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Showing papers on "Amplifier published in 1969"


Journal ArticleDOI
TL;DR: Light pulses propagation in nonlinear laser medium, obtaining equations of motion for density matrix was studied in this paper, where it was shown that light pulses propagate in a nonlinear nonlinear medium.
Abstract: Light pulses propagation in nonlinear laser medium, obtaining equations of motion for density matrix

241 citations


Patent
31 Jul 1969
TL;DR: In this article, a step-wave power converter circuit comprising a plurality of equal or unequal inverter modules connected in series or parallel is proposed to obtain fast response to a cyclical AC or variable DC input reference signal.
Abstract: To obtain fast response to a cyclical AC or variable DC input reference signal by a stepped-wave power converter circuit comprising a plurality of equal or unequal inverter modules connected in series or parallel so that the module output voltages add algebraically, the composite instantaneous output stepped-wave voltage is compared with the instantaneous voltage values of the limits of a control band placed about the reference signal. One or more inverter modules are switched to produce a step change whenever the composite output voltage is outside the control band limits. An application is a fast response switching power amplifier for driving sonar transducers.

105 citations


Journal ArticleDOI
TL;DR: Atomic coherence and inhomogeneous broadening effects on laser amplifier ultrashort electromagnetic high peak power pulses were studied in this paper, where they showed that the broadening effect on the laser amplifier can be very strong.
Abstract: Atomic coherence and inhomogeneous broadening effects on laser amplifier ultrashort electromagnetic high peak power pulses

98 citations


Journal ArticleDOI
TL;DR: It is found that for high-frequency operation, the current-switching system using simple epitaxial transistors provides the highest output power with least likelihood of transistor failure, although with a somewhat lower efficiency than the voltage-switch.
Abstract: The transition and saturation loss mechanisms of the two basic tuned Class-D amplifiers are studied in detail, as functions of drive waveform, signal frequency, and type of transistor. The charge control approach is used to derive optimum drive waveforms, together with approximate expressions for the various contributions to transition time that are verified experimentally. It is found that for high-frequency operation, the current-switching system using simple epitaxial transistors provides the highest output power with least likelihood of transistor failure, although with a somewhat lower efficiency than the voltage-switch. The voltage-switching system is found to be preferable when simple epitaxial transistors are not used. An example is given of a current-switching amplifier designed to deliver a continuous power of 1 kW at 500 kHz with an overall system efficiency of greater than 90 percent into a variable load.

91 citations


Journal ArticleDOI
TL;DR: In this article, two amplifier configurations are defined: the combined medium amplifier (CMA) and the separated medium amplifier(SMA), and two material constants are defined, and then used to compare materials in terms of SMA applicability at high frequencies.
Abstract: The subject of acoustoelectric surface wave delay line amplification is reviewed. Two amplifier configurations are defined: the combined medium amplifier (CMA), and the separated medium amplifier (SMA). These configurations are compared and the problems associated with each one defined. A more detailed description of the SMA is given along with experimental results. A brief analysis is presented; two material constants are defined, and then used to compare materials in terms of SMA applicability at high frequencies.

90 citations


Patent
12 Dec 1969
TL;DR: In this article, a gain-ranging amplifier with a plurality of fixed gain amplifier stages connected in a cascade is described, and means for taking the output signal from any one of the fixed-gain amplifier stages.
Abstract: A gain-ranging amplifier is disclosed comprising a plurality of fixed gain amplifier stages connected in cascade and means for taking the output signal from any one of the fixed gain amplifier stages. Control means are described whereby such output signal is taken from the amplifier stage immediately preceding the first such stage which is being overdriven at a particular point in time by the signal which is being amplified. Specific circuits are disclosed for use in seismic geophysical exploration applications and means for generating a signal representative of the amount of gain utilized in amplifying the input signal and for monitoring the input signal are described.

78 citations


Patent
23 Jan 1969
TL;DR: In this paper, the time constant of a high pass filter in the ECG preamplifier was reduced to 1.0 Hertz to reduce the effect of low frequency noise on the output voltage.
Abstract: An amplifier for an electrocardiographic monitoring system. The band-pass of the amplifier is such that ordinarily all frequency components of the ECG signal are amplified to the same extent. In the presence of a low frequency noise signal which causes the output voltage to exceed a maximum limit in either direction, the low frequency 3-db. point is raised from .05 Hertz to 1.0 Hertz. This is achieved simply by lowering the time constant of a high pass filter in the amplifier. The shorter time constant reduces the effect of low frequency noise on the output voltage. While some of the low frequency components in the ECG signal are attenuated, most of the usable information in the signal is retained. The shorter time constant also provides a faster recovery for the amplifier following large direct current voltage changes. This is especially beneficial when the patient electrodes of the monitoring system are switched and they induce a charge in the DC component of the ECG signal which might saturate the ECG preamplifier. Similarly, in the presence of high frequency noise signals the high frequency 3-db. point is lowered for a similar purpose.

70 citations


Book
01 Jan 1969

68 citations


Patent
07 Jul 1969
TL;DR: In this article, a solid-state voltage-controlled capacitor (varactor or varicap) UHF television tuner is described, which includes a pre-selector tuned circuit, an amplifier stage inductively coupled to the preselector circuit, and an oscillator stage, both the oscillator and the amplifier stage being inductively coupling to the diode mixer stage from which an IF signal is derived.
Abstract: A solid-state voltage-controlled capacitor (varactor or varicap) UHF television tuner is described which includes a varicap preselector tuned circuit, a varicap tuned RF amplifier stage inductively coupled to the preselector circuit, and a varicap tuned oscillator stage, both the oscillator stage and the amplifier stage being inductively coupled to the diode mixer stage from which an IF signal is derived. The tuner employs a single tuning voltage source to tune across the entire UHF range and also includes provision for AGC. Trimmer capacitors and inductance adjusting devices of unique and advantageous configuration are employed to align the tuner. Further disclosed are unique methods of assembly and alignment for the tuner.

66 citations


Journal ArticleDOI
TL;DR: In this article, the rotational relaxation rate constant krot of the CO2 00°1 upper laser level was determined by observation of the transient change in the cw gain of a 9.6μ P(20) laser amplifier induced by passage of a 20nsec 10.6
Abstract: The rotational relaxation rate constant krot of the CO2 00°1 upper laser level has been determined by observation of the transient change in the cw gain of a 9.6‐μ P(20) laser amplifier induced by passage of a 20‐nsec 10.6‐μ P(20) laser pulse through the amplifier.

66 citations



Journal ArticleDOI
W. Jutzi1
01 Jun 1969
TL;DR: In this article, a lumped distributed amplifier was built in a hybrid technique with microwave Schottky-barrier field effect transistors and tested with a flat frequency response up to about 2 GHz.
Abstract: A lumped distributed amplifier is built in a hybrid technique with microwave Schottky-barrier field-effect transistors and tested. A not yet optimized structure has a flat frequency response up to about 2 GHz and negligible phase distortions; ps-puIses are amplified with negligible overshoot.

Proceedings ArticleDOI
Erling L. Lien1
01 Jan 1969
TL;DR: In this paper, a klystron amplifier with above 65 percent efficiency at the 100 kW power level at a frequency of 800 MHz was described, which was obtained by using a combination of second harmonic and fundamental frequency cavities in the buncher system.
Abstract: A klystron amplifier yielding above 65 percent efficiency at the 100 kW power level at a frequency of 800 MHz will be described. The high efficiency is obtained by using a novel combination of second harmonic and fundamental frequency cavities in the buncher system.

Patent
25 Jun 1969
TL;DR: In this paper, a method and apparatus for controlling a process variable wherein the variable is controlled primarily by a digital computer but where a part of the control function is performed by an analog controller is presented.
Abstract: A method and apparatus for controlling a process variable wherein the variable is controlled primarily by a digital computer but where a part of the control function is performed by an analog controller. When the control is by the computer, an output signal is passed intermittently from the computer to a memory amplifier, the output signal of which is a control signal that may be used for correcting the process variable. When control is by the controller, the memory amplifier operates as a summing amplifier for negative feedback control.

Journal ArticleDOI
TL;DR: In this article, a Ndglass laser system is described which emits a 4 GW diffraction-limited laser pulse, at a radiance of 2×1017 W/cm2−sr.
Abstract: A Nd‐glass laser system is described which emits a 4 GW diffraction‐limited laser pulse, at a radiance of 2×1017 W/cm2‐sr. The device consists of a spatially mode‐selected Q‐switched oscillator, operating in the lowest‐order HE11 transverse mode, followed by a series of amplifiers that are coupled with appropriate beam‐expanding optics. A beam with a far‐field pattern corresponding to Fraunhofer diffraction, is approached through use of the proper gain distribution in the first amplifier and a 50% over‐expanded beam to allow uniform illumination of a physical aperture placed in front of the second amplifier. This system requires high optical‐quality laser rods capable of transmitting a diffraction‐limited beam. The induced optical distortions of the amplifiers during the pumping are minimized by appropriate Nd‐doping concentration, surface treatment, flashtube arrangement, and filtering of the pump light, yielding uniformity of pumping over almost the full cross section. Some experimental results on long‐path air breakdown, efficient second‐harmonic generation, and durability of laser glasses are described.

Patent
Jay I Black1
03 Mar 1969
TL;DR: In this article, a fuel viscosity sensor is incorporated in a fuel control system for a gas turbine engine to assure a constant engine power output irrespective of fuel viscoity changes.
Abstract: The disclosure illustrates a fuel viscosity sensor incorporated in a fuel control system for a gas turbine engine to assure a constant engine power output irrespective of fuel viscosity changes. The viscosity sensor comprises a proportional fluidic amplifier having a laminar flow element, series connected with one control jet. The fluidic amplifier is connected to the pressurized fuel supply and its output is proportional to the fuel viscosity. The pressure output from this amplifier is used to correct a flow-metering device for viscosity changes.

Patent
05 Jun 1969
TL;DR: In this article, a solid state apparatus for amplifying signals in the microwave frequency range by phase coherent addition of the signal output of a plurality of amplifier elements achieves high power output and wide bandwidth operation, with improved signal-to-noise ratio while operating within the permissible limits of power gain for each of the amplifying elements.
Abstract: A solid state apparatus for amplifying signals in the microwave frequency range by phase coherent addition of the signal output of a plurality of amplifier elements achieves high power output and wide bandwidth operation, with improved signal-to-noise ratio while operating within the permissible limits of power gain for each of the amplifying elements. A plurality of parallel connected, solid state amplifiers are connected at equally spaced distances between tapered input and output transmission lines which, respectively, distribute microwave power equally to each of the parallel connected amplifier elements and provide for phase coherent addition of the signal outputs of each of the amplifier elements.

Patent
18 Nov 1969
TL;DR: In this article, a method and apparatus for generating phase and amplitude modulated signals to be transmitted and for demodulating the transmitted signals with improved reliability and accuracy is disclosed, where a modulator at the transmitter is adapted to continuously group digital data into multibit words of equal length.
Abstract: A method and apparatus for generating phase and amplitude modulated signals to be transmitted and for demodulating the transmitted signals with improved reliability and accuracy is disclosed. A modulator at the transmitter is adapted to continuously group digital data into multibit words of equal length. The modulator is responsive to predetermined multibit subgroups within each multibit word to differentially phase modulate a carrier signal during successive modulation periods. The modulator is further responsive to the remaining bits within each multibit word to amplitude modulate the carrier signal during successive modulation periods. A demodulator is provided at the receiver. A differential phase detection portion of the demodulator reconstitutes the multibit subgroup digital data phase encoded at the modulator. A variable gain amplifier at the receiver varies the amplitude of the received signal in accordance with derived gain selection commands. The gain selection commands are derived from an amplitude detection portion of the receiver. The amplitude detection portion also provides a digital output indicative of the remaining portion of the multibit words originally encoded. The derived gain selection commands vary the gain of the receiver amplifier to cause the output amplitude levels of the amplifier to accurately correspond to the originally encoded amplitude levels. The accurately corresponded amplitude levels insure correct amplitude detection at the receiver.

Patent
08 Oct 1969
TL;DR: In this article, an apparatus consisting of an electrode for detection of biopotentials and a high-input impedance, low-noise amplifier with and in direct contact with the electrode, the input terminal of the first active device of the amplifier being epoxy bonded to the electrode.
Abstract: An apparatus is disclosed comprising an electrode for detection of biopotentials, and a high-input impedance, low-noise amplifier packaged with and in direct contact with the electrode, the input terminal of the first active device of the amplifier being epoxy bonded to the electrode. The amplifier is designed with thick film resistors, and without any capacitors, thus minimizing noise generation in the amplifier.

Patent
03 Nov 1969
TL;DR: In this paper, an improved sensing circuit particularly adapted for use with a piezoelectric transducer or the like, which transducers are characterized by their extremely high internal impedance is described.
Abstract: An improved sensing circuit particularly adapted for use with a piezoelectric transducer or the like, which transducer is characterized by its extremely high internal impedance. The transducer is disposed in a normally balanced input circuit so that there is effectively zero current flowing through the transducer when it is not activated. A unity-voltage-gain, highcurrent-gain amplifier is biased to its linear conduction operating point so as to present an extremely high dynamic input impedance to the output signal from the transducer. The amplifier output is applied to trigger a variable threshold, variable current output control circuit having a relay as an indicating device.

Patent
28 May 1969
TL;DR: In this article, the authors proposed voltage-controlled AC signal attenuators including diodes which are advantageously suitable for use as an automatic gain control in a television receiver, for example, or for attenuating any UHF or highfrequency signals.
Abstract: Disclosed are television receivers of the type having voltagecontrolled AC signal attenuators including diodes which are advantageously suitable for use as an automatic gain control in a television receiver, for example, or for attenuating any UHF or high-frequency signals. These novel attenuators, when incorporated in a television receiver, (1) substantially eliminate pole-shifting distortion by permitting the RF and IF amplifiers to be operated at one biaspoint, (2) protect the amplifier from overload by preamplification attenuation of the incoming signals, (3) improve system cross modulation, (4) permit use of field effect transistors, and (5) assure minimum degradation of the amplifier noise figure.

Journal ArticleDOI
01 Apr 1969
TL;DR: In this paper, a surface acousto-electric amplifier utilizing a composite spatially adjacent structure of lithium niobate and a silicon film was described, achieving 6 dB stable terminal gain at 107 MHz with dc drift field power of 7W, electronically variable attenuation of 100 dB, and net electronic gain up to 1200 MHz.
Abstract: Experiments are described for a surface acousto-electric amplifier utilizing a composite spatially adjacent structure of lithium niobate and a silicon film. Principal observations include 6 dB stable terminal gain at 107 MHz with dc drift field power of 7W, electronically variable attenuation of 100 dB, and net electronic gain up to 1200 MHz. The use of the silicon film as a nonreciprocal Rayleigh wave transducer is also described.

Patent
Mark F Eisenberg1
08 May 1969
TL;DR: A power amplifier circuit is capable of providing high-frequency output signals over a wide voltage range as mentioned in this paper, where at least two transistors are coupled in series to a load terminal and the transistors were energized by respective voltage sources having different magnitudes.
Abstract: A power amplifier circuit is capable of providing high-frequency output signals over a wide voltage range. At least two transistors are coupled in series to a load terminal and the transistors are energized by respective voltage sources having different magnitudes. The transistors are biased so that they operate as amplifiers in sequence in response to an input signal of increasing magnitude. The overall power dissipation in the circuit is low for a wide range of output signals.

Patent
19 Jun 1969
TL;DR: In this article, the authors proposed a power combiner for an oscillator or power amplifier when multiple negative-resistance devices are needed, providing a means for avoiding or suppressing undesired oscillations which may occur at multiple frequencies or in nonsynchronous phase relationships.
Abstract: This invention relates to microwave networks in which radio frequency energy from a multiplicity of sources may be combined into a single transmission line when these sources are of the same frequency and have the same phase. A significant feature of the invention is that energy will be absorbed when the multiple sources have different frequencies or if they have different phases at the same frequency. A particular application of the network is a power combiner for an oscillator or power amplifier when multiple negative-resistance devices are needed, providing a means for avoiding or suppressing undesired oscillations which may occur at multiple frequencies or in nonsynchronous phase relationships.

Patent
03 Nov 1969
TL;DR: In this article, a proportional combination of the voltage across the output terminals with a measure of the output current and actuating switching means across the input terminals is used to protect push-pull amplifiers from short duration overloads.
Abstract: Protection for amplifiers and the like is provided by proportionally combining a measure of the voltage across the output terminals with a measure of the output current and actuating switching means across the input terminals when a proportional combination exceeds a predetermined value. Transistors may be employed as the amplifier and switching means, and push-pull amplifiers may be so protected. In one embodiment a current-responsive protection device protects both transistors of a push-pull circuit. Multiple proportioning ranges may be provided in a non-linear protection arrangement, and the protection device may be rendered insensitive to short duration overloads. Reverse current protection may also be provided by the addition of one or more diodes.

Patent
28 Apr 1969
TL;DR: A serial-parallel analogue-to-digital converter as discussed by the authors utilizes a conventional ADC having a relatively low number of channels together with at least one amplifier which may be set at different amplification factors, a conventional digital-toanalogue converter, and an arithmetic device that generates the digital output.
Abstract: A serial-parallel analogue-to-digital converter system utilizes a conventional ADC having a relatively low number of channels together with at least one amplifier which may be set at different amplification factors, a conventional digital-toanalogue converter, and an arithmetic device that generates the digital output, to provide a fast conversion and an output having a substantially greater number of channels and a correspondingly high resolution. The conventional ADC is utilized several successive times at increasingly higher sensitivity through the use of the amplifier which may have its gain increased and its zero offset changed with each succeeding use of the ADC. Various means are described which may be employed for reducing or eliminating any errors which could be generated in the operation of this system. Additionally, particular circuit configurations are described which may be advantageously employed in the system for effecting the necessary gain changes with a minimum of error in result and a minimum of circuit complexity.

Journal ArticleDOI
TL;DR: A system-oriented approach to the design of inductorless tuned integrated circuits is described, which uses the phase-locked loop (PLL) techniques to obtain the desired tuning and interference-rejection characteristics.
Abstract: A system-oriented approach to the design of inductorless tuned integrated circuits is described. This design method uses the phase-locked loop (PLL) techniques to obtain the desired tuning and interference-rejection characteristics. The PLL approach does not require tight control of component tolerances, and offers a higher selectivity and frequency capability than the corresponding active-RC synthesis methods. In this paper, basic design parameters for phase-locked integrated circuits are given, and two separate design examples are described. First is a high- frequency (1 to 25 MHz) FM amplifier/detector, which forms a monolithic replacement for the IF strip and the detector sections of a conventional FM receiver or TV sound system. The second is an integrated FM multiplex receiver for multi-channel telemetry applications, which has the selectivity of a 6-pole bandpass filter and can be tuned by means of an external resistor or capacitor from a fraction of a cycle to over 300 kHz.

Patent
Charles A Walton1
15 Jan 1969
TL;DR: In this paper, the authors show how an AMPLIFIER is connected with an INVERTING INTEGRATOR in the CONVERTER CIRCUIT to perform both plug-and-play AMPLIFICATION and INEGRATION as well as providing a high input IMPEDANCE.
Abstract: AN ANALOG TO DIGITAL CONVERTER IS SHOWN WHEREIN AN AMPLIFIER IS CONNECTED IN THE CONVERTER CIRCUIT TO PERFORM BOTH FUNCTIONS OF AMPLIFICATION AND INTEGRATION AS WELL AS PROVIDING A HIGH INPUT IMPEDANCE. THE CONVERTER INPUT IS SHORTED WHILE DRIFT VOLTAGES DUE TO THE AMPLIFIER INTEGRATOR ARE COMPENSATED BY AMPLIFYING THE DRIFT VOLTAGE AND UTILIZING THE AMPLIFIED VALUE AS DRIFT COMPENSATION BY FEEDBACK TO THE INPUT. AN UNKNOWN VOLTAGE SIGNAL IS NEXT COUPLED TO THE POTENTIOMETRIC FEEDBACK CONNECTED AMPLIFIER AND THE INPUT SIGNAL IS INTEGRATED FOR A PREDETERMINED TIME. A REFERENCE VOLTAGE OF LIKE SIGN TO THE UNKNOWN ANALOG SIGNAL IS THEN INTEGRATED WHILE THE AMPLIFIER IS CONNECTED AS AN INVERTING INTEGRATOR. THE TIME THAT IS NECESSARY FOR THE INTEGRATOR OUTPUT VOLTAGE TO REACH ITS INITIAL ZERO LEVEL IS MEASURED BY A DIGITAL REPRESENTATION GENERATING MEANS SUCH AS A COUNTER AND YIELDS A DIGITAL REPRESENTATION OF THE INPUT ALONG SIGNAL.

Patent
11 Aug 1969
TL;DR: In this article, a sample and hold circuit including charge storage capacitors and switches connected between input and output amplifiers is proposed to provide substantially improved isolation of a hold capacitor from the input amplifier, as during the hold period, and also to provide compensation for the transient jump in voltage developed at the hold capacitor during switching.
Abstract: The invention concerns a sample and hold circuit including charge storage capacitors and switches connected between input and output amplifiers and operable to provide substantially improved isolation of a hold capacitor from the input amplifier, as during the hold period, and also to provide compensation for the transient jump in voltage developed at the hold capacitor during switching.

Patent
19 Aug 1969
TL;DR: An automatic temperature control circuit in a high-frequency heating apparatus comprising a differential amplifier circuit receiving at one of its input terminals signals from a temperature-setting voltage circuit and at another input terminal signals from the thermister provided with a heating needle which contacts with a load to be heated and amplifying the difference between said two signals, and a voltage control circuit taking said amplified difference of signals and controlling a power voltage in highfrequency amplitude control circuit is presented in this paper.
Abstract: An automatic temperature control circuit in a high-frequency heating apparatus comprising a differential amplifier circuit receiving at one of its input terminals signals from a temperature-setting voltage circuit and at another input terminal signals from a thermister provided with a heating needle which contacts with a load to be heated and amplifying the difference between said two signals, and a voltage control circuit taking said amplified difference of signals and controlling a power voltage in a high-frequency amplitude control circuit. A high-frequency power amplifier circuit in the heating apparatus is thereby controlled so that the temperature of the heating needle at its contact point with the load can be kept under a predetermined degree of temperature.