초록 ▼

High speed serial data bits of a data stream are received, stored, shifted and compared in parallel to bit contents of a known correlation word. For each bit match a known signal change is provided on a common terminal. High speed current or voltage changes on the common terminal are proportional to

High speed serial data bits of a data stream are received, stored, shifted and compared in parallel to bit contents of a known correlation word. For each bit match a known signal change is provided on a common terminal. High speed current or voltage changes on the common terminal are proportional to the number of matching bits and are monitored to detect presence of the correlation word in the received data stream. The circuit has minimum number of components and built-in temperature compensation.

대표청구항 ▼

A high speed correlation circuit for detecting presence of a known digital correlation word in a serial data stream, comprising: a serial-to-parallel shift register means having an input coupled to receive and store consecutive bits of said serial data stream and to shift said stored bits by one bit

A high speed correlation circuit for detecting presence of a known digital correlation word in a serial data stream, comprising: a serial-to-parallel shift register means having an input coupled to receive and store consecutive bits of said serial data stream and to shift said stored bits by one bit position in succession when a new bit is received thereby, said shift register means having a plurality of parallel outputs each containing one bit stored in said shift register means; a presettable memory means coupled to store respective bits of said known correlation word, said memory means having a plurality of parallel outputs each containing one bit stored in said memory means; a plurality of logic gates each having a first input coupled to one parallel output of said shift register means and a second input coupled to a corresponding parallel output of said memory means, each logic gate having an output coupled to provide an output signal of a first known logic signal level when matching bits are obtained at its respective inputs and output signal of a second known logic signal level when its input bits do not match, respectively; a plurality of resistors each having a first terminal coupled to an output of one said logic gate, the other terminals of said resistors being coupled to a common terminal, each said resistor having a value selected to apply an appreciable amount of current to said common terminal when one of said first or said second known logic signal level is provided by said logic gate; means coupled to maintain said common terminal at a predetermined constant voltage level to obtain a substantially linearly changing current thereon with the number of bit matches obtained by said logic gates; a current-to-voltage converter means coupled to said common terminal for substantially linearly converting said current changes thereon to corresponding voltage changes; and means coupled to an output of said current-to-voltage converter means for detecting a known voltage magnitude obtained on said common terminal in response to a predetermined number of matching bits obtained by said plurality of logic gates.