Showing papers on "Relaxation oscillator published in 1996"

A novel low-cost capacitive-sensor interface

Abstract: This paper describes the design of a new capacitive sensor interface. The interface is based on the use of a novel type of oscillator whose frequency is insensitive to low- and high-frequency interfering signals by the application of a third order high-pass filter and special dither techniques. The fully integrated 0.7 /spl mu/m CMOS circuit shows an inaccuracy of less than 100 aF with respect to a 2 pF reference capacitor over a -30/spl deg/ to +70/spl deg/C temperature range. The applied measurement concept guarantees high stability, high accuracy and a negligible influence of parasitic capacitances without the need for calibration.

A high-resolution, linear resistance-to-frequency converter

Abstract: A resistance-to-frequency converter consisting of a Wheatstone bridge followed by an integrator and a comparator is described. In concept the circuit represents a relaxation oscillator whose frequency changes linearly with a resistance change detected by the bridge. Analyses show that a resolution better than 0.05% is possible with the simple configuration, and an excellent linearity is maintained over the wide resistance change by using a simple compensation method. The converter is therefore suited as a signal conditioner of a resistive sensor. Experimental results are included to demonstrate its performance.

Temperature-compensated piezoelectric oscillator

Abstract: A temperature compensated piezoelectric oscillator includes: an oscillation circuit that drives a piezoelectric element with a current; a direct-current-stopping fixed capacitor; a frequency-temperature compensated circuit that compensates the deviation of an oscillation frequency caused by a change of temperature; and a piezoelectric transducer which includes a piezoelectric element driven in a prescribed frequency; where the above elements are connected serially; wherein the frequency-temperature compensated circuit includes a temperature compensation voltage generation section which generates a voltage based on a parameter that is changed in a temperature detection unit, in which the parameter changes according to the surrounding temperature; wherein the temperature compensation voltage generation section includes: a low-temperature control voltage generation section which generates a voltage that compensates a temperature characteristic of the piezoelectric element in a low temperature, where "low" indicates temperatures lower than a common temperature in the temperature characteristic of the piezoelectric element; and a high-temperature control voltage generation section which generates a voltage that compensates the temperature characteristic of the piezoelectric element in a high temperature, where "high" indicates temperatures higher than a common temperature in the temperature characteristic of the piezoelectric element; wherein the low-temperature control voltage generation section includes: a low-temperature first-degree voltage generation circuit which generates the voltage that linearly changes with temperature; a low-temperature high-degree voltage generation circuit which generates the voltage that behaves like a high degree function in a low temperature state of the voltage generated by the low-temperature first-degree voltage generation circuit; and a low-temperature voltage composite circuit which synthesizes voltages generated by the low-temperature first-degree voltage generation circuit and the low-temperature high-degree voltage generation circuit; and wherein the high-temperature control voltage generation section includes: a high-temperature first-degree voltage generation circuit which generates the voltage that linearly changes with temperature; a high-temperature high-degree voltage generation circuit which generates the voltage that behaves like a high degree function in a high temperature state of the voltage generated by the high-temperature first-degree voltage generation circuit; and a high-temperature voltage composite circuit which synthesizes voltages generated by the high-temperature first-degree voltage generation circuit and the high-temperature high-degree voltage generation circuit.

Simulation and modeling of phase noise in open-loop oscillators

Abstract: This paper presents a discussion about the definition of phase noise for general oscillation waveforms; a numerical method for transistor-level simulation and characterization of phase noise in open-loop (free running) oscillators; application of the phase noise simulation method to harmonic, relaxation and ring oscillators and a technical discussion of the phase noise characterization results; comparisons of the results of phase noise simulations for harmonic, relaxation and ring oscillators with the results of related work in the literature.

Resonant Tunnel Diodes as Submillimetre-Wave Sources

Abstract: Resonant-tunnelling diodes (RTDS) are one of the only quantum-transport devices that operate effectively at room temperature, and are well known for their high-speed coherent generation and switching characteristics associated with the negative differential resistance (NDR) region. This paper addresses their capability as high-frequency coherent sources. Two types of sources will be addressed here: (i) quasi-sinusoidal oscillators connected to a resonant circuit, and (ii) relaxation oscillators connected to a high-frequency energy-storage element, such as a length of transmission line. To date, the highest-frequency sinusoidal oscillator was a waveguide-mounted InAs-AlSb RTD that performed up to 712 GHz. Transmission-line relaxation oscillators have been demonstrated only at microwave frequencies but show promise as submillimetre-wave sources. Their output waveform consists of a sequence of pulses having a repetition rate determined by the electrical delay of the transmission line and a pulse width determined by the switching time of the diode. Because they do not require DC-bias stability in the NDR region, they are quite amenable to power-combining techniques, such as parallel arrays, and could behave in an analogous manner to the atomic species in a mode-locked laser.

Low power oscillation circuit and non-volatile semiconductor memory having ring oscillator

Abstract: An low-power consumption integrated ring oscillator capable of stable operation throughout a wide voltage range without undergoing a large frequency change includes a first constant voltage generating circuit having an enhancement mode P-MOS transistor and a depletion mode N-MOS transistor and a second constant voltage generating circuit having a depletion mode N-MOS transistor and an enhancement mode N-MOS transistor. A first constant voltage generated by the first constant voltage circuit is applied to a gate electrode of a P-MOS transistor of transmission gates connected between respective cascaded inverters of the ring oscillator. A second constant voltage generated by the second constant voltage generating circuit is connected to the gate electrode of an N-MOS transistor of the transmission gates. By this construction, current consumption is reduced and battery lifetime can be increased. The boosting circuit for writing and erasing an EEPROM circuit may be formed with the low power ring oscillator.

Voltage-controlled oscillator circuit

Abstract: There is disclosed a voltage-controlled oscillator circuit capable of being operated at low power supply voltages and accomplishing low electric power consumption. The circuit permits the duty cycle to be controlled well. The circuit is capable of operating at high speeds. The circuit comprises a first and a second dynamic latch circuits producing oscillation output. Each dynamic latch circuit consists of a series combination of a P-channel MOS transistor and an N-channel MOS transistor. An output terminal is connected to the junction of these two transistors. The output from each latch circuit is inverted according to the voltage at the gate of each MOS transistor and dynamically latches the state of the output. This inversion is performed by turning on the MOS transistors by first and second capacitive elements and by first and second comparator circuits. The capacitive elements are charged and discharged by the outputs from the dynamic latch circuits. Voltages for charging the capacitive elements are applied to the comparator circuits. The switching operation is performed at a higher speed than where a flop-flop is used. Consequently, the oscillation frequency is improved. These MOS transistors do not simultaneously conduct and so electric currents passing through the transistors can be suppressed. Since the timing at which the inversion is made is determined by the charging rates of the capacitive elements, the duty cycle can be controlled well.

An Experimental Study of a Population of Relaxation Oscillators With a Phase-Repelling Mean-Field Coupling

Abstract: The dynamical behavior of a system of coupled relaxation oscillators is studied experimentally. A population of up to 15 coupled electronic op-amp relaxation oscillators is used as a prototype for the real collections of limit-cycle oscillators frequently found in many physical, biological, and technological systems. The oscillators interact via an all-to-all or mean-field coupling. The rarely studied case of antiferromagnetic interactions, in which oscillators tend to repel each other in phase, is considered. The behavior of the system is significantly different from the predictions of the limited theory that is currently available. The novel behavior observed includes the existence of numerous distinguishable phase-locked states and an exponential distribution of the duration of transients. The critical coupling strength necessary for the oscillator system to completely phase-lock is measured. A simple geometrical model of the dynamics of the system during the transient is presented as a means of understanding the exponential distribution of transient lengths. In addition, a phase-response oscillator model is shown to exhibit similar transient behavior.

High performance voltage controlled oscillator that is cost efficient

Abstract: A high-performance voltage controlled oscillator without use of variable capacitance (varicap) diodes which is easy in fabrication in an semiconductor IC form. The voltage controlled oscillator includes:a differential amplifier having a differential pair of transistors (Q1, Q2); an LC resonance circuit having a coil (L0) and a capacitor (C0); a phase shift circuit for receiving a differential output of the differential amplifier via a buffer of transistors (Q3, Q4) and for providing its output for the differential amplifier in a positive feedback mode; and a current control circuit for variably controlling an operating current (Ie) of the phase shift circuit according to a controlled voltage applied from a circuit other than those in the voltage controlled oscillator.

Magnetic-field sensor based on a relaxation oscillator

Abstract: A new magnetic-field-sensitive device with frequency output has been developed using a novel relaxation oscillator. The frequency output is a linear function of the magnetic-field variations from 1 to 1000 G. Experimental results show a sensitivity of 12 Hz G−1. Further digital signal conditioning is achieved by means of a microcontroller.

Variable-frequency oscillator configuration

Abstract: A variable-frequency oscillator configuration, in particular for tuners, includes a feedback network for an oscillator amplifier. The feedback network contains a series circuit formed by two resonant circuit inductors and a resonant circuit capacitor, connected in parallel with a series circuit formed by a further resonant circuit capacitor and a variable capacitor. A switching device is connected to a coupling node between the two inductors, for short circuiting the first resonant circuit capacitor and the resonant circuit inductor connected thereto under the control of a switching signal. The feedback network can consequently be switched over between two frequency bands and is symmetrical with regard to the high-frequency effect.

Parabolic and triangular wave oscillator with sliding mode

Abstract: On the basis of the theory of variable structure control systems (VSCS) with sliding modes, a new mathematical method for the design of high performance electronic triangular- and parabolic wave generators has been proposed. Theoretically obtained results were verified experimentally using a conservative oscillator controlled by a microprocessor.

Switching mode limit-cycle resonant oscillator as a relaxation oscillator

Abstract: Switching Mode Limit-Cycle Resonant Oscillators constitute a distinct and useful class of systems in the field of oscillators. Previous works have described the oscillatory processes of such systems as being closely similar to those of other limit-cycle oscillators. The present paper shows analytically, and demonstrates by way of simulation, that the dynamic behaviour of such systems at relaxation is unique. A comprehensive comparative analysis of the presently less known systems and the relatively similar well known Rayleigh oscillator and other related oscillators is carried out by relying on numerical simulation work.

Programmable oscillator using one capacitor

Abstract: A programmable oscillator comprising a switching circuit, a first driver circuit, and a second driver circuit, the oscillator being programmable to switch at a first switching frequency or a second switching frequency by utilizing only one external capacitor and two external resistors. Only one driver circuit is active at a time to charge and discharge the capacitor at one of the switching frequencies. The driver circuits are made active or inactive by a control circuit.

Coupled relaxation oscillators with highly stable and accurate quadrature outputs

Abstract: Coupled relaxation oscillators can have extremely accurate and stable quadrature outputs. A model is presented to predict the stability of the phase relation. It is confirmed by measurements and shows the power of the concept.

Oscillator based tamperproof precision timing circuit

Abstract: An oscillator that has a substantially-constant voltage source configured such that it does not require the voltage source to be tuned to a particular voltage to oscillate a particular frequency. The oscillator has greater precision and reliability since the inputs of the comparator are periodically switched to reduce the effects of comparator bias and to equalize the voltage stresses on the inputs of the comparator. Greater precision is also achieved through the use of a discrete resistor and a discrete capacitor to define the frequency of the oscillator. The present invention provides an oscillator and method to generate a periodic signal that is tamperproof because the circuitry that defines the period is either integrated onto the integrated circuit or contained within the package containing the integrated circuit. The oscillator may be used as a frequency reference in a speed governor circuit and that speed governor may be included in an integrated circuit such that the speed governor disables a functional block of the integrated circuit when the clock frequency exceeds a frequency limit.

An injection-locked oscillator standard cell

Abstract: The new injection-locked oscillator (ILO) standard cell consists of a differential comparator and even stages of an inverter chain. The ILO has a very simple design and is highly suitable for standard cell applications. The new ILO can be used as a stand alone voltage control oscillator (VCO) or as a building block of a digital phase lock loop. Applications of this circuit include VCO, clock recovery, and clock synthesizer. The characteristics as well as simulation and testing results of the new ILO are presented.

Simulating oscillators using SPICE

Abstract: SPICE generation of the output signals from electronic oscillator circuits is obtained by transient analysis. Simulation success is software specific and depends upon how the transient analysis function is configured. Different tricks, which are oscillator configuration specific, may be applied to achieve simulation output. In the final analysis, one must remember that simulation is not a complete and full replacement for circuit construction and testing. Accurate analysis is given for resonant or relaxation circuits.

The dynamics of coupled nonlinear oscillators: from relaxation oscillators to neurons

Abstract: The dynamics of coupled nonlinear oscillators are extremely rich and important for a large variety of physical, technological, and biological systems. We present results for three different applications: a study of the complex behavior of several coupled electronic relaxation oscillators; a network of electronic neurons designed to simulate the dynamics of a cat retina; and an array of coupled nonlinear oscillators that can perform scene segmentation and pattern recognition.

Low-power CMOS current-conveyor relaxation oscillators

Abstract: The purpose of this paper is to investigate in detail the design of a current conveyor circuit suitable for implementation of low-voltage, low-power RC and crystal oscillators, and to show the design and performances of such oscillators. All circuits are based on the Fabre-Normand translinear conveyor. Circuits are biased in the subthreshold region whenever possible.

Device of the phase-locked loop type for demodulating a frequency-modulated signal

Abstract: Device of the phase-locked loop type for demodulating a frequency-modulated signal. Device for frequency demodulation, using a phase-locked loop. According to the invention, for linearizing the variation of the frequency of a local oscillator (11) as a function of its control signal (Vb), a variable capacitance (Cv) is formed by an electronic module (20) which supplies the equivalent of a capacitance whose variation as a function of the control voltage (Vb) has a linearity deviation which is established for compensating the linearity deviation of the frequency of the oscillator as a function of the value of the capacitance (Cv).

The relaxation oscillator as a resonance photon detector

Abstract: A commercially available neon indicator lamp in a Relaxation Oscillator (RO) configuration has been demonstrated to be capable of detecting light intensities of the order of nanowatts under ambient light conditions with a subpicometer spectral resolution. The RO has also been shown as capable of acting as a wireless light switch with light intensities of the order of 1 µW. Temporal excitation studies have also shown the predominant mechanism describing the observed frequency changes in the RO to be a result of laser perturbation of the neon lamp when it is in the Townsend-discharge region and not in the abnormal glow.

Electronic temp-controlled automatic speed regulator

Abstract: The utility model relates to a motor speed regulating device which is composed of a controllable silicon voltage regulating circuit and a temperature detection control circuit. The controlled silicon voltage regulating circuit is connected with a rectifier through a power supply, the rectifier provides pulsating direct current voltage for the controlled silicon, the control electrode of the controlled silicon is connected with a relaxation oscillator formed by a triode circuit, and trigger pulse is generated. The temperature detection control circuit uses a detector diode as a temperature-sensing element used for controlling the conducting degree of the triode circuit, and the conducting angle of the controlled silicon can be regulated through changing the time constant of the circuit and causing the trigger pulse to advance or lag. The utility model achieves the stepless non-contact speed regulation, having the advantages of good linear variation and energy saving, and prolonging the service life of appliances.

Voltage controlled self-temperature compensated crystal oscillators with ns-gt cut quartz resonators

Abstract: In this paper, voltage controlled self-temperature compensated oscillators made with NS-GT cut quartz resonators (VC-S-TCXOs in what follows) are introduced and their frequency stability (obtained by controlling input voltage to VC-S-TCXO) is discussed. An oscillator circuit consists of a CMOS inverter, a variable capacitor diode, resistors, and capacitors. The primary oscillator frequency of the coupled quartz resonator is first derived from the electric equivalent circuit of the oscillator. The oscillator frequency is given by a function of the coupling coefficient, which in turn is given as a function of the load capacitance CL. Since frequency stability by controlling the input voltage to VC-S-TCXO is dictated by the VC circuit, the VC circuit was investigated in detail in order for the circuit independent of temperature to be obtained. Using the VC circuit, the oscillator frequency was controlled by the input voltage and the temperature stability of the oscillator frequency was less than 4 × 10−9 at a temperature range of -30 to 85 °C. Furthermore, it has been demonstrated experimentally that the frequency stability of the VC-S-TCXO directly after voltage control does not depend on the frequency temperature characteristics of the quartz resonator, time interval between the voltage control, or rate of temperature change.

Loose synchrony in relaxation oscillator networks with time delays

Abstract: Coupled relaxation oscillators have been shown to exhibit robust properties of synchrony and desynchrony. We study a network of such oscillators with the inclusion of time delay in the coupling. Analytic results for a pair of oscillators show loose synchrony as a stable solution for a wide range of initial conditions and time delays. Computer simulations show a network of oscillators with time delay coupling can display loose synchrony. Simulations of oscillator networks with variations in time delays and connection strengths between oscillators demonstrate loose synchrony is still achieved.

Synchronisation phenomena in RC oscillators coupled by one nonlinear negative resistor

Abstract: There have been many investigations on mutual synchronization of oscillators. We analyze the van der Pol type LC oscillators coupled by one resistor, and confirm that this system can take a large number of steady states, ideal for the realization of memory or CNN applications. However, as this system includes inductors, it is not suitable for VLSI implementation. In this paper, we investigate the synchronization phenomena in RC oscillators coupled by one negative resistor using both computer calculations and circuit experiment. In this system, we achieve 2-phase oscillations without using an inductor. So it is available to VLSI implementation and the phase state of this system is binary. It is more suitable for the structural elements of cellular neural networks.

Accurate rc oscillator

Abstract: An accurate RC oscillator circuit (10) for generating a signal of a predetermined frequency that accurately oscillates between two precise voltage levels, i.e., a low threshold voltage (VL) and a high threshold voltage (VH) is disclosed. The oscillator circuit uses first and second comparators (16, 18) having their outputs respectively coupled to set and reset inputs of a flip flop (20). The output of the flip flop is coupled to a series RC network for controlling the charging and discharging of the voltage across a capacitor (14) of the RC network. The interconnection (12) of the series RC network is coupled to an input of both the first and second comparators. The other input of the first comparator is coupled to a circuit (24) for applying a modified version (V'H) of the high threshold voltage such that the signal generated by the oscillator circuit does not exceed the precise high threshold voltage (VH). Likewise, the other input of the second comparator is coupled to a circuit (25) for applying a modified version (V'L) of the low threshold voltage such that the signal generated by the oscillator circuit does not fall below the precise low threshold voltage (VL).

1996 ieee international frequency control symposium low-power cmos current-conveyor relaxation oscillators

Abstract: The purpose of this paper is to investigate in detail the design of a current conveyor circuit suitable for implementation of low-voltage, low-power RC and crystal oscillators, and to show the design and performances of such oscillators. All circuits are based on the Fabre- Normand translinear conveyor. Circuits are biased in the subthreshold region whenever possible.

Controlled oscillator circuit for controlling an oscillator for use within a phase-locked loop

Abstract: The output frequency (14) of an oscillator circuit (10) can be controlled by replacing at least one of the reactive components (40), such as a capacitor or inductor, with a synthesized element (22). The synthesized element creates a signal that corresponds to the response of the reactive component it is replacing. The synthesized element may be a current source (44), such as a field effect transistor, that is capable of operating at low voltages.