Patent ID: 7411997

Claim:
A receiving apparatus which obtains a signal from a transmitter, wherein said transmitter spreads the signal with a spreading code and transmits the spread signal to said receiving apparatus, said receiving apparatus comprising: a signal receiving section which receives the spread signal; a reception-side filter section which accepts said received spread signal as an input sequence and filters the received spread signal; a code generating section which generates a spreading code that is same as that used in the spreading by said transmitter; a code-side filter section which accepts said generated spread code as an input sequence and filters the geneerated spread signal; and a correlation detection section which performs correlation detection on a result of filtering in said reception-side filter section with respect to a result of filtering in said code-side filter section and obtains the signal from said transmitter, wherein each of said reception-side filter section and said code-side filter section is a filter apparatus with respect to a predetermined real impulse constant r (−1<r<1), a predetermined non-zero real number constant x, a predetermined delay time constant D (D>0) and a predetermined positive integer M, comprising: an input terminal which accepts an input signal; a delay amplification section which outputs M signals that are said acceted input signal delay amplified with a delay time t 0 and an amplification factor a 0 , with a delay time t 1 and an amplification factor a 1 , . . . , and with a delay time t M−1 and an amplification factor a M−1 , respectively; an adding section which outputs a sum of M output signals; and an output terminal which outputs the added M output signals; and wherein, t 0 is greater than 0, t 0 , t 1 , . . . , t M−1 is an arithmetical progression of a common difference D, and a 0 , a 1 , . . . , a M−1 is a geometrical progression of a common ratio -r or −1/r.