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US 5,207,491 AGranted
Fast-switching frequency synthesizer
AssigneeMotorola, Inc.
InventorAlan P. Rottinghaus
Life of this patent
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Abstract
A fast-switching frequency synthesizer utilizes a time-varying presteering voltage injection at the voltage controlled oscillator ("VCO") with feedback to allow the VCO and synthesizer to rapidly change between two given frequencies.
Claims20
A synthesizer for generating a frequency, comprising:
- a voltage controlled oscillator ("VCO") having a voltage control line and an output,
- a phase detector having a frequency reference, an input and an output,
- a frequency divider having an input and an output,
- the VCO output coupled to the frequency divider input, the frequency divider output coupled to the phase detector input, the phase detector output coupled to the voltage control line, and
- means for controlling the synthesizer frequency, comprising:
- changing means for changing the frequency divider to a first divisor value;
- injecting means for injecting a first waveform to the voltage control line at a fixed time with respect to changing to the first divisor value;
- sampling means for detecting and sampling the phase detector output responsive to changing to the first divisor value thereby forming a first sample signal;
- adjusting means for adjusting the first waveform based on the first sample signal.
6 more elements
In a synthesizer for generating a frequency, comprising:
- a voltage controlled oscillator ("VCO") having a voltage control line and an output,
- a phase detector having a frequency reference, an input and an output,
- a frequency divider having an input and an output,
- the VCO output coupled to the frequency divider input, the frequency divider output coupled to the phase detector input, the phase detector output coupled to the voltage control line, and
- a method for controlling the synthesizer frequency, comprising the steps of:
- (a) changing the frequency divider to a first divisor value;
- (b) injecting a first waveform to the voltage control line at a fixed time with respect to changing to the first divisor value;
- (c) detecting and sampling the phase detector output responsive to changing to the first divisor value thereby forming a first sample signal;
- (d) adjusting the first waveform based on the first sample signal.
6 more elements
Dependencies are inferred from the claim text.