linear interpolation

- the interpretation of values in tiers between the first point and the last point.

## Example

The following is a PitchTier with three points:

Between 0.10 and 0.20 seconds, the pitch rises linearly from 170 to 180 Hz, and between 0.20 and 0.45 seconds it falls linearly from 180 to 110 Hz. This is linear interpolation: at all times between two adjacent points, the pitch values follow the straight line that connects the two points.

(Before 0.10 seconds and after 0.45 seconds there is constant extrapolation.)

## Linear interpolation in Praat

Praat uses linear interpolation in all tiers and grids with values at time points (PitchTier, IntensityTier, DurationTier, AmplitudeTier, FormantGrid).