Abstract: An apparatus (100) uses power recovery from a combining circuit (125) to improve efficiency. A power combiner (125) generates multiple output signals (127, 133) from a combination of input signals (113, 114). One of the output signals from the power combiner is coupled to a power recovery circuit (135), and energy is recovered and preferably stored for later use.

Abstract: The present invention provides high power linear amplification of an amplitude and/or phase modulated signal using multiple saturated (or if desired, unsaturated) amplifiers driven by an appropriate set of switched, and/or phase modulated constant amplitude signals derived from the input signal. The present invention combines three amplitude reconstruction techniques and implements the amplitude reconstruction modulator digitally.

Abstract: A device includes a passive coupler circuit with lumped elements for coupling a first A.C. signal having a given center frequency (fo) present on a first primary port (P1) to two second A.C. signals phase shifted through 180.degree. present on two secondary ports (P3, P4). The device has a first and a second elementary circuit (B, B') phase shifting through 180.degree. respectively, a differential input terminal (1, 1') and a summation input terminal (2, 2') and first and second output terminals (3, 4; 3', 4'), elementary circuits being connected to each other so that the differential input terminal (1) of the first circuit (B) feeds first primary port (P1), the differential input terminal (1') of the second circuit (B') feeds a second primary port (P'1) connected to ground via an impedance (Zo), the output terminals (3, 4; 4', 3') of the first and second circuits (B, B') are coupled crosswise respectively, and feed said secondary ports (P3, P4), and the summation input terminals (2, 2') are short-circuited.

Abstract: A high efficiency power amplifier 600 consists of a non-linear radio frequency (RF) Doherty power amplifier (67) and a linearization circuit, such as, for example, a Cartesian Feedback circuit (33), an RF feedback circuit (38), an IF feedback circuit (48), or a feedforward circuit (55). The Doherty amplification stage (67) may be implemented with a BJTs, FETs, HBTs, H-FETs, PHEMTs, or any other type power transistor technology or device.

Abstract: An amplifier circuit for providing an amplified signal in response to an input signal. The amplifier circuit includes an input network for applying the input signal to a selected at least one of a plurality of amplifier stages. An output network is provided for coupling the amplified signal from the selected at least one amplifier stage. The appropriate amplifier stage is selected by a control circuit in response to a desired power value of the amplified signal. By selectively activating only the amplifier stage(s) that are necessary to provide the desired level of output power, increased DC efficiency can be accomplished in applications that require an amplifier which operates linearly over a wide dynamic range.

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: A stacked power amplifier is provided in which an input signal is independently coupled to each of a series of amplifying devices in the stack. A transformer is used at the input circuit of each device to create an RF swing across each amplifying device which is substantially equal. This results in an equal distribution of RF and DC voltage among the devices in the stack.

Abstract: A Built-In Self-Test (BIST) circuit and test method are employed for automated testing of a programmable analog gain stage. The BIST circuit and operating method advantageously use the natural redundancy of a multiple-channel circuit for detecting circuit faults. More specifically, the BIST circuit utilizes the natural redundancy of the identical signal paths for multiple-channel, such as stereo, audio operation. A left channel and a right channel ideally function identically so that a fault in one channel of the left channel and the right channel signal paths is detected by mutually comparing the operation of the two channels.

Abstract: An RF power amplifier system is provided including a plurality of the DC voltage sources of different magnitudes. An RF source provides an RF drive signal. N RF actuatable power amplifiers are provided. Each amplifier, when actuated, is connectable to a selected one of the voltage sources for providing an RF output signal amplified in accordance with the magnitude with the selected voltage source. One or more of the N RF power amplifiers are actuated in dependence upon the value of an input signal. One of the voltage sources is selectively connected to each of the actuated RF power amplifiers. The amplified RF output signals are additively combined to provide a combined RF output signal.

Abstract: A transmitting apparatus which can suppress unnecessary power consumption. An optimal signal line is selected from a plurality of signal lines (53-56) having different gains provided by respective signal amplifying devices to perform gain adjustment on a signal to be transmitted, which is supplied to an input terminal (58), so as to optimize power consumption of each signal amplifying device in accordance with a gain value, and to halt the operation of the signal amplifying device on a signal line which is not selected. Therefore, unnecessary power consumption can be suppressed.

Abstract: A high output power is obtained for an audio power amplifier using an amplifier circuit topology wherein channels or stages of a multi-channel class AB monolithic integrated circuit are paralleled in order to drive a low impedance dual voice coil speaker. The stages are paralleled by connecting their outputs through isolation resistors. These resistors prevent the differences in output bias voltages from resulting in a short circuit from power to ground. In addition, the resistors are sufficiently small to achieve the correct speaker damping factor, yet large enough to prevent excessive quiescent current. The separate amplifier channels or stages are paralleled through isolation resistors which increases current drive resulting in a higher output power to the loud speaker.

Abstract: An apparatus and method of reducing a peak envelope power of a linear power amplifier (10) amplifying a plurality of channels is provided. The method includes the steps of measuring (104) the peak envelope power of the linear power amplifier, measuring a channel activity level (101) of each channel of the plurality of channels, and, when the peak envelope power exceeds a first threshold, changing (103, 106) at least one parameter of a channel of the plurality of channels having a channel activity level exceeding a second threshold to reduce the peak envelope power.

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: In an amplifier which generates an output voltage which is proportional to an input voltage and can be picked off between the outputs of two push-pull output stages and has peak-to-peak values of up to twice the supply voltage of the push-pull output stages, each push-pull output stage is driven by a differential amplifier having a positive and a negative differential input in each instance and whose polarity is so defined that the outputs of the two push-pull output stages have voltages of like polarity when identical voltages are present between the positive and negative differential inputs of the two differential amplifiers, a differential input of one differential amplifier being connected with a differential input of like polarity of the other differential amplifier. The remaining two differential inputs of the differential amplifiers are provided for applying a voltage proportional to the input voltage.

Abstract: An amplifying apparatus for linearly amplifying a desired signal using a pair of coupled non-linear amplifiers is disclosed. The amplifying apparatus comprises a limiter for separating amplitude variations from the desired signal and producing a constant amplitude signal bearing the phase of the desired signal and an amplitude related signal. In addition, a drive signal generater produces two drive signals each dependent on the constant amplitude signal and the amplitude related signal such that each drive signal depends on the phase of the desired signal and such that the sum of the squares of the amplitudes of the drive signals is constant. Finally, a coupler couples the two drive signals to produce two constant amplitude signals for driving the pair of non-linear power amplifiers and for coupling the outputs of the power amplifiers to produce two amplified output signals, one of which is the linearly amplified desired signal and the other of which is a waste energy signal.

Abstract: In a variable output amplifier apparatus, an input signal is distributed by a distributing unit as first signals to a plurality of variable gain units having different gains. Second signals generated from the variable gain units are combined by a combining unit to generate an output signal. A plurality of power supply control units apply power supplies to the variable gain units, respectively. The variable gain units and the power supply control units are controlled by a control unit. When one of the variable gain units and one of the power supply control units are activated, the corresponding power supply is turned ON. When they are deactivated, the corresponding power supply is turned OFF.

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 power amplifier (10) provides linear amplification of noise-like multi-carrier signals over a wide range of power levels. A power divider (40) divides an input signal for distribution in three amplifier networks (70, 72, 74) for selective amplification based upon input signal levels. Each amplifier network (70, 72, 74) is biased to respond when the efficiency of the previous stage diminishes. Successive staging of amplifier networks (70, 72, 74) broadens the efficiency bandwidth of power amplifier (10). A combiner (28) merges output signals from each successive amplifier networks to provide an improved efficiency output to a power amplifier (10) load.

Abstract: In a hybrid matrix amplifier array (100), the amplitude of each of a plurality of input signals is measured (132-136, 202). In response to the signal amplitude measurements, an overload condition that will result in an amplifier overload in said hybrid matrix amplifier array is estimated (204, 206, 138). In response to the estimation of the overload condition, the signal amplitude of at least one of the plurality of input signals is modified to prevent the overload condition in the hybrid matrix amplifier array. An overload condition may be estimated if the sum of the amplitudes of the input signals exceeds a threshold (206). In one embodiment, all input signals are modified by proportionately reducing the amplitude of each of the plurality of input signals (304).

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: An amplifier with adaptive output capacity allocation (201) including a processor (203), coupled to a signal, for examining the signal to determine a first capacity requirement and a second capacity requirement, and an amplifier (213), coupled to the processor and the signal, for processing the signal in accordance with the first capacity requirement and the second capacity requirement to provide an output signal thus maximizing power out of the amplifier given incoming signal conditions.

Abstract: An amplifier system is disclosed. The amplifier system includes a plurality of input terminals and a plurality of amplifier channels. It further discloses switching means for selectably connecting each of the plurality of input terminals to each of the plurality of amplifier channels when the input terminal is active, prioritizing means for prioritizing the connection of each of the plurality of input terminals to each of the plurality of amplifier channels and control means for controlling the switching means in accordance with the means for prioritizing the connection so that for each amplifier channel, the active input terminal with the highest priority is connected to the amplifier channel. Also disclosed are means for limiting the output level of each amplifier channel in accordance with the input terminal that is connected to the amplifier channel.

Abstract: An input signal (102) and a dithering signal (106) are coupled to an input of a n by m transform matrix (98). The input signal (102) and the dithering signal (106) are transformed to produce m transformed signals, which are then amplified using a plurality of amplifiers (64). The amplified signals are then input into an m by n inverse transform matrix (100) that performs an inverse transform to produce a low noise output signal. The low noise output signal may be passed through a band pass filter (74) to remove out-of-band noise derived from the dithering signal and provide a filtered output signal (110). The transform matrix (98) and inverse transform matrix (100) may be implemented with Fourier transform matrices or a Butler transform matrices.

Abstract: A method for amplifying an RF input signal using a power amplifier (105, 107 or 205, 207) comprises the steps of dividing or quadrature splitting (103) the RF input signal into an in-phase signal and a quadrature phase signal. A carrier amplifier bias input (111, 211) signal is varied relative to the magnitude of the RF input signal. A peaking amplifier bias input (113, 213) signal is varied relative to the magnitude of the RF input signal. The in-phase signal is amplified using a carrier amplifier (105, 205) to produce a first amplified signal. The quadrature phase signal is amplified using a peaking amplifier (107, 207) to produce a second amplified signal. The first amplified signal and the second amplified signal are combined (115, 117), in phase, to produce an output signal.

Abstract: In a preferred embodiment, a low distortion power sharing amplifier network capable of amplifying a plurality of input signals includes a plurality of amplifiers, each for amplifying an approximately equal amount of RF signal power. The power sharing arrangement prevents any one of the amplifiers in the network from operating too deep into saturation even when the plurality of input signals vary widely in power. Distortion is reduced by coupling at least one feed-forward loop to the amplifier network.

Abstract: A process for linearizing the gain and phase-frequency characteristics of traveling-wave tubes and transistor amplifiers at different power levels is suggested, wherein the signal is divided between two branches and again united into the output signal, and in which the signal is divided between partial networks with compressing gain behavior, which are placed between two 3-dB couplers, and gain compression or gain expansion of the partial signals (E or K) is generated at two gates (KOMP, EXP) by the reflection behavior, which is different corresponding to the signal level, and the level of the nonlinear, gain-expanded partial signal (E) is raised by a linear amplifier (E2), and the additionally amplified, gain-expanded signal (E2) and the gain-compressed signal (K) are then united into the output signal with an adding network.

Abstract: A self-calibrating, remote programmable signal conditioning amplifier system employs information read from a memory attached to a measurement transducer for automatic calibration. The signal conditioning amplifier is self-calibrated on a continuous basis through use of a dual input path arrangement, with each path containing a multiplexer and a programmable amplifier. A digital signal processor controls operation of the system such that a transducer signal is applied to one of the input paths, while one or more calibration signals are applied to the second input path. Once the second path is calibrated, the digital signal processor switches the transducer signal to the second path, and then calibrates the first path. This process is continually repeated so that each path is calibrated on an essentially continuous basis. Dual output paths are also employed which are calibrated in the same manner.

Abstract: A circuit arrangement for transmitting audio signals includes a signal amplifier having four power amplifiers each with an input and an output, a first and a third one of the four power amplifiers are non-inverting for applied audio signals, and a second and a fourth one of the four power amplifiers are inverting, the inputs of the first and second power amplifiers receiving a first audio signal and the inputs of the third and fourth power amplifiers receiving a second audio signal. In a first configuration mode for audio signals of low amplitude, the first and fourth power amplifiers each form a single-ended amplifier and the outputs of the second and/or the third power amplifier carry a reference potential. In a second configuration mode for audio signals of higher amplitude, the first and second power amplifiers form a first bridge amplifier, and the third and fourth power amplifiers form a second bridge amplifier.

Abstract: A preamplifier for processing an audio signal includes an equalizing and amplifying circuit comprised of parallel operational amplifiers, each with a feedback impedance circuit and an adjustable source impedance circuit. The adjustable source impedance circuit provides the preamplifier with a super-gain region in the high audio and supersonic frequency range. A summer adds the output of the parallel operational amplifiers to produce a single output signal. The parallel operational amplifiers, with the summer, gives the preamplifier unique low noise characteristic with an improved signal to noise ratio over a single operational amplifier with the same gain. The preamplifier may include an optional second stage for further equalizing and amplifying of the output signal.

Abstract: An RF power amplifier including a splitter, two branch circuits, and a combiner. The splitter has an input line receiving an RF signal, a first output line carrying a first output signal derived from the RF signal, and a second output line carrying a second output signal derived from the RF signal. A first branch circuit receives the first output signal and generates therefrom a first derived signal. A second branch circuit receives the second output signal and generates therefrom a second derived signal therefrom. The first branch circuit includes a first power amplifier and a phase shifting element. The second branch circuit includes a second power amplifier. The combiner, which has a first input receiving the first derived signal and a second input receiving the second derived signal, combines the first and second derived signals to produce a power output signal therefrom.

Abstract: A signal amplifier includes four amplifier stages which can be arranged in two different configuration modes, a first configuration mode in which a series arrangement of two loads is arranged between output terminals of a first and a third one of the amplifier stages, a reference potential being applied to a node between the loads, a first signal to be amplified being applied to an input of the first amplifier stage, and a second signal to be amplified being applied to an input of the third amplifier stage, and a second configuration mode in which a first one of the loads is arranged between the output terminal of the first amplifier stage and an output terminal of a second amplifier stage, and a second one of the loads is arranged between the output terminal of the third amplifier stage and an output terminal of a fourth amplifier stage, and the first signal to be amplified being applied to an input of the first amplifier stage and an input of the second amplifier stage and the second signal to be amplified

Abstract: A method and apparatus for producing amplified signals for communications having reduced adjacent channel energy involving generating a first signal having an undesired amount of adjacent channel energy, generating a second signal corresponding to the undesired amount of adjacent channel energy, and subtracting the second signal from the first signal to remove the undesired amount of adjacent channel energy. Several embodiments are disclosed.

Abstract: A power amplifier includes a power distributor for dividing an input signal into a plurality of equally power-distributed signals; a plurality of amplifying elements for amplifying the plurality of equally power-distributed signals divided by the power distributor, respectively; a power coupler for coupling respective output signals of the plurality of amplifying elements; and a variable resistance element provided between nodes having the same phase as each other on power transmission lines in at least one side of each input side and each output side of the plurality of amplifying elements. By the constitution, it is possible to prevent occurrence of a parasitic oscillation and thus contribute to an improvement in yield as a product.

Abstract: The peaking of multiple input signals applied to the inputs of two or more distinct amplifiers, and the resultant intermodulation, can be reduced, or avoided, by: a) dividing each of the input signals into components from which the original input signals can be reconstructed, e.g., by using a Butler matrix of order greater than 2.times.2; b) developing a specially constructed signal which is likewise divided into components; c)supplying a component of each of the input signals and a component of the specially constructed signal to at least one of the amplifiers; and d) constructing amplified versions of the original input signals from the outputs of the amplifiers, e.g., by using another identical Butler matrix. The specially constructed signal is generated so as to reduce: 1) peaking at the one of amplifiers whose input signal peaking results in the highest peak during a particular time period; and 2) intermodulation in the output signals.

Abstract: A combiner-amplifier is provided which has first current feedback amplifier which amplifies a first received signal by a predetermined gain value. A second current feedback amplifier amplifies a second received signal by the predetermined gain value. A combiner is operatively coupled to the first and the second current feedback amplifiers to combine the amplified first received signal with the second received signal together to generate a combined signal which is attenuated by the predetermined gain value such that the combined signal has approximately a unity gain over the first and the second received signals within a bandwidth of at least 45 megahertz.

Abstract: An amplifying apparatus for linearly amplifying a desired signal using a pair of coupled non-linear amplifiers is disclosed. The amplifying apparatus comprises a limiter for separating amplitude variations from the desired signal and producing a constant amplitude signal bearing the phase of the desired signal and an amplitude related signal. In addition, a drive signal generater produces two drive signals each dependent on the constant amplitude signal and the amplitude related signal such that each drive signal depends on the phase of the desired signal and such that the sum of the squares of the amplitudes of the drive signals is constant. Finally, a coupler couples the two drive signals to produce two constant amplitude signals for driving the pair of non-linear power amplifiers and for coupling the outputs of the power amplifiers to produce two amplified output signals, one of which is the linearly amplified desired signal and the other of which is a waste energy signal.

Abstract: An amplifying apparatus for linearly amplifying a desired signal using a pair of coupled non-linear amplifiers is disclosed. The amplifying apparatus comprises a limiter for separating amplitude variations from the desired signal and producing a constant amplitude signal bearing the phase of the desired signal and an amplitude related signal. In addition, a drive signal generater produces two drive signals each dependent on the constant amplitude signal and the amplitude related signal such that each drive signal depends on the phase of the desired signal and such that the sum of the squares of the amplitudes of the drive signals is constant. Finally, a coupler couples the two drive signals to produce two constant amplitude signals for driving the pair of non-linear power amplifiers and for coupling the outputs of the power amplifiers to produce two amplified output signals, one of which is the linearly amplified desired signal and the other of which is a waste energy signal.

Abstract: In a variable gain amplifier apparatus, wide input dynamic range can be secured and low noise characteristic can be obtained by employing first and second variable gain amplifiers have different noise characteristics and different saturation input levels and receive a same input signal. Output signals of the first and second variable gain amplifiers are added to each other to provide an output signal of the variable gain amplifier apparatus. Desired noise characteristic and saturation input level characteristic of the variable gain amplifier apparatus can be obtained by selecting the noise characteristics and the saturation input levels of the first and second variable gain amplifiers appropriately. This allows the variable gain amplifier apparatus to have a wide input dynamic range and low noise characteristic.

Abstract: A self-configurable, dual bridge, power amplifier has a window comparator sensing the level of input signals fed to the amplifier which-drives a plurality of configuring switches capable of configuring the amplifier as a single bridge amplifier driving a first and a second loads connected in series or as two distinct bridge amplifiers each driving one of the two loads. As long as the two levels of the input signals remain comprised between a range defined by a negative voltage reference and a positive voltage reference, the amplifier is configured as a single bridge driving the two loads in series, thus reducing sensibly power dissipation. Several embodiments of the configuring means are shown.

Abstract: A modulation amplifier includes a signal converter, a summator and a plurality of high frequency stages (3.sub.1-m or 4.sub.1-n). The high frequency stages (3.sub.1-m) are driven by equiphased control signals (s.sub.1-m); the high frequency stages (4.sub.1-n) are driven by control signals (t.sub.1-n) of different phase .PHI..sub.1-n. The high frequency stages (3.sub.1-m or 4.sub.1-n) can be selected in an arbitrary manner by the control signals (s.sub.1-m or t.sub.1-n). The summator adds the high frequency output signals (x.sub.1-m or y.sub.1-n) of the high frequency stages (3.sub.1-m or 4.sub.1-n). The output signal can be conveyed, for example, to a low pass and a subsequent load. The phases (.PHI..sub.1-n) of the output signals (y.sub.1-n) of the high frequency stages (4.sub.1-n) correspond to those of the control signals (t.sub.1-m). So many high frequency stages (3.sub.

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: The apparatus includes output stage amplifiers for receiving the respective outputs of preamplifiers provided in correspondence to the left and right channels in a stereo system. Negative feedback circuits are provided in the respective output stage amplifiers for reducing the amount of low-band negative feedback. Switch circuits are turned on in response to feedback signals from the respective negative feedback circuits for supplying the feedback signals at the input to the output stage amplifiers.

Abstract: A multi-function, balanced phase shifter and switch having a particular application as a balanced switched low-noise amplifier. The switch includes a hybrid input coupler that couples a first input signal at a first input port and a second input signal at a second input port into a first path and a second path of the switch. Each of the first path and the second path include at least one amplifier and a phase shifter. The phase shifters include a hybrid coupler and two switching devices that are simultaneously switched on or off by a single control signal. Output from the two paths are applied to an output hybrid coupler that couples the output from the two paths into first and second output ports of the switch. By controlling the two control signals applied to the phase shifters to selectively switch the switching devices on and off, signals at the input ports can be selectively amplified and switched to the output ports in a balanced, low-noise manner.

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: An amplifier array having digitally adjustable total gain and being constructed of a multiplicity of switchable individual amplifiers, includes at least two parallel, selectively triggerable gain paths having input and output sides. Each of the gain paths has an input amplifier and a switching amplifier being connected downstream of the input amplifier and being switchable in stages. A multiplexer has inputs connected to the output side of the gain paths and has an output. An amplifier array input is connected to the input side of the gain paths and an amplifier array output is formed by the output of the multiplexer. In a mobile radio receiver having the amplifier array, a total gain of the amplifier array is adjusted for setting an output signal of the mobile radio receiver at a constant level.

Abstract: An oscilloscope preamplifier includes N inputs and Z outputs. A programmable cross-point multiplexer provides a first operating mode in which each of N inputs is connected to a different output thereby providing a preamplifier with Z channels, a second operating mode in which one input is multiplexed to all the outputs which are interleaved to maximize the sampling rate, and a range of operating modes in between. The programmable multiplexer includes a switching amplifier connected between each input and each output. Dials on the preamp select the mode by causing a microprocessor to program latches which activate or deactivate the switching amplifiers. A voltage divider is connected across inputs of the multiplexer to provide a programmable attenuator with selectable attenuation levels.

Abstract: A Doherty-type power amplifier suitable for satellite telecommunication systems provides linear amplification of noise-like RF signals that have multiple carriers spread over a large instantaneous bandwidth. Efficiencies of 40% to 50% are achieved using PHEMT devices. The power amplifier includes a carrier amplifier that operates a low power levels and a peak amplifier that operates at high power levels. For low power levels, the carrier amplifier delivers its output into twice the optimum load resulting in high efficiency, while the peak amplifier is turned off. At high power levels, both the carrier and the peak amplifier is working into an optimum load and maximum power is delivered. Output matching sections are used to transform the very low optimum load impedance of the PHEMT devices prior to phase shifting and combining.

Abstract: An amplifying apparatus for linearly amplifying a desired signal using a pair of coupled non-linear amplifiers is disclosed. The amplifying apparatus comprises a limiter for separating amplitude variations from the desired signal and producing a constant amplitude signal bearing the phase of the desired signal and an amplitude related signal. In addition, a drive signal generater produces two drive signals each dependent on the constant amplitude signal and the amplitude related signal such that each drive signal depends on the phase of the desired signal and such that the sum of the squares of the amplitudes of the drive signals is constant. Finally, a coupler couples the two drive signals to produce two constant amplitude signals for driving the pair of non-linear power amplifiers and for coupling the outputs of the power amplifiers to produce two amplified output signals, one of which is the linearly amplified desired signal and the other of which is a waste energy signal.

Abstract: A method and apparatus (100) is for providing self adjustment of a multistage radio frequency power amplifier (RFPA) (200). The apparatus (100) includes a transmit input stage (150) and a controller (110). Included in the multistage RFPA (200) are N RFPA stages (201) coupled in parallel to an N-way RF splitter (210) and to an N-way RF combiner (220), and a power sense stage (225) which generates a forward power sense signal (167). Each of the N RFPA stages (210) includes an adjustable power amplifier (PA) (300). The controller (110) optimizes a gain match and a phase match of the multistage RFPA (200) by adjusting signals which are coupled to each adjustable PA (300). The adjustments are made in response to the forward power sense signal (167) while the controller (110) controls the test input stage (150) which generates a predetermined test signal (155).

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).