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US 5,175,884 AGranted
Voltage controlled oscillator with current control
AssigneeMotorola, Inc.
InventorJose I. Suarez
Life of this patent
Estimating the term…
Abstract
An apparatus (200) and method for adjusting the bias current of the oscillating device (320) in a VCO (202) in response to changes in the tuning voltage of the VCO to achieve reduced sideband noise.
Claims12
A circuit for setting a bias current of an oscillating device, the oscillating device having an output whose frequency is controlled by a tuning voltage, the circuit comprising:
- sensing means, coupled to the oscillating device, for sensing the tuning voltage of the oscillating device;
- and
- control means, responsive to the sensed tuning voltage, for controlling the bias current of the oscillating device, by setting a current value according to predetermined data relating to bias currents for minimizing sideband noise for each of a plurality of tuning voltages.
A frequency synthesizer comprising:
- a VCO, having a bias current and an output whose frequency is controlled by a tuning voltage;
- sensing means for sensing the level of the tuning voltage;
- and
- control means for controlling the bias current, in response to the level of the tuning voltage, by setting a current value according to predetermined data relating to bias currents for minimizing sideband noise for each of a plurality of tuning voltages.
1 more element
A radio comprising:
- a VCO having a bias current and an output whose frequency is controlled by a tuning voltage;
- sensing means for sensing the level of the tuning voltage;
- and
- control means for controlling the bias current, in response to the level of the tuning voltage, by setting a current value according to predetermined data relating to bias currents for minimizing sideband noise for each of a plurality of tuning voltages.
1 more element
A method for controlling the bias current of a VCO comprising the steps of:
- (a) measuring sideband noise levels of a VCO corresponding to a plurality of bias currents and VCO tuning voltages to produce a set of bias current values that minimize the sideband noise for each of the plurality of VCO tuning voltages;
- (b) storing the set of current values and their corresponding VCO tuning voltages produced in step (a);
- (c) sensing the level of the tuning voltage of the VCO;
- and
- (d) adjusting the level of the bias current of the VCO to correspond to the bias current value stored in step (b) that corresponds to the sensed tuning voltage.
2 more elements
Dependencies are inferred from the claim text.