Abstract: An amplifier stage including a differential pair (T1, T2) is provided with a resistive ladder (R1 . . . R2n) coupled between the second control electrodes of said differential pair. Taps on mirror positions along the resistive ladder (R1 . . . R2n) are switchably connected to first and second current source transistors (T3, T4), the current source transistors having their control electrodes connected to the first main electrodes of the transistors forming the differential pair. By placing the switches in series with the current source transistors (T3, T4), the influence of the non-linear impedance of the switches is reduced to negligibly small proportions as the output impedance of the current source transistors (T3, T4) is considerably higher than the impedance of the switches. Thus, a linear conversion impedance is obtained.

Abstract: A power amplifier has a distortion control circuit responsive to a clipping detector for loading said amplifier input with a signal sufficient to reduce the input to the tube grids to a level below clipping.

Abstract: A transconductance amplifier having a digitally variable transconductance includes a differential stage having a first differential output coupled to an output terminal via a first current mirror and a second differential output coupled to the output terminal via a second and third current mirror. The first and third current mirrors have multiple output branches for selectively supplying output currents to the output terminal in response to a binary transconductance control signal. In this way a digital control of the variable transconductance is realised, which can be used advantageously in a variable gain stage and in an automatic gain control circuit including such a variable gain stage.

Abstract: A balanced current amplifier mirrors either a fully differential or single ended input signal into common output circuits in a manner to generate a fully differential output signal without any d.c. bias. Input signal nodes are maintained at a desired voltage by circuit elements other than those of the current mirror circuits, thus freeing the current mirroring elements from having to be sized for this purpose. The sizes of the output transistors are adjustable in order to set the gain of the circuit. In addition to amplifier circuits, a full-wave rectifier, a comparator, and a filter, all operating with current signals, are described. A single circuit module may include all of these circuits with a user provided the capability to program the module to perform any one or more of these functions.

Abstract: An integrated circuit has at least two components described in the form of two ideally matched transistors, each of which operate interdependently as a function of temperature and at least one physical parameter associated with each of said components when implemented in integrated form. The circuit further includes compensation means, disposed in the integrated circuit, for generating and applying a bipolar compensation signal to at least one of said components so that said two components interdependently operate predictably, consistently and independently of temperature variations and differences between the physical parameter of said two components. The bipolar current is necessary so that both the level and polarity of the compensation signal can be appropriately adjusted during the manufacture of the integrated circuit as a wafer so as to eliminate the need to compensate for any mismatches in the two components following such manufacture.

Abstract: A mist cooled distributed amplifier utilizing a connectorless module. The amplifier comprises modules that are connected to waveguides in a honeycomb. The RF signals are distributed to and combined from the modules using a distributed waveguide manifold. Cooling is accomplished by forming channels between the modules through which mist is transmitted and collected and condensed at the output end.

Abstract: A low frequency amplifier comprising, in series, a first input stage, an intermediate amplifying stage and a final stage. The intermediate amplifying stage comprises a capacitor which is discharged when the amplifier is disabled, and is charged to a predetermined bias value when the amplifier is operative. To prevent voltage peaks at the output of the amplifier during the transient interval between the disabled and operating condition of the amplifier, a second input stage is provided which is only turned on during the transient interval, and is connected to the capacitor to detect its voltage and charge it. During the transient interval, the final stage is disabled. Upon the capacitor reaching the predetermined charge value, the second input stage practically turns itself off, and is then disabled; and, at the same time, the first input stage and the final stage are enabled to turn on the amplifier.

Abstract: In a high frequency amplifying circuit, an impedance matching circuit has an impedance matching inductance, and a switching diode connected in parallel with the inductance. The diode is selectively opened or closed in accordance with the input level, thereby changing an impedance matching condition. When the input level is low, an amplified output is produced by impedance matching which is implemented by the inductance itself. When the input level increases up to a level nearly causing saturation to occur, the diode is opened and rendered conductive with the result that the impedance matching characteristic changes. As a result, a phase characteristic is prevented from being deteriorated by a changed in input level.

Abstract: A class AB low voltage output stage with improved current drive capability where the signal input to the stage modulates the base drive currents of both an output transistor sourcing current to a load and an output transistor sinking current from the load. Coupling the base drive currents by means of the input amplifier permits higher drive currents to be obtained for the output transistors without increasing the quiescent current of the circuit.

Abstract: A broadband amplifier includes an amplifier device and input and output networks formed of microstrips. The impedance of the output microstrip is chosen by taking the geometric mean of the real parts of one of the scattering parameters of the amplifier device, at the lower and upper limits of the frequency range of interest, and by taking the geometric mean of the system impedance with the result obtained previously. The final result of these calculations is the impedance of the output network. The impedance of the input network is made to be at least twice, and preferably twice, the impedance of the output network. The amplifier is also provided with a slope compensation circuit. It has been discovered that an amplifier designed in this manner exhibits remarkable flatness over a five-octave range. The amplifier circuit is therefore suitable for use in cable television and other broadband telecommunications applications, where the frequency range of interest may be 30 MHz to 1000 MHz.

Abstract: A first amplifier channel between an input and output includes an input transistor emitter and a first output transistor emitter connected together to form a first emitter pair. A current source is connected to the emitter pair via a transistor which is controlled by a latch. Programming the latch permits the channel to be turned on or off. The emitter pair is connected to a positive voltage through a resistor and to ground through a diode to force it to a controlled off voltage, which prevents signals from passing when the channel is off. There is a output driver amplifier in a feedback circuit. An outdisable circuit controls the voltage and current of the output driver amplifier to place the output in a state in which it appears electrically as an open circuit when the channel is off. Multiple programmable amplifiers can be combined to make a multiplexer, a selectable gain circuit, or a selectable attenuation circuit, all with high band width and high signal integrity.

Abstract: A circuit that injects an auxiliary signal into an existing signal path, thereby adding it to an existing main signal, while minimizing attenuation, distortion, or other perturbation to the main signal. The present invention provides for a active distributed signal injector that includes two transmission lines. An input port is coupled to the first transmission line for receiving the main signal, and a main output port is coupled to an output end of the first transmission line for outputting the main signal. The second transmission line is terminated at an output end and has an injected signal input port at an input end of the second transmission line. A plurality of high impedance amplifiers bridge between the transmission lines, and a plurality of inductors are coupled between each of the high impedance amplifiers. A plurality of transmission lines may be optionally employed in the second transmission line.

Abstract: An amplifier array for high-frequency signals includes a differential amplifier with transistors capacitively coupled to the emitters. The differential amplifier therefore has high-pass characteristics. The input signals are each supplied to the differential amplifier through a respective high-pass. This results in an integratable amplifier array with strong damping for base-band signal components and band-pass characteristics for high-frequency useful signal components.

Abstract: A power amplifier circuit for efficiently generating an output signal into a load at more than one alternative power level has at least two amplifiers, each having optimum efficiency at different power output levels. The power amplifier circuit may be operated in several modes, including activating one amplifier during an entire cycle of an input signal to be amplified, or alternatively activating one amplifier based on a control signal that is independent of the amplified output signal. In either case, remaining amplifiers are deactivated. Coupling between the amplifiers prevents deactivated amplifiers from impeding the flow of power from the activated amplifier to the load. In another aspect of the invention, optimum efficiency at different power output levels is achieved by means of coupling each amplifier to a common power source and to the load via an impedance matching circuit, the impedance transformation being different for different amplifiers.

Abstract: An apparatus and method for programming an amplifier includes an amplifier and a portable programmer that is removably connectable to the amplifier. The portable programmer includes a microprocessor, a keypad, and a display screen. The amplifier includes a programming input port, a signal processing circuit, a power amplifier and a control circuit. When the portable programmer is connected to the amplifier, information relating to parameter of various signal processing circuit elements can be read and modified through the programmer. The information input via the keypad and displayed on the display screen is transmitted from the programmer via the microprocessor to the signal processing control circuit to change signal processing functions and/or signal process function parameters of at least one of the signal processing circuit elements. As a result, processing of a signal transmitted through the amplifier is changed so that a sound produced by the signal can be modified.

Abstract: A differential amplifier is connected to a push-pull-type source follower circuit that receives biphase signals. The source follower circuit has a first set of FETs including a first source follower FET and a first current source FET and a second set of FETs including a second source follower FET and a second current source FET. A first coupling capacitance element connects the first current source FET and the second source follower FET, and a second coupling capacitance element connects the second current source FET and the first source follower FET. A diode or a resistor connects the source terminals of the first and second current source FETs to a voltage source.

Abstract: A circuit for controlling the output level of a power amplifier is disclosed. A current comparator (230) compares a reference current with a sensed current which is representative of the power amplifier current state. The reference current is used not only for comparison with the sensed current but also for setting the power amplifier (104). The current comparator (230) provides an output, based on the comparison, that is coupled to the power amplifier so that the power amplifier current is maintained at an optimum level for minimizing temperature dependent variations and substantially leveling the power of the power amplifier.

Abstract: The present invention is an apparatus and method for detecting differential mode signals in an environment where differential mode signals co-exist, and might be corrupted by, common mode signals. The most basic apparatus of the present invention essentially comprises first and second input leads through which both differential mode and common mode signals are input; a first amplifier block having a gain that is substantially one; and at least an inverting node and a non-inverting node connected to the first and second input leads. The output of the amplifier block is fed back to the input of the non-inverting node of the amplifier block in a manner to increase differential mode impedance while maintaining a low common mode impedance. Various embodiments of the basic presently claimed circuitry provides for additional methods of monitoring the level of common-mode signal introduced to the apparatus and other fault detection functions.

Abstract: An amplifier circuit has a wide frequency range which is broader than the frequency range expected from its circuit parameters. The amplifier circuit comprises a plurality of unit amplifier circuits connected in parallel. Each unit amplifier circuit contains an odd number of inverters serially connected from the first stage to the last stage, an input capacitance connected to the input terminal of the first stage, and a feedback capacitance connecting the output terminal of the inverter of the last stage to the input terminal of the inverter of the first stage. Thus, the amplifier circuit operates in a wide frequency range with little decrease in gain at high frequencies.

Abstract: The op-amp circuit described herein utilizes current summing to substantially eliminate cross-over distortion. Therefore, the op-amp circuit is characterized by linearity over the operable voltage range of the amplifier. Additionally, the op-amp circuit is capable of rail-to-rail input and output voltage swings. Furthermore, the op-amp circuit is capable of operating with a power supply voltage as low as two volts when fabricated in modern CMOS fabrication processes, without requiring special processing steps. An output circuit within the op-amp circuit is configured with pullup and pulldown devices which combine to provide output voltages throughout the operable range of the op-amp. However, when an output voltage equal to the power supply voltage is desired, the pulldown device substantially stops its pulldown current flow. Therefore, the pullup device charges the output conductor of the op-amp circuit fully to the power supply voltage.