Yasuo Tsuzuki

Fast start-up crystal oscillator circuits

This paper presents a reduction method of the start-up time after the switch-on of the D.C. power supply of a crystal oscillator circuit. It is shown that a fast start-up crystal oscillator can easily be obtained by changing only the circuit connection of the crystal resonator. The new scheme can be applied to the usual Colpitts crystal oscillator circuits, to the cascode crystal oscillator circuits, and also to the overtone crystal oscillator circuits.

Formulation of nonlinear negative resistance for calculation of start-up characteristics of crystal oscillators

This paper presents an algebraic formula of the nonlinear characteristics of the negative resistance of a transistor crystal oscillator circuit. This formula is very useful for the calculation of the start-up characteristics of a crystal oscillator as the start-up behavior depends on the nonlinear characteristics of the negative resistance.

Analysis of start-up characteristics of CMOS crystal oscillators

A method for analysis of the start-up characteristics of CMOS crystal oscillators is described. The cause of oscillation just after DC power supply switched on is described and confirmed by experiment. The analytical method is outlined for calculation of the overall start-up characteristics of the amplitude of oscillation. Experimental results are given to verify the usefulness of this method.<<ETX>>

Low drive level crystal oscillator circuit

This paper presents a design method of a transistor crystal oscillator circuit in which the steady oscillation occurs at very low drive level. It has been shown that the reduction ratio of up to 1/50 of the resonator current can be obtained.

Computer Analysis of Colpitts Crystal Oscillator

In this paper, a novel analyzing method o f crystal oscillators is described. In an ordinary oscillator, such as colpitts oscillator, an oscillation can be achieved by connecting a crystal resonator to an active circuit having a capacitive reactance and a negative resistance . In the present method, the negative resistance and equivalent capacitance of the circuit are first calculated by use of a circuit simulation program based on nonlinear models of active devices. Then the oscillation frequency and its signal level are obtained for a specified crystal resonator. In this work calculations have been made on a colpitts oscillator widely used in the frequency range up to 3 0 MHz. The important design parameters of the oscillator, such as the l vel and the frequency dependences of both the equivalent capacitance and the negative resistance, the oscillation frequency and level and the oscillation frequency change due to the power supply voltage variation, have been calculated with satisfactory agreements with measurements. It is concluded from these results that this analyzing method is useful for the analysis and design of crystal oscillators.

Measurement method of VHF elastic vibrations by optical fiber interferometric sensing

A measurement method is presented for elastic vibration modes with extremely small vibration amplitudes in the very high frequency (VHF) range. The measurement system is an optical fiber interferometric sensor, which detects optical phase modulations caused by the elastic vibrations being tested to give the vibration amplitudes. Extensive use of recent optical fiber technology along with a signal processing technique enables the authors to achieve detailed measurements of vibration amplitudes as small as 0.1 A at frequencies as high as nearly 150 MHz.<<ETX>>

Evaluation of nonlinear elastic coefficient causing frequency shifts in AT-cut resonators

The authors describe an experimental evaluation scheme of the fourth order nonlinear elastic constant of quartz C/sub 6666/ using AT-cut resonators. The evaluation has been made from measured quadratic frequency changes against excitation currents and actual vibration amplitude distributions of thickness-shear vibrations measured by an optical fiber vibration sensor. More reasonable estimates of C/sub 6666/ were obtained compared with those previously reported which vary considerably from each other.<<ETX>>

Improvements of Laser Interferometric Measurement System of Vibration Displacements

Abstract : Improvements have been made on the laser interferometric measurement system of vibration displacements of quartz crystal resonators. In this paper, the following modifications have been made: the DC phase control and the small-deviation low-frequency phase modulation are introduced on a laser beam. The amplitude of the vibration displacement is obtained as a digital data. A measurement and processing of data are made by the computer system. The improved system can be used to the measurement of vibration displacement down to five angstroms within a few percent repeatibility in the frequency range from 1 MHz to 10 MHz. Using this system, the detailed vibration displacement distributions of a plano convex SC-cut quartz crystal resonators have been measured.

Measuring Method of Equivalent Series Capacitance and Negative Resistance of Quartz Crystal Oscillator Circuits

Abstract : A measuring method has been developed to obtain the oscillator circuit input impedance characteristics, so that the oscillator circuit operation performance can be estimated without connecting a crystal resonator. The operation performance of the crystal oscillator can be estimated without connecting a crystal unit if we measure how the input impedance, which is usually represented by an equivalent capacitance and a negative resistance, behaves with the frequency and amplitude of the driving signal current of the circuit. In this paper a measuring method of the equivalent capacitance and the negative resistance of the oscillator circuit has been considered. The equivalent capacitance and the negative resistance are measured by comparing them with a reference capacitance and a reference resistance, respectively.

Method of Measuring VHF Elastic Vibration Modes by Optical Sensing

This paper describes an optical measurement method of elastic vibration modes with extremely small vibration amplitudes in the very high frequency (VHF) range. The measurement system is an optical fibre interferometric sensor, in which optical phase modulations caused by elastic vibrations under study are detected and processed to give the vibration amplitudes. Extensive use of recent optical fibre technology and a signal processing technique enabled us to achieve detailed measurements of vibration modes with amplitudes as small as 0.1 A at frequencies as high as 150 MHz.