Abstract: A testing apparatus that comprises an electrical device. A first circuit is in electrical communication with the electrical device. The first circuit including an amplifier. First and second couplers are electrically connected to the first circuit and arranged in series with the amplifier. The amplifier is positioned between the first and second couplers. A second circuit has a first end in electrical communication with the first coupler and a second end in electrical communication with the second coupler. The total gain of the first coupler, the second coupler, the portion of the first circuit between the first and second couplers, and the second circuit is approximately zero.

Abstract: A testing apparatus that comprises an electrical device. A first circuit is in electrical communication with the electrical device. The first circuit including an amplifier. First and second couplers are electrically connected to the first circuit and arranged in series with the amplifier. The amplifier is positioned between the first and second couplers. A second circuit has a first end in electrical communication with the first coupler and a second end in electrical communication with the second coupler. The total gain of the first coupler, the second coupler, the portion of the first circuit between the first and second couplers, and the second circuit is approximately zero.

Abstract: A resonator filter comprising a housing formed with a conductive material. The housing defines a first cavity, a second cavity, and an intermediate wall positioned between the first and second cavities. The housing defines an opening between the first and second cavities. First and second center conductors are positioned within the first and second cavities, respectively. A coupling wire is connected between the first center conductor and the housing. The coupling wire and the center conductor have substantially equal thermal expansion coefficients.

Abstract: A redundant balanced amplifying apparatus. The apparatus comprises a signal path. A portion of the signal path is split into a first and second sets of signal branches. The first and second sets of signal branches are parallel. A plurality of amplifiers are arranged so that each signal branch within the first and second sets of signal branches flows through at least one amplifier. A first set of switches are arranged to selectively shunt signal branches within the first set of signal branches. The first set of switches have at least one switch. A second set of switches are arranged to selectively shunt signal branches within the second set of signal branches. The second set of switches have at least one switch.

Abstract: A circuit arrangement that reduces selected intermodulation. The circuit arrangement includes a signal amplifier coupled to a bandpass filter via an electrical path. Signal energy outside the passband is reflected back into the amplifier and causes intermodulation. The electrical path is constructed with a length that reduces intermodulation, where the length is an odd multiple of one-fourth the wavelength of a predetermined frequency in the passband. The length of the electrical path reduces intermodulation because certain signals reflected by the bandpass filter are approximately 180.degree., or an odd multiple thereof, out of phase. Energy of problematic signals that are near the edge of the passband or in the stopband is reduced, such as third order intermodulation product and pairs of signals that produce third order intermodulation products.

Abstract: A bandpass filter arrangement that includes a weakly coupled coaxial resonator to reduce the fluctuation in frequency response of the filter arrangement. A bandpass filter is coupled to the output of a low noise amplifier. The characteristic fluctuation in frequency response in the passband of the bandpass filter is reduced with a coaxial resonator that is disposed proximate the filter arrangement.

Abstract: A combination notch/bandpass filter uses first and second adjacently-located cavities in the conductive housing to respectively provide a tunable, first-stage notch filter and a second-stage bandpass filter. An opening in a wall provides a passage for energy from the first cavity to the second cavity. In the first cavity, a resonator is located adjacent the opening, along with a notch-filter tuning member having one end arranged opposite the resonator and spaced therefrom by a distance to permit the wide end of a coupler to be suspended therebetween. An elongated portion of the coupler carries filtered energy from the first cavity to the second cavity.

Abstract: For use with various types of devices conditioning radio signals, a temperature compensating cavity resonator includes a practicable and effective assembly.

Abstract: A combined resonator-cavity filter includes a number of cavity structures designed for cooperative arrangement within a housing. The resonator cavities are constructed and arranged to pass energy in an assigned frequency band. The cavities include a first cavity structure having a corresponding cavity volume and constructed to provide a first Q, and a second cavity structure having its corresponding cavity volume and constructed to provide a second Q. The cavity volume corresponding to the second cavity structure is less than the cavity volume corresponding to the first cavity structure. Other aspects are directed to the arrangement and uses of sets of such cavity structures as part of a combined duplexer-receiver having the same housing.