Abstract: A transformation network is provided capable of interfacing between an unbalanced port (110) and a plurality of differently phased balanced ports (120, 130). A balun (165) has a choke (140) and connects the unbalanced port (110) to a balanced pair of nodes. An additional node (145) is provided on the balun. First and second unbalanced phase shift transmission lines (150, 155) have a common ground conductor connected to the additional node (145) of the balun (165). A phase-shifted balanced port (130) is thus provided by center conductors of these first and second unbalanced phase shift transmission lines (150, 155) when the other ends of these transmission lines are coupled to the balanced nodes of the balun (165) and the common ground conductor of these transmission lines is connected to the additional node (145) of the balun.

Abstract: A communication system to be used between a plurality of individuals with the communication system being mounted in conjunction with head wear. Generally, the individuals are engaged in some type of related activity such as riding bicycles. Within each head wear is incorporated a receiver that is to be located directly adjacent an ear of the user. Also mounted on the head wear of each user is an elongated unit with this elongated unit including a microphone in one end thereof and an antenna at the opposite end thereof. This unit is pivotally mounted on the head wear between an inactive position and a using position. When in a using position, the microphone is located directly adjacent to the mouth of the user. When in the inactive position, the microphone is located in an out-of-the-way position spaced some distance from the mouth of the user.

Abstract: A radiation shield for a hand-held cellular telephone is made up of a metal strip placed between the antenna rod of the telephone and the speaker. The strip has a flat body portion and an upper portion that is curved away from the rod. Overall length of the strip is slightly longer than the antenna rod, and its width is 1 to 1 1/2 inches. Radiation fields reaching the head of a user whose ear is placed near the speaker are substantially reduced by the shield.

Abstract: A radio module for a radio base station of a mobile radio system which transmits and receives radio signals from stationary or moving mobile radio stations over given frequencies. A module comprises an antenna part and a transceiver part of given mechanical construction. Each module of a base station transmits and receives over a given specific frequency which may be different when transmitting and receiving but which is not the same frequency as that used by any other module in the station. A radio base structure is comprised of a plurality of modules, each having its own specific or individual transmitting and receiving frequency and being provided with suppression means which prevent a module from disturbing neighboring modules. A radio base structure having diversity reception is also provided.

Abstract: A cellular radiotelephone includes an antenna that is moveable between a first position and a second position. In the first position, the antenna is substantially parallel to the face of the radiotelephone thereby reducing the profile of the radiotelephone. Accordingly, the radiotelephone may be easier to store in a confined space such as a shirt pocket. In the second position, the antenna is canted away from the face of the radiotelephone thereby increasing the distance between the user's head and the antenna during use. Accordingly, the electromagnetic shielding caused by the user's head is reduced.

Abstract: A system (10) for combining a plurality of transmission channels within a multiple channel communication system includes a master computer (20) that controls the transmission frequency and schedule of a plurality of channel transmitters (18). Each channel transmitter (18) is electrically connected to a channel transmitter combiner filter (12). Each channel transmitter combiner filter (12) is fixedly tuned to a unique bandwidth window along the electromagnetic spectrum, and two sets (24), (26) of channel transmitter combiner filters are formed of the channel transmitter combiner filters (12) whose unique bandwidth windows are adequately spaced for electrical isolation along the electromagnetic spectrum. Each set (24), (26) of channel transmitter combiner filters is electrically connected to a common antenna (28) by means of a three decibel (3 dB) coupler (22).

Abstract: The antenna switch of the present invention switches from a portable radio's internal antenna to an external, vehicle adapter antenna. The second antenna is part of the vehicle adapter that supplies DC power to the vehicle adapter. A 1/4-wavelength transformer couples the internal antenna to the portable radio's transceiver. Diodes couple transformer and antenna to ground. A 1/2-wavelength transformer couples the vehicle adapter to the transceiver. When the portable radio is connected to the vehicle adapter, DC power is supplied to the diodes causing them to appear as a short thus making the first transformer appear as an open circuit. This causes a signal from the transceiver to be conducted to the second antenna on the vehicle adapter.

Abstract: The present invention teaches an oscillator and transmitter. The balanced oscillator comprises a resonator for generating a reference signal having a resonating frequency, a first oscillator for providing a first oscillating output in response to the resonating frequency, and a second oscillator for providing a second oscillating output in response to the resonating frequency. The second oscillating output has a magnitude equal to the first oscillating output while oscillating 180 degrees out of phase with the first oscillating output. The transmitter comprises an antenna for radiating the first and second oscillating output signals.

Abstract: In a radio transmitter (100) that includes a power amplifier (104) and an antenna (106), a method for enhancing an operating characteristic of the radio transmitter (100) can be accomplished in the following manner. The power amplifier (104) provides a signal (113) to a variable matching network (111), wherein the signal (113) comprises energy to be radiated by the antenna (106). The variable matching network (111) couples the signal (113) to a sampler (112) that is operably coupled to an output of the variable matching network (111 ) and the antenna (106). The sampler (112) samples a forward component (114) and a reflected component (115) of the signal (113). The radio transmitter (100) processes the sampled forward and reflected components (116, 118) to produce a feedback control signal (120). The feedback control signal (120) is used to adjust the variable matching network (111 ), such that an operating characteristic of the radio transmitter (100) is enhanced.

Abstract: The antenna element mounting of the present invention enables an antenna to be mounted between the printed circuit boards of a radio instead of along side the boards. The shielding of the printed circuit boards has an indentation along one edge of each shield. When the shields are mated, the indentations form a channel into which the antenna is mounted.

Abstract: A radiotelephone wrist device includes a case having a transceiver and a strap attached to the case for fastening the device to a user's wrist. The strap has a top layer and a bottom layer. The top layer is attached to the bottom layer by a pivot mechanism which facilitates rotating at least a portion of the top layer with respect to the bottom layer. A microphone is located on the strap and electrically connected to the transceiver. A speaker is located at an end of the top layer of the strap and electrically connected to the transceiver. A first antenna is located in the bottom layer of the strap. A second antenna is located in the rotatable portion of the top layer of the strap.

Abstract: A combination antenna and microphone extension assembly is rotatably mounted on a portable communication unit to enable deployment from a stored position alongside the housing of the unit to an extended operating position with the antenna deployed and a speaking region connected through an acoutstic cavity in the assembly to the microphone on the unit providing extended spacing between the speaker on the housing and the speaking region to span the distance between the mouth and ears of the user.

Abstract: A radio apparatus, particularly a radio telephone has an antenna which, rather than extending away from the housing of the apparatus, is bent around the housing to overlap it in a clip-like formation. The antenna acts as a fixed antenna to receive and transmit radio signals but is less vulnerable to damage and breakage their conventional fixed antennas. The antenna also acts a clip enabling the apparatus to be clipped over a pocket or belt.

Abstract: A portable radio communication device has an antenna which can be extended for use and retracted for storage, and can transmit a signal at the same level of electric energy when the antenna is stored as when the antenna is extended. When the antenna is retracted and stored, the stored condition is detected by a detecting switch. In response to a detected signal from the detecting switch, a transmission output controller produces an increased transmission output control signal to increase the level of electric energy of the signal to be transmitted which is higher than a normal level of electric energy of signals transmitted from the antenna. When the increased transmission output control signal is generated, a power amplifier amplifies a signal to be transmitted which is supplied from a transmission signal generator, and supplies the amplified signal to the antenna. Therefore, even when the antenna is stored, it can radiate the signal at the same level of electric energy as when the antenna is extended.

Abstract: In a communications system including a base station coupled to a transmission antenna by means of a transmission feeder cable, and coupled to a receiving antenna by means of a receiving feeder cable, a method and system for testing the antennas and feeder cables includes a testing apparatus located at or near the antenna end of the feeder cables. A processor located within the testing apparatus initiates tests in response to commands received from the base station by means of a digital interface, which preferably uses one or both feeder cables as a communications medium. The testing apparatus includes directional couplers for each of the feeder cables, and corresponding power detectors for measuring both forward (incident) and reverse (reflected) power. A test tone generator places a known signal on the receiving feeder cable to enable the receiving antenna VSWR to be measured, as well as to transmit the test tone down to the base station for use in measurement of receiving feeder cable attenuation.

Abstract: When a radio frequency (RF) circuit is integrated into a movable housing element of an electronic device one must consider the affects of the surrounding area when the RF circuit is in a functioning position. A preferred embodiment is a radiotelephone (100) having an antenna (105) integrated into a movable housing element (101). The antenna (105) has two functioning positions, an opened and a closed position. The antenna (105) is tuned for efficiency when the movable housing element (101) is in the opened position. When the movable housing element (101) is in the closed position, a first pair of conductive plates (107, 109) located in the movable housing element (101) and a second conductive plate (113) located in the second housing element (103) are positioned to retune the antenna (105) due to the detuning affects caused by the close proximity of other electronic components located in the second housing element (103).

Abstract: In a portable satellite communication equipment including a transponder for transmission and reception, and an antenna portion which is electrically coupled to the transponder, the antenna portion has first and second common flat antennae. The first and the second common flat antennae are common to both the transmission and the reception and are foldably coupled to each other.

Abstract: An accessory for cellular telephones or marine band telephones that will afford some protection to cellular telephone and marine band telephone users from the alleged brain, head and body damage caused by electro-magnetic radiation and microwave radiation of cellular telephone use or marine band use and to also provide a comfortable handle when using and carrying the cellular telephone or marine band telephone.

Abstract: A radio communication device (100) includes an offset antenna (104) and a housing (101). The offset antenna (104) includes an offset portion (108) and radiating portion (116). The antenna (104) is coupled to the radio housing (101) through a pivot mechanism (106) so that the antenna could rotate from a stowed position (114) to a deployed position (112). In the deploy position (112), the antenna is away from the user, a distance equal to the sum of the width (110) and the offset portion (108). This separation of the antenna from the body provides for significant improvement in the antenna performance.

Abstract: Disclosed herein is a mobile communicator comprising an antenna (3) built in a portable telephone body (1), and a circuit board (2) built in the communicator body (1) and provided with a ground electrode pattern (2a) arranged between an outer surface part (1a), which is brought into contact with or near a portion of a human head, and the antenna (3). A transmission output of the antenna (3) toward the human head is attenuated by the ground electrode pattern (2a) of the circuit board (2).

Abstract: An oscillating circuit includes a resonator for outputting a signal, an amplifier for amplifying the signal output from the resonator, and a radiator for transmitting a radio wave by resonating the signal amplified by the amplifier. The amplifier has a transistor connected to the resonator and a fixed inductor applying an alternating current load to the transistor. The transistor outputs a signal to be adjusted by the fixed inductor to finely adjust the frequency of the radio wave.

Abstract: An adapter assembly for adapting a portable cellular telephone to receive an external replacement antenna or an external direct feed connection includes an adapter element and a retention element. The adapter element includes an antenna receiving bore at one end, and a positioning member at the other end, and further includes a latching member operable between first and second operative positions. The retention element includes a base cap with an extending actuator that biases the latching member into the second operative position where the adapter element is in engagement with body of the telephone.

Abstract: A radio transmitter circuit is provided comprising: a power amplifier coupled to an antenna for transmission of radio signals; linearizer means, such as a Cartesian feedback linearizer or a predistortion equalizer, for compensating for non-linearity in the power amplifier; means for inputting a training sequence to the linearizer means and outputting a training signal from the power amplifier resulting from the training sequence; and a feedback circuit for feeding the training signal output from the power amplifier back to the linearizer means to adjust the linearizer means and/or feedback circuit. Means are provided for inhibiting transmission of radio signals through the antenna while the training signal is being output from the power amplifier.

Abstract: An easy-to-use portable telephone is provided. The telephone has telephone proper 1, antenna 2, operating switch 3, and antenna moving mechanism 4. On the telephone proper 1, the back of the side on which the operating buttons 1a are provided and the left and right sides constitute hand-held sections, which are held by the left hand. The antenna 2 is provided to be extendable and retractable from the top side of telephone proper 1. The operating switch 3 is provided on the left-hand side of the telephone proper I and it is located such that when the user holds the telephone proper 1 with the left hand, it can be operated by the thumb. The antenna moving mechanism 4 moves antenna 2 upward when the "Talk" c is selected by operating switch 3 and moves antenna 2 downward when "Standby" b is later selected. The antenna moving mechanism 4 has micro-motor 5, motor control section 6, screw rod 7 , and nut 8.

Abstract: A method of matching the resonant frequency of an antenna resonant circuit (18, 46) to the output frequency of a transmitter output stage (26), the method includes the step of providing a powering signal from the transmitter output stage (26) to the antenna resonant circuit (18, 46). The method further includes the step of receiving at the antenna resonant circuit (18, 46) the powering signal, the antenna resonant circuit (18, 46) comprising a tuning circuit (48). The tuning circuit (48) is operable to variably modify the resonant frequency of the resonant circuit (18, 46). At its output the antenna resonant circuit (18, 46) provides a phase correlation signal having a known relationship to the frequency difference between the resonant frequency and the powering signal. A phase comparator (60) then receives the powering signal and the phase correlation signal and correspondingly adjusts the resonant frequency of the resonant circuit (18, 46) based upon the known phase relationship.

Abstract: An offset transmission line coupler (115) for a transmitter output signal (123) generated by an RF signal amplifier (103) includes a through-path transmission line (201) and a coupled-path transmission line (202) electromagnetically coupled thereto by multiple serpentine-like portions (such as portions 641,642, 643 and 644 in FIG. 6), which are disposed on opposite sides of the through-path transmission line (201) for enhancing coupling sensitivity and eliminating degradation in the amount of coupling due to variations in the transmission line plating registration. Offset portions (641,643) on one side of the through-path transmission line (201) provide substantially the same amount of coupling as the offset portions (642,643) on the other side of the through-path transmission line (201).

Abstract: A balanced oscillator and transmitter circuit is provided which includes a pair of balanced Colpitts-type oscillators for generating an enhanced power radiating output signal. The balanced oscillators share a series resonance input tank. Each oscillator has an amplification stage which preferably includes a Colpitts-type configured transistor. The transmitter circuit further includes first and second output tanks having first and second radiating elements which may include a pair of inductors. An oscillating current signal is generated by the oscillator and is commonly transmitted through the pair of radiating elements. Each radiating element transmits radiating output signals which are combined and summed in total to provide an efficient radiating output signal. Alternately, the first and second output tanks may include a center-tapped transformer coupled to a third radiating element.

Abstract: A method and circuit for detecting and reducing the impedance mismatch between the directional coupler and the antenna of an RF communications system exposed to externally generated RF signals. The impedance mismatch is detected by the quadrature multiplication of the signal passing through a directional coupler in the forward and reverse directions with the detection being enhanced by the use of a forward direction signal substantially devoid of externally generated RF signal components.

Abstract: An antenna suitable for a radio telephone which is primarily comprised of a duplexer, a transmitter, and a receiver. The antenna is fabricated as a cover for sealing a box-like duplexer. At the same time, the cover is set up by a microstrip antenna which is comprised of a dielectric substrate and conductive pattern layers formed on the top and bottom surfaces of the dielectric substrate.

Abstract: In a mobile communication system where a service area is divided into a plurality of coverage areas defined by a plurality of mobile base stations, at least one of the shape and size of the coverage areas is changed in accordance with a number of mobile stations being serviced within each of the coverage areas, so that such a number of mobile stations is brought within a predetermined range.

Abstract: In sector cell base stations, directive antennae with box-shaped reflectors are widely used. By way of a testing antenna incorporated such a reflector box, stable and appropriate electromagnetic coupling to the antenna elements of the directive antenna can be realized and undesirable coupling from outside the reflector box can be prevented, thereby improving the reliability of the testing system.

Abstract: A base-site (304) combines baseband frequency hopping and fast-synthesizer hopping to produce an economical frequency hopping communication system (300). The base-site (304) combines the fast-synthesizer frequency hopping capability of transmitters (307-309) with baseband frequency hopping to produce a frequency hopping communication system (300) which serves the same number of subscribers served by transmitters (208-213) in a purely baseband hopping communication system (200), but with fewer transmitters (307-309). The implementation of frequency-selective cavities (312-317) having very low loss eliminates the need for wideband hybrid combiners (112-114), which in turn eliminates transmitted-signal power loss experienced in a purely fast-synthesizer frequency hopping communication system (100).

Abstract: A radio transmitter apparatus arranged such that transmission efficiency is improved by switching the load impedance on the final stage in response to the power source voltage or the transmission output power.

Abstract: A portable radio communication apparatus includes a printed circuit board, an antenna section and a radio section installed on the board, a housing, and a connector. The radio section includes electronic parts of which connecting terminals are connected to the printed circuit board and of which conductor sections formed on outer surface thereof are connected to the grounding section. The housing accommodates therein the printed circuit board, the antenna section, and the radio section. The housing has a conductor film formed on an inner surface thereof. The conductor sections of the electronic parts are connected to the conductor film on the inner surface of the housing via the connector. Since the shielding case and the connector conventionally used are unnecessary, the size and weight of the apparatus can be reduced.

Abstract: A radio transceiver having improved impedance matching characteristics between a rod-like antenna and transmitting and receiving portions. An impedance matching circuit is provided between the antenna and a duplexer to impedance-match therebetween at a frequency within a desired signal frequency band. A transmitting signal and a receiving signal may have substantially different frequencies in which case the impedance matching circuit operates advantageously in a range between these signals, respectively. The impedance matching circuit includes a first inductor inserted between the antenna and the duplexer, a first capacitor inserted between the antenna and ground potential, and a parallel resonance circuit composed of a parallel circuit of a second capacitor and a second inductor inserted between the duplexer and ground potential.

Abstract: A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a "telemetered sensor beacon" that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20-100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning.

Abstract: A radiation shielding apparatus for a radio transmitting device, such as a cellular phone. A radiation shield is disposed between a radiation component and a user to prevent unwanted exposure of the user to emanating radiation from the radiation emanating component. The cellular telephone radio transmitting device may be a hand-held cellular telephone, and the radiation emanating component may be an internal or external antenna or any other electromagnetic radiation source, such as a transmitter. The radiation shield can be retrofitted to an existing cellular telephone, or may be designed specific for different models of cellular phones. The radiation shield can absorb, block and/or reflect electromagnetic wave radiation to shield the user of such cellular telephones from unwanted and possibly harmful exposure to electromagnetic wave radiation.

Abstract: A wireless transmission-reception control system in which the data transmitted as a radio wave from more than one wireless transmitter along with an ID code are received by a wireless receiver and decoded at a front end decoder. The ID code of the transmitted data thus received is compared by a comparer with the ID code of the transmitted data already registered at a data register to discriminate if a collation of the data is to be made [or not], and only the transmitted data, the registration of which is confirmed, are decoded to have an output generated. The wireless transmitters each have different, fixed ID codes, and the wireless receiver may be switched over at least between a mode of registering an ID code and a mode of generating an output after the decoding of the transmitted data.

Abstract: A range accentuating device for remote control transmitters, used in connection with automobile and other types of accessories and options, is provided. The invention is comprised of an antenna, and a receptacle to couple the remote control transmitter, via mutual coupling, to the antenna. When the remote control transmitter is coupled to the antenna and the remote control transmitter is activated, the signal from the remote control transmitter is accentuated.

Abstract: A baby monitor transmitter is provided for use in combination with a receiver unit. The transmitter includes an arcuately shaped antenna which conforms to an arcuate shape of an upper edge of the transmitter housing. The antenna may be pivoted outwardly away from the housing to a plurality of predetermined positions. In addition, the transmitter includes a clip member which may be used to hang the transmitter on various supporting surfaces. The clip member includes a vertical leg extending parallel to a rear surface of the transmitter and the vertical leg may be moved toward and away from the housing in order to accommodate supporting structures of different sizes.

Abstract: A antenna switching apparatus for a dual-mode transceiver which includes a transmission and reception antenna, a transmitting circuit, a receiving circuit, and a separating filter of large insertion loss is connected to the transmission and reception antenna, the transmitting circuit, and the receiving circuit for separating a transmission high frequency signal and a reception high frequency signal having different carrier frequencies, in which transmission and reception in the digital mode of the transmission and reception switching system and the transmission and reception in the analog mode of the simultaneous transmission and reception system is possible further includes an analog-to-digital change-over switch which changes-over mutual connections among the transmission and reception antenna, the transmitting circuit, the receiving circuit and the separating filter in response to the analog or digital mode, a blocking filter of low insertion loss for blocking a high frequency band of spurious signals caus

Abstract: The invention relates to a circuitry by means of which it is possible to switch to a mobile telephone that antenna out of two or more antennae which has the best signal, without substantial alterations in the mobile telephone itself. According to the invention, the antennae (A, B), the antenna selection switch (2) and the peripheral circuits (5, 6) connected to it constitute an integrated part which is separate from the actual mobile telephone (1) but can be coupled to it by means of an antenna cable (3), and the antenna cable (3) is coupled to the radio part of the mobile telephone (1) by mediation of a signal combining circuit (4) which transfers to the antenna cable (3) the supply voltage (V) and the antenna selection switch (2) control pulse, and transfers and selects the RF signal.

Abstract: A radio-frequency amplifier (50) has an impedance transformation network (66) with a control input (70) for controlling the transformation characteristic of the transformation network (66). The radio-frequency amplifier (50) amplifies an input signal to produce an amplified radio-frequency output signal to a load (68). The control circuit selects a power level for the output signal, in response to a control signal, by transforming the impedance of the load to a transformed impedance at the output of the radio-frequency amplifier, so that the efficiency of the radio-frequency amplifier is not substantially degraded as the power level for the output signal is changed.

Abstract: A method is offered of automatically beamforming a radio frequency transmitter having an array antenna. The beamformed signal is transmitted for the benefit of a target communication unit based upon characteristics of a received signal. The method includes the steps of determining a transmit equalizer transfer function and receive equalizer transfer function for each array element of the antenna array based, at least in part, upon application of common input signals and comparison of outputs. The method further includes adaptively filtering a received signal, from a communication unit based, at least in part, upon the determined receive equalizer weights, to provide a receive beamform array. A beamformed signal may then be transmitted to the communication unit based upon the transmit equalizer weights and receive beamform array.

Abstract: For setting up LOS radio links between mobile calling transmitting/receiving stations and other mobile or stationary remote transmitting/receiving stations in a predetermined operating area, especially in the frequency range above 1 GHz, every mobile station is provided with an electronic memory with an associated processor. The memory stores the respective geographical and topographical data of the operating area. Prior to the setting-up of a radio link, the transmission loss between the stations is calculated in accordance with known model calculations on the basis of the geographical and topographical data stored in the memory by inputting into the processor the current location data of the calling station and the remote station.

Abstract: An oscillating apparatus comprising: an oscillator unit for oscillating in the microwave band; an output unit electromagnetically coupled to the outputting unit of the oscillator unit for taking an oscillation output outside; and an antenna element electromagnetically coupled to a part of the outputting unit, or a part of the output unit for radiating part of the oscillation output in an electromagnetic wave.

Abstract: An improved short distance, battery powered, amplitude modulated RF transmitter for transmitting encoded security data. An oscillator stage provides a control crystal and filter which are feedback coupled between the emitter and base of a transistor to oscillate at the fifth overtone of the fundamental crystal frequency. A filter tuned to the third harmonic of the overtone frequency selects the carrier frequency which is coupled via a resistive attenuator to an amplifier/filter stage, before the carrier is amplitude modulated with encoded security data. The improved transmitter circuit compensates for crystals exhibiting variations in series resistance and provides increased output power and improved frequency stability to temperature and over time. A foil antenna stage is augmented with the plates of the battery power supply to further improve performance.

Abstract: A radio frequency message apparatus for aiding ambulatory travel by handicapped persons such as blind individuals. The apparatus generally comprises a portable, radio frequency transceiver and a stationary, radio frequency base transceiver unit. The portable radio frequency transceiver is carried on the person of the handicapped individual and transmits a message request signal in response to manual activation of a transmit button thereon by the handicapped individual. The message request signal is received by the base transceiver, which causes the base transceiver to transmit a pre-recorded message signal back to the portable transceiver unit in radio frequency form. The message signal contains location identifying information such as the streets of an intersection at which the base unit is located.

Abstract: RF power is sampled and measured at the input and output of a solid state power amplifier using directional couplers and matched square law detectors. Outputs from the detectors are applied to differential inputs of a DC operational amplifier. Outputs from the detectors are compared and filtered in the operational amplifier and the resulting difference signal is applied to a control input on a switching type power supply. The power supply converts a DC input voltage to the various positive and negative voltages required to operate the RF devices in the solid state power amplifier. When the control loop is closed, the supply voltage varies to maintain a constant operating point resulting in constant gain, efficiency, and linearity for the overall solid state power amplifier despite variations in signal levels and signal composition. In another embodiment, the solid state power amplifier has a series of single-ended low power amplifiers terminating in an output high power module.

Abstract: Systems for transmitting and/or receiving electromagnetic signal radiation are disclosed. The inventive systems are distinguished from previous such systems in that each includes at least one resonant cavity comprising a housing containing a body, e.g., a cylindrical or helical body, of relatively high T.sub.c superconducting material. Significantly, this body is fabricated using a new, unconventional procedure. As a result, the body exhibits substantially lower surface resistances than either previous such bodies of relatively high T.sub.c superconducting material, fabricated using conventional procedures, or bodies of copper, at 77 Kelvins and at frequencies ranging from about 10 MHz to about 2000 MHz. Moreover, as a consequence, the resonant cavity containing the unconventionally fabricated body exhibits much higher quality factors, Q, at the above temperature and frequencies, than previous such cavities containing either conventionally fabricated bodies of relatively high T.sub.