Synthesizers generate a multiplicity of frequency output signals from a single input frequency clock-reference signal. The number of different output frequencies the synthesizer is capable of producing is referred to in the art as the synthesizer's accumulator modulus (M). The resolution of a synthesizer denotes the steps or difference in hertz between the output frequencies the synthesizer is capable of producing.
Two standards in the electronics industry influence synthesizer circuit design: first, the popularity, low cost and efficienc of digital electronics; and second, reference clock input signals typically have frequencies based on exponential variations of the decimal number 10 (i.g. 10.sup.D =1 MHz, or 10 MHz where D=6 and 7 respectively). Together, these two factors anticipate the fact that current synthesizer devices include digital electronics that are designed to perform decimal mathematics.
Examples of decimal based frequency generators are found in Goldberg U.S. Pat. No. 4,752,902, and Jackson U.S. Pat. No. 3,735,269. To achieve one hertz resolution in these devices, it is required to set the accumulator modulus equal the input clock frequency. In other words, (M=10.sup.D) in these devices. Decimal based synthesizers having 1 hertz resolution are plagued with a number of problems. Namely, synthesizers having decimal moduli are larger, slower and have less resolution than an accumulator of equivalent bit count which performs binary arithmetic. In McCune Jr. U.S. Pat. No. 4,746,880, a binary based synthesizer is disclosed. However, it is not capable of achieving one Hertz resolution from an industry standard decimal number clock reference frequency.
Accordingly, there is a need for a hertz resolution synthesizer which performs binary arithmetic and operates on standard decimal number input clock frequencies.