Fractional Frequency Synthesizer

A simple technique is presented for using standard IC logic elements to synthesize frequencies. In particular, certain fractional multiples of a primary frequency may be synthesized for which no convenient techniques are available at digital logic levels. By utilizing the harmonic content of repetitive digital waveforns, sum and difference frequencies may be extracted from the output of the digital logic network. In effect, the new technique provides a type of digital mixing to accomplish frequency synthesis (or conversion) which is compatible with modern digital circuits. The circuit complements available techniques for division by an integer.