Sample-rate conversion by arbitrary ratios

The paper suggests and describes two methods for sample-rate conversion by arbitrary ratios, either between any two fixed or varying sampling frequencies. The first method is based on an impulse-invariant transform of an analog filter. A parallel form realization structure is presented, The second method combines regular IIR- or FIR-interpolators for integer or rational conversion ratios with low-order Lagrange-interpolators. An efficient realization structure is presented. Examples concerning sampling rate conversion of speech signals are given for both methods.