초록 ▼

A method of synthesizing a finite impulse response digital filter includes a phase of calculating the impulse response g(t) of an analog filter the transfer function of which is defined by a predetermined bandwidth B, shape factor SF and out-band attenuation level A. The coefficients of the digital

A method of synthesizing a finite impulse response digital filter includes a phase of calculating the impulse response g(t) of an analog filter the transfer function of which is defined by a predetermined bandwidth B, shape factor SF and out-band attenuation level A. The coefficients of the digital filter are extracted by sampling the resulting impulse response. The calculation phase consists in expanding the impulse response into an integer number M of Hermite functions predetermined in accordance with the shape factor SF. The coefficient extraction phase includes sampling of the expanded impulse response after the calculation phase in a time window the duration of which is dependent on the out-band attenuation level A using a sampling period At that is dependent on the bandwidth B.

대표청구항 ▼

[ There is claimed:] [1.] A method of synthesizing a finite impulse response digital filter for an input signal and outputting a filtered signal including a phase of storing samples of an input signal to be filtered, a phase of calculating the impulse response g(t) of an analog filter, the transfer

[ There is claimed:] [1.] A method of synthesizing a finite impulse response digital filter for an input signal and outputting a filtered signal including a phase of storing samples of an input signal to be filtered, a phase of calculating the impulse response g(t) of an analog filter, the transfer function of which is defined by a predetermined bandwidth B, shape factor SF and out-band attenuation level A and a phase of extracting the coefficients of the digital filter by sampling said impulse response, a phase of multiplying the extracted coefficients by a sample of the input signal, a phase of summing outputs of multiplied extracted coefficients by the samples of the input signal to deliver said input signal, wherein said calculation phase consists in expanding said impulse response into an integer number M of Hennite functions predetermined in accordance with said shape factor SF and said coefficient extraction phase includes sampling of the expanded impulse response after said calculation phase in a time window the duration of which is dependent on said out-band attenuation level A using a sampling period .DELTA.t that is dependent on said bandwidth B.