New method for generating frequency modulation

The paper describes how asynchronons delta sigma modulation can be used to generate frequency modulation. Present FM modulators have an inherent nonlinearity in the voltage/frequency characteristic, and as a consequence they are restricted to small percentage frequency deviations. The ADSM-FM modulator is inherently linear, allowing a wide percentage frequency deviation to be obtained. When incorporating this ADSM-FM modulator in the design of an FM broadcast exciter a system results which has an order of magnitude improvement in both signal/noise ratio and harmonic distortion compared with conventional designs.