Showing papers on "RLC circuit published in 1981"

Telemetric differential pressure sensor with the improvement of a conductive shorted loop tuning element and a resonant circuit

Abstract: An improvement in design of an implantable telemetric differential pressure sensing device enabling thinner, more compact, and simplified construction for the device; increased pressure sensitivity and range of measurement; and a wider class of applications for such pressure sensing devices in diagnostic medicine and clinical monitoring. The implanted device includes a thin, planar, closed, conductive loop which moves with a flexible diaphragm, the diaphragm moving upon changes in the difference of two bodily pressures on its opposite sides. The position of the conductive loop relative to a resonant circuit fixed in the device determines the resonant frequency of the resonant circuit. The resonant frequency is detected telemetrically outside the body, and its value is used to determine the difference in the two bodily pressures.

Apparatus for reducing subsynchronous frequencies in a power supply

Abstract: A protective circuit for reducing subsynchronous natural resonant frequency signals in a multiphase power supply system includes a damping resistor connected in series with each phase winding of the system. A resonant circuit tuned to the rated line frequency of the system is connected in parallel with each resistor so that signals having frequencies other than the rated line frequency will be damped by the resistors. An inductor can also be placed in parallel with each resistor to maximize the damping effect of each resistor at predetermined subsynchronous frequencies.

Switched-capacitor filter circuit having at least one simulated inductor and having a resonance frequency which is one-sixth of the sampling frequency

Abstract: A switched-capacitor filter circuit having at least one simulated inductor and having a resonance frequency which is one-sixth of the sampling frequency as pulse-controlled switches co-operatively operable for connecting a first capacitor to a pair of input terminals during a first clock phase and simultaneously connecting a second capacitor to the output of an inverting integration circuit, followed by discharge of the first capacitor to a capacitor in the integration circuit during a second clock pulse phase, followed by a third clock pulse phase during which the first capacitor is charged from the output of the integration circuit and the second capacitor is simultaneously connected to the pair of input terminals and during a fourth clock pulse phase the second capacitor discharges to the capacitor in the integration circuit.

Circuit for alternate transmission and reception with only one sound source transducer

Abstract: A circuit is provided for supplying a transmission oscillator voltage suitable for a piezoelectric sound source transducer in which the transducer also serves as a receiving transducer. The circuit contains an electrical series resonant circuit having a capacitor C and an inductor L with L·C=(1/2 π f.sub.0).sup.2, wherein the electrical series resonant circuit is matched to the series resonant frequency f 0 of the transducer and is connected parallel to the transducer. The circuit further contains a pair of diodes, connected anti-parallel to one another, and connected in parallel to either the inductor L or to the capacitor C, with the output of the receiver being connected to the capacitor C or to the inductor L.

Measuring and control device using the damping effect of a resistive effect element on the inductor of a tuned circuit

Abstract: A detection type device that includes an arrangement for detecting the energy absorbed by a resistive effect element in proximity to the inductor of a resonant circuit. The resonant circuit uses a direct current source to alternatively charge it and then let it ring through a switch connected between the direct current source and the resonant circuit. Two different parameters of the same oscillating signal generated by the resonant circuit are detected and compared. The difference is the result of a ratio of these parameters that accurately reflects the energy absorbed by the resistive effect element. This difference is used for measurement and control purposes.

Circuit for injecting simulating-noise signals in a power line

Abstract: A simulated-noise signal is injected in the power line of equipment under test without loss of AC power by the use of a series resonance circuit having a resonance frequency equal to the frequency of the AC power supply. The series resonance circuit is connected in the power line in parallel with the equipment, and a capacitor is connected to the power line in parallel with the series resonance circuit and the equipment. A switching element is used to short-circuit the resonance circuit when noise simulation is not carried out. For the simulation of lightening strikes the circuit further comprises a simulated-noise signal generator including a capacitor charged by a DC power supply, a first switching element to discharge the charge of the capacitor to the equipment, and a second switching element for establishing a by-pass of the discharging current. By closing the second switching element after the first switching element is closed, a square-wave signal is fed to the equipment. In order to simulate ringing-surge signals, the circuit includes a generator to generate a damped-wave signal similar to a ringing signal. This generator has a capacitor charged by a DC power supply, a switching element for discharging the charge of the capacitor to the equipment, and an inductance coil connected to the discharging circuit. When the switching element is closed, a damped-wave signal is fed to the equipment.

Filter and phase shift circuit for a television automatic flesh color correction system

Abstract: A frequency selective signal translating circuit is disclosed for use in a color television receiver including an automatic flesh tone color correction network which provides a reference signal for color demodulators of the receiver. The circuit comprises an input bandpass filter for attenuating unwanted frequency components from the reference signal output of the correction network. The filter is followed by a phase shifter for shifting the phase of the filtered reference signal as required for proper demodulator operation. The filter comprises a fixed alignment, single-tuned, series resonant circuit coupled in series between the correction network output and the demodulator reference signal inputs.

Tunable coupling network

Abstract: A tunable coupling network for a frequency multiplier stage providing a passband for a desired harmonic of a fundamental frequency and rejection notches for undesired harmonic frequencies. The passband of the network can be tuned by changing the value of at least one circuit element to track the desired harmonic of the fundamental frequency over a range of fundamental frequencies. In so doing, the rejection notches also move so that they maintain fixed ratios with respect to the passband frequency as the passband moves. In one embodiment the network comprises first and second tunable circuits each including a variable reactive element. The first resonant circuit includes a variable capacitor and two fixed inductors. The second resonant circuit includes a variable inductor and two fixed capacitors. The two resonant circuits are coupled by an interstage coupling capacitor.

Voltage-controlled RF oscillator employing wideband tunable LC resonator

Abstract: Stray capacitance is reduced in a wideband tunable oscillator network by arranging the resonant circuit as one or more series circuit branches wherein a variable capacitance such as a varactor diode is interposed between two substantially identical inductors. In the disclosed VHF-UHF oscillator, the inductors are realized by TEM transmission lines of the stripline variety. The stripline is formed by a multilayer printed circuit board arrangement and two resonant circuit branches are interconnected in a manner that permits biasing of the varactor diodes without the use of blocking capacitors in the resonant circuit path.

Phase-locked loop including non-linear phase detector of the sample and hold type

Abstract: A non-linear phase detector is disclosed which compensates for gains occuring during tuning a frequency generator of a known phase locked loop circuit which incorporates a Varactor tuned resonant circuit as a VCO. The phase detector is of the sample and hold type and incorporates a Varactor rather than a hold capacator to compensate for non-linear gains which occur when tuning the frequency generator across its band spread. Additionally, bias compensation is provided for the resonant circuit Varactor to offset its contact potential.

EHV Protection Problems

Abstract: This paper presents a broad overview of system considerations affecting protective relaying applications on extra-high voltage (EHV) systems. Discussions include the effects of line parameters on relaying, transient response of current transformers and coupling capacitor voltage transformers, control circuit and relay surge protection, sub-synchronous resonance problems, stability considerations, influence of harmonics and power line noise on carrier relaying, automatic reclosing considerations and simulation of transmission line transients for relay applications.

Differential transformer core for pulse currents

Abstract: A plurality of relatively high magnetic permeability strips are interleaved to form layers of a closed loop differential transformer core. Although the material of each layer by itself may have a relatively square hysteresis loop, the core formed of a plurality of interleaved layers of such material has a substantially more rounded hysteresis loop. Such a core can advantageously be used in a ground fault interruption circuit in which power leads pass through a central opening in the core to form a primary winding and a secondary winding wound on the core may have a capacitor connected in circuit therewith to complete a resonant circuit. By virtue of its more rounded hysteresis loop, the core, in cooperation with the capacitor, permits the establishment of a resonant current in the secondary circuit which is sufficient to trip a circuit breaker after a few cycles of operation of the alternating current or pulsed unidirectional primary current when a small differential current exists between the power leads as a result of a ground fault.

Experimental Characterization of Fin Line Discontinuities Using Resonant Techniques

Abstract: The equivalent circuit parameters of inductive strips and of impedance steps in unilateral fin line are presented. They have been obtained from the measured resonant frequencies of a rectangular cavity containing these circuit elements.

Low-Loss High-Peak-Power Microstrip Circulators

Abstract: Smalll-signal magnetic losses due to coupling of the microwave signal to the spinwave manifold in a ferrite circuit under perpendicular pumping may be suppressed by biasing it between the subsidiary and main resonances. This paper describes the realization of two microstrip circulators biased in such a way. These magnetic conditions also coincide with those required to suppress spinwave instability at large-signal level. A device, using a triangular resonator, exhibited no nonlinear loss up to 1500-W peak at which power level thermal breakdown of the circuit metalization occurred both at the impedance step of the quarter-wave transformer and at the apex of the triangular resonator. A similar device using a disk resonator exhibited no nonlinear loss up to 2200-W peak at which power level breakdown of the circuit metalization again took place. A circulator using a disk resonator with a similar material but biased at magnetic saturation displayed nonlinear loss at 80-W peak.

Measuring device for reactance change

Abstract: PURPOSE:To eliminate the effect of the temperature change and then ensure an accurate measurement for the reactance change, by always giving the control to maintain the frequency of the power source at the serial resonance frequency of the circuit. CONSTITUTION:Capacitor 21 is connected to detecting coil 20 of the measuring device, and thus a serial resonance circuit of L-C-R is formed. Phase comparating circuit 25 connected by power source 23 is connected across resistance 22 via current waveform detecting circuit 24. Thus the phase comparison is carried out between the power voltage waveform and the current waveform of the resonance circuit. At the same time, the output of circuit 25 is connected to control circuit 26, and the change of the self-inductance of coil 20 is detected from the phase difference between the voltage and the current. Also the voltage signal having the phase difference of 0 is supplied to V/F converter 27. Thus power source 23 is always controlled to the resonance frequency. In such way, the resonance state is maintained to ensure an accurate measurement of the reactance change irrespective of the resistance which receives the effect of the temperature change.

Detector for number of revolutions of internal combustion engine

Abstract: PURPOSE:To surely detect the number of revolutions of an internal combustion engine by receiving the radio waves radiated from an ignition device and generating the constant time pulses corresponding to rotating speeds. CONSTITUTION:The noise radio waves radiated from an ignition device are band- selected in a resonance circuit 11 via an antenna 10, is frequency-converted 12 and is applied to a detecting circuit 13. The modulated waveform obtained through detection is pulse-shaped with a filter 15, and operates a Schmitt circuit 16, the output thereof triggers a monostable multivibrator 17. Thereby, constant time pulses are obtained in a terminal 18.

Improvements in and relating to electrical inverters

Abstract: An inverter which includes a resonant electrical circuit (3, 4) and a charging transistor (12) arranged to charge an energy storage component (3) of the resonant circuit periodically in synchronism with oscillations in the circuit so as to maintain the oscillations. A part of the oscillatory energy of the resonant circuit is transferred to an output circuit so that the inverter supplies output power. The charging transistor (12) forms part of a current-limiting switch and is controlled by a control circuit which is arranged to monitor the potential difference across the transistor (12) and to switch it on to charge the resonant circuit (3,4) at or near zero potential difference. The charging transistor (12) then adds energy to the resonant circuit (3, 4) until the current-limit is reached. Charging is then stopped by the switching off of the transistor (12). The inverter may include an automatic current-limit adjustment to compensate for output voltage changes and may include also a start-up circuit which operates when the charging transistor has not operated for a set time.

Code transmission unit

Abstract: PURPOSE:To perform economical code transmission, by changing the impedance of higher harmonic resonator provided at the transmission section according to the transmission code, in the transmission unit taking power line as the code transmission path CONSTITUTION:Transmitters A, C and receivers B, D are connected to the high voltage power line E via current transformers 4, 5 and transformer F In transmitting codes from the transmitter A to the receiver D, the control circuit 1 changes the resistive component of the resonance circuit 3 in resonance with higher harmonics Thus, the degree of voltage drop of higher harmonics of the power line E is changed with this The third higher harmonic tuning circuit 13 of the receiver C receives the frequency component of the third higher harmonics with emphasis and the codes of higher harmonics are detected at the code detection circuit 11 Thus, because low frequencies are used for transmission line and no flicker failure is given, the transmission line can be constituted with economy

Diode switch circuit including resonant circuit

Abstract: PURPOSE:To improve the isolation characteristics, by connecting two capacitors in series connection with each other, in parallel with the diode and connecting the inductance between the connection points of two capacitors and ground. CONSTITUTION:When the diode 12 is off, the series LC resonance circuit consisting of the lambda connection with the capacitor offered by the diode 12 and a pair of capacitors 13, 14 and the inductance 15 is constituted. Further, when the diode 12 is ON, the series LC resonance circuit consisting of a pair of capacitors 13, 14 and inductance 15 is constituted. Thus, the resonance frequency can be made different by turning-on and -off of the diode 12.

Antenna with two mutually inclined ferrite rods - each having coil and capacitor forming two coupling resonant circuits

Abstract: The antenna has a ferrite rod with a coil wound around it and connected to a capacitor to form a resonant circuit tuned to a transmitter's carrier wave. A second ferrite rod is located at an angle of 60 to 90 degrees to the first rod and also has a coil wound around it and connected to a capacitor to form a resonant circuit tuned to the same carrierwave. The two resonant circuits form a critically-coupled bandpass filter. The normalised coupling is chosen to lie between 0.5 and 2, preferably 1. The two resonant circuits are magnetically decoupled but electrically coupled via coupling capacitors.

Device for supply of spurious noise on power source current

Abstract: PURPOSE:To apply stable spurious noise without giving power loss to a load, by connecting a resonance circuit in parallel to the load and by resonating this circuit with charged electric charge of a capacitor. CONSTITUTION:Switches SW1 and SW2 are turned on and off respectively to charge capacitor C3. After that, when switches SW1 and SW2 are turned off and on respectively, charged electric charge of capacitor C3 is dicharged through power source lines l1 and l2. The discharge current becomes the damping oscillation wave signal having the frequency determined by capacitor C3, inductance L2, and load 2. The damping oscillation wave is applied repeatedly by repeating operations of switches SW1 and SW2.

Frequency conversion circuit

Abstract: A frequency conversion circuit in which effects of odd order terms in the input and output characteristics of the active elements of the circuit, which otherwise would produce IM interference, are eliminated. A superposition signal composed of two signals of different frequencies is applied, in opposite phases, to control inputs of a differential pair of transistors. A common load is coupled to the differential pair with the odd order terms being cancelled at the common connection point of the differential pair. The common load is preferably a resonant circuit.

Clock pulse generating circuit

Abstract: PURPOSE:To enable to generate clock pulse less in the interference between codes with a simple constitution, by forming the timing component in combination with a delay line and an exclusive logical sum circuit CONSTITUTION:An NRZ code phi1 input to a terminal 1 is distributed into two; one is fed to one input of an exclusive logic circuit 3 and another is delayed at a delay line 2 by the width of 1/2-bit and fed to another input terminal of the circuit 3 as a signal phi2 The output signal phi3 of the circuit 3 is fed to a resonance circuit 4 which takes the width of one bit of th signal phi1 as a period Since the circuit 4 has higher Q, even if the input signal phi3 is intermittent to a certain degree, a continuous wave phi4 is obtained at the output of the circuit 4, and the signal phi4 is shaped at a wave shape circuit 5 to obtain a clock pulse phi5 The signal phi1 is read in from a latch circuit 6 in the clock pulse phi5, and the output is delivered to a terminal 7 The signal phi3 produces the timing component which drives the circuit 4 when the signal phi1 changes from high to low level and from low to high level

Inverter ballast circuit with shoot through prevention, auto transformer coupling and overload prevention

Abstract: An inverter ballast for fluorescent lamps utilizing a resonant circuit coupled to the lamp and operated from a source of DC power through transistors. The transistors are controlled by a sensing means in the resonant loop which insures that the transistor switch at zero current. Furthermore, the coupling means for the load controls a source of heater voltage to the anodes of the fluorescent light which operate at very low current, an antisaturation circuit made up of separate windings are on the current transformer and connected to the switching transistor bases and through diodes to the power supply to prevent "shoot through" current in the transistors. An autotransformer is used as a high leakage reactance transformer; and a circuit is provided to prevent overload of the resonant circuit in case of lamp failure. Shoot through currents are prevented, and overload of the resonant circuit is prevented, and an autotransformer coupling of the resonant circuit to the load is used.

Resonant power inverter and method of operation thereof

Abstract: The module includes a resonant power circuit (10) for coupling to a load. First and second switching elements (CR1, CR2) are coupled to the resonant circuit for alternately supplying a flow of current. Trigger generator means (46) provided for supplying trigger signals to enable alternately the first and second switching elements. Control means (10) is coupled to the trigger generator for operating the power module both in a first mode in which the resonant circuit current is controlled by varying the repetition rate of the trigger signals, and in a second mode in which the trigger signal repetition rate is fixed and the resonant circuit current is controlled by varying the on/off duty cycle of the module.

Coaxial resonance circuit

Abstract: PURPOSE:To obtain a small-sized resonance circuit by coupling capacitance with a dielectric coaxial line whose length is shorter than specific wavelength. CONSTITUTION:A dielectric material 31 is formed cylindrically and hollowed, and its internal surface 35, external surface 32, and one end surface are made entirely into electrically good conductors to form conductor parts 20, 21, and 22; and its length L is set less a quarter as long as the wavelength of resonance frequency. To a center conductor part 21 on the other end surface 36 where no conductor part is provided, one terminal electrode of a capacitor 4 is connected through a connecting conductor part 34 at the same potential, thus grounding both said terminal of the capacitor 4 and the conductor part 22.

Vital contact checking circuit

Abstract: A vital contact checking circuit which senses the state of the back contact of a relay in either a dynamic or static situation. In the former, a signal is coupled from its source to a detector by a coupling device, such as a transformer, and an additional winding on the transformer is connected to the heel and back contact of the relay whose contact is being checked. When a circuit is established through the back contact the additional winding is short circuited, thereby preventing the signal from the source from reaching the detector and effectively eliminating it. A variation of this scheme, also for use in a dynamic situation, involves using the coil structure in a resonant circuit, the sensing winding causing detuning when the back contact is closed so that again, the detector does not receive the signal from the source. For performing a vital check on a static contact, another scheme is utilized because a failure in the oscillator or detector circuit of the schemes already described would give the same indication as a closed back contact. Therefore, the primary and secondary windings of the main transformer are wound on separate cores and the sensing winding links the individual cores so that the detector produces an output only if the sensed contact is indeed closed.

Object identification sensor and circuit - has inductive sensor coupled to amplitude and phase shift detection circuit

Abstract: An identification system uses an amplitude and phase change to identify either a disc or coin. The sensing stage is provided by an inductive coil (51) through which is passed the object using a guide track. The coil is set at an angle of 45 degrees to the guide path. A resonance circuit (5) is provided by locating a capacitor (52) in series that is supplied with an alternating voltage. The output of the resonance circuit is coupled to a phase comparator (1) and the signal amplified (2) to control a voltage controlled oscillator (3). This controls an amplitude regulator (4). The output is rectified (6) to generate an output to identify the passage of the coin.

Resonance circuit and electronic circuit

Abstract: PURPOSE:To obtain a small-sized resonance circuit without complicated connection with a circuit part and a decrease in Q value by inserting a dielectric coaxial line into a through hole formed in a substrate for a microwave integrated circuit, and connecting it to an earth conductor part. CONSTITUTION:Part of a dielectric coaxial line 1 is inserted into a substrate 6 constituting a microwave integrated circuit, and a coating 4 of conductive metal formed on end surface of the coaxial line 1 is connected to conductive metal coating the internal surface of a circular hole at the center part at the same potential and also connected to a conductive pattern 5 as the earth conductor of the microwave integrated circuit at the same potential. The other end surface of the coaxial line 1, on the other hand, has only the center conductor connected to a capacitor 9 through a conductive pattern 8 on the microwave integrated circuit substrate 6 and further to an earth pattern part 51 on the substrate 6.