Transversal correlator

A method for correlating an input signal with a predetermined bit sequence, comprising the steps of:

• storing said predetermined bit sequence in a buffer register;
• loading said bit sequence into a circulating register connected in parallel with the buffer register in response to a parallel load command;
• sampling the input signal periodically to produce a series of analog samples;
• storing a preset number of said analog samples in a corresponding set of storage circuits with each new sample replacing the oldest stored sample;
• circulating said bit sequence through said circulating register;
• and
• correlating the bit sequence in said circulating register with said analog samples stored in said storage circuits to produce a correlation pulse when said bit sequence in said circulating register is aligned with a corresponding sequence of said analog samples in said storage circuits.

A method for correlating an input signal with a predetermined bit sequence, comprising the steps of:

• providing said input signal serially to each of a plurality of correlator subsections, said input signal delayed in propagation between each of said subsections;
• sampling said input signal within each of said correlator subsections to produce a series of analog samples for each of said correlator subsections;
• storing a predetermined number of said analog samples in storage circuits in each of said subsections;
• circulating a different section of said bit sequence in a circulating register in each of said subsections;
• correlating the section of the bit sequence circulating in each subsection with the corresponding analog samples stored in the storage circuits in the subsection to produce a correlation signal when the section of the bit sequence is aligned with the stored analog samples;
• and
• summing the correlation signals produced from each of said subsections to produce a correlation output signal.

Apparatus for correlating an input signal with a preselected bit sequence, comprising:

• sampling means for periodically sampling said input signal to produce a series of analog samples, said sampling means including a clock register means which receives a periodic sample signal at periods which are multiples of the period of the clocked rate of said clock register, said clock register means having a plurality of cells therein;
• storage means for storing a preset number of said analog samples, each new sample replacing the oldest stored sample, said storage means including a plurality of storage circuits each connected to receive said input signal and connected to a corresponding cell of said clock register means to receive a sample command signal;
• buffer register means for storing said preselected bit sequence;
• circulating register means parallel connected to said buffer register means for receiving said bit sequence from said buffer register means in response to a parallel load signal, said circulating register means including a shift register with the last cell thereof connected to the first cell thereof for sequentially circulating said bit sequence through the cells of the shift register;
• and
• correlation means for correlating said bit sequence and said circulating register means with said stored analog samples to produce a correlation signal when said bit sequence in said circulating register means is aligned with a corresponding sequence of said analog samples in said storage means.