Showing papers on "RLC circuit published in 1970"

Circuit arrangement for suppressing interferences in an fm radio receiver

Abstract: A circuit arrangement for interference suppression in which the signal is applied through a gating circuit which is blocked during interference to a storage capacitor whose voltage remains constant during interference. To reduce the distortion as a result of a pilottone serving for the stereo detection of a stereo signal a parallel resonant circuit tuned to the pilot tone is incorporated in series with the storage capacitor.

Remote monitor system

Abstract: A system for remotely monitoring the changeable state of a moveable subject employs an illuminator having an electrical resonator which establishes an oscillating ''''near'''' magnetic field over the area to be monitored. The illuminator''s resonator is driven into resonance and a sensor provides an information signal that is a measure of the oscillatory energy in the resonator. The monitored subject carries a pair of resonant circuits tuned to be set into resonance by inductive coupling to a near magnetic field. One of the resonant circuits is arranged so that its resonant frequency or its energy dissipation (Q) is affected by variations of the monitored state. When at resonance, that resonant circuit causes a change in the oscillatory energy in the illuminator''s resonator which is detected by the sensor and appears in the information signal. The other resonant circuit carried by the monitored subject is insensitive to the monitored state and is tuned to a frequency different from the resonant frequency of the sensitive resonant circuit. When at resonance, the insensitive circuit causes a change in oscillator energy in a resonator which supplies energy to that circuit through a ''''near'''' magnetic field. The energy change is detected and a ''''standard'''' signal is obtained with which the information signal is compared.

Object detection apparatus

Abstract: A passive ultrasonic vehicle detection apparatus for use with a vehicle such as an automobile, truck, or bus for detecting and indicating the presence of other vehicles in predetermined regions rearward of the subject vehicle, for example, in travel lanes adjacent to the travel lane of the subject vehicle or in so-called ''''blind'''' zones of the subject vehicle. When a vehicle is present in one of the adjacent lanes or in a blind zone, signals including ultrasonic signals which are generated inherently by the vehicle, for example, due to a combination of factors such as engine and body vibrations, and engine and tire noises, are received by a frusto-conical signal-receiving horn mounted in a rearward location of the subject vehicle and applied to a piezoelectric crystal transducer. The piezoelectric transducer has a predetermined resonant frequency equal to the frequency of particular ultrasonic signals generated inherently by all existing engine-driven road vehicles. The piezoelectric transducer operates in response to the various signals received from the frusto-conical signal-receiving horn to produce an electrical output voltage which is greatest for ultrasonic signals of the predetermined resonant frequency. The output voltage produced by the piezoelectric transducer is then applied to a resonant circuit tuned to the predetermined resonant frequency to achieve the desired system bandwidth. The output signal produced by the resonant circuit is amplified and applied to an astable multivibrator which operates to produce a train of output pulses for periodically applying the vehicle battery voltage to an integrator circuit. The integrator circuit operates to integrate the voltage pulses received thereby and to operate a driver circuit when a predetermined threshold voltage level is achieved. The driver circuit operates a lamp or other indicator to indicate the presence of the vehicle in the adjacent lane or blind zone.

Digital transducer system

Abstract: A digital measuring transducer system is disclosed wherein a pair of oscillators are employed in combination with a mixer to produce an output from the mixer having a pulse repetition frequency equal to the difference in pulse repetition frequencies between the two oscillators and representative of a sensed condition. At least one of the oscillators employs a resonant circuit in the feedback path and a pressure-variable capacitive sensor is connected into the resonant circuit to vary the output frequency of the associated oscillator to produce a difference in frequencies between the two oscillators and a resultant output from the mixer indicative of the pressure condition adjacent the sensor. The second oscillator may be a reference oscillator providing a predetermined reference output frequency or the second oscillator may have a pressure-variable capacitive sensor associated therewith such that the pulse or digital output from the mixer is representative of differential pressure.

Television tuning circuit utilizing voltage variable capacitance

Abstract: A tunable resonant circuit includes a pair of inductors serially connected between input and output terminals. The parallel combination of a third inductor and a voltage-responsive capacitance device are coupled from the junction of the pair of inductors to a point of reference potential.

Load Dependence of Gunn-Oscillator Performance

Abstract: A detailed analysis of an experimental resonator as a basis for determining the output power and the tuning range of Gunn oscillators as functions of the fundamental resonant-load resistance. Differing n/sub 0/L products (1.2 and 4.8x10/sup 12/ cm/sup -2/) lead to strikingly different results which are related to the delayed-and quenched-domain resonant modes, respectively. Variations of the second-harmonic frequency termination cause the fundamental output power of Gunn oscillators to change by a factor of up to 5, this change being accompanied by a frequency pulling of a few percent. From detailed impedance measurements it is concluded that the maximum fundamental power occurs if the second-harmonic circuit is tuned near an open-circuit resonance, the total circuit susceptance being somewhat capacitive.

Resonant circuit apparatus for detecting electromagnetic conductive bodies

Abstract: An apparatus for detecting the presence of electromagnetic conductive bodies comprises two coils which are coupled through a high gain, high impedance amplifier and tuning capacitor with the other end of each coil going to ground so as to form a tank circuit. The coils are mounted so as to be essentially de-coupled with their axes mutually perpendicular. One of the coils is self resonant with a natural resonant frequency in the audio range. The circuit is tuned to the natural resonant frequency by the tuning capacitor and inductive coupling between the coils improves when the circuit is near an electromagnetic conductive body. A capacitor circuit is employed to detect and measure shift in one or more of the tank circuit parameters including output signal level, frequency and phase.

High voltage generating apparatus utilizing piezoelectric transformers

Abstract: In a high voltage generating apparatus utilizing a piezoelectric transformer having two driving electrodes and an output electrode, a signal of a definite frequency is applied across the driving electrodes via an inductance element, a capacitor is connected in parallel with the driving electrodes to form a resonance circuit together with the inductance element and the resonance frequency of the resonance circuit is made substantially equal to the natural resonance frequency of the piezoelectric transformer which is equal to an odd higher harmonic of the signal frequency.

Circuit arrangement for generating in a picture display device a sawtooth current of line frequency having an amplitude varying at field frequency

Abstract: A circuit arrangement for generating by means of a modulator in a colour picture display device a sawtooth correction current of line frequency flowing through the line deflection coils and having an amplitude varying at field frequency for the purpose of obtaining a better colour superposition in the corners of the screen of the display tube, comprising means to add an additional correction current which flows in the same direction as the first mentioned current and which is proportional to the third power of both the line and the field deflection currents. Said means may be a saturable coil or a resonant circuit which is tuned to a frequency which lies between the like frequency and twice the value thereof. In the latter case the voltage present across the circuit may be used for correcting the North-South pincushion distortion. Also, the modulator is controlled by an amplifier comprising a linear and a voltage-dependent resistor which ensure that a third-power component is added also to said field deflection current.

Induction heating apparatus

Abstract: A circuit for supplying a series of current pulses to an output coil, such as a coil used for induction heating, can be constructed utilizing a timing circuit adapted to be connected to a DC power supply and a resonant circuit including the output coil connected to the timing circuit. The timing circuit used includes a current discharge or release means such as an SCR (silicon-controlled rectifier) and a trigger means such as a trigger diode (bidirectional diode thyristor) for actuating or firing the release means in response to current supplied by the power supply so that the release means will supply current to the resonant circuit. The current supplied to the resonant circuit results in the development of a resonant current in opposition to the supplied current. Such resonant current feeds back to the timing circuit so as to render the release means no longer operative to supply current to the resonant circuit until such time as thereafter the trigger means, as a result of power supplied to it from the power supply, actuates the release means so that it will again supply current to the resonant circuit.

Linearity compensation for a voltage-controlled oscillator

Abstract: A circuit using a voltage-controlled oscillator with a hyperabrupt junction diode in the series resonant circuit is operated as a variable frequency modulation circuit. An amplifier with an inductor in the base circuit of a common base configuration is used to present an impedance with a frequencydependent real part to the series resonant circuit of the oscillator. The nonlinearities in the characteristic of the hyperabrupt junction diode are compensated by the frequencydependent real input impedance to achieve linear operation.

Retuning Effects and Dynamic Instability of a Radio‐Frequency Capacitive Discharge

Abstract: A discharge plasma is established in air at pressures of 0.2–20 Torr in the rf electric field between parallel‐plate electrodes in a resonant circuit at 14 MHz. By adjusting a calibrated tuning capacitor in parallel with the electrodes, one can observe a wide range of plasma conditions extending from normal extinction at low rf potential and power to an apparent dynamic instability at high potential and power. The loading effect of the plasma is found to be that of a lossy capacitance. Net input rf power to the plasma‐loaded circuit at the tuning condition just below the threshold for dynamic instability is found to be ∼10 times that for a plasma maintained at the tuning condition for the resonant circuit without plasma. The retuning effects are discussed on the basis of the nonlinearity of the plasma medium, and a possible mechanism for the dynamic instability is proposed.

A Compact Thin Film Lumped Element Circulator Using a Capacitor, Common to All Three Arms, for Broadbanding or Switching

Abstract: A thin film lumped element circulator using only cross-over capacitances and a single capacitor comon to all three ports, the equivalent circuit of which is shown in Figure 1a, has yielded a 20 dB bandwidth > 30%.

Hybrid t-junction constructed in waveguide having a cut-off frequency above the operating frequency

Abstract: A hybrid T-junction constructed in waveguide for operation below its cut-off frequency. The series arm of the hybrid provides a parallel resonant circuit in series with the symmetrical arms of the hybrid. The shunt arm provides a series resonant circuit at the midpoint of the series arm. The equivalent circuit is a lumped circuit bridged-T, which exhibits the properties of balance and isolation associated with bridge networks.

Evaluation of UMTS RLC Parameters for MPEG-4 Video Streaming

Abstract: Universal Mobile Telecommunication Systems (UMTS) known as Third Generation (3G) mobile phone systems using Wideband Code Division Multiple Access (WCDMA) standard aim to provide a high bit rate of services to enable a high quality of multimedia communications. The 3G specification entity, 3GPP, has defined a reliable link layer protocol, Radio Link Control (RLC), for hiding transmission errors from upper layers. Due to the complexity of the protocol and the a number of parameter configurations available, there are many ways that can degrade a system performance, such as incorrect parameters configuration, buffer missmanagement, protocol stalling, etc. MPEG-4 is widely used for video stream services due to its good video quality at low bit rate. In this paper, we have studied on the impacts of RLC parameters, especially RLC timer and polling mechanism, for MPEG-4 video stream transmission by using a computer simulation. Our simulation results provide some suggestions value to optimize such parameters, e.g. RLC time and polling.

Damped sinusoidal current pulse generator and method

Abstract: A damped sinusoidal electromagnetic field is produced by oscillatory current flow in a conductor of an inductive component of an underdamped LC resonant circuit. Energy is stored in the resonant circuit when the resonant circuit is coupled to a steady state D.C. electrical energy source by the triggering into conduction of an SCR connected in series with the resonant circuit and the D.C. source. Energy is transferred to the resonant circuit by an inductor connected in series therewith. The inductance of the inductor is sufficiently less than that of the inductive component of the resonant circuit such that sufficient energy is stored in the resonant circuit at a sufficient rate to cause current flow in the SCR to ultimately cease. Thereupon the SCR shuts off the transfer of energy from the D.C. source to the resonant circuit, and damped sinusoidal oscillation occurs in the resonant circuit to produce a damped sinusoidal electromagnetic field. The SCR is intermittently triggered into conduction to produce an intermittent series of damped sinusoidal electromagnetic fields.

Pulse shaping circuit with multiplier application

Abstract: A pulse shaping circuit comprising a series resonant circuit and a shunt resistor-diode damping circuit in combination with a square wave input and a grounded base transistor load to provide a pulse of controlled width and amplitude. The damping circuit dissipates all but the first half cycle of resonant circuit ringing. A dual circuit employs a parallel resonant circuit and common emitter load transistor. In a frequency multiplier application, the resonant circuit is tuned to the desired harmonic frequency and a bandpass filter is connected at the transistor output.

Ac shielded electrode arc working

Abstract: A method of AC electrode shielded arc working wherein an RLC circuit is included in series with the AC supply source and the electrode for maintaining a continuous AC arc, the magnitudes of the components in the RLC circuit being correlated with the required reignition potential of the shielded atmosphere and the metal oxide surface of the workpiece.

Power conversion system

Abstract: A circuit for obtaining power from a source and delivering a lower D.C. voltage to a load. A first silicon controlled rectifier is fired to charge up a series resonant circuit to approximately twice the input voltage. When the capacitor is fully charged, a signal fires a second silicon controlled rectifier to discharge the capacitor into the load. When the potential on the capacitor and its associated inductance has been reduced to the proper point, the second rectifier cuts off to end the cycle.

Theft detection system

Abstract: 1,212,504. Inductive signalling; transponders. EURONICS Ltd. 29 March, 1968 [30 Dec., 1966], No. 58271/66. Headings H4L and H4U. A system for detecting the unauthorized removal of articles through an exit, comprises a transmitter generating an inductive field across or adjacent to the exit and a plurality of miniaturized oscillators, one oscillator being attached to each article. As described, the oscillators are energized by rectification of the signal from the transmitter and retransmit a signal on a different frequency from that received to one or more receivers coupled to an alarm system. The oscillators themselves may include an audible alarm. One transistor oscillator described includes an energizing circuit tuned to one frequency and retransmits on a different frequency, the incoming signal being rectified by a diode. In a further embodiment, the oscillator consists of a resonant circuit comprising an inductor, a capacitor and a diode in series, the diode generating harmonics, one of which is utilized as the alarm signal. The oscillator may be included in a price tag label.

Input stage for a receiver particularly for the medium wave

Abstract: A receiver input stage for the reception of signals in a broad frequency range comprising an input resonant circuit and an output resonant circuit that is identical to the antenna-input circuit. The input and output circuits are coupled and tuned by means of variable capacity coupling and tuning diodes respectively.

High frequency amplifier

Abstract: A high-frequency amplifier intended for use primarily in radio transmitters, and particularly in transmitters used in aircraft. The circuit preferably is a push-pull circuit utilizing a pair of power transistors. A capacitor is connected between the emitter and collector leads of each transistor. The capacitance of the capacitor has a value such that the capacitor and the output inductance of the transistor together form a resonant circuit whose center frequency coincides with the center frequency of the band of the second harmonic signals produced by the amplifier, thus effectively minimizing second harmonic voltages in the transistors. Preferably, the capacitors are formed by parallelplate transmission lines which also are used to interconnect the electrodes of the transistors, and to form input and output leads of the circuit. The parallel-plate transmission lines have very low inductances; their use minimizes the lead inductances of the amplifier. An output transformer is provided which performs the function both of an output transformer and a radio-frequency choke.

Monitoring the Lateral Disposition of a Moving Strip of Material

Abstract: 1,183,974. Electro-physical measurement-dimensions. ALLEGHENY LUDLUM STEEL CORP. June 5, 1967, No.25933/67. Heading G1N. [Also in Division G3] An arrangement monitoring transverse deviations in the position of a moving strip comprises capacitor elements co-operating with one or both edges of the strip to vary the tuning of a resonant circuit. Measurement The dielectric effect of a non-conductive material between the plates of a capacitor may be used or, as shown in Fig. 2, a conductive strip 30 cooperates with two edge plates 32, 34 to vary the tuning of circuits including secondary windings 24, 26 energized from a primary 20. Signals from tappings on the secondaries are rectified at Dl, D2 and applied differentially to the output at A, B. Alternative shapes and arrangements of edge plate are illustrated in Fig. 5 (not shown). Automatic Control Fig. 4 The output of the measuring circuit is connected (at windings 54, 56) to a pair of magnetic amplifiers 48, 50, to control a four-way valve supplying a hydraulic actuator 42 for the stripsteering-roll 36. Positional feedback is provided by a potentiometer 66 also driven by actuator 42 and connected in a bridge circuit with potentiometer 68 to energize feedback windings 61, 62.

Design Criteria for DC Switch with Resonant Circuit Connected Between Thyristors

Abstract: Based on an analysis of the circuit by Gentry et al.[1], a generalized design diagram is presented for determining optimum values of the L-C commutating circuit components of a dc switch with a resonant circuit connected between thyristors.

Sawtooth current generator

Abstract: A sawtooth current generator is disclosed which provides a linear time varying current for the coil of a magnetic deflection system of a television display tube. The coil is coupled to the collector of a transistor and the transistor is coupled to a resonant circuit which provides feedback to sustain the circuit oscillations and to actuate the transistor. In addition, a diode is coupled to the collector of the transistor. A constant voltage is maintained across the inductor by the alternate conduction of the transistor and the diode so that a linear time varying current flows in the inductor.

Operation of series connected gunn effect devices

Abstract: 1276674 Gunn effect oscillators GENERAL ELECTRIC CO 3 June 1969 [13 June 1968] 27988/69 Heading H3T [Also in Division H1] In a circuit, for generating an R.F. current, having a plurality of Gunn effect devices each comprising at least one Gunn diode, the devices 11A, 11B and 11C (Fig. 1), are connected in series with an anti-resonant circuit 12, for providing the R.F. voltage, and when a sufficient biasing voltage 13 is connected to this series connection the high field space charge domains nucleating in each Gunn effect diode are incompletely formed and have a substantial net negative space charge and the impedance of the anti-resonant circuit 12 is such that the total voltage applied to each Gunn diode due to the superimposed bias voltage and the R.F. output varies in each R.F. cycle between values above the threshold voltage and below the domain quenching voltage for the diode. The resonant circuit 12 is tuned to a R.F. which satisfies a predetermined inequality relationship between the average dielectric relaxation time of the semi-conductor material of the device and the period of the R.F. output so that domains nucleated in each device are not completely formed and have a substantial net negative space charge. The supply 13 may be a pulsed, continuous wave, bidirectional or unidirectional voltage and the anti-resonant circuit 12 includes a resistive load 16. The devices may be of GaAs, cadmium telluride or zinc selenide and may have tin electrodes. The devices may be connected in a coaxial cylinder resonator (35, Fig. 7, not shown), having the bias voltage fed via an input coaxial line 37, the output being taken via a coaxial line 40. A hole 36 in the coaxial line forms a by-pass capacitor. In a modification (Fig. 8, not shown) the devices 11 may be replaced by a plurality of series-connected Gunn effect devices (42) connected in parallel with a further similar series connection of devices. Alternatively a plurality of devices may be connected in parallel (Fig. 10) and then connected in series with a further parallel group of devices. The devices may be soldered between molybdenum bars 44-47 which are bonded to a heat sink 50 which may be of beryllia. The spaces between the devices may form passageways through which cooling fluid can be circulated.

A New Starting Circuit for Self-Excited Inverters

Abstract: A new starting circuit has been developed for self-excited inverters and oscillators. This new starting circuit over-comes a number of shortcomings and disadvantages of previously used single-and multiple-pulse circuits. Analysis and design of the circuit is presented, as well as a description of its application in an ac-to-dc power supply.

A Simple Analysis of the Foster-Seely Discriminator

Abstract: This paper presents a simple, straightforward analysis of a Foster-Seeley discriminator. Because this analysis differs from the classical approach, it can be seen that there are two distinct sources of distortion. These sources are the resonant circuit of the discriminator and the output portion of the circuit. An analytic proof of the linearity of the output portion is given. It is shown that the resonant circuit is the dominant source of distortion and that it may be minimized by proper selection of circuit components.