Abstract: A two dimensional array of resistive bolometers (B) is arranged in rows and columns. Amplifiers (A0, A1 etc) amplify signals obtained from the bolometers. Instead of providing one amplifier per column, a smaller number of amplifiers is used each of which is connected to a plurality of column sense lines (L) via a multiplexer (M0, M1 etc).

Abstract: An amplifier system including a vacuum tube amplifier having an input signal terminal and an output signal terminal, wherein the vacuum tube amplifier is for amplifying an input signal supplied to the input signal terminal, a phase comparator having a first input terminal responsive to the input signal and having a second input terminal coupled to the output signal terminal of the vacuum tube amplifier, and a phase shifter having a first input terminal responsive to the input signal, a second input terminal coupled to an output terminal of the phase comparator, and an output terminal coupled to the input signal terminal of the vacuum tube amplifier.

Abstract: A multiplexing amplifier has a differential amplifier for amplifying multiple input signals which are selected by a plurality input select circuits. The select circuits are comprised of longtail transistor pairs which are activated by current steering diodes controlled by input selection signals.

Abstract: An input change-over amplifier is capable of effecting a change-over in outputting two signals having different frequencies, without lowering the signal levels thereof. Two signals having different frequencies are fed into two input terminals of an amplifying element. When a signal is input through one input terminal, the other input terminal is grounded. When a signal is input through the other input terminal, the above one input terminal is grounded. In this way, it is possible to effect a change-over in outputting two signals having different frequencies, without lowering the signal levels thereof. Further, since two signals can be fed into an amplifying element through different paths, it is not necessary to provide a matching circuit at a connection point of signal paths. Therefore, the number of required electronic parts can be reduced, an oscillator which is compact in size can be manufactured, and a necessary circuit can be designed within only a short time.

Abstract: A circuit and method for automatically adjusting a common mode rejection ratio. The circuit includes a mixing circuit for mixing two input signals received via first and second channel input terminals, eliminating noise from the input signals, and supplying a corresponding output signal; and a controller for simultaneously supplying a DC voltage having a predetermined level to the two channel input terminals when a main power source is initially applied, detecting the level of a voltage fed back from an output terminal of the mixing circuit, and controlling an output voltage level of the mixing circuit based on the detected voltage level.

Abstract: A high-frequency amplifier that can reduce the size, weight and price of a device that contains this high-frequency amplifier. The high-frequency amplifier has, for example, an input matching circuit of the low-pass type and an input matching circuit of the high-pass type, connected in parallel and provided at the input side or terminal of a power amplification circuit. Matching is thereby performed corresponding to either one of two kinds of transmission input signals, whose frequencies are different from each other, by the input matching circuit of the low-pass type, and by the input matching circuit of the high-pass type, respectively. Moreover, for example, an output matching circuit of the low-pass type and an output matching circuit of the high-pass type are connected in parallel and provided at the output side or terminal of the power amplification circuit.

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: 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 detector amplifier includes a first stage, a second stage and a low voltage supply. The first stage has a first input for receiving a first input signal, and an output for outputting a first output signal, and amplifies and/or demodulates the first input signal to form the first output signal. The second stage is coupled in series to the first stage and has a first input for receiving the first output signal, a second input for receiving a second input signal, and an output for outputting a second output signal. The second stage amplifies and/or demodulates the first output signal and the second input signal to form the second output signal. The low-voltage supply is coupled in series with the first and the second stage for supplying a DC current to the stages.

Abstract: An amplifier system embodying the invention includes an input stage comprising one or more differential amplifiers having a high degree of common mode rejection. The inputs of the differential amplifiers of the input stage are AC coupled to different signal input terminals which are adapted to receive small information signals riding on large common mode signals. The AC coupling blocks any dc level associated with the input signals from affecting the amplifier system and the high degree of common mode rejection maintains the gain of the amplifiers relatively constant over a wide range of common mode signals. The outputs of the differential amplifiers of the input stage are connected in common to an output node to sum their output signals and to reduce random noise associated with the input signals and the input stage. The output node of the input stage is AC coupled to the input of a second stage whose output is in turn AC coupled to a third output stage to reduce the effect of amplifier offsets.

Abstract: An active load applied to the gate transmission line termination of distributed power devices reduces the low frequency noise power appearing at the output of the device. The active load, including at least one active device such as a field effect transistor, operates by transforming the input impedance of a low noise amplifier to the desired load impedance. The active load is connected to one end of an input transmission line having a plurality of impedances connected in electrical series. An input terminal is connected to the opposite end. An output transmission line, also having a plurality of impedances connected in series, has an output terminal at one end and a terminating output impedance at the other. A plurality of active devices are connected to junction points between the series connected impedances of the input and output lines.

Abstract: An analog multiplier includes a plurality of input stages that are selectively coupled to inputs of a common amplifier through coupling elements and logic circuitry that selectively controls conduction through the coupling elements to the amplifier. The coupling elements include transistors that are common base connected to a bias supply for shunting capacitive feed through to the amplifier.

Abstract: Apparatus and methods are disclosed for providing a low power, low noise preamplifier, especially useful with a Forward Looking Infrared (FLIR) sensor array. Utilizing a differential amplifier, where one half of the differential pair is shared among a plurality of channels, the power consumption of the amplifier is effectively reduced. Such an arrangement also eliminates the need for bulky coupling capacitors used in ac-coupled, single ended amplifiers. In addition, cross-talk between sensor outputs caused by detector ground impedance is reduced.

Abstract: This invention is a constant current, noninverting, voltage amplifier powered by a single polarity of electrical power with respect to a ground potential. In a preferred embodiment, the amplifier consists essentially of a single transistor having a reference voltage applied to a base input thereof and an analog video signal coupled via a resistor to an emitter of the transistor. Also coupled to the emitter is a constant current source, with a collector of the transistor coupled to a monitor.

Abstract: An amplifier circuit having a switch (SW), wherein the switch selects one of a plurality of input voltage-to-current converting amplifiers (GM1 to GMn), and the input amplifier, thus selected, converts an input signal into a current. This current is added to a feedback signal current. Hence, even if the signals input to the voltage-to-current converting amplifiers have different DC potentials, the DC potential difference does not appear in the output. The DC potential of the output signal of the amplifier circuit is determined by the reference voltage (V.sub.REF) of a feedback voltage-to-current amplifier (GM.sub.NF) and hence remains constant at all times.

Abstract: In accordance with the teachings of this invention, a novel wide-band, DC coupled, single-ended voltage-to-current converter and gain control circuit is provided. Of importance, the circuit of this invention is designed to receive an input signal referenced to ground such that for zero input current, zero output current is provided. A replica bias circuit is used which allows the output signal to be a function of the input signal without offsets introduced by bias currents used throughout the circuit.

Abstract: A new instrumentation amplifier design uses three operational amplifiers (op amps), each of which has a feedback circuit connected from its output to its inverting input. The first op amp has a unity gain feedback, and is connected through a gain setting resistor to the inverting input of the second op amp. The output of the third op amp is connected through a resistor to the inverting input for the second op amp, while the third op amp's non-inverting input is connected to one of the second op amp's inputs. Differential voltage input signals are applied to the non-inverting inputs of the first and second op amps, while a reference voltage is applied to the inverting input of the third op amp. The circuit is capable of operating with a single voltage supply (V+) by setting the negative voltage supply together with the reference voltage at ground potential. It has a simplified gain equation based upon the ratio between the feedback resistor for the second op amp and the gain setting resistor.

Abstract: An amplifier stage includes an operational amplifier having inverting and non-inverting inputs and an output and a resistive tee network coupled in the feedback loop between the inverting input and output to the non-inverting input which network is reference to the voltage applied at the non-inverting input for setting the gain of the amplifier stage. The amplifier stage may be combined with a differential pressure sensor for providing a single ended output voltage in response to the differential voltage outputs of the pressure sensor being applied to the inverting and non-inverting inputs of the amplifier stage.

Abstract: A double balun circuit is provided by connecting two pairs of circut types. The first circuit, a distributed divider circuit, includes first and second pluralities of field effect transistors, a common input transmission line, and a first and second output transmission lines. The common input transmission line is disposed to successively couple the input electrodes of each transistor of both the first and second pluralities of transistors. The output lines are disposed to successively couple the output electrodes of the respective ones of the plurities of transistors. Each output transmission line is coupled to one of the pair of output terminals of the circuit.

Abstract: A video display system having a forward locking infrared sensor which emits a linear video signal together with a digital graphics generator which generates digital video signals in a plurality of colors; together with a signal video amplifier for amplifying both the linear signal and the high data rate digital signal; the video amplifier having a plurality of curent regulators for regulating the current through a particular resistor where the current regulation is a function of the received linear and digital video signals; the video amplifier also having the capability of current regulation through the resistor in response to variations in the voltage source voltage and thereby eliminating the need for an additional power source voltage regulator.

Abstract: A multifunction amplifier uses a finite transconductance amplifier to provide an amplifier with a high impedance input and a desired output impedance. A pair of appropriate polarity binary signals are summed to form a ternary signal which may be filtered by a filter circuit upon command. The ternary signal, filtered or unfiltered, is input to one input of a differential transconductance amplifier while a feedback signal via a feedback path from an output node of the finite transconductance amplifier is input to the other input. The outputs of the differential transconductance amplifier are equally amplified by a pair of output current gain amplifiers. A unity gain bias level shifter is provided between one of the differential outputs and one of the pair of output amplifiers. The output amplifiers combine the amplified output currents at the output node.

Abstract: An amplifier system having an input active device at its first input and having its second input provided through an inverting means to that first input.

Abstract: A switch capacitor summing amplifier is disclosed having a coupling means to couple desired signals to the active amplifier in response to an enable signal. The coupling is performed in synchronism to the "odd" phase of the sampling signals thereby improving noise, transient and DC offset performance while minimizing switch impedance sensitivity.

Abstract: A bank of differential amplifier circuits includes specialized circuits to provide multi-channel differencing with a minimum number of active devices such that the differences between pairs of analog input signals, such as available from patient monitoring electrodes, are derived with half the number of active devices normally utilized. In one embodiment, two operational amplifier circuits are used in a differencing channel which functions together to provide differencing, a properly delayed input signal for use in another differencing channel, high input impedance buffering, a low impedance output for each differential amplifier channel, time-coincident, matched outputs for each differential amplifier channel, and with an additional operational amplifier, a DC rejection circuit which does not affect the low output impedance or the differencing function, thereby to eliminate the necessity of providing separate buffers and active delay circuits which can result in the use of twice the number of active devices.

Abstract: A mixer/amplifier circuit for selectively mixing a first input signal with a local oscillator signal or amplifying a second input signal. The mixer/amplifier circuit includes a transistor, a first circuit arrangement responsive to a first switching signal for enabling the transistor to operate as a grounded-base transistor to amplify the second input signal supplied to the emitter thereof, and a second circuit arrangement responsive to a second switching signal for enabling the transistor to operate as a grounded-emitter transistor to mix the first input signal supplied to the base thereof with the local oscillator.

Abstract: A steering circuit (10) in a differential amplifier having a pair of differentially arranged input amplifiers (A1 and A2) steers current from a pair of current sources (11 and 12) in such a way as to enhance slew rate without increasing offset voltage. The steering circuit is formed with a pair of steering amplifiers (A3 and A4) arranged in a differential configuration through a pair of resistors (R3 and R4).

Abstract: A multistage amplifier with a low noise figure linearly amplifies an input signal having a level which varies over a wide range. The first stage of the amplifier provides a low noise figure and sufficient power gain to ensure overall low noise performance. An interstage amplifier is protected from saturation by first and second variable attenuators, which are controlled by a level detector. The level detector detects the level of the input or output signal of the interstage amplifier and controls the forward bias current of a diode in each of the variable attenuators. The first variable attenuator functions as a level compressor for signals input to the interstage amplifier having a level higher than a preset level. The second variable attenuator functions as a level expander of the output signal from the interstage amplifier to equalize the signal level compressed by the first variable attenuator.

Abstract: A stereo amplifier circuit which comprises a first circuit responsive to a first input signal and to a second input signal for generating a first output signal which corresponds to the potential difference between the first and second input signals, a second circuit responsive to the first and second input signals for generating a second output signal which corresponds to the potential difference between the second and first input signals, a third circuit responsive to the first and second input signals for generating a third output signal which corresponds to the sum of the first and second input signals. The third output signal contains signal components being antiphasic to the first and second input signals.

Abstract: A differential amplifier which incorporates at its preceding stage resistances and condensers combined with each other and serving as a low-pass filter, thereby omitting a conventional low-pass filter separate from a differential amplifier provided at a weight detection circuit for a load cell weighing scale or other detection circuit.

Abstract: The present invention provides a modified distributed amplifier which is capable of accepting two or more independent inputs and amplifying them without giving rise to a large number of significant intermodulation products. This modified distributed amplifier effectively comprises two or more unmodified distributed amplifiers (as V.sub.11 to V.sub.18 and V.sub.21 to V.sub.28) joined so as to have a common output line (10) but individual, independent, input lines (111 and 211). The join is preferably "back-to-back" (in a parallel sense) so that the individual distributed amplifiers are in some sort of interleaved arrangement.

Abstract: A multi-channel amplifier apparatus for oscillation or pulse packets wherein there is provided an amplifier having an input connected by a number of input time-delay lines with a respective input channel, each of which is correlated to an oscillation or pulse packet. The output of the amplifier is connected by means of respective series circuits of an output time-delay line and an output switch connected thereafter with a respective output channel correlated to the corresponding oscillation packet.

Abstract: For the common mode rejection in an amplifier arrangement comprising preferably a plurality of operational amplifiers for a plurality of desired signals to be processed, which signals are superimposed by a stronger spurious signal, it is an object to supply the desired signals such as physiological measuring signals for EEG and EKG measurements at positive inputs of the respectively associated single amplifiers, while each negative input is connected to the junction of a voltage divider consisting of two resistors, which voltage divider is arranged between the respective amplifier output and a reference potential.

Abstract: A multiple-stage active RC distributed filter having multiple inputs and a single output for producing filtering of large groups of notes for tone coloration in electronic musical instruments. Output signals from the keying circuits may be applied to selected input stages of the filter through a resistor matrix to produce the desired tone coloration. Voicing may be further modified by one or more compensation networks at the filter output.

Abstract: In a radio receiver IF amplifier, a high gain AGC circuit produces a constant signal output regardless of input signal levels in excess of a threshold value. A summing amplifier responds to the AGC voltage and the IF amplifier current to develop a d-c potential directly proportional to the signal input to the amplifier both above and below the AGC threshold. This voltage is useful in the squelch and signal strength meter circuits.

Abstract: This invention relates to amplifiers for producing an accurate amplified version of a low voltage wave form. Specifically, the amplifier of the invention comprises independently fed first and second resistors connected to a common output which feeds a third resistor via a voltage to current converter, the other end of the third resistor being driven from the same point as the first resistor, the ratio of the resistances of the first and second resistors being made equal to the amplification required so that when the low voltage wave form is fed to the second resistor and a wave form approximating to the required output and of slightly higher voltage is fed to the first and third resistors, the voltage at the common output is proportional to the error in the approximated wave form and the voltage thereby developed across the third resistor by the voltage current converter is approximately equal to the error.

Abstract: An edge-guided mode microstrip device similar to an edge-guided mode isolr having opposed straight and tapered edges along which microwave energy is adapted to travel with the exception that in the subject invention the thickness of the ferrite substrate underlying one tapered edge is abruptly changed in order to obtain mismatch thereat causing energy traveling along said one tapered edge to be reflected back along the same edge to the port whence it came. Coupling a microwave power amplifier to a port of a microwave circulator by means of a respective power reflector according to the subject invention provides a simple yet effective power combiner for microwave signals.

Abstract: An edge-guided mode microstrip device having a pair of input ports and a mon output port, with two separate ferrite substrates each having a microstrip conductor electrically connected between a respective input port and the common output port. Both microstrip conductors additionally each have a conductive or inner edge spanned by a resistive film which acts as a resistive load. The other or outside conductive edge of each of the conductors includes an exponentially tapered segment which when a predetermined biasing magnetic field is applied transversely relative to the field of the substrates, causes input microwave energy at the two input ports to travel along the respective exponentially tapered edges and combine at the common output port. Any reflective energy returning from the output port will travel along the inner edges and be absorbed in the resistive load.