Phase-locked loop with adjustable bandwidth
AssigneeAnalog Devices International Unlimited Company
InventorNiall Kevin Kearney
Life of this patent
Estimating the term…
Abstract
Aspects of this disclosure relate to a VLIF receiver with automatic phase noise adjustment. The presence of an interfering signal is sensed within a bandwidth around a desired channel frequency. Then the local oscillator phase noise is automatically adjusted to optimize blocking. The phase noise adjustment includes increasing the bandwidth of a phase-locked loop.
Claims20
A phase-locked loop having adjustable bandwidth to enhance adjacent channel rejection and blocking performance, the phase-locked loop configured to provide an oscillator signal for demodulating a receive signal in a radio frequency receiver, the phase-locked loop comprising:
- a phase detector comprising an output;
- a loop filter comprising an input in communication with the output of the phase detector, the loop filter configured to modify interferer blocking resilience of the radio frequency receiver by modifying a phase noise profile of the oscillator signal;
- and
- a bandwidth control circuit configured to operate the loop filter in a first configuration having a first bandwidth in response to no interferer being detected in the receive signal, the first configuration of the loop filter configured to enhance far-out interferer blocking resilience of the radio frequency receiver, the bandwidth control circuit further configured to operate the loop filter in a second configuration having a second bandwidth in response to an interferer being detected in the receive signal, the second configuration of the loop filter configured to enhance close-in interferer blocking resilience of the radio frequency receiver, the second bandwidth being greater than the first bandwidth.
A method to adjust the bandwidth of a phase-locked loop in a receiver to enhance adjacent channel rejection and blocking performance of the receiver, the phase-locked loop configured to provide an oscillator signal for demodulating a receive signal in the receiver, the method comprising:
- operating a loop filter of the phase-locked loop in a first configuration having a first bandwidth in response to no interferer being detected in the receive signal;
- detecting an interferer in the receive signal prior to channel select filtering;
- and
- operating the loop filter in a second configuration having a second bandwidth that is greater than the first bandwidth in response to detecting the interferer in the receive signal.
A receiver with adaptive phase noise, the receiver comprising:
- an antenna configured to transmit and receive radio frequency signals;
- an interferer detector configured to detect interferers in a received radio frequency signal;
- and
- a phase-locked loop configured to generate an oscillator signal for use in demodulating the received radio frequency signal, the phase-locked loop including a phase detector comprising an output, a loop filter comprising an input in communication with the output of the phase detector, wherein the loop filter is configured to modify interferer blocking resilience of the receiver by modifying a phase noise profile of the oscillator signal, and a bandwidth switch circuit configured to adjust a bandwidth of the phase-locked loop to a first bandwidth in response to not detecting the interferer in the receive signal to enhance far-out interferer blocking resilience of the receiver, and to adjust the bandwidth of the phase-locked loop to a second bandwidth that is greater than the first bandwidth in response to detecting the interferer in the receive signal to enhance close-in interferer blocking resilience of the receiver.
Dependencies are inferred from the claim text.