Statistics are as follows:
MeanF0 Mean fundamental frequency (Hz).
SDF0 Standard deviation of fundamental frequency (Hz).
RAP Relative Average Perturbation. Mean perturbation measured for eavh cycle by comparing duration of cycle to mean duration of a window of three cycles centered on the cycle (%).
PPQ Pitch Perturbation Quotient. Mean perturbation measured for eavh cycle by comparing duration of cycle to mean duration of a window of five cycles centered on the cycle (%).
APQ Amplitude Perturbation Quotient. Mean perturbation measured for eavh cycle by comparing amplitude of speech in cycle to mean amplitude of a window of eleven cycles centered on the cycle (%).
HNR Harmonic to Noise Ratio. Calculated from the autocorrelation function (dB).
H1H2 Average ratio of energy in first harmonic compared to second harmonic (dB).
SPI Soft Phonation Index. Ratio of energy in low frequency region (70-1600Hz) to energy at high frequency (1600-4500Hz) (dB).
Analysis is only performed over voiced and non-silent regions of the signal. The voicing decision is based on comparisons to a low-frequency and high frequency limit, which can be modified by program options.
Options and their meanings are:
-I Identify program and version number.
-i item Select input item.
-l lolimit Set low-frequency limit for voicing decision. Default 50Hz.
-h hilimit Set high-frequency limit for voicing decision. Default 500Hz.
SP.xx Speech waveform used for shimmer measurement.
TX.xx Any excitation period data item.
1.0 Mark Huckvale