One of the types of objects in Praat. For tutorial information, see Intro 4. Pitch analysis.
A Pitch object represents periodicity candidates as a function of time. It does not mind whether this periodicity refers to acoustics, perception, or vocal-cord vibration. It is sampled into a number of frames centred around equally spaced times.
Pitch commands
Creation:
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• Sound: To Pitch (filtered autocorrelation)...: for intonation and vocal-fold vibration
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• Sound: To Pitch (raw cross-correlation)...: for voice analysis
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• Sound: To Pitch (raw autocorrelation)...: for raw periodicity
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• Sound: To Pitch (filtered cross-correlation)...
Drawing:
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• Pitch: Draw...
Viewing and editing:
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• PitchEditor
Synthesis:
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• Pitch: To PointProcess: create points in voiced intervals.
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• Sound & Pitch: To PointProcess (cc): near locations of high amplitude.
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• Sound & Pitch: To PointProcess (peaks)...: near locations of high amplitude.
Conversion:
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• Pitch: To PitchTier: time-stamp voiced intervals.
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• Pitch & PointProcess: To PitchTier...: interpolate values at specified times.
Inside a Pitch object
With Inspect, you will see the following attributes:
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xmin
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start time, in seconds.
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xmax
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end time, in seconds.
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nx
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the number of frames (≥ 1).
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dx
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time step = frame length = frame duration, in seconds.
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x1
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the time associated with the first frame, in seconds. This will usually be in the range [xmin, xmax]. The time associated with the last frame (i.e., x1 + (nx – 1) dx)) will also usually be in that range.
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ceiling
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a frequency above which a candidate is considered voiceless.
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framei, i = 1 ... nx
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the frames (see below).
Attributes of a pitch frame
Each frame contains the following attributes:
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nCandidates
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the number of candidates in this frame (at least one: the “unvoiced” candidate).
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candidatej, j = 1 ... nCandidates
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the information about each candidate (see below).
Attributes of each candidate
Each candidate contains the following attributes:
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frequency
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the candidate's frequency in Hz (for a voiced candidate), or 0 (for an unvoiced candidate).
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strength
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the degree of periodicity of this candidate (between 0 and 1).
Interpretation
The current pitch contour is determined by the path through all first candidates. If the first candidate of a certain frame has a frequency of 0, or a frequency above ceiling, this frame is considered voiceless.
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