Crystal oven

About: Crystal oven is a research topic. Over the lifetime, 955 publications have been published within this topic receiving 10380 citations. The topic is also known as: oven-controlled crystal oscillator & OCXO.

Method and Apparatus Used at the Bureau of Standards in Testing Piezo Oscillators for Broadcast Stations

Abstract: A piezo oscillator may be used either to check the frequency of the station or to control its frequency. Most of the piezo oscillators tested by the Bureau are for use in checking the frequency of the station. Piezo oscillators are capable of high precision in the measurement of their frequency if a beat note is produced by adjusting another generator to a similar frequency. This principle is employed in the methods and apparatus described in the paper. After preliminary tests to determine the suitability of the quartz plate and its fundamental frequency, the piezo oscillator is kept in a temperature-controlled room for not less than two days, during which frequency measurements are made. The method consists in measuring the frequency of the piezo oscillator under test in terms of a 200-kc temperature-controlled piezo oscillator. This is accomplished by adjusting a radio-frequency generator to the frequency which the piezo oscillator under test should have. This adjustment is made using harmonics from a 10-kc generator which is kept accurately set in terms of the 200-kc standard by observing a special form of beat indicator. The frequency difference between the test piezo oscillator and the generator set in terms of the standard is measured by comparison with an audio-frequency generator. A frequency meter of special design is used to check the frequency difference and determine the sign of the correction to be applied. The method described is also useful in the calibration of frequency meters and the measurement of station frequencies.

A Very Precise Micropower 2 MHZ Quartz Oscillator

Abstract: A 2 MHz oscillator has been developed consuming only 400 nA under 15 V supply voltage The careful oscillator topology choice and circuit design result in a frequency deviation of less than 005 ppm/V and a maximum frequency stability with respect to Q variations

Thermal effects on frequency fluctuations in quartz crystal oscillators

Abstract: This paper deals with the correlation between the thermal behavior of the oven and phase fluctuations of the oven-controlled oscillator. Experiments to measure the thermal stability of the oven control are presented. A conventional oscillator equipped with a LD-cut quartz resonator is first used in the B-mode in order to measure the temperature fluctuations of its oven. The same resonator is then used in its C-mode to record the phase fluctuations of the oscillator. Obviously, the quartz resonator is previously characterized in terms of temperature dependence. Frequency-temperature curves are given for B and C modes in order to obtain the thermal sensitivity of the resonator. In a first step, thermal fluctuations of the oven are obtained through the measurement of the B-mode oscillator frequency in the time domain, by means of Allan standard deviation. Then, it can be translated into C-mode frequency fluctuations using the thermal sensitivity of the resonator C-mode. At least, power spectral density of phase fluctuations of such an oven-controlled oscillator is related to temperature sensitivity and discussed.

Fluidic oscillator with crystal registering frequency - in which oscillation crystal seals one outlet of the oscillator

Abstract: The fluidic oscillator has an arrangement for using it to determine the mixture ratio of gases by measuring the sound velocity of the gas mixture by means of the oscillator frequency. The oscillation crystal (15) closes one outlet (10) of the oscillator, which itself is connected to the inside of the space containing the gas mixture through a diffuser (6). This leads to two external return (11, 12) and two main channels (9, 10) one of which is connected to a suction pump (14) while the other, containing the oscillation crystal, leads through a preamplifier (16) to control equipment (18). An oscillation frequency dependent on the length of the return channels and the signal propagation velocity is generated, the oscillation frequency being an expression of the density of the gas flowing into the oscillator.

Some developments of the piezo-electric crystal as a frequency standard

Abstract: Part (1) deals with some observed errors in quartz piezo-electric resonators employed as frequency standards. It is shown that these are due to (a) frictional loading, and (b) losses arising from atmospheric humidity. The methods adopted to eliminate these are discussed, and the development of calibration apparatus employing the resonators as reference standards is dealt with. Part (2) is in the main concerned with the use of the improved quartz crystal as a control element in a valve-maintainted source of oscillations. The frequency-stability characteristic of such a system is investigated, the errors are found to be largely due to the valve system, and methods designed to eliminate these are discussed. Finally a complete calibration equipment consisting of a multivibrator system with a range of 1-6 000 kilocycles per sec. in steps of 1 kilocycle per sec., centrally controlled by a quartz crystal, is shown.