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US 4,914,405 AGranted
Frequency synthesizer
AssigneeMarconi Instruments Limited
InventorJohn N. Wells
Life of this patent
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Abstract
A low-noise frequency synthesizer comprises a low-noise oscillator, such as a crystal oscillator, a multiplier, a divider and a phase-locked loop and is adapted to provide an output signal which is a combination of the multiplied and divided frequency. Thus, a large number of frequencies are available as an output in small increments determined by the division ratio of the divider.
Claims8
A frequency synthesizer comprising
- an oscillator for generating a signal having a predetermined frequency;
- means for multiplying said predetermined frequency by an integer value;
- means for dividing said predetermined frequency by an integer value;
- a phase locked loop for combining the outputs of said multiplying means and said dividing means, said phase-locked loop comprising a phase detector, a voltage controlled oscillator and a mixer, said voltage controlled oscillator being steered to a frequency substantially equal to the multiplied frequency .+-. the divided frequency, the output of said phase lock loop providing the output of said frequency synthesizer;
- and
- phase detector switch means for selectively switching said phase detector into and out of said phase-locked loop.
3 more elements
A frequency synthesizer comprising
- an oscillator for generating a signal having a predetermined frequency;
- means for multiplying said predetermined frequency by an integer value, said means including
- a series chain of multipliers an input coupled to said oscillator, each of the multipliers in said series chain multiplying a signal applied thereto by a fixed integer value;
- and
- multiplier switch means coupled to the output of each of the multipliers in said series chain;
- means for dividing said given frequency by an integer value;
- and
- a phase locked loop for combining the outputs of said multiplying means and said dividing means, said phase lock loop including a mixer for receiving via said multiplier switch means the output from at least one of said series chain of multipliers.
5 more elements
A frequency synthesizer comprising
- an oscillator for generating a signal having a predetermined frequency;
- means for multiplying said predetermined frequency by an integer value to provide a multiplied signal;
- a first output line coupled to the output of said multiplying means, said first output line providing as a first output of said frequency synthesizer said multiplied signal;
- means for dividing said predetermined frequency by an integer value to provide a divided signal;
- a phase locked loop for combining the outputs of said multiplying means and said dividing means to obtain a signal which is a combination of said multiplied and divided signals;
- and
- a second output line coupled to the output of said phase locked loop, said second output line providing as a second output of said frequency synthesizer said combination of said multiplied and divided signals.
4 more elements
Dependencies are inferred from the claim text.