Patent ID: 7257148

Claim:
A radio system using an impulse signal sequence for reducing narrowband interference at a frequency f caused by another radio transmitting apparatus in another radio system, the system comprising: an impulse signal generator for generating an impulse signal based on a spread signal obtained by multiplying a data sequence by a spread code sequence; a delay circuit for delaying the impulse signal by a predetermined time based on a reciprocal of the frequency f from said another radio transmitting apparatus; a subtractor, wherein a subtraction signal is generated by subtracting a delayed signal from said delay circuit generated by delaying the impulse signal formed by the impulse signal sequence by 1/f second from the impulse signal from the impulse signal generator, and the subtraction signal is transmitted as a radio signal such that the frequency f of the transmitted radio signal is attenuated sufficiently to avoid interference with a signal transmitted by said another radio transmitting apparatus; and a receiver for receiving the radio signal, the receiver having a receive delay circuit for delaying the radio signal by 1/f to produce a delayed radio signal, and a receive subtraction circuit for adding an opposite phase radio signal to the delayed radio signal.