mha_spec_t Struct Reference

Inheritance diagram for mha_spec_t:

Public Attributes
mha_complex_t *	buf
	signal buffer More...
unsigned int	num_channels
	number of channels More...
unsigned int	num_frames
	number of frames in each channel More...
mha_channel_info_t *	channel_info
	detailed channel description More...

Detailed Description

\ingroup mhasignal
\brief Spectrum signal structure 

This structure contains the short time fourier transform output of the windowed input signal. The member num_frames describes the number of frequency bins in each channel. For an even FFT length , this is . With odd FFT lengths, it is . The imaginary part of the first bin is zero. For even FFT lengths, also the imaginary part at the Nyquist frequency is zero.

Data order of FFT spectrum.

Only the FFT bins for the positive frequencies, 0, and the Nyquist frequency are stored in this structure. The negative frequencies are not stored, because for a real-valued time signal they are the complex conjugates of the positive frequencies.

The negative frequencies still contribute to the signal's level. Refer to Central Calibration for a description of the scaling and how the level would be computed from the spectrum. It is recommended to use the library function MHASignal::rmslevel to compute the unweighted level correctly in Pascal, or MHASignal::colored_intensity to compute a possibly weighted intensity.

Member Data Documentation

buf

mha_complex_t* mha_spec_t::buf

signal buffer

num_channels

unsigned int mha_spec_t::num_channels

number of channels

num_frames

unsigned int mha_spec_t::num_frames

number of frames in each channel

channel_info

mha_channel_info_t* mha_spec_t::channel_info

detailed channel description

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The documentation for this struct was generated from the following file:

• mha.hh