Showing papers on "Relaxation oscillator published in 1980"

Apparatus for reproducing disc record

Abstract: Apparatus for maintaining a constant linear velocity for a PCM disc record which includes a detector for optically detecting the PCM signal on the record and supplies the output to a differentiating circuit and a rectifier circuit with the output of the rectifier circuit supplied to a peak detector circuit which supplies its output to a level comparator that also receives a reference level from a reference source. A first phase comparator also receives the output of the rectifier circuit and controls a voltage controlled oscillator through a low pass filter and the output of the voltage controlled oscillator is supplied to the phase comparator. A divider receives the output of the voltage controlled oscillator and supplies a first input to a phase comparator which also receives an input from a reference frequency generator. The outputs of the level comparator and the phase comparator are supplied to the motor drive circuit which controls the drive motor for the disc record.

Trajectory Divergence for Coupled Relaxation Oscillators: Measurements and Models

Abstract: The exponential divergence of nearby phase space trajectories is a hallmark of nonperiodic (chaotic) behavior in dynamical systems. We present the first laboratory of measurements of divergence rates (or characteristic exponents), using a system of coupled tunnel diode relaxation oscillators. This property of sensitive dependence on initial conditions is reliably associated with broadband spectra, and both methods are used to characterize the motion as a function of the coupling strength and natural frequency ratio of the two oscillators. A simple piecewise linear model correctly predicts the major periodic and non-periodic regions of the parameter space, thus confirming that the chaotic behavior involves only a few degrees of freedom.

Gated oscillator including initialization apparatus for enhancing periodicity

Abstract: A gated oscillator is disclosed wherein the first period of oscillation is substantially equal to the steady state period of oscillation. The gated oscillator is of the type wherein oscillations are produced by charging and discharging a capacitor between respective first and second voltage levels. When the oscillator is stopped, the capacitor potential is maintained at the first voltage level, so that when the oscillator is started, the capacitor begins its charging cycle at the first voltage level.

Low voltage, low power RC oscillator circuit

Abstract: A resistor-capacitor oscillator circuit (10) is provided and includes a voltage comparator circuit (12). A capacitor (20) is connected to an input terminal (14) of the voltage comparator circuit (12). A resistor divider network (30) is coupled to an input terminal (16) of the voltage comparator circuit (12) for generating a reference voltage. A delay circuit (50, 52) is coupled to an output terminal (42) of the voltage comparator circuit (12). A discharge device (54) is coupled to the delay circuit (50, 52) and to the capacitor (20) for discharging the capacitor (20). A switching device (40) is coupled to the output (42) of the voltage comparator circuit (12) and to the resistor divider network (30) for controlling the application of the reference voltage to voltage comparator circuit (12).

RF Generator monitor circuit

Abstract: An RF generator monitor circuit is provided for checking for variation in frequency of an RF generator outside predetermined limits. The circuit includes means for sampling the output of an RF generator, means for clamping the sample signal to prevent damage to the circuit from an exceptionally strong signal, means for converting the clamped sample signal to a positive going square wave, and for amplifying the square wave. Also included is a phase locked loop integrated circuit having the amplified square wave as an input. The phase locked loop integrated circuit includes a linear voltage-controlled oscillator and two different phase comparators. The input square wave signal is compared to the voltage controlled oscillator and an error voltage proportion to phase differences is produced. The error voltage is used as a control for the voltage controlled oscillator. When the input square wave signal is within the predetermined frequency limits the error voltage causes the voltage controlled oscillator to be adjusted to a frequency equal to that of the input signal. When the input signal is outside the predetermined limits the phase comparators provides output signals indicative thereof.

Relaxation oscillator including constant current source and latch circuit

Abstract: An oscillator circuit which demonstrates stable operation over a wide range of supply voltages and process variations. A latch circuit is controlled utilizing a timing capacitor. A constant current source is applied alternately to opposite sides of the timing capacitor through a series of switching gates which bootstrap the voltage across the timing capacitor, with the switching gates being controlled by the output of the latch circuit.

Compensated current feedback oscillator ballast for fluorescent lamps and the like

Abstract: A power source for operating gas discharge lamps and other loads at high frequency, typically utilizing a dc source or a rectified ac source to produce a high frequency output. An inverter with oscillator circuit and first transformer has the secondary or load winding connected to a second transformer which provides a feedback signal to the transistor of the oscillator circuit through another transistor which functions as a variable resistance in the base drive of the oscillator transistor for maintaining power to the load substantially constant. A third winding on the inverter transformer is used to provide a control signal to the base circuit of the variable resistance for protecting the circuit components during an open secondary or no load condition.

Electronic timepiece with illumination lamp battery voltage drop compensation circuit

Abstract: In an electronic timepiece having a quartz crystal controlled standard frequency oscillator and a device which temporarily imposes a heavy load on the battery when activated, means are provided for changing a value of a circuit constant in the oscillator circuit, such as capacitance or resistance, when the load device is activated. This change in circuit constant value serves to decrease the value of the minimum battery supply voltage below which the oscillator circuit ceases to function, thereby ensuring reliable operation of the oscillator circuit when the timepiece battery voltage drops due to current being supplied to the load device.

Closed loop constant current tuned oscillator

Abstract: A transformer coupled, resonant feedback, tuned oscillator circuit in which the output current to a low power variable load is maintained constant by incorporating into the circuit an additional feedback circuit which provides a DC error voltage to the oscillator circuit enabling it to compensate for variations in core loss resistance, variations in load, and variations in other circuit parameters. The feedback circuit includes two separate electronic switches both of which are connected to a voltage averaging circuit and an error amplifier which compares the voltage of the averaging circuit against an adjustable reference voltage whereby the DC error voltage is generated and supplied to the center tap of the transformer feedback winding. Because oscillator transformer core resistance variations can be compensated for, the design of the oscillator transformer can be simplified and readily available, not specially designed, transformers can be utilized.

Electronic security memory including on-off controlled oscillator

Abstract: A security memory having a transistor oscillator with feedback, a power supply input, a control input, and an a.c. output as well as an amplifier. This memory designed in accordance with relay security standards, is of the negative control type, which stores the disappearance of a logic signal which is a function of at least one logic variable. To this end its control input is energized with a voltage whose absolute value is smaller than that of the supply voltage of the oscillator and is connected to the collector of the transistor via a diode, which collector in its turn is connected to a capacitor via a first transformer winding, which capacitor starts and sustains the oscillation.

Synchronisation circuit controlling oscillator frequency - incorporates resonant frequency of input circuit in receiver, and has control unit with comparator and operational amplifier

Abstract: The synchronisation circuit has two frequency-control loops. The first loop consists of a first converter, a first control and the receive oscillator. The second loop consists of a second converter, a second control and a sample oscillator. The controls consist of comparators or operational amplifiers. The converters receive reference signals. A reference converter is provided as a third converter. The loop converters have two inputs; one receiving the reference signal and the other the oscillator signal.

Control circuit for multivibrator

Abstract: A multivibrator in which a timing capacitor is connected between the collector of a first transistor and the base of a second transistor and in which a current source connected to the collector of the first transistor provides the charging current for the timing capacitor. The conduction path of a third transistor is connected between the collector and base of the first transistor and its control electrode is connected to a control voltage point for controlling the charging period of the capacitor and for ensuring oscillation when the multivibrator is connected as an astable multivibrator.

Low voltage fluorescent lamp operating circuit

Abstract: A circuit for starting and operating a low-voltage tioures- cent lamp (10) from a 120 volt AC supply (12,14). The circuit includes a choke type ballast (26) connected in series with the lamp and inductively coupled to a pulse train generator comprising an RC energy storage circuit (30) connected across the line and a voltage sensitive transistorized relaxation oscillator (36) having a divider network for sensing lamp voltage. In a preferred embodiment, the circuit is employed in a preheat mode of operation in combination with an electronic starter (16) circuit comprising a PTC resistor (64), a silicon diode (62) and SCR (60) series connected across the lamp.

Low frequency astable oscillator having switchable current sources

Abstract: A low frequency oscillator of the astable type having good frequency stability, fast starting, good immunity to DC loading, and suitable for fabrication in integrated circuit form. First and second switching transistors of the astable multivibrator are cross-coupled by a coupling capacitor and a frequency determining crystal. Base drive to the respective switching transistors and charging current to the capacitor and crystal are provided by a pair of differential amplifiers which are referenced to a forward biased diode. The differential amplifiers are also connected to respective collector terminals of the switching transistors. The capacitor is of small value suitable for containment within an integrated circuit with the oscillator circuit. The differential amplifiers substantially increase the impedance levels in the oscillator and shift base drive to the switching transistors to minimize the effects of DC loading at the output terminals of the oscillator.