A METHOD OF SYNTHESISING AN APPROXIMATE IMPULSE RESPONSE FUNCTION

摘要

A method of synthesising an approximate impulse response function from a measured first impulse response function in a given sound field includes:- sampling an early part of the impulse response for the given sound field; synthesising a part impulse response which approximates to the sampled part of the given impulse response by curve fitting using a plurality of basis functions such as raised sine functions provided by respective multi-tap FIR filters P, Q, R, said part impulse response including scattering artefacts; synthesising subsequent further part impulse responses using the same filters; applying an envelope function which decreases the amplitude with increasing time, and constructing an extended approximate impulse response by combining successive part impulse responses with irregular overlap to minimise audible artefacts. The synthesised impulse response function has psycho-acoustic properties similar to those of the original impulse response function, and enables fewer taps to be employed. The method can be applied to the synthesis or ear response transfer functions. Uses for mobile telephones, musical instruments and games are disclosed. Extension to sonar and radar applications is also envisaged.