Pulse-Frequency Modulation

Pulse-frequency modulation (PFM) has been successfully employed as the encoding technique in a number of small U. S. Earth satellites where reduction of power and weight are prime considerations. This paper is concerned with the introduction of some of the more basic principles of PFM. Rather than presenting a rigorous proof on the orthogonality of this type of modulation, a comparison is made to the better-known characteristics of coded binary sequences. It is shown that PFM with quantized frequencies has the same communication efficiency in the presence of additive white Gaussian noise as a corresponding set of coded binary sequences with an equal number of quantized levels