Spur cancellation for spur measurement
AssigneeSkyworks Solutions, Inc.
InventorsTimothy A. Monk, Rajesh Thirugnanam
Life of this patent
Estimating the term…
Abstract
A spur measurement system uses a first device with a spur cancellation circuit that cancel spurs responsive to a frequency control word identifying a spurious tone of interest. A device under test generates a clock signal and supplies the clock signal to the first device through an optional divider. The spur cancellation circuit in the first device generates sine and cosine weights at the spurious tone of interest as part of the spur cancellation process. A first magnitude of the spurious tone in a phase-locked loop in the first device is determined according to the sine and cosine weights and a second magnitude of the spurious tone in the clock signal is determined by the first magnitude divided by gains associated with the first device.
Claims21
(canceled)
A method of determining a presence of a spurious tone in a signal, the method comprising:
- receiving an indication of a first frequency corresponding to a spurious tone to be measured in a first signal;
- generating a second signal in a phase-locked loop based on the first signal and a feedback signal;
- determining a presence of the spurious tone in the second;
- determining a first magnitude of the spurious tone in the second signal;
- and
- dividing the first magnitude of the spurious tone in the second signal by a plurality of gain factors to determine a second magnitude of the spurious tone in the first signal.
The method of claim 21 further comprising receiving a second indication of a second frequency corresponding to an additional spurious tone to be measured in the first signal.
A spur measurement system comprising:
- a phase-locked loop responsive to an indication of a spurious tone in a first signal, the phase-locked loop configured to determine the presence of the spurious tone in a second signal generated based on the first signal, to determine a first magnitude of the spurious tone in the second signal, and to determine a second magnitude of the spurious tone in the first signal by dividing the first magnitude by a plurality of gain factors of the phase-locked loop.
A spur measurement system comprising:
- a first phase-locked loop configured to receive a first signal, the first phase-locked loop including a first spur cancellation circuit configured to cancel a first spurious tone in a second signal generated based on the first signal, the first spur cancellation circuit further configured to determine a first magnitude of the first spurious tone in the second signal, and to determine a second magnitude of the first spurious tone in the first signal by dividing the first magnitude by a plurality of gain factors of the first phase-locked loop;
- and
- a second phase-locked loop configured to receive the first signal, the first phase-locked loop including a second spur cancellation circuit configured to cancel a second spurious tone in a third signal generated based on the first signal, the second spur cancellation circuit further configured to determine a third magnitude of the second spurious tone in the second signal, and to determine a fourth magnitude of the second spurious tone in the first signal by dividing the third magnitude by a plurality of gain factors of the second phase-locked loop.
Dependencies are inferred from the claim text.