DIGITAL INTERPOLATION FILTER

摘要

PROBLEM TO BE SOLVED: To provide a digital interpolation filter whose circuit scale can be reduced through the use of the relation of the integer ratio of coefficients, when the relation becoming the integer ratio exists between the specified coefficients. SOLUTION: A coefficient multiplication circuit 2-2 multiplies an oversampling signal x(t)} outputted from an oversampling circuit 1 by a basic coefficient A2 and outputs a multiplication result signal A2x(t)}. The multiplication result signal A2x(t)}, outputted from the coefficient multiplication circuit 2-2, is inputted to an addition circuit 4-2 and an integer times circuit 5. The integer times circuit 5 multiplies the inputted signal A2x(t)} by N times and outputs an integer times signal NA2x(t)} to an addition circuit 4-3. The integer times signal NA2x(t)} is equal to A3x(t)}.