A multi-tune filter system and a control system for operating the multi-tune filter system are described herein. The multi-tune filter system is a tunable frequency range filter. Further, the multi-tune filter system is a digitally programmable filter with an adjustable passband between first and second customizable frequency bounds f1, f2.

A reduction in size and cost of a filter capable of changing a pass band is realized. A filter includes a first distributed constant line, a first impedance element, a second impedance element, and a first switch. The first impedance element and the first switch are connected in series between the first distributed constant line and a ground point. The second impedance element is connected between the first distributed constant line and the ground point.

A variable filter and method of switching a resonant frequency of the variable filter from an initial frequency to a desired frequency, where the variable filter has a tunable frequency and a variable Q. With the variable filter operating at the initial frequency and an initial Q, the variable filter is Q-spoiled toward a low-Q state. The variable filter is tuned toward the desired frequency and the tunable resonator is Q-enhanced from the low-Q state to achieve a desired filter response.

A variable filter and method of switching a resonant frequency of the variable filter from an initial frequency to a desired frequency, where the variable filter has a tunable frequency and a variable Q. With the variable filter operating at the initial frequency and an initial Q, the variable filter is Q-spoiled toward a low-Q state. The variable filter is tuned toward the desired frequency and the tunable resonator is Q-enhanced from the low-Q state to achieve a desired filter response.

A circuit interrupter including a busbar, a Rogowski coil disposed around the busbar and structured to sense current having a first frequency flowing through the busbar, a test injector circuit structured to input a test signal having a second frequency to the Rogowski coil, high or band pass filter circuitry structured to receive an output of the Rogowski coil, the output including a first component having the first frequency and being proportional to the current through the busbar and a second component having the second frequency and being proportional to a temperature of the Rogowski coil, and to attenuate the first component of the Rogowski coil output, and an electronic trip unit including a temperature measurement unit structured to receive an output of the high or band pass filter circuitry and to estimate the temperature of the busbar based on the output of the high or band pass filter circuitry.

A circuit interrupter including a busbar, a Rogowski coil disposed around the busbar and structured to sense current having a first frequency flowing through the busbar, a test injector circuit structured to input a test signal having a second frequency to the Rogowski coil, high or band pass filter circuitry structured to receive an output of the Rogowski coil, the output including a first component having the first frequency and being proportional to the current through the busbar and a second component having the second frequency and being proportional to a temperature of the Rogowski coil, and to attenuate the first component of the Rogowski coil output, and an electronic trip unit including a temperature measurement unit structured to receive an output of the high or band pass filter circuitry and to estimate the temperature of the busbar based on the output of the high or band pass filter circuitry.

A waveguide low profile slide-screw impedance tuner for seamless on-wafer integration uses rotating metallic tuning probe. This ensures high resolution in the area where the probe penetration is maximum (high GAMMA), a smooth increase of depth (basic anti-electrical discharge—“Corona” form) and compensation for the negative phase trajectory at higher GAMMA, native to traditional vertically moving stub-probes in waveguide tuners. Also, using rotating disc-probes simplifies the tuner mechanics, eliminates the cumbersome precise vertical axis and gear and flattens the tuner profile for best direct connection with wafer-probes.

In tuning a radio frequency (RF) module including a non-volatile tunable RF filter, a desired frequency and an undesired frequency being provided by an amplifier of the RF module are detected. The non-volatile tunable RF filter is coupled to an output of the amplifier of the RF module. A factory setting of an adjustable capacitor in the non-volatile tunable RF filter is changed by factory-setting a state of a non-volatile RF switch, such that the non-volatile tunable RF filter substantially rejects the undesired frequency and substantially passes the desired frequency. The adjustable capacitor includes the non-volatile RF switch, and the factory setting of the adjustable capacitor corresponds to a factory-set state of the non-volatile RF switch. An end-user is prevented access to the non-volatile RF switch, so as prevent the end-user from modifying the factory-set state of the non-volatile RF switch.

In tuning a radio frequency (RF) module including a non-volatile tunable RF filter, a desired frequency and an undesired frequency being provided by an amplifier of the RF module are detected. The non-volatile tunable RF filter is coupled to an output of the amplifier of the RF module. A factory setting of an adjustable capacitor in the non-volatile tunable RF filter is changed by factory-setting a state of a non-volatile RF switch, such that the non-volatile tunable RF filter substantially rejects the undesired frequency and substantially passes the desired frequency. The adjustable capacitor includes the non-volatile RF switch, and the factory setting of the adjustable capacitor corresponds to a factory-set state of the non-volatile RF switch. An end-user is prevented access to the non-volatile RF switch, so as prevent the end-user from modifying the factory-set state of the non-volatile RF switch.

A triple-mode dielectric resonator filter includes: a dielectric resonator positioned in a cavity of a housing and formed perpendicular to a longitudinal direction of the housing; a dielectric support coupled to the dielectric resonator through a bonding process and mounted and fixed by a fixing screw passing through a screw fixing mounting hole in the cavity of the housing and fixed to support the dielectric resonator at a predetermined height; and compensation blocks formed to protrude at regular intervals on a side surface of the dielectric resonator to allow the dielectric resonator to operate in three modes. A band pass filter composed of a dielectric resonator and an NRN stub achieves an improved insertion loss, high compression properties and a stable structure compared to a typical band pass filter using an NRN stub.