Abstract: A cavity filter includes a housing having a positioning portion, a cover on top of the housing which have a pair of first positioning holes, a sliding plate with movably support on the positioning portion and mounted between the positioning portion and the cover to be configured to adjust a resonating frequency of the cavity filter, and a tuning structure fixed on the cover and having a pair of first positioning poles. The sliding plate includes a plurality of elastic arms, each of which is made of insulated material and supported by the positioning portion. Each of the pair of first positioning poles extends through the corresponding first positioning holes to touch the corresponding one of the plurality of elastic arms of the sliding plate.

Abstract: A cavity filter includes a slider, a driving device, and an adapter. The slider is used to slide relative to and couple with a plurality of resonators located in the cavity filter to adjust a resonating frequency of the cavity filter. The driving device is used to drive the slider slide relative to the plurality of resonators and includes a shaft having a free end. The adapter is installed between the slider and the driving device and rotateably connected to the free end of the shaft with a gap configured between the free end and the adapter.

Abstract: A cavity filter includes a housing, a plurality of resonators received in the housing, a cover covering the opening, a sliding plate, and a plurality of tuning posts. The housing defines an opening and comprises at least one pair of positioning portions. The plurality of tuning posts are fixed in the cover corresponding to the plurality of resonators. The sliding plate is disposed between the cover and the plurality of resonators, and is slidably positioned at the at least one pair of positioning portions. The sliding plate comprises a plurality of tuning cells and at least one elastic arm. The plurality of tuning cells is coated with a metallic layer and corresponds to the plurality of resonators. The at least one elastic arm extends from the sliding plate and elastically resists the cover.

Abstract: A cavity filter includes a unitarily formed piece, a cap, a cover, and a tuning adjustment screw. The unitarily formed piece includes a bottom plate portion, a resonator tube body portion formed on a center of the bottom plate portion, and a sidewall portion extending from the bottom plate portion surrounding the resonator tube body portion. The resonator tube body portion defines a resonating cavity therein. The cap is attached onto a distal end of the resonator tube body portion. The cap and the resonator tube body portion cooperatively forms a resonator tube. The cover is attached to the sidewall portion, and the cover includes a screw hole. The cover, the sidewall portion, and the bottom plate portion cooperatively forms a chamber. The tuning adjustment screw is extending through the cover, threadedly engaged in the screw hole and aligned with the resonator tube.

Abstract: A cavity filter includes a slider, a driving device, an adapter and a resilient member. The slider is used to slide relative to and couple with a plurality of resonators located in the cavity filter to change a resonating frequency of the cavity filter. The driving device is used to drive the slider slide relative to the plurality of resonators. The adapter is installed between the slider and the driving device. The resilient member is elastically connected between the slider and the adapter and used to absorb vibrations of the driving device to make the slider move on an even keel.

Abstract: A cavity filter includes a housing having a positioning portion, a cover covering on the housing and defining a pair of first positioning holes, a sliding plate movably supported on the positioning portion and mounted between the positioning portion and the cover to be configured to adjust a resonating frequency of the cavity filter, and a tuning structure fixed on the cover and having a pair of first positioning poles. The sliding plate includes a plurality of elastic arms, each of which is made of insulated material and supported by the positioning portion. Each of the pair of first positioning poles extends through the corresponding first positing hole to touch the corresponding one of the plurality of elastic arms of the sliding plate.

Abstract: A cavity filter defines a cavity with an opening on a top portion thereof and includes a lid to cover the opening of the cavity. A plurality of resonators are secured on a bottom portion opposite to the top portion of the cavity. The lid includes a plurality of bases extending from the lid toward the plurality of the resonators, respectively. A plurality of threaded holes penetrating the lid and one of the bases faces to the plurality of resonators, respectively. Each threaded hole includes a stopper portion extending from an inner surface of the threaded hole inward to form a step defining a hole in communication with the threaded hole. Each threaded hole corresponds to a tuning post to adjust a resonating frequency of the cavity filter.

Abstract: A cavity filter includes an enclosure, resonators secured inside the enclosure, a lid, a slider, and a driving device. The enclosure includes a bottom portion, sidewalls extending from edges of the bottom portion to define a cavity. Each sidewall defines a positioning portion at a top surface thereof. The lid covers the enclosure. The slider includes tuning cells each partially coated with metal and positioned opposite to one of the resonators. The slider is movably disposed between the lid and the resonators and slides on the positioning portions. The driving device is located inside the enclosure and drives the slider to move along the positioning portions to adjust a resonating frequency of the cavity filter.

Abstract: A cavity filter includes a unitarily formed piece, a cap, a cover, and a tuning adjustment screw. The unitarily formed piece includes a bottom plate portion, a resonator tube body portion formed on a center of the bottom plate portion, and a sidewall portion extending from the bottom plate portion surrounding the resonator tube body portion. The resonator tube body portion defines a resonating cavity therein. The cap is attached onto a distal end of the resonator tube body portion. The cap and the resonator tube body portion cooperatively forms a resonator tube. The cover is attached to the sidewall portion, and the cover includes a screw hole. The cover, the sidewall portion, and the bottom plate portion cooperatively forms a chamber. The tuning adjustment screw is extending through the cover, threadedly engaged in the screw hole and aligned with the resonator tube.

Abstract: A fork assembly includes a fixed board, a ground portion, a trigger portion, a switch and a resilient element. The ground portion includes a first arm and a second arm located opposite to the first arm, one end of each of the first arm and the second arm is connected to the fixed board, and the other end is free. The trigger portion includes a third arm and a fourth arm located opposite to the third arm, one end of each of the third arm and the fourth arm is connected to the fixed board. The switch is fixed on the other end of the third arm, and includes a normally open contact. The resilient element is configured on the other end of the fourth arm and corresponding to the normally open contact of the switch. The first, second, third and forth arms are conductively and resiliently connected together.

Abstract: A fixation arrangement for a resonator of a cavity body includes a cavity body including a base, a resonator defining a cavity and comprising a bottom, a screw including sharply arc-shaped head and securing the resonator on the base of the cavity body, and a sticky element located between the screw head of the screw and the bottom of the resonator.

Abstract: A radio frequency (RF) signal communication system provided with amplifier predistortion comprises an antenna for wireless communication. Through the antenna and a receiving path of the system, RF signals are received and transmitted to a baseband module. The transmission path of the system comprises a predistorter and an amplifier, in which the predistorter performs predistortion to compensate signal distortion under the amplification by the amplifier. A coupler is utilized to sample a portion of RF signals output by the amplifier as the feedbacks for the predistortion.

Abstract: A multi-cavity filter includes a main body and a lid body. The main body includes a bottom portion and a plurality of sidewalls extending from the bottom portion so as to cooperatively define a plurality of cavities each with a top opening. The lid body covers on the cavities of the main body and is snugly mounted on the main body by screws. The lid body defines a plurality of grooves to improve flexibility.

Abstract: An cavity filter includes a housing, a plurality of resonators received in the housing, a cover covering the opening, a sliding plate, and a plurality of tuning posts. The housing defines an opening and comprises at least one pair of positioning portions. The plurality of tuning posts is fixed in the cover corresponding to the plurality of resonators. The sliding plate is disposed between the cover and the plurality of resonators, and is slidably positioned at the at least one pair of positioning portions. The sliding plate comprises a plurality of tuning cells and at least one elastic arm. The plurality of tuning cells is coated with a metallic layer and corresponds to the plurality of resonators. The at least one elastic arm extends from the sliding plate and elastically resists the cover.

Abstract: An exemplary intermediate frequency (IF) signal loss compensation circuit for an outdoor unit of a communication system includes a sending circuit, a detection circuit, a receiving circuit, and a control circuit. The detection circuit detects in substantially real-time the loss of signal transmitted via a cable from the indoor to the outdoor unit, and transmits loss signal to the control circuit. The control circuit compares the loss signal with a pre-stored signal to determine the loss and then, the control circuit gives loss signals of the sending circuit a variable gain compensation according to the loss. The control circuit also gives loss signals of the receiving circuit a variable gain compensation in advance. The IF signal loss compensation circuit can detect the IF signal loss in substantially real-time, giving the IF signal a variable gain compensation for the loss.

Abstract: A cavity filter includes an enclosure, resonators secured inside the enclosure, a lid, a slider, and a driving device. The enclosure includes a bottom portion, sidewalls extending from edges of the bottom portion to define a cavity. Each sidewall defines a positioning portion at a top surface thereof. The lid covers the enclosure. The slider includes tuning cells each partially coated with metal and positioned opposite to one of the resonators. The slider is movably disposed between the lid and the resonators and slides on the positioning portions. The driving device is located inside the enclosure and drives the slider to move along the positioning portions to adjust a resonating frequency of the cavity filter.

Abstract: A cavity filter defines a cavity with an opening on a top portion thereof and includes a lid to cover the opening of the cavity. A plurality of resonators are secured on a bottom portion opposite to the top portion of the cavity. The lid includes a plurality of bases extending from the lid toward the plurality of the resonators, respectively. A plurality of threaded holes penetrating the lid and one of the bases faces to the plurality of resonators, respectively. Each threaded hole includes a stopper portion extending from an inner surface of the threaded hole inward to form a step defining a hole in communication with the threaded hole. Each threaded hole corresponds to a tuning post to adjust a resonating frequency of the cavity filter.

Abstract: A fork assembly includes a fixed board, a ground portion, a trigger portion, a switch and a resilient element. The ground portion includes a first arm and a second arm located opposite to the first arm, one end of each of the first arm and the second arm is connected to the fixed board, and the other end is free. The trigger portion includes a third arm and a fourth arm located opposite to the third arm, one end of each of the third arm and the fourth arm is connected to the fixed board. The switch is fixed on the other end of the third arm, and includes a normally open contact. The resilient element is configured on the other end of the fourth arm and corresponding to the normally open contact of the switch. The first, second, third and forth arms are conductively and resiliently connected together.

Abstract: A fixation arrangement for a resonator of a cavity body includes a cavity body including a base, a resonator defining a cavity and comprising a bottom, a screw including sharply arc-shaped head and securing the resonator on the base of the cavity body, and a sticky element located between the screw head of the screw and the bottom of the resonator.

Abstract: A circuit for canceling a direct current (DC) offset in a communication system includes a digital-to-analog (D/A) converter assembly (30), a summing circuit (40), an inphase-to-quadrature (I/Q) modulator (50), a detecting module (70), and a microcontroller (80). The D/A converter assembly converts digital DC offset regulation signals to analog DC offset regulation signals. The summing circuit sums up the DC offset regulation signals and corresponding vectors of a received base band signal. The I/Q modulator converts the summed base band signal to a radio frequency (RF) signal. The detecting module detects an energy variation due to DC offset contained in the radio frequency (RF) signal. The microcontroller regulates the DC offset regulation signals output from the D/A converter assembly to minimize the energy variation detected by the detecting module. In the invention, the circuit saves energy and enhances qualities of communication signals.