Double-accumulator implementation of the convolution function

A circuit for convolving or correlating two functions comprising:

• a multiply-accumulator for multiplying a coefficient by an input data sample, said multiply-accumulator having a plurality of inputs and an output, said coefficient being proportional to a derivative of at least one of said two functions;
• a memory for holding said coefficient and input data samples, said memory having an input to receive said input data samples, an output for providing the coefficient and the input data samples to the multiply-accumulator, and an input to receive address information for determining what information to place on said output;
• an address generator having an output for providing information to said memory;
• and
• an accumulator having an input for receiving the output of said multiply-accumulator and an output for providing a result.

A method of correlating or convolving two functions using a first memory and a second memory, comprising the steps of:

• multiplying a number of input data samples by an equal number of coefficients, said coefficients derived from a derivative of at least one of the two functions, to produce a number of products;
• storing in said first memory the sum of said number of products and an output of said first memory;
• and
• storing in said second memory the sum of the output of said first memory and an output of said second memory.