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 power amplifier including: a first amplifier PA2 having an input terminal and an output terminal; a passive circuit PC3 having an input terminal and an output terminal; and a first switch SW2 having a single-pole terminal and two multi-throw terminals, one of the multi-throw terminals of the first switch SW2 being connected to the input terminal of the first amplifier PA2 and the other of the multi-throw terminals of the first switch SW2 being connected to the input terminal of the passive circuit PC3. This makes it possible to provide a power amplifier and a communication unit which can be operated with different frequencies, output powers or modulation types.

Abstract: A redundancy combiner assembly has two amplifiers connected in parallel along a waveguide path to a hybrid. The hybrid is connected through a transfer switch to an antenna. The hybrid contains a movable coupling plate. The coupling plate has a coupling array to allow combining of signals of the amplifiers in one position. When one of the amplifiers fails, the coupling plate is replaced by a metal wall and the output from the failed amplifier is directed by the switch to a dump load while the output from the operating amplifier is directed to the antenna. The assembly is controlled by a controller, which monitors the amplifiers and controls the movement of the coupling plate and the switch.

Abstract: An RF power amplifier network with a redundant power supply comprising a plurality of RF power amplifiers. Each RF power amplifier includes a power supply unit and an amplifier load. The power supply unit is adapted for receiving a primary input voltage Vin and producing a secondary output voltage Vout, and the power supply unit is further adapted for generating a power supply fail signal upon failure of the power supply unit. The network further includes a supply bus to which is connected each power supply unit of each RF power amplifier, and each amplifier load of each RF power amplifier. A switch associated with each of the power supply units is responsive to the fail signal for disconnecting the power supply unit from the bus in the event of failure of the power supply unit.

Abstract: A power combiner including a plurality of phasing transmission lines (122) supporting a set of amplifiers (103-105) coupled thereto, and a plurality of matching transmission lines (123-124). The set of amplifiers (103-105) have a selectable number of amplifiers between a minimum and a maximum value having gain levels between a minimum and a maximum value. Each of the matching transmission lines (123-124) is coupled to one of the phasing transmission lines (122) at one end and coupled to a common node (126) at the other end. Each of the matching transmission (123-124) lines has a characteristic impedance determined according to a function of the minimum and the maximum number of amplifiers in the set of amplifiers (103-105) and the minimum and maximum gain levels in the set of amplifiers (103-105).

Abstract: The present invention teaches a variety of driver amplifiers having a transmit mode suitable for driving the load resistance of a network with an amplified version of the input signal, and a standby mode wherein the driver amplifier consumes substantially no current and isolates the load resistance from the input signal. These amplifiers are also characterized in that during transitions back and forth between standby mode and transmit mode, a minimum of standby transient leaks out onto the network. Further, the noise power delivered to the network in standby mode is substantially minimized, the remaining noise being primarily due to thermal noise produced by a resistor utilized to provide matched termination to the network.

Abstract: A device and a method for combining outputs of a plurality of linear power amplifiers while preventing loss of signals.

Abstract: A system and method for providing distributed amplification of a plurality of input signals is disclosed. The preferred embodiment of the disclosed invention utilizes two substantially different matrixes to dissect an input signal for amplification and subsequent recombination. The unique matrixes disclosed provide for the distributed amplification of any even number of input signals, therefore reducing the number of linear power amplifiers required where a number of input signals other than a power of two are used.

Abstract: A power delivery system (500) including a power splitter (502), a plurality of power amplifier modules (508) responsive to the power splitter (502), a power combiner (504), and a gateway controller (506) is provided. Each of the plurality of power amplifier modules (508) include an input switch (520), a variable attenuator (524), an RF power amplifier (526) responsive to the variable attenuator (524) and the input switch (520), an output switch (530) responsive to the RF power amplifier (526), and an alarm detector (532) for indicating an alarm condition of the RF power amplifier (526). The power combiner (504) is responsive to the plurality of power amplifier modules (508), and the gateway controller (506) is in communication with each of the plurality of power amplifier modules (508). The plurality of power amplifier modules controlled in accordance to whether a sleep criteria has been met.

Abstract: A dc-offset canceler circuit is provided, which cancels a dc offset more effectively. This circuit includes a first differential pair of emitter-coupled first and second bipolar transistors driven by a first constant current source/sink, and a second differential pair of emitter-coupled third and fourth bipolar transistors driven by a second constant current source/sink. The first and second differential pairs are coupled by a coupling capacitor. An emitter of a fifth bipolar transistor is connected to the emitters of the first and second transistors. An emitter of a sixth bipolar transistor is connected to the emitters of the third and fourth transistors. Bases of the first and fifth transistors are connected to a first input terminal. A base of the second transistor is connected to the first input terminal through a first resistor. Bases of the fourth and sixth transistors are connected to a second input terminal.

Abstract: In a hybrid matrix amplifier array (100), a configurable digital transform matrix (116) is initialize with a matrix of transform coefficients. A plurality of digital input signals (M.sub.1 -M.sub.4) are received at inputs of the configurable digital transform matrix (116). The plurality of digital input signals are transformed to produce a plurality of transform digital signals (A.sub.1 -A.sub.4) using the matrix of transform coefficients. The plurality of transform digital signals are converted to a plurality of transformed analoged signals (206) to produce a plurality of transformed analog signals. The transformed analog signals are amplified (104, 208) to produce amplified transformed signals. Finally, the amplified transformed signals are inverse transformed (102, 210) to produce output signals that correspond to a respective digital input signal (M.sub.1 -M.sub.4).

Abstract: A power delivery system (500) including a power splitter (502), a plurality of power amplifier modules (508) responsive to the power splitter (502), a power combiner (504), and a gateway controller (506) is provided. Each of the plurality of power amplifier modules (508) include an input switch (520), a variable attenuator (524), an RF power amplifier (526) responsive to the variable attenuator (524) and the input switch (520), an output switch (530) responsive to the RF power amplifier (526), and an alarm detector (532) for indicating an alarm condition of the RF power amplifier (526). The power combiner (504) is responsive to the plurality of power amplifier modules (508), and the gateway controller (506) is in communication with each of the plurality of power amplifier modules (508).

Abstract: Microwave switches are shown which can route signals in an operating frequency band along selectable signal paths between a plurality of microwave ports. The switches are especially suited for forming switching systems that can substitute redundant components for failed components. In one embodiment, waveguide transmission lines and microwave ports are serially coupled in a closed loop with other waveguide transmission lines arranged transversely across the loop. In another embodiment, waveguide modules are formed of three waveguides coupled to a microwave port and the waveguide modules are serially arranged. In each waveguide of these embodiments, conductive reeds are movable between a signal-attenuating position abutting the interior surface of the waveguide and a signal-conducting position substantially coaxial with the waveguide and coupled to the microwave ports at each waveguide end.

Abstract: A power amplifier includes a plurality of signal amplifying stages. An amplitude compensator positioned prior to the ultimate signal amplifying stage equalizes the signal amplitudes in the frequency band of interest to provide a substantially flat frequency response. Fail-soft operation is established by providing switchably redundant amplifiers. When an operating amplifier is detected as failing, automatic switching is performed to replace the failing unit with an identical unit to maintain amplifier operation. High-power amplification is accomplished by splitting a preamplified signal into a plurality of signals, amplifying the lower level signals so obtained, and then recombining the amplified signals.

Abstract: A waveform generator is provided having a power divider for dividing power from a signal source fed thereto to a plurality of output terminals. A plurality of amplifiers is provided. A plurality of switches, each one thereof being coupled to a corresponding one of the plurality of amplifiers couples the power at the plurality of output terminals to a power combiner through a selected one, or ones of the plurality of switches and the corresponding one, or ones of the amplifiers coupled thereto, in accordance with control signals fed to the plurality of switches. A controller is provided having a shift register section. The shift register section has a plurality of successively coupled storage stages, each stage providing one of the control signals for a corresponding one of the plurality of switches.

Abstract: A multi-port amplifier system for multi-beam communication antennas in which redundancy is achieved without using RF switches. The multi-port amplifiers are divided into sets of stages arranged in tree fashion and the amplifier stages can be turned off without degrading port-to-port isolation. In one embodiment there are thirty-two input ports 1 through 32 and thirty-two corresponding output ports 1 through 32 wherein input port 1 is functionally connected to output port 1 and so on. An input signal to each of the input ports 1 through 32 is connected to a separate one of a first group of sixteen, four stage multi-port hybrid circuits. The outputs of the first group of multi-port hybrid circuits are connected through solid-state power amplifiers to a second group of sixteen, four stage multi-port hybrid circuits which are also labeled according to the input port numbers to which they are functionally connected.

Abstract: An intermodulation distortion (IMD) detection system improves IMD reduction capability of power shared linear amplifier networks. In one embodiment, first and second power sharing networks, preferably Butler Matrices, are provided with a plurality of linear amplifier circuits coupled therebetween. A plurality of input signals are applied to respective input ports of the first power sharing network, with a portion of each input signal amplified by each amplifier circuit and then recombined in the second power sharing network so that each amplified input signal appears at only one output port of the second power sharing network. An antenna coupled to each of these output ports then radiates the amplified signal energy associated with one of the input signals. A test signal, which may be a dual tone signal, is applied to another input port of the first power sharing network, where it is split and amplified by each amplifier circuit.

Abstract: A power output amplifier for use with electric guitar wherein the individual pairs of power tubes are of two or more differing types which may be selected by the user to operate alternately or simultaneously.

Abstract: A power combiner including a plurality of phasing transmission lines (122) supporting a set of amplifiers (104) coupled thereto, and a plurality of matching transmission lines (124). The set of amplifiers (104) having a selectable number of amplifiers between a minimum and a maximum value. Each of the matching transmission lines (124) is coupled to one of the phasing transmission lines (122) at one end and coupled to a common node (126) at the other end. Each of the matching transmission (124) lines has a substantially equivalent characteristic impedance determined according to a function of the minimum and the maximum number of amplifiers in the set of amplifiers (104).

Abstract: A communications amplifier system which includes a primary preamplifier circuit, a secondary preamplifier circuit and a bypass circuit mutually exclusively selectable through a relay switching means which is automatically activated to bypass the primary preamplifier with the secondary preamplifier or the secondary preamplifier with the bypass circuit in the event of malfunction. In the standby mode, the secondary preamplifier is not connected to DC power or RF signal input.

Abstract: A combining circuit for Class-E RF power amplifiers includes a transformer for each power amplifier to be combined, the respective secondaries of the transformers being connected in series to the RF load of the system. Each of the transformers further has a tertiary winding, with one end connected to a first common circuit node, and the other end being connected to a second common circuit node via an inductance. A switchable reactive network is connected to the second common circuit node, and in the event that one of the power amplifiers is removed from the circuit, such as due to failure thereof, the primary terminating impedance of the transformer connected thereto will become a high impedance, and by appropriate switching of the reactive network, in combination with the remaining circuit components, the matching impedance necessary to maintain optimum operation of the remaining power amplifiers is achieved, with a benign VSWR being presented to the remaining power amplifiers.

Abstract: A transmitter which includes N amplifiers connected together by a common signal input and which output to a common load. The transmitter also includes N identical series LC circuits, each connected between an amplifier output and the common load, with the common points between each inductance and capacitance connected together. The extremely modular nature of the device makes the transmitter easy to reconfigure if one of the amplifiers fails.

Abstract: A system for extending the frequency range of an RF amplifier by improving the VSWR, and power handling capability of the amplifier, comprising a broadband reversing transformer, a first and a second amplifier coupled by means of a first and a second through-line quadrature coupler with the first quadrature coupler being connected to the inputs of the two amplifiers and the second quadrature coupler being connected to the outputs of the two amplifiers. The broadband reversing transformer is inserted in series with one of the two amplifiers enabling a signal at frequencies out of the passband of the quadrature couplers to pass through the through-lines port of the quadrature couplers, and thereby greatly extending the frequency range over which quadrature couplers may be used while, at the same time, retaining the usual combining and VSWR advantages of the couplers within their passbands.

Abstract: A circuit for selecting and combining power signals of a pair of parallel amplifiers (3,4) using phase shifters (5,6) having fixed phase. Either amplifier (3,4) may be selected to produce a power signal of power P at the circuit output (9), where P is the power at the output (11,12) of each amplifier (3,4). Alternatively, power from the two amplifiers (3,4) may be combined to produce a signal of power 2P at the circuit output (9). By using a passive circuit to achieve the selection and combination, the use of heavier and less reliable relay switches is avoided.

Abstract: A power combiner which maintains substantially constant power combining efficiency with variable output power includes a set of unit amplifiers that are coupled by the power combiner. The power combiner includes a first plurality of a quarter wavelength transmission line sections coupled to the output of each unit amplifier. The second end of each one of the first plurality of quarter wavelength transmission line sections are successively coupled by a corresponding second plurality of quarter wavelength transmission line sections, with the succeeding or last one of said unit amplifiers having its quarter wavelength transmission line section coupled to an output terminal. The power combiner permits unit amplifiers in the amplifier module to be switched off in succession as less output power is required while maintaining substantially constant power combining efficiency, and hence substantially constant D.C. to r.f. conversion efficiency.

Abstract: A power combiner includes an input power splitter driving a plurality (N) of amplifiers. The amplifier outputs have Z.sub.0 output impedance and are coupled by transmission (TX) lines of Z.sub.0 characteristic impedance to the junction point of a lossless power combiner. Short-circuiting switches located .lambda./4 from the junction power disconnect failed amplifiers from the combiner. According to the invention, a number M<N of the shorting switches are open during normal operation, so the impedance presented by the parallel TX lines at the junction of the combiner is Z.sub.0 /M. An impedance transformer associated with the combiner transforms the junction point impedance Z.sub.0 /M to Z.sub.0 at the combined output port, for example, by a .lambda./4 line having an impedance .sqroot.Z.sub.o.sup.2 /M.

Abstract: The realization that field effect transistor current can be controlled by adjusting the gate voltage and thereby controlling the amplifier power consumption with only a slight degradation of RF gain and signal quality is utilized in a hot standby radio system configuration. The standby amplifier is left in an ON condition with the gate voltage adjusted to a low value until such time as the amplifier is needed for active service. At this time the gate voltage is adjusted to the optimal value and the amplifier is operated in a normal condition. The standby mode still allows tests to ascertain whether or not the amplifier is operational while conserving substantial amounts of power.

Abstract: A redundancy switching system which provides four reserve devices is disclosed which is suitable for use with from eight to twelve channels. The switches in the input switching network of this redundancy system are connected in first and second sections. Each section includes a ring of switches and two switches connected as appendages to the ring. Only as many switches are needed to control the input connection to the redundant devices as there are redundant devices. A similar number of switches are needed to control the output connection of the active devices.

Abstract: A first multi-port hybrid coupler is formed by n2.sup.n-1 (where n is an integer equal to or greater than 2) hybrid couplers alone, which are divided into n stages, each including 2.sup.n-1 hybrid couplers. A signal input to any one of N (=2.sup.n) input terminals of the first stage is distributed equally to N output terminals of the nth stage. The N output terminals of the nth stage of the first multi-port hybrid coupler are connected to N amplifiers at the input side thereof, respectively, and the N amplifiers are connected at the output side to a second multi-port hybrid coupler. The second multi-port hybrid coupler is identical in construction with the first multi-port hybrid coupler, but its input terminals and output terminals are reverse from those of the latter and the input terminals of the second multi-port hybrid coupler are connected to the N amplifiers in an order reverse from the order of arrangement of the output terminals of the first multi-port hybrid coupler.

Abstract: A communications tower mounted amplifier system which includes a primary preamplifier circuit, a backup preamplifier circuit, and a bypass circuit mutually exclusively selectable through a relay switching means remotely controllable for bypassing the primary preamplifier with the backup preamplifier or the bypass circuit in the event of malfunction. The system includes an AC-to-DC power source and a backup battery system.

Abstract: The present invention relates to a driver circuit for use in connecting a source of RF drive voltage to a power amplifier stage. The driver is comprised of a transformer having a center tap, a first terminal connected to a first branch of the transformer and a second terminal connected to a second branch of the transformer. A first capacitor is connected between the source and the center tap. A second capacitor is connected across the first and second terminals. The first terminal is connected to the input of the amplifier and the dummy load is connected to the second terminal. The dummy load can be replaced by a second power amplifier stage having an input impedance similar to the input impedance of the first mentioned power amplifier.

Abstract: The present invention relates to an N-way non-hybrid power combiner arrangement for microwave amplifiers. In operation, sensing means (19.sub.1, 19.sub.2, . . . , 19.sub.N) are coupled in a one-to-one relationship with the individual amplifiers (12.sub.1, 12.sub.2, . . . , 12.sub.N) to monitor amplifier performance and sense amplifier failure. In one embodiment of the present invention, shorting devices (20.sub.1, 20.sub.2, . . . , 20.sub.N) are disposed adjacent to the outputs of the individual amplifiers and coupled to the associated sensing means in a one-to-one relationship. In an alternative embodiment, open-circuiting devices (30.sub.1, 30.sub.2, . . . , 30.sub.N) are disposed at a predetermined distance from the amplifier outputs along the transmission lines (24.sub.1, 24.sub.2, . . . , 24.sub.N) and coupled to their respective sensing means.

Abstract: A split-band, redundant amplifier system is disclosed. The system has at least two identical amplifiers (1, 2) each capable of amplifying signals having frequencies within a predetermined pass band. A first filter (3) divides signals into at least two contiguous split-bands within the pass band. A second filter (5) combines the signals in the split-bands. In normal operation, the amplifiers are connected in parallel between the two filters, and each amplifier amplifies signals in only one of the split-bands. Switches (SW1, SW2, SW3, SW4, SW5, SW6, SW7, and SW8) are connected to the amplifiers and the filters and are operative to selectively connect an input signal to the first filter or to one of the amplifiers and to selectively connect the output of the second filter or the output of one of the amplifiers to the output of the system. A sensing circuit (7) is connected to the outputs of each of the amplifiers and detects when an amplifier becomes inoperative.

Abstract: A redundancy system for use in a communications satellite. Eight traveling wave tube amplifiers are provided for five communications channels in a manner such that full service is maintained even though any three of the amplifiers have failed. A ten-switch network connects the five channels to the inputs of the eight TWT amplifiers, and a mirror-image ten-switch network connects the outputs of the eight TWT amplifiers to the five channels.

Abstract: Under non-fault conditions the power from two equal power transmitters A and B having a relative phasing of 90.degree. is combined in the network of this invention to provide at an output thereof a power of A + B. The network preferably comprises two 3db short-slot 90.degree. couplers connected in cascade with the first coupler normally operating and the second coupler shorted or decoupled in the coupling slot region by means of shorting posts or the like. If transmitter B fails this condition is sensed and the second coupler has its associated decoupling means withdrawn so that the couplers form a zero db cross-over coupler delivering the total power of transmitter A to the output. For a failure condition of transmitter A a decoupling means is also associated with the first coupler so the entire network can be decoupled delivering the total power of transmitter B to the output under that condition. With a failure of either transmitter A or B there is the possibility of inoperation of the decoupling means.

Abstract: An improved low-noise microwave amplifier comprises a circuit arrangement coupled in parallel with a GaAs FET amplifying stage for reducing transmission loss in case of dc power failure or amplifying stage failures. The circuit arrangement comprises two microwave circulators and a microwave isolator connected therebetween.

Abstract: A high-reliability power amplifier employs passive automatic switching between parallel amplifier channels to provide a constant output power level, which is independent of the failure of an individual channel. The reliability of the amplifier network is improved by amplifying the input signal through parallel channels. Passive switching between channels and a constant level of power output are provided through a hybrid junction.

Abstract: An RF power amplifier parallel redundant circuit employs three amplifiers. Under normal operation when all three amplifiers are functioning, the output from a comparator holds a 0.degree., 60.degree. two-bit phase shifter in the 60.degree. position. When anyone of the amplifiers or any pair of amplifiers fail, the comparator output causes the two-bit phase shifter to switch to the 0.degree. position. The system holds the power output constant at one-fourth the value of each individual amplifier for single or double failures. Only one simple switching position operation is required.

Abstract: Variable current generator arrangement for controlling the position of remote load components allowing replacement of a main control current generator by an auxiliary control current generator. The main control current generator is a current injector with high output impedance. The auxiliary control current generator is a voltage follower with low output impedance. For performing switchover, a switch means allows the voltage across the load component to be applied to an analog store means and the voltage in said store means to be applied to the voltage follower.

Abstract: A diode switch device coupled between two circulators provides signal continuity around an active radio frequency circuit during a failure mode caused by a loss of local supply voltage. Under a normal nonfailed condition, the diode switch short circuits the bypass path, thereby preventing the input signal from bypassing the protected circuit. In the protected failure mode, the short circuit is removed and the input signal is conducted around the failed active circuit.

Abstract: Apparatus for monitoring a redundant multi-channel analog system and for the forming of an undisturbed mean signal value in which all channels are connected to the inputs of a maximum value selection device and a minimum value selection device with a mean value former having as inputs the signals in all channels and the inverted extreme value signals detected by the two devices.

Abstract: A power amplifier includes a plurality of generally identical amplifier elements connected in parallel between input and output transmission lines for phase coherent addition of the signal outputs of each amplifier element. Resistive elements are connected across normally phase identical points on the transmission lines. If the amplifier becomes electrically unbalanced, power is absorbed in the resistive elements, thus protecting the amplifier elements.

Abstract: A standby microwave transmitter power amplifier tube is switched into a mowave power distribution system for a phased array in microseconds when any transmitter tube feeding any one of the radiating elements fails and all the radiating elements continue to be fed by respective transmitter tubes after the switching is completed, the switching being accomplished by changing electrical length of a quarter-wavelength waveguide stub to one-half wavelength by switching a reciprocal latching ferrite phase shifter in the stub, in response to termination of microwave power from one of the feed tubes.