Digital audio synthesizer

A digital audio synthesizer, comprising:

• an input memory for receiving a series of digital data representing the amplitude spectrum of an audio signal, over consecutive and overlapping time windows,
• a computer that is set up to receive, as an input, a draft digital data set for an active window comprising amplitude-extrapolated data at the start of the window and zero values for the rest of the window, and to establish, as a response, a digital representation of the complex discrete Fourier transform for said set,
• a combiner that is set up to combine the amplitude spectrum input, corresponding to the active window in question, with the digital representation predetermined by the computer, and to call the computer with the resulting data in order to establish a digital representation of the corresponding complex inverse discrete Fourier transform that provides a set of estimated digital data relative to the active window in question;
• and
• an adder for selectively accumulating the estimated digital data that corresponds to a single period of time,
• characterized in that:
• the combiner is set up to calculate an auxiliary digital data set by taking the active set of estimated digital data divided by a window function on each time window;
• the adder is set up to add the active set of estimated digital data multiplied by the window function having the preceding value from the accumulated total;
• and in that it comprises an extrapolator that is set up to calculate the draft digital data set for an active window from the auxiliary digital data set for the preceding window, said auxiliary digital data set being selectively multiplied by the square of the window function.