Abstract: A parallel processor of a distributed sample scrambler of cell-based physical layer of ISDN(Integrated Service Digital Network) used in a 16-bit mode of utopia interface is disclosed. The parallel processor employs a simple logic to process a predetermined bit of pseudo random binary bit stream in parallel, discriminating the cell boundary of the IDSN easily and reliably. The parallel processor comprises a first pseudo random bit stream production block for producing a first pseudo random binary bit stream within a word parallel clock according to a predetermined byte of an ATM(Asynchronous Transfer Mode) cell applied from an external; a second pseudo random bit stream production block for producing a second pseudo random binary bit stream within a word parallel clock according to the predetermined byte of the ATM cell; and a selector for selectively producing one of the first and the second pseudo random binary bit streams according to an external signal.

Abstract: A burst mode optical receiver using two amplifiers having different bandwidth. The receiver includes an optical coupler separating an input optical signal into two parts and outputting the same, a delay circuit formed of a first optical fiber delaying an optical signal packet outputted through the optical coupler by a half of packet duration and a second optical fiber passing the optical signal packet without delay, and a first pre-amplifier having a high bandwidth for receiving an optical signal from the first optical fiber and amplifying the same and a second pre-amplifier having a low bandwidth for receiving an optical signal from the second optical fiber and amplifying the same, for thereby improving a receiving sensitivity without using a preamble bit.