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.

Some Experimental Results with an Atomic Hydrogen Storage Beam Frequency Standard

Abstract: A frequency standard is described in which a quartz crystal oscillator is locked to the hydrogen hyperfine transition using the dispersion of this resonance. The hydrogen storage beam apparatus closely resembles a hydrogen maser with a low-Q cavity below oscillation threshold. Cavity pulling can be reduced to a point where environmental temperature fluctuations limit the stability mainly via the second-order Doppler effect. Locking to the dispersion feature of the resonance eliminates the need for frequency modulation in order to find line-center. The stability of the frequency standard was measured against crystal oscillators and cesium beam frequency standards; stabilities of 4 × 10-13 were recorded for sampling times of 30 seconds and of 3 hours.

Time based predictive algorithm system for a crystal oscillator

Abstract: A system and method include receiving an external reference signal and generating first temperature control commands to maintain a constant ambient temperature for a crystal oscillator using a first temperature control system. The method further includes generating second temperature control commands for a second temperature control system to establish a desired ambient temperature for the crystal oscillator according to a temperature training profile. While at least one of the first and second temperature control systems operates to change an ambient temperature, the method includes extracting a clock from the external reference signal, generating a correction signal to further generate a corrected oscillation based on a difference between the extracted clock and the crystal oscillator and training an adaptive control algorithm based on the correction signal in relation to a determined crystal oscillator response to temperature variations caused by the second temperature control system.

A simple instrument for the measurement of fine scale structure of temperature and humidity, and hence also the refractive index, in the troposphere

Abstract: A description is given of a very simple light weight and inexpensive radiosonde which measures rapid changes in relative humidity and temperature. The temperature is measured using a very thin platinum wire, the resistance of which is determined by the temperature and controls the frequency of a voltage controlled oscillator constituting a frequency-modulated subcarrier in the telemetry system. Sensitivity is typically 30 Hz degC−1 for a 10 μm wire. The sensor responds to changes in temperature up to some 60 Hz. The action of the humidity sensor is based on the relationship between mass and oscillation frequency of a piezoelectric resonator. Using two quartz crystal oscillators, paired in such a way as to give a beat frequency which is virtually independent of temperature, information about the humidity is obtained by measuring the beat frequency from the two crystal oscillators when one of the crystals is covered with a very thin hygroscopic film, the other crystal being insensitive to humidity. The crystal oscillator which is not sensitive to humidity is used as the radio carrier frequency generator for the telemetry system. Sensitivity is typically 10 Hz per percentage relative humidity and the element responds to changes in humidity up to some 50 Hz.