Frequency Counting Modulator

One modulation method called the frequency counting modulator (FCM), which can produce various constant envelope signals, is proposed. The FCM is materialized by only digital circuits and, therefore, is easily implemented in a large scale integrated circuit (LSI). From analytical study of the FCM, design formulas are derived for MSK-type modulation, and modulated signal performance features are clarified in terms of minimum signal distance, the effect of a Gaussian receiving filter, and spectral power concentration.