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US 6,271,737 B1Granted
Communication device with feedback for cancellation of perturbations
AssigneeU.S. Philips Corporation
InventorStephen W. Watkinson
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AssigneeU.S. Philips Corporation
InventorStephen W. Watkinson
Estimating the term…
A communications device, such as a one-way pager, comprises a receiver having a frequency down-conversion means for frequency converting an input signal using a local oscillator signal generated by a signal generating means, which may comprise a frequency synthesizer. The signal generating means (20) comprises a voltage controlled oscillator (VCO) (50) including an oscillator transistor (68) coupled to dc voltage source (54), frequency determining reactive elements coupled to the oscillator transistor (68) for determining the frequency to be generated, at least one of the reactive elements (80) being adjustable in response to an applied voltage and means (82,84) for phase modulating the oscillator transistor (68) in an opposite sense to that caused by voltage perturbations due to noise in the dc voltage supplied by the dc voltage source (54).
A communications device comprising frequency conversion means having a first input for a signal to be frequency converted and a second input for a converting signal generated by a frequency generating means, the frequency generating means comprising a voltage controlled oscillator (VCO) including an active element having a control electrode, a current supply electrode and an output electrode, a dc voltage source coupled between the current supply electrode and the output electrode, frequency determining reactive elements coupled to the active element for determining the frequency to be generated, at least one of the reactive elements being adjustable in response to an applied voltage and means for deriving a dc signal from the dc voltage of the dc voltage source which signal includes at least a component responsive to voltage perturbations in said dc voltage, and means for phase modulating the VCO in response to said dc signal in an opposite sense to a phase modulation caused by modulation of parameters of the active element due to said voltage perturbations.
A communications device comprising frequency conversion means having a first input for a signal to be frequency converted and a second input for a converting signal generated by a frequency generating means, the frequency generating means comprising a voltage controlled oscillator (VCO) including an active element having a control electrode, a current supply electrode and an output electrode, a dc voltage source coupled between the current supply electrode and the output electrode, frequency determining reactive elements coupled to the active element for determining the frequency to be generated, at least one of the reactive elements being adjustable in response to an applied voltage and means for phase modulating the VCO in an opposite sense to a phase modulation caused by the active element due to voltage perturbations in the dc voltage of the dc voltage source, wherein the VCO is part of a phase locked loop frequency synthesizer having a loop filter for applying a control voltage to the adjustable reactive element and the voltage perturbations are added to the control voltage.
A frequency generating circuit comprising a voltage controlled oscillator (VCO) wherein an output of the VCO is applied to a frequency conversion means, the VCO includes an active element having a control electrode and an output electrode, a dc voltage source coupled between the current supply electrode and the output electrode, frequency determining reactive elements coupled to the active element for determining the frequency to be generated, at least one of the reactive elements being adjustable in response to an applied voltage and means for deriving a dc signal from the dc voltage of the dc voltage source which signal includes at least a component responsive to voltage perturbations in said dc voltage, and means for phase modulating the VCO in response to said dc signal in an opposite sense to a phase modulation caused by modulation of parameters of the active element due to said voltage perturbations.
Dependencies are inferred from the claim text.