Showing papers on "Crystal oven published in 1979"

Transfer of Frequency Stability from an Atomic Frequency Reference to a Quartz-Crystal Oscillator

Abstract: This paper presents a study of the transfer of frequency stability from an atomic reference to a quartz-crystal oscillator. The study is done for the cases of active and passive atomic frequency standards in which one makes use of a phase-lock loop and of a frequency-lock loop, respectively. The analysis is made in both the frequency and time domains and covers the cases of the hydrogen and rubidium masers and the passive cesium-and rubidium-frequency standards. The results obtained from numerical calculations are presented under the form of graphs. These results include the fractional frequency spectral density Sy(f) as a function of the Fourier frequency f, and the two sample variance ?2(?) as a function of ?, the sampling time.

Tuning fork type crystal oscillator

Abstract: PURPOSE:To enable to obtain high Q value such as 200,000-300,000 by eliminating loss of oscillation energy, by providing the support resonated with the frequency equal to the resonant frequency of the coupled diapason type crystal oscillator at the base of the coupled tuning fork type crystal oscillator. CONSTITUTION:The coupled tuning fork type crystal oscillator consists of the main body 6, support 7 for the main body 6, bonding part 8 for the lead, boundary 9 between the support 7 and the bonding part 8, and the boundary 10 between the main body 6 and the support 7. Further, the main body 6, support 7 and bonding part 8 are cut out incorporatedly from the crystal ore, and the resonant frequency of the support 7 is equally selected as the resonant frequency of the main body 6. With this constitution, the oscillating displacement of the boundary 9 is zero, and the oscillating displacement of the bonding part 8 is almost zero. Accordingly, even if the bonding part 8 is soldered with leads, no oscillation energy is lost and high Q value such as 200,000-300,000 is obtained, allowing the usage for electronic watches.

Fast warm-up oven controlled piezoelectric oscillator

Abstract: A process and apparatus are disclosed for heating a piezoelectric crystal sonator by infrared radiation.

Temperature-compensated crystal oscillator

Abstract: A control voltage for a crystal oscillation circuit is formed by adding two separately generated voltages. One of these voltages is proportionally variable with changes of temperature. The other voltage generally follows the temperature-frequency slope characteristic of the crystal unit. A use of such a control voltage eliminates the requirement for designing specific voltage generator circuits for each respective type of crystal oscillator, thereby enabling a substantial reduction in the cost of manufacture.

Multifrequency control from a single crystal

Abstract: A piezo-electric crystal vibrating in several modes controls several frequencies generated by voltage controlled oscillators simultaneously. The output of each voltage controlled oscillator is fed to a summing amplifier which drives the crystal. The output of the crystal is fed to individual phase detectors; each phase detector is also supplied with the output of a voltage controlled oscillator and generates a voltage proportional to the phase difference between the voltage controlled oscillator and the crystal output for correcting the output frequency of each oscillator.

Dual heater stabilization apparatus and method for a crystal oven

Abstract: A proportional oven having two heaters mounted to a thermally conductive base stabilizes the temperature of a temperature sensitive crystal mounted on the thermally conductive base by adjusting the ratio of powers applied to the two heaters.

Crystal oscillator compensated for g-sensitivity

Abstract: A crystal reference oscillator with improved g-sensitivity is realized through the use of an appropriately oriented single axis accelerometer. Components of acceleration normal to the plane of zero g-sensitivity of the oscillator are sensed by the accelerometer which returns a correction voltage to the electronic frequency control input of the oscillator. A model is developed that permits determination of accelerometer position relative to the oscillator without prior knowledge of crystal orientation.

Appraisal of the inverted-mesa AT-cut quartz resonator for achieving low-inductance high-Q single-response crystal units

Abstract: A novel design for v.h.f. AT-cut quartz-crystal units is described which enables optimum energy-trapping conditions to be achieved with less restriction in the choice of equivalent electrical parameters than is usual for conventional units. The good suppression of unwanted modes, low inductance values and potentially good frequency stability of this type of unit should lead to its application in both oscillators and filters.

Quartz crystal oscillator

Abstract: A Colpitts type quartz crystal oscillator comprises a resonant circuit consisting of two capacitors connected in series across a quartz crystal, the latter serving as an inductive element. The resonant circuit is connected between the base and collector of a transistor, with the junction of the capacitors being connected to the emitter of the transistor to provide feedback. Means are provided to increase the gain of the transistor and thereby the driving excitation of the crystal above a normal value for a brief length of time after the oscillator is initially energized.

Static and dynamic frequency: Temperature characteristics of quartz vibrators

Abstract: : The frequency-temperature (f-t) behavior of a crystal resonator depends upon temperature, and its spatial and temporal gradients. For quasi-isothermal changes, the static f-t curve can be used to determine frequency shifts that occur. The frequency then depends upon the parameters of the static f-t curve, the temperature range over which the oven cycles, and upon the oven setting point. The maximum frequency excursion has been computed for the AT and SC cuts of quartz in terms of these parameters, as function of orientation angle. When oven cyclings, or other temperature perturbations occur at rates too rapid to be considered quasi-isothermal, additional non-negligible components of frequency shift are introduced. This effect is quantified by means of a simple model which is capable of predicting thermal transient effects for AT cuts. Simulations, using the model, disclose that sinusoidal temperature variations with periods of hours can lead to frequency instabilities much larger than would be expected using the static f-t curve. This effect should be greatly diminished in the vicinity of the SC cut. (Author)