Showing papers on "Crystal oven published in 2003"

Temperature compensation for a variable frequency oscillator without reducing pull range

Abstract: A variable frequency oscillator having multiple, independent frequency control inputs, each coupled to a respective tuning sub-circuit. The tuning sub-circuits are connected in parallel with each other and with a resonator module, which may be a quartz crystal, inductor, or other reactance component. Each tuning sub-circuit consists of two varactors with their respective cathodes coupled to each other and to their corresponding frequency control input. By having the tuning sub-circuits connected in parallel to the resonator, the overall frequency pull range of each frequency control input remains unaffected by the activation of any other frequency control input. Preferably, at least one frequency control input is a temperature compensation control input that can maintain the variable oscillator insensitive to temperature variations while the remaining frequency control inputs provide functional frequency control.

Quartz crystal resonator, quartz crystal unit, and quartz crystal oscillator

Abstract: PROBLEM TO BE SOLVED: To provide a miniature tuning fork quartz crystal resonator capable of vibrating in a flexural mode and having high stability at a frequency for a fundamental mode of vibration, a small equivalent series resistance R 1 and a high quality factor Q, and to provide a quartz crystal unit comprising the quartz crystal resonator, and a quartz crystal oscillator for providing an output signal with a highly stable oscillation frequency. SOLUTION: The tuning fork bent quartz crystal resonator comprises tuning fork arms; and a tuning fork base, each tuning fork arm having a groove on its upper and lower faces, electrodes being deposited to the side of the grooves, and electrodes of different polarity deposited to side faces of each turning arm opposite to the electrodes deposited to the groove side face. The tuning base is connected to a frame via a connection part. Moreover, the quartz crystal oscillator is realized wherein the bent quartz crystal resonator configures the quartz crystal unit, the figure of merit in a fundamental mode of vibration is greater than the figure of merit in a second overtone mode of vibration, and the output signal from the quartz crystal oscillator has the oscillation frequency in the fundamental mode of vibration on the basis of a relation between an amplification factor of an amplifier circuit and a feedback factor of a feedback circuit. COPYRIGHT: (C)2005,JPO&NCIPI

On-board processor compensated oven controlled crystal oscillator

Abstract: An oven controlled crystal oscillator has an onboard processor containing an algorithm used to generate a frequency compensating signal based on a predetermined relationship and a monitored current consumption of a heater.

PLL-controlled oscillator

Abstract: A PLL (Phase-Locked Loop)-controlled oscillator has a temperature-compensated crystal oscillator having a quartz crystal unit, an oscillating circuit connected to the crystal unit, and a temperature compensating mechanism for generating a temperature compensating voltage for compensating for frequency vs. temperature characteristics of the crystal unit, and a voltage-controlled oscillator having an LC oscillating circuit, for being controlled by a PLL using the temperature-compensated crystal oscillator as a reference signal source. The temperature-compensated crystal oscillator has circuit components except for the crystal unit, the circuit components and the voltage-controlled oscillator being integrated in a one-chip IC. The one-chip IC and the crystal unit are integrally combined with each other in the PLL-controlled oscillator.

A parametric quartz crystal oscillator

Abstract: Parametric oscillators have been well studied but currently are not used often. Nevertheless, they could be a low-phase noise solution, at least outside the frequency bandwidth of the resonant circuit. The theoretical aspect of parametric oscillations is briefly reviewed in this paper. Indeed, the basic theory of a simple resistance-inductor-capacitor (RLC) circuit working in parametric conditions easily can be extended toward a resonant loop that includes a quartz crystal resonator. Then, as an application, this study is transposed to a quartz crystal oscillator that has been modeled and tested as a first prototype. Simulation results are compared with those actually obtained.

GPS disciplined offset-frequency quartz oscillator

Abstract: The global positioning system can be used to provide a precise time and frequency reference to control local oscillators. The local oscillator is necessary to provide holdover of time and frequency in the absence of GPS and to average short-term jitter in the GPS signal recovered by the receiver. This paper gives an overview of the hardware design and control strategy for converting the output of a free-running ovened quartz oscillator (OCXO) to the desired standard frequency output by reference to GPS. The method enables the use of a very low aging fifth overtone quartz oscillator, to which final plating of the crystal to trim 'on frequency' is omitted. Sufficient frequency control could not normally be applied to this very stable oscillator by the conventional method of varactor tuning. A compact implementation is achieved with very low spurious frequency content and low phase-noise of the standard frequency output. Performance data is presented.

Programmable oscillator circuit

Abstract: A programmable crystal oscillator is provided having a memory for storing frequency-defining parameters. Typically, one of these parameters is used to program an adjustable capacitive load circuit coupled to a crystal to thereby adjust the crystal source frequency. Additional parameters are used to program the output frequency of a phase locked loop circuit coupled to receive the adjusted source frequency. A further parameter can also be used to divide the output frequency of the phase locked loop circuit to supply a specified output frequency. The oscillators can be manufactured as generic programmable crystal oscillators without regard for output frequency and then quickly programmed to produce customer-specified output frequencies with a high degree of accuracy.

Quartz crystal resonator, unit having resonator, oscillator having unit, electronic apparatus having oscillator, and method for manufacturing electronic apparatus

Abstract: A quartz crystal resonator has a quartz crystal tuning fork base and quartz crystal tuning fork tines connected to the quartz crystal tuning fork base. Each of the quartz crystal tuning fork tines has opposite main surfaces, a groove formed in at least one of the main surfaces, and an electrode disposed in the groove formed in at least one of the main surfaces so that a merit value M 1 of a fundamental mode of vibration of the quartz crystal tuning fork resonator is greater than a merit value M 2 of a second overtone mode of vibration thereof. The merit values M 1 and M 2 are defined by the ratios Q 1 /r 1 and Q 2 /r 2 , respectively, where Q 1 and Q 2 represent a quality factor of the fundamental mode of vibration and the second overtone mode of vibration, respectively, of the quartz crystal tuning fork resonator and r 1 and r 2 represent a capacitance ratio of the fundamental mode of vibration and the second overtone mode of vibration, respectively, of the quartz crystal tuning fork resonator. A piezoelectric constant e 12 of the the quartz crystal tuning fork resonator is within a range of 0.095 C/m 2 to 0.19 C/m 2 in the absolute value.

Design and realisation of a 100 MHz synthesis chain from an X-band reference signal

Abstract: LPMO has undertaken the building of a cryogenic sapphire oscillator with the support of the french space and metrology agencies (CNES and BNM). The aim of this project is to provide a reference oscillator presenting short frequency stability better than 5.10/sup -14/ in order to fulfill reference tests requirements for spatial and metrological applications. The cryogenic oscillator can operate on different frequencies ranging from 8 to 13 GHz depending on the sapphire resonator mode chosen as reference. The exact output signal frequency is not 'a priori' known with a great accuracy due to the large relative uncertainties (of the order of 10/sup -4/) affecting the resonator frequencies theoretical determination. Then a special synthesis chain has to be designed in order to transform the cryogenic oscillator performances to a reference signal whose frequency is fully compatible with most of time and frequency instrumentation. In this paper, we present the design, realization and preliminary tests of a synthesis chain generating a 100 MHz signal from an X-band reference. The performances of the two realized prototypes will enable to transform better than 5.10/sup -14/ short term frequency stability.

Quartz resonator, quartz unit, crystal oscillator, and manufacturing method thereof

Abstract: A small equivalent series resistance R n of the main vibration, crystal oscillator and their preparation with quality factor Q n value is high micro contour crystal oscillator and crystal unit and an output signal consisting of it highly stable oscillation frequency It is to provide a method. [Solution] The contour crystal resonator includes a vibrating portion, a connecting portion, and a supporting portion, which are formed by a particle method and / or a chemical etching method. Further, at least one pair of electrodes is arranged on a surface facing the vibrating portion. In addition, the contour crystal oscillator is housed in the crystal unit, and the figurine merit of the main oscillation is larger than that of the sub oscillation, and the relationship between the amplification factor of the amplifier circuit and the feedback ratio of the feedback circuit. Accordingly, a crystal oscillator whose output signal is the oscillation frequency of the main vibration can be realized with high accuracy. [Selection diagram] Fig. 1

Vehicular electronic apparatus suppressed of interference in receiving a broadcast wave

Abstract: A vehicular electronic apparatus contains a microcomputer, and a crystal oscillator for determining an operating frequency for the microcomputer. An oscillation frequency of the crystal oscillator is selected such that a frequency difference between a frequency of a broadcast wave received by a vehicular receiver and an oscillation frequency of the crystal oscillator or a higher harmonic of the oscillation frequency is 15 kHz or higher or 400 Hz or lower, to suppress an interference in receiving the broadcast wave.

Short-term stability of miniature double oven crystal oscillators using conventional and DHR technology

Abstract: The present work is devoted to experimental research on the influence of thermal fluctuations in the oven-controlled system on phase noise and short-term stability (STS) of the high stability double-oven crystal oscillators (DOCXO). The paper describes the method of the study and discusses obtained results. The research showed that measured level of STS of the DOCXO (3.0-3.5)/spl middot/10/sup -12/ - is not limited by the thermal noise of the ovens. However, improvement of the STS below (1-2)/spl middot/10/sup -12/ will require minimization of the temperature fluctuations in the double-oven system.

Wide range crystal oscillator

Abstract: A structure and associated method to allow an oscillator circuit to operate with a plurality of different crystals. The oscillator circuit comprises a semiconductor device and a crystal. The semiconductor device comprises a primary inverting amplifier and a crystal substitution damping resistor. The crystal is electrically coupled to the primary inverting amplifier. A resistance value of the crystal substitution resistor is adapted to vary in order to control an amount of current flow from the primary inverting amplifier to the crystal. The amount of the current flow to the crystal is dependent upon an electrical property of the crystal.

Frequency stability of a crystal resonator for biosensors

Abstract: This paper describes oscillation frequency stability of a crystal sensor for biosensors used for detection of dioxins, PCB, environmental-stressors, and marker proteins for infections. Present frequency stability is about 0.1 ppm in 9 MHz. Design technology for communication is applied to the crystal unit and oscillator circuit as a sensor. We prepared a crystal unit for filters in an oscillator circuit, and adopted a method that engenders oscillation frequency stability. That method demonstrates performance of 5 ppb at 9 MHz and 14 ppb at 155 MHz.

An oscillator for space

Abstract: These last years a new 10 MHz quartz crystal oscillator family has been designed in LCEP with the support of the French space agency (CNES). It is intended for space applications especially. In this paper, the description of its general features is followed by two parts. The first one described the methodology which has been developed for designing such an oscillator. This part deals with the modeling of noise as well as the mechanical and thermal structure of the oscillator. The second part summarizes main experimental results. This obviously includes the frequency stability of the oscillator and its behavior when various disturbances occur in its environment. We particularly took care of its sensitivity to external temperature changes at the atmospheric pressure and mainly under vacuum. Exhibited frequency sensitivities to a magnetic field and vibrations are also provided.

Accurate characterization of the temperature coefficient of permittivity of sapphire utilizing the dual-mode frequency locked technique

Abstract: In this work we present a new method to obtain accurate characterization of the temperature coefficient of permittivity (TCP) of an anisotropic crystal, which we name the dual-mode frequency locked (DMFL) technique. The technique requires precise simultaneous frequency measurements of two orthogonally polarized modes as a function of temperature. This was achieved by configuring a sapphire resonator as a pound locked dual-mode oscillator and measuring the frequencies with a frequency counter, while simultaneously recording the temperature with a platinum thermometer. From the two data files of frequency versus temperature, and the knowledge of electric and dimensional filling factors (obtained from finite element analysis), it was possible to calculate the integrals of the TCP without resorting to polynomial fits. This resulted in a precise model of the components of the TCP between 50 to 77 K for sapphire. The model is accurate enough to predict within a few degrees K, the frequency turnover temperatures of the difference frequency of a dual-mode oscillator.

Dynamics of the mean signal amplitude of a crystal oscillator with a nonlinear resonator and low drives

Abstract: The effect of "sleeping sickness" in crystal oscillators is associated with the low drive excitation after a long storage when the crystal resonator losses become large and nonlinear. In our work we have experimentally shown that specific approximation fits reasonably well towards drive level dependence (DLD) of the crystal resonator losses, if to start measuring from the noise floor and then gradually increase the piezoelectric current up to the normal drives. Here, the dynamics of the mean signal amplitude of the crystal oscillator with the nonlinear resonator and low drives, is presented

Software compensation type quartz oscillator

Abstract: PROBLEM TO BE SOLVED: To provide a software compensation type quartz oscillator. SOLUTION: A navigation satellite receiver has a quartz oscillator depending on a local ambient temperature. A true frequency bias of the quartz oscillator is calculated locally using a receiver after a GPS satellite was locked on. A basis for an atomic clock is established to measure the true frequency by system lock to the GPS satellite. A temperature of quartz is measured, and is recorded to be correlated to bias measurement of the true frequency. A polynomial of degree nine is generated thereafter to express a frequency drift of the quartz with respect to the temperature, using a data therein. Then, the ambient temperature is measured during initialization of the receiver of which the reference oscillator is not locked locally, the polynomial of the degree nine is exponentiated using a result therein to estimate an actual quartz frequency, and a signal is captured from the observable GPS satellite based thereon. COPYRIGHT: (C)2004,JPO

Highly Stable VHF Crystal Oscillator

Abstract: To meet the demand of space application, the various factors to affect the degree of frequency stability, accuracy and aging rate for very high frequency crystal oscillator are analyzed in this paper. A new very high frequency crystal oscillator has been developed for the safety test system of some rocket on the base of this analysis. The results of airborne test are showed that the oscillator works reliably and the performance has been improved.

High stability quartz oscillators utilizing anharmonic mode LFE resonators

Abstract: The main mode lateral field excited resonators exhibit high value of motional resistance and very low value of motional capacitance. One undesirable property of these resonators is difficult frequency calibration and oscillator frequency adjustment. The anharmonic mode resonators exhibit lower motional resistance and few times higher motional capacitance. Because of that frequency calibration and frequency adjustment in oscillator is significantly easier. Different versions of SC 301 and 310 mode resonators have been designed and elaborated over past several years. The results were optimized practically versions of 301 and 311 mode resonators. For lateral field excited resonators the double oven OCXO oscillator was designed. The resonators were mounted in oscillators. Next the short term stability, long term stability and thermal stability of oscillators were measured, using conventional methods of measurement. The long term frequency stability measurements were carried out in laboratory with ambient temperature stabilization in the range 20plusmn1degC. The oscillators exhibited long term frequency stability below 2 E-11 per day and short term frequency stability below 2 E-13 per second. The analysis of the oscillator parameters measurement showed main influence on them not resonator quality but the oscillator construction and utilized electronic components quality. The result of analysis of these parameters was the new design of hermetically sealed oscillator with carefully selected electronic component. The oscillators were hermetically sealed for prevent of environmental conditions

Generalized noisy model of a single-mode crystal oscillator with a nonlinear resonator

Abstract: Fluctuations in crystal oscillators have been under peer investigation during several decades owing to a number of reasons. In electronics, optoelectronics, and radio electronics systems, the oscillator phase noise influences selectivity of the channels and purity of the signals. In the precise positioning and measuring systems, it is ordinarily the prime limiter of accuracy. During decades, the crystal oscillator theory has passed over three principle stages depending upon improvement of the resonator model. In addition to the classical imagination, it had been noticed a multi-modal nature of crystal resonators. Accordingly, the single-mode net was complicated by the anharmonic series branches. Investigations of the anisochronisms have forced to think that the resonator motional capacity, inductance and losses are drive level dependent (DLD). Finally, the noise studies in the time and frequency domains have required complicating the model by the noise sources and thinking that the resonator motional parameters are flicker-noisy. Generalizing the above-given observation, we combine the model of a single mode crystal oscillator by the piezoelectric resonator and feedback amplifier

Rubidium frequency standard control method and system for voltage-controlled oscillators

Abstract: A rubidium frequency standard control circuit which utilizes an initial sweep hand-off frequency locking process followed by a negative feedback loop for optimization of the stability of the voltage control oscillator employing the rubidium frequency standard.