Disclosed are a transmission system and a device of small scale, low cost and low power for transmitting signal of a rate over 1Gbps using a small scale and low loss ultrawide band pass filter (UWBPF). The transmission system comprises the steps of generating pulse signal by a short pulse generator, band-limiting the pulse signal by passing it through a waveshape forming filter, and transmitting the resulting pulse signal in a certain frequency band through a UWBPF, and receiving and passing the signal wave through a UWBPF of the same frequency range and introducing the signal wave through a pulse detector into the determining part. The UWBPF used is prepared by forming a distribution constant circuit on a lossy substrate having low-pass function.