Having Light-controlled Or Activated Device (i.e., Not Light Signal) Patents (Class 330/59)
  • Patent number: 4090146
    Abstract: A light-indicator circuit is disclosed which permits visual indication of clipping caused by the over-driving of a transistor amplifier. The circuit includes a light-emitting diode connected in parallel with the collector-emitter path of a switching transistor which is biased to conduct during low-signal-level operation of the amplifier. The switching transistor is caused to switch to its non-conducting state when the amplifier is overdriven, thereby activating the light-emitting diode. Means may be provided to delay switch-back once activation of the light-emitting diode has occurred. Means may be provided to inhibit activation of the circuit by over-driving signals of limited duration.
    Type: Grant
    Filed: June 29, 1977
    Date of Patent: May 16, 1978
    Assignee: GTE Sylvania Incorporated
    Inventor: Daniel Scott Pearce
  • Patent number: 4088962
    Abstract: A self biasing low input impedance differential amplifier for current mode applications requiring wide bandwidth with response down to DC. A shunt-shunt differential mode feedback system in combination with a series-shunt common mode feedback system is connected between an input amplifier stage and an output amplifier stage. An additional shunt-series common mode feedback signal is applied to the input stage to short out the common mode component of the amplifier input signal and minimize input signal drift. High open loop gain in the differential feedback loop provides low impedance amplifier inputs.
    Type: Grant
    Filed: April 6, 1977
    Date of Patent: May 9, 1978
    Inventor: Ted R. Trilling
  • Patent number: 4079331
    Abstract: A condition responsive element, disclosed as a negative temperature coefficient thermistor, operates in conjunction with a bridge circuit to provide a differential input to a special direct current amplifier system. The amplifier system utilizes a combination of positive feedback and negative feedback with the negative feedback always exceeding the level of the positive feedback under steady state operating conditions. The output of the amplifier means further is connected to the lowest energizing potential for the amplifier means through a network that includes a relatively fixed voltage dropping means so that changes in the negative feedback can be made to change the gain of the amplifier system with a minimum of offset or change in calibration of the condition responsive device.
    Type: Grant
    Filed: February 9, 1977
    Date of Patent: March 14, 1978
    Assignee: Honeywell Inc.
    Inventors: B. Hubert Pinckaers, Robert T. Ruminsky
  • Patent number: 4079335
    Abstract: A circuit for providing adaptive level control in a sound-recording device. A feed-back signal drives a variable attenuator which controls the input level to the audio amplifier stage. Means are provided for preventing voltage spikes at turn-on from adversely affecting the operation of the attenuator and which provide stable sensitivity control.
    Type: Grant
    Filed: November 4, 1976
    Date of Patent: March 14, 1978
    Assignee: Bolex International SA
    Inventor: Franz Doerig
  • Patent number: 4066973
    Abstract: Isolating apparatus is disclosed which provides electrical isolation between an analog signal input and an equivalent analog signal output. The input analog signal is converted to a series of positive and negative pulses. Optical coupling devices are responsive to the series of positive and negative pulses for providing a series of similar positive and negative pulses which are electrically isolated but optically coupled. These isolated pulses are then converted to the equivalent analog signal output. The optical coupling comprises photo emitters one of which is activated when the analog to pulse converter output is positive and another of which is activated when it is negative. The photo emitters are operably associated with photo detectors which are operable in a switching mode. Feedback is not required around the optical coupling devices. An averaging circuit at the output provides an analog representation of the input signal.
    Type: Grant
    Filed: September 15, 1976
    Date of Patent: January 3, 1978
    Assignee: Contraves-Goerz Corporation
    Inventor: Paul F. McNally
  • Patent number: 4060771
    Abstract: An electrical circuit for suppressing the effect of interfering alternating oltages of various frequencies superimposed upon a direct current signal in an electric measurand transmitter, such as in an electromechanical precision or fine balance, which comprises a signal line for carrying said direct current signal and interfering alternating voltages, means for low energy capacitively coupling-out of interfering alternating voltages of frequencies lower than a predetermined limit frequency from the signal line, means for energy amplifying and for inverting 180.degree. in phase said coupled-out voltages, and means for capacitively coupling-back into the signal line the amplified and inverted coupled-out voltages.
    Type: Grant
    Filed: August 10, 1976
    Date of Patent: November 29, 1977
    Assignee: Sartorius-Werke GmbH (und vorm. Gottinger Prazisions-Waagenfabrik GmbH)
    Inventors: Franz Josef Melcher, Christian Oldendorf
  • Patent number: 4056719
    Abstract: A two-way transmission system, which utilizes solid state circuitry and a pair of opto-couplers, achieves high linearity and provides high electrical isolation between input and output signals without the use of the traditional hybrid transformer. Each opto-coupler includes a single light emitting diode (LED), two light detecting diodes (LDDs), and an amplifier. The LED is connected to the output of the amplifier and is physically located with respect to the two LDDs such that light emitted by the LED impinges on the photosensitive areas of the LDDs. The first LDD is coupled to the input of the amplifier, and the second LDD is coupled to output circuitry. This opto-coupler is relatively temperature insensitive and compensates for the inherent nonlinearity of the LED. These characteristics facilitate the use of the opto-coupler in systems which require relatively high linearity and temperature stability.
    Type: Grant
    Filed: August 2, 1976
    Date of Patent: November 1, 1977
    Assignee: Bell Telephone Laboratories, Incorporated
    Inventor: Sigurd Gunther Waaben
  • Patent number: 4050028
    Abstract: A first operational amplifier feeds a DC signal to first and second inverter means which are operated in opposite senses of polarity and which convert the DC output signal of the first operational amplifier to first and second stepped-up differential AC voltages at the same predetermined synchronized frequency. These stepped-up voltages are then converted to corresponding first and second DC voltages. A second operational amplifier is connected to the output of the first operational amplifier which drives a LED-photoconductor circuit to provide further system gain.
    Type: Grant
    Filed: December 10, 1976
    Date of Patent: September 20, 1977
    Inventor: Robert E. Vosteen
  • Patent number: 4048573
    Abstract: A differential amplifier is connected to an amplifier for comparing an amplifier input signal with the signal fed back by the amplifier feedback circuit. The output of the differential amplifier is coupled to a full wave rectifier the output of which controls an attenuator connected between a source of electrical input signals and the amplifier. When the amplifier is operating in its linear range, the differential amplifier inputs are identical and it does not produce an output. Under this condition, the input signal is not attenuated. However, in the presence of amplifier clipping, the differential amplifier produces an output which, after full wave rectification, operates to increase the attenuation, and thus reduce the amplitude of the signal applied to the amplifier; clipping is limited.
    Type: Grant
    Filed: October 15, 1976
    Date of Patent: September 13, 1977
    Assignee: McIntosh Laboratory, Incorporated
    Inventors: Ronald C. Evans, Sidney A. Corderman
  • Patent number: 4032853
    Abstract: A relatively simple, inexpensive, effective circuit for detecting overdriving of a radio frequency amplifier by an amplitude modulated signal. The input and output signals of the amplifier are coupled to peak detectors. A light emitting diode which provides a visual indication of the overdrive condition is coupled between the peak detectors.
    Type: Grant
    Filed: October 28, 1976
    Date of Patent: June 28, 1977
    Inventor: Eugene B. Hibbs, Jr.
  • Patent number: 4032843
    Abstract: A device for coupling a signal value out of a circuit which itself is floating at some relatively high voltage (termed common-mode voltage). A sensor for converting the parameter to be measured to a signal voltage, together with an amplifier and light-emitting diode are powered by a floating power supply of minimal power rating at the location of the common-mode voltage. An optical fiber link, which itself has great electrical insulation characteristics, joins the LED with a solid state light-to-electric transducer at a relatively remote location. Circuit means responsive to the light-to-electric transducer are included for outputting an analog value representative of the quantity to be measured at the point of the common-mode voltage. This LED, fiber optic link and light-to-electric transducer constitute a first OCI (optically coupled isolator).
    Type: Grant
    Filed: June 21, 1976
    Date of Patent: June 28, 1977
    Assignee: International Telephone and Telegraph Corporation
    Inventor: Richard S. Loucks
  • Patent number: 4030041
    Abstract: An analog isolator includes a circuit wherein a power transformer has a primary winding for connection to an A.C. source, a first and second power take-off secondary windings and a first and second signal secondary windings. The A.C. signal of the first signal secondary winding is compared with an input signal to provide cross-over pulses. Those pulses are applied to control an isolator device such as a photocoupler. The output signal from the photocoupler is applied as gate control signals to control the selective gating of the signals from the second signal secondary winding. The selectively gated signals are applied either to a sample-and-hold arrangement or to an integrating smoothing circuit to provide effectively a reconstruction of the input signal but conductively isolated from the input circuit.
    Type: Grant
    Filed: August 28, 1975
    Date of Patent: June 14, 1977
    Assignee: Honeywell Inc.
    Inventor: Toshihiko Sasaki
  • Patent number: 4025869
    Abstract: An amplifier capable of operation in four modes singly or in combinations is disclosed. The modes are: DC amplification mode, AC amplification mode, suppressed baseline mode, and offset correction mode. In the DC amplification mode, the amplifier operates as a conventional DC amplifier. In the suppressed baseline mode, the outputs of the input and output amplifiers are connected back to their input stages through a long time constant integrator resulting in the suppression of any DC output voltage. In the AC amplification mode an RC decoupling network is inserted in the inputs to the input amplifier means to pass AC signals and reject DC components. In the offset correction mode, the inputs of the input and isolator amplifier means are shorted to create zero differential at the summing junctions thereof. Any offset voltage present at the output of the input amplifier means or output amplifier means is suppressed by means of integrated feedback to the input stage of the input and output amplifier means.
    Type: Grant
    Filed: April 12, 1976
    Date of Patent: May 24, 1977
    Assignee: Beckman Instruments, Inc.
    Inventor: Leland Bryan Smith
  • Patent number: 4009447
    Abstract: A measuring circuit including a piezoelectric transducer contains an output charge amplifier circuit with a semiconductor element connected across the storage element of the charge amplifier. The semiconductor element controls the resetting or zeroing of the storage element to thereby effect control of the operation of the charge amplifier. Typically, the semiconductor element may be a field effect transistor, photo-device, etc., and the control of the same may be remotely controlled.
    Type: Grant
    Filed: July 20, 1973
    Date of Patent: February 22, 1977
    Assignee: Kistler Instrumente AG
    Inventors: Hans-Joachim Wolf, Franz Meier, Hans Ulrich Baumgartner
  • Patent number: 3996462
    Abstract: A signal transformation network which is uniquely characterized to exhibit a very low input impedance while maintaining a linear transfer characteristic when driven from a voltage source and when quiescently biased in the low microampere current range. In its simplest form, it consists of a tightly coupled two-transistor network in which a common emitter input stage is interconnected directly with an emitter follower stage to provide virtually 100 percent negative feedback to the base input of the common emitter stage. Bias to the network is supplied via the common tie point of the common emitter stage collector terminal and the emitter follower base stage terminal by a regulated constant current source, and the output of the circuit is taken from the collector of the emitter follower stage.
    Type: Grant
    Filed: June 23, 1975
    Date of Patent: December 7, 1976
    Inventors: James C. Administrator of the National Aeronautics and Space Administration, with respect to an invention of Fletcher, David L. Farnsworth
  • Patent number: 3982197
    Abstract: A network for clamping a circuit node to a voltage level when the circuit is subjected to high radiation levels. The network includes a first resistor connected in series with a first radiation responsive element between said circuit node and a first point of potential and a second resistor connected in series with a second radiation responsive element between said circuit node and a second point of potential. In response to high radiation levels, the equivalent impedance of the radiation responsive elements decreases considerably and the potential at the circuit node is clamped to a voltage which is primarily determined by the potentials applied at said first and second points and the ratio of the first and second resistors.
    Type: Grant
    Filed: February 4, 1974
    Date of Patent: September 21, 1976
    Assignee: RCA Corporation
    Inventor: Otto Heinrich Schade, Jr.
  • Patent number: 3980964
    Abstract: A noise reduction circuit for uncompressed and randomly compressed audio signals comprises a variable gain stage providing a gain which varies with the magnitude of a DC control signal fed to a control terminal thereby, an AC to DC converter for generating a DC signal proportional to the amplitude of the AC signal fed thereto and a filter for passing middle and upper frequencies and for eliminating or substantially reducing the low frequencies fed thereto and coupled between the audio signal input and the input to said AC to DC converter.
    Type: Grant
    Filed: June 20, 1975
    Date of Patent: September 14, 1976
    Inventor: Robert M. Grodinsky
  • Patent number: 3978423
    Abstract: A dynamic expander which is particularly suitable for restoring the original dynamic range of prerecorded stereo sound program material is disclosed. In this embodiment, the expander comprises first and second variable gain amplifiers respectively coupled to a stereo input. The gain of the amplifiers is controlled by a common slow-attack, slow-decay time-constant circuit. An input of the time-constant circuit is coupled to the stereo input and the time-constant circuit responds thereto to provide a control signal which is indicative of the volume of the program material but which varies in accordance with the characteristics of a non-linear element in the time-constant circuit and with the slow-attack and slow-decay characteristics of the time-constant circuit. The control signal of the time-constant circuit drives a light-emitting-diode (LED) which, in turn, determines the resistance of a pair of matched, light-controlled-resistors (LCR's).
    Type: Grant
    Filed: August 19, 1974
    Date of Patent: August 31, 1976
    Assignee: B-Cubed Engineering, Inc.
    Inventor: Stephen Michael Bench
  • Patent number: 3972004
    Abstract: The charge preamplifier comprises an input stage driven by the signal to be amplified, the input stage being connected to an amplification stage associated with an output stage, and a circuit for applying optoelectronic feedback from the output to the input of the preamplifier. The input stage comprises a cooled field-effect transistor, the signal to be amplified being applied to the input gate of the transistor. The load resistance of the transistor is provided by a second field-effect transistor mounted in series with an inductance coil.
    Type: Grant
    Filed: November 26, 1974
    Date of Patent: July 27, 1976
    Assignee: Commissariat a l'Energie Atomique
    Inventor: Gerard Libs
  • Patent number: 3955149
    Abstract: Common-mode and differential-mode active electrical and electro-optic feedback systems are formed with a plurality of physically interchangeable circuits. One of a plurality of input stage amplifiers can be connected to one of a plurality of loads through intermediate and output stage amplifiers. A plurality of interchangeable feedback stage amplifiers are then connected from various stage amplifiers back to the input stage amplifier. Such arrangements control the gain and the input and output impedances of the system independently for both the common and differential-modes.
    Type: Grant
    Filed: October 23, 1974
    Date of Patent: May 4, 1976
    Inventor: Ted R. Trilling
  • Patent number: 3953806
    Abstract: A sequence of light emitting diodes are progressively illuminated with progressively increasing instantaneous amplifier output signal amplitude with the last pair of light emitting diodes illuminated simultaneously to indicate amplifier clipping.
    Type: Grant
    Filed: January 12, 1973
    Date of Patent: April 27, 1976
    Assignee: Bose Corporation
    Inventor: Joseph L. Veranth
  • Patent number: 3943367
    Abstract: A voltage probe is provided for measuring high frequency transients during lectromagnetic pulse simulator testing of electronic devices. A probe tip module including input terminals for receiving transient voltages, a differential amplifier producing a representative output voltage in response to the transients received and a lamp driver amplifier selectively driving one or another of a pair of light emitting diodes in logarithmic response to the output of the differential amplifier is coupled with the testing geometry. The light output of the diodes is coupled through two respective fiber optics devices to respective photodetector inputs of two signal channels which convert the photodetector outputs to suitable driving signals for a dual trace oscilloscope.
    Type: Grant
    Filed: June 10, 1975
    Date of Patent: March 9, 1976
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventor: George H. Baker
  • Patent number: 3940715
    Abstract: A distortion measurement system for measuring distortion as low as 0.002% includes an ultra low distortion oscillator having a relatively fast response which is achieved by switching the time constant of the control loops of the oscillator during settling. The analyzer section included in the distortion system has a unique notch filter which provides low distortion. This is achieved by adding together two 90.degree. all pass phase shifters. In addition, automatic tuning is provided by two feedback control loops; one is responsive to out-of-phase signals which controls the RC filter circuits of the phase shifters and the other responds to the in-phase signals which controls the output summing junction of the notch filter. Finally, a feedforward type of simultaneous tuning is accomplished by ganging the oscillator frequency adjustment with the analyzer.
    Type: Grant
    Filed: September 25, 1974
    Date of Patent: February 24, 1976
    Assignee: Sound Technology, Inc.
    Inventor: Jack G. S. Lum