A method using a phase locked loop (PLL) includes receiving a reference frequency. The method further includes generating a control signal based on the reference frequency. The method further includes adjusting an output signal based on the control signal. Adjusting the output signal includes operating a plurality of switches in response to the control signal, wherein operating the plurality of switches comprises selectively electrically connecting a first ground plane to a first floating plane, wherein the first floating plane is between the first ground plane and the signal line, and the first floating plane is a same distance from a substrate as the first ground plane.

A multi-frequency tuning circuit includes a first branch including a first inductor and a first capacitor arranged in series and a second branch including a second inductor and a second capacitor arranged in series. The circuit is arranged within a circuitry module configured to be positioned between a source and a load, the first branch and the second branch both associated with loads, from the source, having low impedance frequencies. In order to improve transmitter antenna output power for downhole tools, the tuning circuit creates high impedance at operating frequencies between frequencies corresponding to low impedance.

A multi-frequency tuning circuit includes a first branch including a first inductor and a first capacitor arranged in series and a second branch including a second inductor and a second capacitor arranged in series. The circuit is arranged within a circuitry module configured to be positioned between a source and a load, the first branch and the second branch both associated with loads, from the source, having low impedance frequencies. In order to improve transmitter antenna output power for downhole tools, the tuning circuit creates high impedance at operating frequencies between frequencies corresponding to low impedance.

The present invention discloses a parameter tuning approach for bypass damping filter to suppress subsynchronous resonance in power systems, namely determining the parameters of capacitor, inductor and damping resistor in BDF. Using this approach, the parameters of capacitor and inductor in BDF can be adjusted, so that the frequency where the negative electrical damping of generator reaches minimum can be away from the frequency range of low frequency oscillation mode and typical frequencies of each torsional mode; the parameter of damping resistor in BDF can be further adjusted so that the minimum value of negative electrical damping is in reasonable range. The application of BDF with parameters tuned by the present invention contributes to the suppression of both the torsional interaction effect and the transient torque amplification effect.

The present invention discloses a parameter tuning approach for bypass damping filter to suppress subsynchronous resonance in power systems, namely determining the parameters of capacitor, inductor and damping resistor in BDF. Using this approach, the parameters of capacitor and inductor in BDF can be adjusted, so that the frequency where the negative electrical damping of generator reaches minimum can be away from the frequency range of low frequency oscillation mode and typical frequencies of each torsional mode; the parameter of damping resistor in BDF can be further adjusted so that the minimum value of negative electrical damping is in reasonable range. The application of BDF with parameters tuned by the present invention contributes to the suppression of both the torsional interaction effect and the transient torque amplification effect.

A method includes receiving a series of radio frequency (RF) signals, where, from RF signal to RF signal of the series of RF signals, a carrier frequency is changed in accordance with a frequency hopping pattern. The method further includes, while receiving the series of RF signals, sensing an environmental condition by, for a frequency hop of at least some frequency hops of the frequency hopping pattern, adjusting a characteristic of a wireless sensor to maintain proximal alignment of a resonant frequency of the wireless sensor with the carrier frequency corresponding to a present frequency of the at least some frequency hops and generating a value to represent the adjustment of the characteristic, where a set of values is generated for the at least some frequency hops and where the set of values is used to determine a sensed value of the environmental condition.

A multi-frequency tuning circuit includes a first branch including a first inductor and a first capacitor arranged in series and a second branch including a second inductor and a second capacitor arranged in series. The circuit is arranged within a circuitry module configured to be positioned between a source and a load, the first branch and the second branch both associated with loads, from the source, having low impedance frequencies. In order to improve transmitter antenna output power for downhole tools, the tuning circuit creates high impedance at operating frequencies between frequencies corresponding to low impedance.

A multi-frequency tuning circuit includes a first branch including a first inductor and a first capacitor arranged in series and a second branch including a second inductor and a second capacitor arranged in series. The circuit is arranged within a circuitry module configured to be positioned between a source and a load, the first branch and the second branch both associated with loads, from the source, having low impedance frequencies. In order to improve transmitter antenna output power for downhole tools, the tuning circuit creates high impedance at operating frequencies between frequencies corresponding to low impedance.

An apparatus and method for implementing a compact and tunable microwave resonator using NbN kinetic inductance, comprising: a DC source, an attenuator, an oxygen-free copper cavity, a superconducting coil, a first-stage amplifier, a second-stage amplifier, a vector network analyzer and a control computer, a small-sized tunable resonator whose size is reduced by 10-20 times as compared with an ordinary thin film microwave resonator is implemented in a microwave frequency band by using high kinetic inductance of an ultra-thin NbN thin film in a superconducting state, the tunability of the resonator lies in that the ultra-thin NbN thin film serves as the LC resonance circuit, a dc-SQUID is connected to the end of the resonator, and a change in the external magnetic field causes a change in the equivalent inductance of the dc-SQUID, thereby changing the total inductance of the resonator and modulating the resonant frequency of the resonance circuit.

An apparatus and method for implementing a compact and tunable microwave resonator using NbN kinetic inductance, comprising: a DC source, an attenuator, an oxygen-free copper cavity, a superconducting coil, a first-stage amplifier, a second-stage amplifier, a vector network analyzer and a control computer, a small-sized tunable resonator whose size is reduced by 10-20 times as compared with an ordinary thin film microwave resonator is implemented in a microwave frequency band by using high kinetic inductance of an ultra-thin NbN thin film in a superconducting state, the tunability of the resonator lies in that the ultra-thin NbN thin film serves as the LC resonance circuit, a dc-SQUID is connected to the end of the resonator, and a change in the external magnetic field causes a change in the equivalent inductance of the dc-SQUID, thereby changing the total inductance of the resonator and modulating the resonant frequency of the resonance circuit.