Matching filter calculating correlation valve utilizing exclusive-or of two data and exclusive-or of two codes corresponding to the input data

A matched filter for calculating a correlation value between an input data sequence of a specified length and a code sequence of a specified length, comprising:

• an input data circuit calculating an exclusive-OR of two input data, wherein
• said input data circuit includes a first delay system and at least a second delay system, the first delay system having a plurality of delay elements connected in series, and the second delay system having a plurality of delay elements connected in series;
• said second delay system is provided with an associated second input circuit, wherein
• said second input circuit includes a first exclusive-OR circuit, a second exclusive-OR circuit, and a selector,
• said first exclusive-OR circuit calculates an exclusive-OR of an output of an initial delay element of said first delay system and an input data,
• said second exclusive-OR circuit calculates an exclusive-OR of an input data and a result of an exclusive-OR of outputs of said first delay system and said second delay system,
• said selector selects between the output of said first exclusive-OR circuit and said second exclusive-OR circuit based on a select signal and supplies the resulting selected signal to an initial delay element of said second delay system;
• a circuit calculating an exclusive-OR of two codes corresponding to the two input data, respectively;
• and
• a correlation calculation means that, using the output of the initial delay element of the first delay system, the output of the initial delay element of the second delay system, the exclusive-OR of the two codes, and the code corresponding to one of the two input data, calculates a correlation value of the two input data and the two codes.