A low-frequency high resolution digital synthesizer

A high-resolution digital frequency synthesizer was designed to provide modulation and fine frequency interpolation in a new cesium frequency standard. Requirements include resolution, spectral purity, phase-continuous frequency modulation, simplicity, and low power. The authors describe how these requirements were satisfied with a direct digital frequency synthesizer (DDFS). The DDFS consists of a 34-b phase accumulator feeding a 14-b wide address map and a 12-b digital-to-analog converter (DAC). For output frequencies in the range 131.0 to 132.5 kHz, the level of spurious sidebands, is less than -85 dBc. This is compatible with the expected performance of the DAC.<<ETX>>

[1]  E. M. Mattison,et al.  Phase noise in direct digital synthesizers (atomic clocks application) , 1988, Proceedings of the 42nd Annual Frequency Control Symposium, 1988..

[2]  J. F. Garvey,et al.  An exact spectral analysis of a number controlled oscillator based synthesizer , 1990, 44th Annual Symposium on Frequency Control.

[3]  K. McNab,et al.  A Short Survey of Frequency Synthesizer Techniques , 1986, 40th Annual Symposium on Frequency Control.

[4]  Robin P. Giffard,et al.  Architecture and algorithms for new cesium beam frequency standard electronics , 1992, Proceedings of the 1992 IEEE Frequency Control Symposium.

[5]  Richard K. Karlquist.  A new RF architecture for cesium frequency standards , 1992, Proceedings of the 1992 IEEE Frequency Control Symposium.

[6]  H. Samueli,et al.  An Analysis of the Output Spectrum of Direct Digital Frequency Synthesizers in the Presence of Phase-Accumulator Truncation , 1987, 41st Annual Symposium on Frequency Control.

[7]  A. L. Bramble,et al.  Direct Digital Frequency Synthesis , 1981 .

[8]  B. Gold,et al.  A digital frequency synthesizer , 1971 .

[9]  H. Samueli,et al.  The optimization of direct digital frequency synthesizer performance in the presence of finite word length effects , 1988, Proceedings of the 42nd Annual Frequency Control Symposium, 1988..