const

Returns:: Epsilon.

inline double GetRelativeFloorInDecibels() const

Returns:: Relative floor.

inline bool IsValid() const

Returns:: True if this object is valid.

bool Run(const std::vector<double> &input, std::vector<double> *output) const

Parameters:

input – [in] \((N/2+1)\)-length spectrum.
output – [out] \((N/2+1)\)-length spectrum.

Returns:

True on success, false on failure.

bool Run(std::vector<double> *input_and_output) const

Parameters:: input_and_output – [inout] \((N/2+1)\)-length spectrum.
Returns:: True on success, false on failure.

class OperationInterface

Interface of spectrum operation.

Public Functions

virtual bool Run(std::vector<double> *input_and_output) const = 0

Parameters:: input_and_output – [inout] Input/output spectrum.
Returns:: True on success, false on failure.