Frequency synthesizer
First Claim
1. A frequency synthesizer comprising:
- an oscillator having its oscillating frequency controlled by a voltage or a current;
first differential phase generating means for outputting a value corresponding to a differential phase of a reference signal at a predetermined frequency as a first differential phase;
second differential phase generating means for extracting phase information from an oscillating signal corresponding to an output of said oscillator and for outputting the phase information as a second differential phase;
comparing means for calculating the difference between said first and second differential phases;
signal processing means for integrating an output of said comparing means; and
means for converting an output of said signal processing means to a voltage or a current to control said oscillator.
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Accused Products
Abstract
A frequency synthesizer which comprises a voltage controlled oscillator; a unit for outputting a value corresponding to a differential phase of a reference signal at a predetermined frequency as a first differential phase; a unit for sampling an oscillating signal corresponding to an output of the voltage controlled oscillator K times per period of a repeating frequency fr (fr is an arbitrary frequency) and for repetitively generating phase information of the oscillating signal in the form of saw-tooth-like wave; a unit for calculating the difference between adjacent phase information in phase information of the oscillating signal outputted as a saw-tooth-like wave, and for outputting this difference as a second differential phase; a comparator for calculating the difference between the first and second differential phases; a signal processing unit for integrating an output of the comparator; and a unit for converting an output of the signal processing unit to a voltage to control the voltage controlled oscillator.
88 Citations
97 Claims
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1. A frequency synthesizer comprising:
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an oscillator having its oscillating frequency controlled by a voltage or a current; first differential phase generating means for outputting a value corresponding to a differential phase of a reference signal at a predetermined frequency as a first differential phase; second differential phase generating means for extracting phase information from an oscillating signal corresponding to an output of said oscillator and for outputting the phase information as a second differential phase; comparing means for calculating the difference between said first and second differential phases; signal processing means for integrating an output of said comparing means; and means for converting an output of said signal processing means to a voltage or a current to control said oscillator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 60, 79)
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14. A frequency synthesizer comprising:
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an oscillator having its oscillating frequency controlled by a voltage or a current; first differential phase generating means for outputting a value corresponding to a differential phase of a reference signal at a predetermined frequency as a first differential phase; second differential phase generating means for extracting phase information from an oscillating signal corresponding to an output of said oscillator and for outputting the phase information as a second differential phase; comparing means for calculating the difference between said first and second differential phases; signal processing means for integrating an output of said comparing means; means for converting an output of said signal processing means to a voltage or a current to control said oscillator; control signal generating means for detecting changes in a dividing number N; and phase difference detecting means for detecting a phase difference between an output of said first differential phase generating means and an output of said second differential phase generating means on the basis of an output of said control signal generating means, and for compensating for an initial value previously given as a control value for said voltage controlled oscillator on the basis of said phase difference.
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15. A frequency synthesizer comprising:
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an oscillator having its oscillating frequency controlled by a voltage or a current; first differential phase generating means for outputting a value corresponding to a differential phase of a reference signal at a predetermined frequency as a first differential phase; second differential phase generating means for extracting phase information from an oscillating signal corresponding to an output of said oscillator and for outputting the phase information as a second differential phase; comparing means for calculating the difference between said first and second differential phases; signal processing means for integrating an output of said comparing means; means for converting an output of said signal processing means to a voltage or a current to control said oscillator; and gain control means for changing a closed loop gain of said frequency synthesizer corresponding to an externally inputted gain control signal.
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16. A frequency synthesizer comprising:
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an oscillator having its oscillating frequency controlled by a voltage or a current; first differential phase generating means for outputting a value corresponding to a differential phase of a reference signal at a predetermined frequency as a first differential phase; second differential phase generating means for extracting phase information from an oscillating signal corresponding to an output of said oscillator and for outputting the phase information as a second differential phase; comparing means for calculating the difference between said first and second differential phases; signal processing means for integrating an output of said comparing means; means for converting an output of said signal processing means to control said oscillator; and frequency error compensating means for deriving a changing amount (differential value) of an output signal from said comparing means for a constant period to compensate for a control signal for said oscillator on the basis of said changing amount.
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17. A frequency synthesizer comprising:
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an oscillator having its oscillating frequency controlled by a voltage or a current; first differential phase generating means for outputting a value corresponding to a differential phase of a reference signal at a predetermined frequency as a first differential phase; second differential phase generating means for extracting phase information from an oscillating signal corresponding to an output of said oscillator and for outputting the phase information as a second differential phase; comparing means for calculating the difference between said first and second differential phases; signal processing means for integrating an output of said comparing means; means for converting an output of said signal processing means to a voltage or a current to control said oscillator; control signal generating means for detecting changes in a dividing number N; phase difference detecting means for detecting a phase difference between an output of said first differential phase generating means and an output of said second differential phase generating means on the basis of an output of said control signal generating means, and for compensating for an initial value previously given as a control value for said voltage controlled oscillator on the basis of said phase difference; gain control means for changing a closed loop gain of said frequency synthesizer corresponding to an externally inputted gain control signal; and frequency error compensating means for deriving a changing amount (differential value) of the output of said comparing means for a constant period to compensate for a control signal for said oscillator on the basis of said changing amount.
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18. A frequency synthesizer comprising:
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first saw-tooth-like wave generating means for generating a saw-tooth-like wave based on a reference signal supplied from a reference oscillator; second saw-tooth-like wave generating means for generating a saw-tooth-like wave based on a previously specified dividing number N and an output of a voltage controlled oscillator; means for calculating the difference between outputs of said first saw-tooth-like wave generating means and outputs of said second saw-tooth-like wave generating means and for outputting a difference signal; means for performing signal processing for said difference signal to output said processed difference signal as an oscillation control signal for said voltage controlled oscillator; control signal generating means for detecting changes in said dividing number N; and phase difference detecting means for detecting a phase difference between the output of said first saw-tooth-like wave generating means and the output of said second saw-tooth-like wave generating means on the basis of an output of said control signal generating means and for compensating for an initial value previously given as a control value for an oscillating frequency of said voltage controlled oscillator on the basis of said phase difference. - View Dependent Claims (22, 26, 27, 28, 29, 33, 37, 41, 42, 61, 62, 63, 64, 68, 69, 70, 80, 81, 82, 83, 87, 88, 89)
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19. A frequency synthesizer comprising:
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first saw-tooth-like wave generating means for generating a saw-tooth-like wave based on a reference signal supplied from a reference oscillator; second saw-tooth-like wave generating means for generating a saw-tooth-like wave based on a previously specified dividing number N and an output of a voltage controlled oscillator; means for calculating the difference between outputs of said first saw-tooth-like wave generating means and outputs of said second saw-tooth-like wave generating means and for outputting a difference signal; means for performing signal processing for said difference signal to output said processed difference signal as an oscillation control signal for said voltage controlled oscillator; and gain control means for changing a closed loop gain of said frequency synthesizer corresponding to an externally inputted gain control signal. - View Dependent Claims (23, 30, 34, 38, 65, 84)
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20. A frequency synthesizer comprising:
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first saw-tooth-like wave generating means for generating a saw-tooth-like wave based on a reference signal supplied from a reference oscillator; second saw-tooth-like wave generating means for generating a saw-tooth-like wave based on a previously specified dividing number N and an output of a voltage controlled oscillator; means for calculating the difference between outputs of said first saw-tooth-like wave generating means and outputs of said second saw-tooth-like wave generating means and for outputting a difference signal; means for performing signal processing for said difference signal to output said processed difference signal as an oscillation control signal for said voltage controlled oscillator; and frequency error compensating means for deriving a changing amount (differential value) of said difference signal for a constant period to compensate for said oscillation control signal on the basis of said changing amount. - View Dependent Claims (24, 31, 35, 39, 66, 85)
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21. A frequency synthesizer comprising:
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first saw-tooth-like wave generating means for generating a saw-tooth-like wave based on a reference signal supplied from a reference oscillator; second saw-tooth-like wave generating means for generating a saw-tooth-like wave based on a previously specified dividing number N and an output of a voltage controlled oscillator; means for calculating the difference between outputs of said first saw-tooth-like wave generating means and outputs of said second saw-tooth-like wave generating means and for outputting a difference signal; means for performing signal processing for said difference signal to output said processed difference signal as an oscillation control signal for said voltage controlled oscillator; control signal generating means for detecting changes in said dividing number N; phase difference detecting means for detecting a phase difference between the output of said first saw-tooth-like wave generating means and the output of said second saw-tooth-like wave generating means on the basis of an output of said control signal generating means and for compensating for an initial value previously given as a control value for an oscillating frequency of said voltage controlled oscillator on the basis of said phase difference; gain control means for changing a closed loop gain of said frequency synthesizer corresponding to an externally inputted gain control signal; and frequency error compensating means for deriving a changing amount (differential value) of said difference signal for a constant period to compensate for said oscillation control signal on the basis of said changing amount. - View Dependent Claims (25, 32, 36, 40, 67, 86)
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43. A frequency synthesizer comprising:
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first saw-tooth-like wave generating means for generating a saw-tooth-like wave based on a reference signal supplied from a reference oscillator; second saw-tooth-like wave generating means for generating a saw-tooth-wave based on a previously specified dividing number N and an output of a voltage controlled oscillator; means for calculating the difference between an output of said first-saw-tooth-like wave generating means and an output of said second saw-tooth-like wave generating means to output a difference signal; bit number reducing means for converting a data word length of an input signal to a shorter data word length, said bit number reducing means comprising; a first quantizer for quantizing said difference signal; a first subtractor for calculating the difference between an output of said first quantizer and an input signal for said first quantizer; a noise shaping circuit receiving an output of said first subtractor as an input; a delay circuit for delaying the output of said first quantizer; an adder circuit for adding an output of said delay circuit and an output of said noise shaping circuit; a D/A convertor for converting an output of said adder circuit to an analog signal; and filter means for filtering an output of said D/A convertor to supply the filtered output to said voltage controlled oscillator as an input signal. - View Dependent Claims (44, 45, 46, 47, 48, 49, 52, 54, 55, 57, 58, 71, 72, 73, 75, 76, 77, 78, 90, 91, 92, 94, 95, 96, 97)
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50. A frequency synthesizer comprising:
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an oscillator having its oscillating frequency controlled by a voltage or a current; first differential phase generating means for outputting a value corresponding to a differential phase of a reference signal at a predetermined frequency as a first differential phase; second differential phase generating means for extracting phase information from an oscillating signal corresponding to an output of said oscillator and for deriving a second differential phase; comparing means for calculating the difference between said first and second differential phases; signal processing means for integrating an output of said comparing means; a first quantizer for quantizing an output signal of said signal processing means; a first subtractor for calculating the difference between an output of said first quantizer and the output signal of said signal processing means; a noise shaping circuit receiving an output of said first subtractor as an input; a delay circuit for delaying the output of said first quantizer; an adder circuit for adding an output of said delay circuit and an output of said noise shaping circuit; a D/A convertor for converting an output of said adder circuit to an analog signal; and filter means for filtering an output of said D/A convertor to supply the filtered output to said voltage controlled oscillator as an input signal. - View Dependent Claims (51, 53, 56, 59, 74, 93)
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Specification