Frequency synthesizer having microcomputer supplying analog and digital control signals to VCO
First Claim
1. A frequency synthesizer, comprising:
- (A) an oscillator for generating a desired output frequency and including;
(1) coarse-tuning means having a first input for receiving a digital input signal and for selecting one of a plurality of frequency ranges; and
(2) fine-tuning means having a second input for receiving an analog input signal and for applying said signal to a variable reactance component in a resonating circuit, for selecting a desired frequency within a selected frequency range;
(B) a computer, including;
(1) a storage device for storing said oscillator'"'"'s characteristics in the form of a digital table of the input signals corresponding to a plurality of frequency values, each identified by digital data;
(2) an input for receiving input data representing the desired oscillator frequency; and
(3) signal generating means for generating, from said stored digital table and said input data, a digital signal indicating the frequency range of said desired oscillator frequency, and an analog signal indicating the specific oscillator frequency desired;
(C) an electrical circuit for applying said generated digital signal to said first input of the oscillator to coarse-tune the oscillator with respect to the desired frequency, and said generated analog signal to said second input of the oscillator to fine-tune the oscillator with respect to the desired frequency;
(D) a frequency measuring circuit for digitally measuring the actual output frequency of the oscillator and for outputting a signal corresponding thereto; and
(E) a feedback circuit for feeding back to said computer the output signal from said frequency measuring circuit and for controlling, in response thereto, the digital and analog signals generated by said computer.
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Accused Products
Abstract
A frequency synthesizer includes an oscillator which may be coarse-tuned by a first input receiving a digital signal for selecting one of a plurality of frequency ranges, and fine-tuned by a second input receiving an analog signal for selecting the desired frequency within the selected frequency range. The synthesizer further includes a computer storing the oscillator'"'"'s characteristics in the form of a digital table of the input signals corresponding to a plurality of frequency values, each identified by digital data. The computer receives input data representing the desired oscillator frequency and generates from the stored digital table, a digital signal indicating the frequency range of the desired oscillator frequency, and an analog signal indicating the specific oscillator frequency desired, and applies both signals to the oscillator. A frequency measuring circuit measures the actual output frequency of the oscillator and outputs a signal corresponding thereto. This signal is fed back to the computer for controlling, in response thereto, the digital and analog signals generated by the computer.
72 Citations
14 Claims
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1. A frequency synthesizer, comprising:
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(A) an oscillator for generating a desired output frequency and including; (1) coarse-tuning means having a first input for receiving a digital input signal and for selecting one of a plurality of frequency ranges; and (2) fine-tuning means having a second input for receiving an analog input signal and for applying said signal to a variable reactance component in a resonating circuit, for selecting a desired frequency within a selected frequency range; (B) a computer, including; (1) a storage device for storing said oscillator'"'"'s characteristics in the form of a digital table of the input signals corresponding to a plurality of frequency values, each identified by digital data; (2) an input for receiving input data representing the desired oscillator frequency; and (3) signal generating means for generating, from said stored digital table and said input data, a digital signal indicating the frequency range of said desired oscillator frequency, and an analog signal indicating the specific oscillator frequency desired; (C) an electrical circuit for applying said generated digital signal to said first input of the oscillator to coarse-tune the oscillator with respect to the desired frequency, and said generated analog signal to said second input of the oscillator to fine-tune the oscillator with respect to the desired frequency; (D) a frequency measuring circuit for digitally measuring the actual output frequency of the oscillator and for outputting a signal corresponding thereto; and (E) a feedback circuit for feeding back to said computer the output signal from said frequency measuring circuit and for controlling, in response thereto, the digital and analog signals generated by said computer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of controlling an oscillator for generating an output signal having a desired frequency, comprising:
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(A) storing in a storage device an oscillator'"'"'s characteristics in the form of a digital table of the input signals corresponding to a plurality of frequency values, each identified by digital data; (B) receiving the value of a desired frequency; (C) computing the values of a coarse-tuning signal and a fine-tuning signal for said oscillator, according to said digital table and said desired signal; and (D) applying said coarse tuning signal to said oscillator to select one of a plurality of frequency ranges; and
applying said fine-tuning signal to said oscillator to select a desired frequency within a selected frequency range. - View Dependent Claims (12, 13, 14)
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Specification