Phase locked frequency synthesizer with single input wideband modulation system
First Claim
1. Apparatus for modulating a phase-locked loop including a voltage controlled oscillator having an input for receiving a modulation signal from a modulation source, said apparatus comprising:
- first means, coupled to said modulation source, for coupling at least high frequency signals from said modulation source to said input of said voltage controlled oscillator;
second means, coupled to said modulation source, for blocking high frequency signals and for boosting low frequency signals received from said modulation source; and
means for summing signals from said first means and second means to provide a compensated modulation signal to said input of said voltage controlled oscillator.
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Accused Products
Abstract
A single input wideband modulation system for a phase locked loop is achieved by interposing the inverse analogue of the closed phase locked loop transfer function between the modulation source and the VCO modulation input. A first branch of the interposed circuit directly passes high frequency signals from the modulation source to a summing device tied to an input of the VCO. A second branch of the interposed circuit boosts low frequency signals and blocks high frequency signals recieved from the modulation source and passes such signal to the summing device where signals from the first and second branches are summed to permit wideband modulation of the VCO. All the modulation processing is performed outside the phase locked loop.
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Citations
29 Claims
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1. Apparatus for modulating a phase-locked loop including a voltage controlled oscillator having an input for receiving a modulation signal from a modulation source, said apparatus comprising:
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first means, coupled to said modulation source, for coupling at least high frequency signals from said modulation source to said input of said voltage controlled oscillator; second means, coupled to said modulation source, for blocking high frequency signals and for boosting low frequency signals received from said modulation source; and means for summing signals from said first means and second means to provide a compensated modulation signal to said input of said voltage controlled oscillator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Apparatus for modulating a phase locked loop including a voltage controlled oscillator having an input for receiving modulation signals from a modulation source, said apparatus comprising:
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means coupled to said modulation source for receiving modulation signals from said modulation source; and means, coupled to said means for receiving, for providing an inverse replica of the frequency characteristic of the phase locked loop to said voltage controlled oscillator input to thereby provide wideband modulation of said phase locked loop. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for wideband modulating a phase locked loop having a predetermined frequency characteristic including a voltage controlled oscillator having an input for receiving modulation signals, said method comprising the steps of:
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providing modulation signals from a modulation source; generating, by processing said modulation signals, an inverse replica of the frequency characteristic of the phase locked loop; and coupling said inverse replica to said input of said voltage controlled oscillator to thereby provide wideband modulation of said phase locked loop. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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Specification