Abstract: Digital mixers which permit mixing of asynchronous signals may be constructed of Rapid Single Flux Quantum (RSFQ) logic elements. The logic elements may include an RSFQ non-destructive readout cell (NDRO), an RSFQ D flip-flop, an RSFQ XOR circuit, and an RSFQ T flip-flop. A binary tree arrangement of T flip-flops can be used to provide in-phase and quadrature phase-divided replicas of a reference signal. The mixing elements can be either an XOR circuit, a dual port NDRO circuit functioning as a multiplexer or an RS type NDRO functioning as an AND gate. The RSFQ logic elements utilize Josephson junctions which operate in superconducting temperature domains.

Abstract: A high performance radio frequency receiver includes a low noise amplifier with large binary and stepped gain control range, controlled impedance, and enhanced blocker immunity, for amplifying and converting a radio frequency signal to a current; a pulse generator for generating in-phase and quadrature pulses; a crossover correction circuit and pulse shaper for controlling a crossover threshold of the pulses and interaction between in-phase and quadrature mixers; and a double balanced mixer for combining the RF signal with the pulses to generate an intermediate frequency or baseband zero intermediate frequency current-mode signal. The in-phase and quadrature pulses have a duty cycle of 20-35%. The intermediate frequency signal and second order harmonics may be filtered with a high frequency low pass filter and a current injected complex direct-coupled filter.

Abstract: A method of receiving signals from an aircraft transponder is provided that enables ADS-B signals to be decoded even though parts of the signal may be overlapped due to interference. A plurality of antennas are summed and subtracted in pairs in order to create directional signal channels, which are then assessed for the confidence of the signals received. Where a channel contains a section of the signal of low confidence, the signal from another channel may be substituted for that section.

Abstract: An antenna assembly for a wireless communications device has an antenna, a filter circuit, and a connector constructed to engage a wireless communications device. A filter circuit includes a band-pass filter and a first notch filter disposed in serial electrical communication with the band-pass filter, the band-pass filter operable to permit the passage of oscillatory electrical signals in a first frequency range, the first notch filter operable to impede the passage of oscillatory electrical signals in a second frequency range, the second frequency range residing within the first frequency range.

Abstract: A receiver system and a demodulator system are configured to receive and demodulate, respectively, multi-gigabit millimeter wave signals being wirelessly transmitted in the unlicensed wireless band near 60 GHz.

Abstract: Apparatus, and an associated method, for a receiving station, such as the receive part of a mobile station, that has diversity antennas. The receiving station includes both legacy demodulators and a diversity demodulator. Calculations are made to determine signal indicia associated with the signal energy detected at the diversity antennas. Responsive to the signal indicia, selection is made as to whether to utilize demodulation data, demodulated pursuant to a diversity demodulation technique or pursuant to a legacy demodulation technique. As the characteristics of received signals change, reselection of the demodulation is correspondingly made, such as on a frame-by-frame basis of frame-formatted data.

Abstract: A method and system for protecting a LNA by acquiring a radio frequency control channel signal at a tower top low noise amplifier (TTLNA) system. In response to acquiring the radio frequency control channel signal, LNA mode information is determined from the acquired radio frequency control channel signal. Based at least in part on the determination, the TTLNA is configured to either receive mode when the LNA mode information indicates receive mode or transmit mode when the LNA mode information indicates transmits mode. In an exemplary embodiment, the TTLNA is configured to receive mode only after a determination is made that there is no transmit energy present on the feedline connecting the BTS and the antenna. In another exemplary embodiment, the TTLNA is initialized in transmit mode.

Abstract: An RF mixer provides extended dynamic range with reduced noise by utilizing degeneration inductors in the RF input section of a doubly balanced mixer. Degeneration inductors are also utilized in a mixer having a class AB input section. A current mirror in the class AB input section is also inductively degenerated for further noise reduction. The input section is biased by an all-NPN bandgap reference cell which is tightly integrated into the input section so as to reduce the power supply voltage required for the reference cell. The mixer can be optimized for wide input voltage ranges or low distortion.

Abstract: This document discloses, among other things, a front end circuit having a selectable center frequency. The center frequency is selected based on a control signal proportional to a phase difference between a reference frequency and an amplifier output. A resonant frequency of a tank circuit coupled to the amplifier is tuned using the control signal.

Abstract: The demodulator by direct frequency conversion comprises a vector addition device having: a first circuit (1) that furnishes, starting from a first AC signal (LO), a respective AC signal to n outputs that are not all of the same amplitude and of the same frequency, but are out of phase with regard to one another in such a manner that each one is not either in phase nor in opposite phase with any other; a second circuit (2) that splits a second AC signal (RFin) toward n outputs; a number n of summers (3a, 3b, 3c) each receiving, at the input, a respective output of the first circuit (1) and a respective output of the second circuit (2), and; a respective power sensor (4a, 4b, 4c) for each summer, whereby the number n is greater than or equal to 3. The demodulator also comprises digital processing means (5, 6) that furnish the result of the demodulation.

Abstract: A multi-channel superheterodyne receiver employs a low intermediate frequency (IF) and both high-side injection and low-side injection of a selected local oscillator (LO) signal into the mixer in order to position image frequencies outside the passband of a single image reject filter. Any channel that falls within a used portion of the image reject filter passband can be downconverted with image rejection if the utilized bandwidth portion is no greater than about 4 times the IF minus the bandwidth of a channel in the filter passband. Low side injection is used for channels falling within the lower half of the passband of the image reject filter, while high-side injection is used for channels falling within the upper half thereof. The image always remains outside the passband and the receiver can accommodate a greatly increased number of channels.

Abstract: A circuit arrangement is disclosed with a radio-frequency mixer in which a plurality of preamplifiers in a receiver have a common output node. This node is connected to a common, broadband radio-frequency mixer via common coupling capacitances. Switching means can be used to connect and disconnect the preamplifiers, which can be associated with various frequency bands, independently of one another. The present principle can be applied in multiband receivers in mobile radio and allows integration using little chip area with good radio-frequency characteristics.

Abstract: To provide an antenna device adapted to interrupt jamming waves and enable cost reduction, a high-pass filter (HPF) adapted to interrupt general-use frequencies at least near a low-frequency side of a pass band intended for use is provided as a frequency selection circuit 11A on the antenna 1 side in an initial-stage LNA 2A. By setting a low-side cutoff frequency to 900 MHz, it is possible to prevent reception of frequencies in a general-use frequency band with a high frequency of use as jamming waves. That is, for example, it is possible to prevent reception of frequencies in 800 to 900 MHz band for mobile cellular telephones and higher harmonics thereof as jamming waves. Further, since an additional filter is not required in the antenna device, the circuit structure can be simplified.

Abstract: An active channelized antenna system includes an antenna array operable over a multi-octave frequency band to provide one or more antenna output signals. An electronics module includes multiplexer circuitry responsive to the one or more antenna output signals configured to divide an input signal spectrum into a plurality of frequency band components each of less than an octave bandwidth. The electronics module includes a plurality of amplifiers each of less than an octave bandwidth to provide an amplified component signal for a respective frequency band. Combiner circuitry included with the electronics module is configured to combine the amplified frequency band components into a composite signal. A transmission medium such as a coaxial cable, fiber optic line or free space, is configured to transmit the composite signal to a remotely located receiver system.

Abstract: A system for tuning an impedance at a node comprises a first component associated with a first impedance when the first component is operating and a second impedance when the first component is not operating. The system further comprises a second component coupled to the first component at a node. The second component is associated with a third impedance when the second component is operating and a fourth impedance when the second component is not operating. An impedance tuning circuit is coupled to the second component at the node and operable to tune an impedance at the node based at least in part upon a plurality of the first impedance, the second impedance, the third impedance, and the fourth impedance.

Abstract: A receiving apparatus includes a receiving module and a processing module. The receiving module is used for receiving a plurality of received signals and selecting the received signals to generate a plurality of input signals. The processing module is used for processing the input signals to generate an output signal.

Abstract: To provide an antenna device adapted to interrupt jamming waves and enable cost reduction, a high-pass filter (HPF) adapted to interrupt general-use frequencies at least near a low-frequency side of a pass band intended for use is provided as a frequency selection circuit 11A on the antenna 1 side in an initial-stage LNA 2A. By setting a low-side cutoff frequency to 900 MHz, it is possible to prevent reception of frequencies in a general-use frequency band with a high frequency of use as jamming waves. That is, for example, it is possible to prevent reception of frequencies in 800 to 900 MHz band for mobile cellular telephones and higher harmonics thereof as jamming waves. Further, since an additional filter is not required in the antenna device, the circuit structure can be simplified.

Abstract: A radio-frequency signal receiver capable of enhancing reception performance includes an antenna for receiving radio-frequency signals, a first switch having an end coupled to the antenna, a filter coupled to the first switch, a second switch having an end coupled to the first switch and an end coupled to the filter, a low noise amplifier coupled to the second switch for amplifying signals received from the second switch, a frequency down converter coupled to the low noise amplifier for down-converting a frequency of signals outputted from the low noise amplifier, a signal processing circuit coupled to the frequency down converter for performing signal processing, and a control circuit for controlling the first and the second switches.

Abstract: A switching circuit comprising: first and second steering switches operable to make or break a path between first and second terminals thereof, and each steering switch further having a control terminal for controlling the switch, the first and second steering switches having their control terminals driven by first and second switching signals, the first and second switching signals having a first frequency and the second switching signal being in anti-phase with the first switching signal and a first chopping switch operable to make or break a path between first and second terminals thereof and being connected in series with at least one of the first and second steering switches and receiving at its first terminal an input to be modulated, wherein the control terminal of the chopping switch is driven by a first switching control signal such that the chopping switch is non-conducting while the first and second steering switches are changing between being conducting and being non-conducting.

Abstract: Methods and systems for a transmitter LOFT cancellation scheme that maintains IQ balance are disclosed. Aspects of one method may include providing current compensation to both differential inputs of a mixer for each of I and Q channels. An initial current compensation of X units may be provided, followed by subsequent compensation as needed. The initial compensation may be provided to each differential input of the mixers used for I and Q channels. The subsequent current compensation for the I channel may be independent of the subsequent current compensation for the Q channel. Subsequent current compensation to a first differential input for a mixer may be increased by Y units while decreasing current compensation to the second differential input of the mixer by Y units. In this manner, the DC common mode level for the mixer may remain the same at the initial DC compensation current of X units for both mixers.

Abstract: Controllable operational transconductance power amplifier (controllable power OTA) including an input stage receiving a differential input signal (Ovin) and deriving therefrom first (i1) and second (i2) low power current signals being coupled to first (ccs1) and second (ccs2) current controlled output current sources being arranged in class B push pull configuration. To obtain an effective gain control while securing power efficiency and linearity, the overall gain of the power OTA is controlled by varying the gain or transconductance of the input stage (c15) and by the use of means for bi-directionally rectifying said first (i1) and second (io) low power current signals and providing in mutual alternation power amplification of said first (i1) and second (i2) low power current signals into first (I01) and second (Io2) mutually exclusive high power current output signals, which are supplied through a current summer to a current output (I0) of said linear power amplifier.

Abstract: An RF unit comprises a tuner, a demodulator and a mixer. At least the tuner and the mixer are disposed on separate first and second substrates. The RF unit further comprises a housing accommodating the first and second substrates. The first substrate and the second substrate are arranged on different levels inside the housing and maintain a predetermined distance between each other.

Abstract: A system, method, and electrical circuit comprises a LNA signal line path comprising a LNA and a first signal mixer operatively connected to the LNA. The circuit further comprises an attenuator signal line path comprising an attenuator and a second signal mixer operatively connected to the attenuator; a radio frequency (RF) power detector operatively connected to an output of each of the LNA and the attenuator, wherein the RF power detector is adapted to vary a front end power gain of the electrical circuit; and logic circuitry operatively connected to the RF power detector, wherein the logic circuitry is adapted to (i) select transmission of a signal through only one of the LNA signal line path or the attenuator signal line path, and (ii) output the selected signal.

Abstract: A frequency mixer includes a semiconductor substrate. An input current feedback amplifier is formed on the semiconductor substrate and receives a radio frequency (RF) signal and a local oscillator (LO) signal. An inverting current feedback amplifier is formed on the semiconductor substrate and connected to the input current feedback amplifier for inverting the LO signal and producing a half-wave signal. An output current feedback amplifier is formed on the semiconductor substrate and connected to an output of the input and inverting current feedback amplifiers and operative as an inverting summer for the RF and LO signals such that the output polarity of the RF signal is reversed.

Abstract: A Gilbert cell mixer for a wireless transceiver includes a first stage that performs voltage to current conversions and that includes first and second transistors that are operated in a saturation region and third and fourth transistors that are operated in a triode region. A second stage communicates with the first stage and that performs frequency conversion. A biasing circuit communicates with the first stage to maintain a substantially constant input linear range over temperature and process variations.

Abstract: An IQ mixer and a method thereof. The IQ mixer comprises a pair of Gilbert cells and a degeneration inductor. Each pair of Gilbert cells comprises a pair of first current generators and a pair of switching networks. The pair of first current generators converts an RF signal pair to currents respectively. The pair of switching networks, coupled to the first current generator, modulates the converted RF signal pair with an oscillation signal pair to generate a mixed signal pair. The degeneration inductor is coupled to all pairs of the first current generators, such that it is shared by the pair of Gilbert cells.

Abstract: Disclosed is a method and apparatus for amplitude modulation of an RF transmit signal using pulse width modulation to control an amount of energy within each period. The apparatus includes a signal processing circuit with an input port for receiving of information indicative of a carrier frequency and modulation data. The signal processing circuit has a first output port and a second output port for providing of output signals having a phase relationship therebetween. A power amplifier is provided for receiving the output signals and for generating a pulse width modulated signal in dependence thereon.

Abstract: A wireless receiver which is used for a digital signal transmission system to wirelessly transmit a digital signal by packetizing and modifying it, selectively sets the shortest arithmetical bit length satisfying a required communication quality when performs demodulation arithmetical processing to demodulate a digital signal to be packet-transmitted, inputs a demodulation arithmetical result by the arithmetical bit length to calculate an error vector magnitude value that is a measure indicating a difference between the arithmetical result and a known ideal result, predicts a bit error rate by using the EVM value as an evaluation criterion, selects an arithmetical bit length by which the bit error rate becomes optimum, and executes the demodulating arithmetical processing by the selected arithmetical bit length.

Abstract: A first and a second signal (base band and local oscillator), respectively modulated to a first and a second frequency, are mixed to deliver an output signal at a frequency obtained by combining the first and second frequencies. The mixing is accomplished through a variable resistance stage controlled by the second signal and connected between a first and a second potential to deliver the mixed output signal. A control stage is configured to drive the resistance variation of the variable resistance stage according to the first signal.

Abstract: An RF amplifier for amplifying a composite RF signal includes a first RF signal and a second RF signal. The amplifier includes a first amplifying stage for providing a first amplified signal a second amplifying stage for providing a second amplified signal, a third amplifying stage for providing a third amplified signal and a fourth amplifying stage for providing a fourth amplified signal, the fourth amplifying stage being arranged after the third amplifying stage. The respective amplified signals are summed up to obtain amplified RF signals.

Abstract: A mixer circuit of a receiving system, requiring low noise characteristics at lower frequency, includes a bypass current source (41) which is connected in parallel with an LO transistor (21) between an IF output terminal (33) and a drain terminal of an RF transistor (11), and a bypass current source (42) which is connected in parallel with an LO transistor (22) between an IF output terminal (34) and the drain terminal of the RF transistor (11), thereby decreasing a current flowing through the LO transistors (21, 22) without decreasing a bias current flowing through the RF transistor (11). Accordingly, it is possible to suppress flicker noises occurring from the LO transistors (21, 22) without lowering the gain of the mixer, thereby realizing a mixer circuit with excellent low frequency noise characteristics, which can improve the NF characteristics at lower frequency.

Abstract: A low noise amplification circuit comprises a low noise amplifier and a filter coupled to the input terminal of the low noise amplifier. The low noise amplifier comprises an amplifying element and a matching input circuit coupled to the input terminal of the amplifying element. When gamma.sub.s shows a reflection factor in the case that signals flow from the input terminal of the amplifying element to the output terminal of the matching input circuit, impedance conversion for setting the gamma.sub.s at a desired value is made entirely or in part by means of setting the output impedance of the filter at the value different from that of characteristic impedance.

Abstract: Methods and apparatus are provided for receiving a first signal and generating an output signal indicative of radio data system (“RDS”) information. A receiver circuit of the invention can include mixer circuitry, lowpass filter circuitry, downsampler circuitry, and decoder circuitry. Advantageously, the receiver circuit can operate entirely within the digital domain, promoting interoperability with digital frequency modulation (“FM”) demodulator circuitry.

Abstract: An apparatus, for automatically selecting a compensation value usable to reduce a second order intermodulation (IM2) product in an output signal of a mixer, may include: a mixer to output a mixed signal; a detector to detect an product in samples corresponding to the mixed signal; a compensation determination circuit to do the following automatically, to apply a plurality of candidate values of a mixer-control signal to the mixer, the mixer-control signal affecting a magnitude of an IM2 product in the mixed signal, to evaluate samples from the detector corresponding to the plurality, respectively, and to select one among the plurality candidate values as the compensation value.

Abstract: A receiver apparatus includes a preamplifier to amplify an input signal, an equalizer configured to subject an amplified signal to an equalization process, an identification reproducer to reproduce the input signal based on an output signal of the equalizer, and a magnetic oscillator arranged on a pre-stage of the preamplifier to improve a SN ratio of the input signal.

Abstract: A multi-band receiver is disclosed. The multi-band receiver includes a low-noise amplifier (LNA) and a mixer. The LNA includes a switched receiving circuit, a loading circuit, and a switching circuit. The switched receiving circuit has a first receiving circuit for receiving a first signal corresponding to a first frequency, and a second receiving circuit for receiving a second signal corresponding to a second frequency. The loading circuit is utilized for providing a specific load to the switched receiving circuit. The switching circuit is used for controlling whether the first signal or the second signal is transferred to the loading circuit. The mixer is coupled to the low-noise amplifier for receiving an output signal generated from the LNA and for down-converting the output signal.

Abstract: An RF receiver front end includes a variable gain low noise amplifier and/or a variable gain mixer to provide gain variability in the receiver. This gain variability may be used during, for example, automatic gain control operations. In at least one embodiment, the variable gain LNA is a broadband device that is capable of supporting multiple wireless standards.

Abstract: A receiver and receiver front end having multiple independent differential inputs, multiple independent differential low-noise amplifiers, and two sets of double-balanced IQ mixers. The double-balanced mixers include cross-coupled PMOS devices that dynamically inject current at zero-crossing points to cancel out tail currents in the mixers. Also, methods of operating the above-discussed receiver and receiver front end.

Abstract: Three-phase mixer-systems comprising at least three groups of mixers (1-4,5-8,9-12,30) for frequency translating signals are (basic idea) provided with balancing means (13-21,31) for suppressing certain mixing products with harmonics of the oscillator signal resulting from unbalance (insight). Said three groups of mixers (1-4,5-8,9-12) each comprise a group of switching transistors (1-3,5-7,9-11) and an amplifying transistor (4,8,12) coupled to said group of switching transistors (1-3,5-7,9-11) and are balanced by said balancing means (13-21) comprising per group of mixers (1-4,5-8,9-12) and per at least one switching transistor of said group of switching transistors (1-3,5-7,9-11) a further switching transistor (13-21).

Abstract: An RF circuit module, in which a power amplifier and a transceiver are united, with reduced interference between its electronic circuit blocks, downsized and still having high performance, and with a stable performance not dependent on the ground land structure on the motherboard, is provided. The ground plane 110 for at least a last-stage amplifier 11 of the power amplifier 10 where the greatest power is generated in the whole RF circuit block, that is, the source of generating the greatest noise and heat for the RF circuit block, is isolated from the ground plane for at least one circuit portion of the transceiver 9 including an LNA 51, receiver 52, transmitter 30, and VCO 70. These ground planes are connected to a common ground plane 480 through different connection conductors, respectively.

Abstract: To realize a mixer with a charge subsampling circuit with which a base band signal can be readily obtained without being affected by noise from wide bandwidth signals or undesired signals. A current generating circuit 8 outputs a current in proportion to the input signal voltage. In response to a control signal from the timing generating block 6, a charge subsampling circuit 7 samples the current at the same sampling frequency as the carrier frequency. In a charge-integrating process accompanying the sampling, weighting is carried out on terms in the transfer function of the FIR filter using a set of selected weights.

Abstract: Disclosed herein is a demodulating device including, first high-frequency receiving means and second high-frequency receiving means for receiving a high-frequency signal of one of a first frequency and a second frequency, first signal strength detecting means and second signal strength detecting means for detecting strengths of signals received by the first high-frequency receiving means and the second high-frequency receiving means, respectively, and strength determining means for performing control so as to make the second high-frequency receiving means receive a high-frequency signal of the first frequency when the first high-frequency receiving means is made to receive the high-frequency signal of the first frequency and the second high-frequency receiving means is made to receive a high-frequency signal of the second frequency and when the second signal strength detecting means does not detect a predetermined signal strength within a predetermined time after the first signal strength detecting means dete

Abstract: An RF sender/receiver front-end is disclosed comprising a terminal for receiving an oscillator signal, at least one distribution unit for distributing the oscillator signal into different signal paths, two or more mixer-arrangements for sending a transmit-signal or for receiving an receive-signal, where each mixer-arrangement comprises a mixer and an amplifier for amplifying the oscillator signal and generating the transmit-signal.

Abstract: A high linearity mixer circuit includes a commutation network comprising four switches to provide an electrical coupling between a first pair of circuit nodes and a second pair of circuit nodes, whereas the coupling has two states and is controlled by a pair of complementary logical signals. The mixer circuit further comprises a first pair of current-sourcing devices coupled to the first pair of circuit nodes and a second pair of current-sourcing devices coupled to the second pair of circuit nodes. The mixer circuit further includes a pair of capacitors to provide AC coupling, either between the first pair of circuit nodes and a first external circuit, or between the second pair of circuit nodes and a second external circuit.

Abstract: Methods and systems for vector combining power amplification are disclosed herein. In one embodiment, a plurality of signals are individually amplified, then summed to form a desired time-varying complex envelope signal. Phase and/or frequency characteristics of one or more of the signals are controlled to provide the desired phase, frequency, and/or amplitude characteristics of the desired time-varying complex envelope signal. In another embodiment, a time-varying complex envelope signal is decomposed into a plurality of constant envelope constituent signals. The constituent signals are amplified equally or substantially equally, and then summed to construct an amplified version of the original time-varying envelope signal. Embodiments also perform frequency up-conversion.

Abstract: An adapter for RF front end processor chip wherein the RF front end processor chip includes a low noise amplifier which is used to receive a RF filter signal so as to generate a first signal. An adapter is used to receive a first signal so as to induce and generate a second signal and a third signal which is electrically reverse. Then a frequency mixer of the RF front end processor chip is used to receive the second signal and the third signal and a resonant signal, the second signal and the third signal are used to generate a medium frequency signal.

Abstract: A low noise mixer comprises a first mixer core configured to receive a radio frequency (RF) input signal having an RF frequency, and a first local oscillator signal, wherein the first local oscillator signal is at a frequency that is nominally twice the frequency of the RF frequency, the first mixer core configured to switch the RF input signal to at least one secondary mixer core at a frequency that coincides with the frequency of the first local oscillator signal, the at least one secondary mixer core configured to receive the switched RF input signal and a second local oscillator signal, where the second local oscillator signal is at the same nominal frequency as the RF input signal, and wherein switching the RF input signal at the frequency of the first local oscillator signal substantially eliminates flicker noise associated with the down-conversion process.

Abstract: A modem generates a new RSSI threshold value in response to a flag signal representing the quality of the threshold value indicated by the result of error detection supplied from one monitor, and supplies the generated threshold value to another monitor. The RSSI threshold value set in the other monitor is rendered variable, the modem thus being able to operate with the threshold value converging precisely in a short time.

Abstract: A mixer is disclosed that includes first and second transconductance modules that, in one embodiment, includes MOSFETs configured to receive a plurality of signals that are to be mixed and a selectively coupled auxiliary current source to inject an auxiliary current into the second transconductance module approximately at or near a zero-crossing point in order to reduce flicker noise and other noise introduced into an output signal during switching. Accordingly, as a first transconductance module approaches a zero-crossing, auxiliary current is injected to reduce the current produced therefrom thereby reducing flicker noise. In a differential mixer, the amount of current produced from a transistor pair to which the signal cycle is being switched is also reduced thereby reducing noise from the transistor pair that is turning on for the next portion of a signal cycle.

Abstract: A radio frequency (RF) front-end includes a plurality of power amplifier modules and a plurality of impedance matching circuits. Each of the plurality of impedance matching circuits includes an input connection and an output connection, wherein outputs of the plurality of power amplifier modules are coupled to corresponding input connections of the plurality of impedance matching circuits to provide a desired loading of the plurality of power amplifier modules and wherein the output connections of the plurality of impedance matching circuits are coupled together to add power of the plurality of power amplifiers.