Phase noise reduction in a variable analogue rf resonator with switched capacitors
AssigneeAnlotek Limited
InventorJorgen Staal Nielsen
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Abstract
An active feedback RF resonator has a signal loop having a signal input and a signal output. The signal loop has a variable gain stage and at least one variable resonator, each variable resonator comprising an inductance element and a variable capacitance element comprising a number of switched fixed value capacitors and a variable capacitor. A phase noise of the active feedback RF signal has a maximum value for an operating frequency of the variable resonator that is based on an operating range of the variable capacitor.
Claims12
An active feedback RF resonator, comprising:
- a signal loop having a signal input and a signal output, the signal loop comprising a variable gain stage and at least one variable resonator, each variable resonator comprising an inductance element and a variable capacitance element comprising a number of switched fixed value capacitors and a variable capacitor;
- wherein a phase noise of the active feedback RF signal has a maximum value for an operating frequency of the variable resonator that is based on an operating range of the variable capacitor.
A method of designing an active feedback RF resonator, comprising the steps of:
- providing a signal loop having a signal input and a signal output, the signal loop comprising a variable gain stage and at least one variable resonator, each variable resonator comprising an inductance element and a variable capacitance element comprising a number of switched capacitors and a variable capacitor, the switched capacitors having fixed capacitance values;
- and
- for each variable resonator:
- calculating an operating factor based on one or more of the following parameters of the variable resonator a minimum Q, a maximum phase noise factor, a range of operating frequencies, and an operating bias voltage and capacitance of the variable capacitor;
- and;
- calculating the number of switched capacitors based on a logarithm of the operating factor.
A method of designing an active feedback RF resonator, comprising the steps of:
- providing a signal loop having a signal input and a signal output, the signal loop comprising a variable gain stage and at least one variable resonator, each variable resonator comprising an inductance element and a variable capacitance element comprising a number of switched capacitors and a variable capacitor, the switched capacitors having fixed capacitance values, and wherein the variable capacitor comprises 40% or less of a total capacitance of the variable capacitance element.
Dependencies are inferred from the claim text.