US Patent 7405499 Waveform generating apparatus, waveform generating method, and decoder

Amplitude, phase and frequency of a sine wave to be generated are calculated on the basis of feature quantity s1 delivered to feature quantity detecting means (2), and are sent to initialization means (3). The initialization means (3) calculates first two points of the sine wave to send the points thus calculated to oscillator (sine wave generating means) (4) as initial value s4. The oscillator (4) sequentially calculates values of respective sample points of waveform by using recurrence formula in accordance with initial value or values instructed from the initialization means (3) to thereby generate a sine wave signal. Thus, sine wave generation is performed without performing modulo-addressing.