Phase locked loop frequency and phase modulators

专利名称：Phase locked loop frequency and phase

modulators

发明人：David P. Owen申请号：US06/607397申请日：19840503公开号：US04543542A公开日：19850924

摘要：A signal generator is arranged to produce frequency or phase modulation atfrequencies which extend from a high value down to zero, i. e. to a d.c. level shift. Theoutput oscillator forms part of a phase locked loop which also includes a variablefrequency divider. A modulation signal is applied to the loop, so that high frequencymodulation signals directly modify the control signal which determines the frequency ofthe oscillator, and so that low frequency modulation signals alter the divisor value of thevariable frequency divider so as to modify the frequency characteristics of the phaselocked loop. Quantization noise is reduced by applying a masking signal to an analogue-to-digital converter which utilizes the low frequency modulation signals to alter thedivisor value.

申请人：MARCONI INSTRUMENTS LIMITED

代理机构：Spencer & Frank

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