Showing papers on "Crystal oven published in 2010"

Significant step in ultra-high stability quartz crystal oscillators

Abstract: The best frequency stability ever measured on a quartz crystal oscillator is reported: this new Boitiers a Vieillissement Ameliore (BVA) oscillator has an estimated flicker frequency modulation floor of 2.5×10−14 at 5 MHz.

Greatly improved small inductance measurement using quartz crystal parasitic capacitance compensation.

Abstract: Generally, quartz crystal inductance frequency pulling in oscillators is very low and therefore is not often used in practice. The new method of improving frequencypullability uses inductance to compensate for quartz stray capacitances. To this end, a special AT fundamental quartz crystal working near the antiresonance frequency is selected. By modifying its equivalent circuit with load inductance and series tuning capacitance, the magnetic sensing of the circuit can be highly improved. The experimental results show that the new approach using the quartz crystal stray capacitance compensation method increases the frequency pulling range (from ≅ 2 kHz/mH to ≅ 600 kHz/mH) by × 300 depending on the type of oscillator, making possible the measurement of nano-magnetic changes.

Parametrically driven quartz UHF oscillator

Abstract: The present invention is a piezoelectric crystal oscillator using parametric amplification to enhance the Q. Parametric amplification is accomplished by driving the same region of the crystal as used for the oscillator with an overtone of the crystal resonator.

Temperature-controlled crystal oscillator

Abstract: The present invention provides a temperature controlled oscillator capable of detecting the surrounding temperature at a high level of precision, and obtaining stable oscillating frequencies. The temperature controlled oscillator of the invention is provided with a circuit substrate having a crystal resonator, an oscillating circuit, and a temperature control circuit, arranged on one or both principal surfaces, and a container main body that accommodates the circuit substrate and has mount terminals on an outer bottom surface thereof. The temperature control circuit includes at least a first temperature sensor that detects an operating temperature of the crystal resonator, a second temperature sensor that detects a surrounding temperature of the container main body, and a heating resistor that applies heat to the crystal resonator, and lead wires extend from the circuit substrate and are connected electrically to the mount terminals. An insulation groove that passes through the circuit substrate in a thickness direction is formed between: a first lead wire closest to the second temperature sensor, and the second temperature sensor; and the heating resistor.

Quartz pressure and temperature transducer assembly with dynamic correction

Abstract: A quartz transducer having four or more crystal-controlled oscillators intended for measurement of applied pressure and temperature. All four oscillators are controlled by crystal quartz resonators operating in the thickness-shear mode. Two crystals measure the pressure and temperature respectively. A third crystal is a reference, and the fourth crystal may be another reference crystal or a second temperature crystal. The output of the latter is either phase leading or phase lagging the thermal response of the main temperature sensor.

Resistorless feedback biasing for ultra low power crystal oscillator

Abstract: An operational transconductance amplifier (OTA) is used as the DC bias feedback of a crystal oscillator to minimize temperature, voltage and process corner variations thereof, and thereby improve the reliability of crystal oscillator operation at ultra low power levels.

Impedance measurement of quartz crystal based on network analysis method

Abstract: A method for the determination of impedance of quartz crystal using automatic network analyzer electrical techniques is introduced in this paper. The vector network analyzer ENA 5070B which is produced by Agilent Company is taken to measure S parameters in short-circuit, open-circuit and crystal-circuit. The algorithm recommended in international standard IEC444-5 is based on theory of two-port S parameter transmission method and relationships between transmission admittance (Y21) and scattering parameters(S parameters). By data analysis, circuit symmetry is good. And around the resonance frequency, amplitude and phase of S parameters have obvious display the crystal characteristics. The phase is not zero on the resonance frequency because of lead inductance and parasitic capacity. The amplitude/phase-frequency curve of crystal impedance, which is in conformity with the stimulation of the crystal model, is achieved. By de-embedding process, high accuracy of series resonant frequency and the impedance around it are measured. Results have created favorable conditions for precisely determining the values of the electrical parameters of quartz crystal units.

High-stability SAW oscillators with cubic frequency temperature curve and excellent aging characteristics

Abstract: We describe the realization of oscillators combined with quartz's innate excellent long-term stability of frequency and frequency temperature characteristics by optimization of SAW oscillator's design conditions using quartz crystal substrates in application on groove structure As a result, we could realize SAW oscillator with cubic frequency temperature curve, inflection point temperature of 28°C at is close to a room temperature and extremely small frequency variation of 11ppm in wide temperature range between −40°Cand +85°C Further, we could get excellent long-term stability lower than 3ppm of frequency variation in 2000 hours high temperature environment test with 85°C SAW resonator that is making up oscillator has gained good resonance characteristics such as Q=14,700 and CI=12Ω with 400MHz We realized high-performance SAW oscillator on practical use with characteristics such as low jitter and low phase noise, in addition excelling in frequency temperature characteristics and frequency long-term stability by oscillating fundamental wave in high-frequency range with 100MHz to 700MHz

The simulation and accomplishment of 80MHz low phase noise crystal oscillator

Abstract: A general pierce circuit and an 80MHz 5th SC-cut Um-1 resistance welding crystal resonator are chosen to accomplish the 80MHz low phase noise crystal oscillator in this paper. In the process, the software-Serenade8.7 is used to guide the design and optimization. Agilent 5052B is also used to measure the phase noise of this experimental sample. The measured phase noise of the prototype 80 MHz crystal oscillator is typically −141 dBc/Hz@100 Hz and −161 dBc@1KHz respectively. Experimental result shows that: using the Serenade8.7 simulation is helpful to design low phase noise crystal oscillator.

Self-identification of differences between aging rates of two frequencies excited in the dual-mode crystal oscillator

Abstract: In this paper we introduce an extension of the self-temperature-sensing of stress compensated (SC) quartz resonator based on simultaneous excitation of two overtones (3rd and 5th overtone) - the slow thickness-shear modes (i.e. the c modes) in dual-mode crystal oscillator (DMXO). The extension is based on implementation of a self-identification of the differences between aging rates (long-term frequency instabilities) of the two mode's frequencies simultaneously excited in the quartz resonator. Processing of two excited c mode's frequencies enables to predict their shifts due to resonator's temperature variations in a wide range, where the characteristics of the c modes are free from significant anomalies.

Low phase noise K-Band oscillator on organic Liquid Crystal Polymer (LCP) substrate

Abstract: In this paper, for the first time, a reflection type K-band oscillator, on low-cost Liquid Crystal Polymer (LCP), organic substrate, is presented. The oscillation frequency is determined by a lambda/2 microstrip resonator coupled to a microstrip line. The measured phase noise and power output of the oscillator are found to be −108 dBc/Hz at 1 MHz offset and −6 dBm respectively, for an oscillating frequency of 25.6 GHz.

Dropping through the floor

Abstract: A quartz crystal oscillator that reduces the noise floor over commercial crystal oscillators by nearly an order of magnitude for the first time in 15 years has been demonstrated by collaborating researchers from the FEMTO-ST Institute, CNRS in France; the Academy of Sciences in the Czech Republic; and Oscil-loquartz in Switzerland. The 5 MHz crystal double-oven prototype, which has a flicker frequency modulation (FFM) floor of 2.5 × 10−14, opens the door to ultra-high stability oscillators for telecommunications, instrumentation and space applications.

The research and realization of the GPS module tame the local VCXO

Abstract: In the design of time calibrator, time calibrator can be achieved on a higher stability, because of the highest stability of constant-temperature crystal oscillator highest stability, but as time goes on, the stability and the frequency stability of constant-temperature crystal oscillator will gradually decline, it will affect the measurement accuracy. In light of the above issues, we purpose a new method to obtain higher stability for it long time work. First, generate the frequency signal by voltage-controlled constant-temperature crystal oscillator; Second, get the signal 1S from the time GPS module; Third, comparison the above tow signals, thus, a error signal is generated; Finally, converter the error signal by digital-to-analog module, and then, use it to control the voltage-controlled constant-temperature crystal oscillator to achieve the purpose of automatic tame.

Bi-stable oscillator circuit for microbalance

Abstract: In accordance with the present invention there is provided a method of detecting a load imparted to the surface of a transducer, for example a load caused by the binding of target molecules to the surface of the transducer. The transducer, which may be resonant device such as a bulk acoustic wave (BAW) transducer, a MEMS or NEMS device, or a quartz crystal 202a, forms part of a quartz crystal microbalance (QCM) and is arranged to be exposed to an environment under test. The crystal has a resonant frequency and forms part of a bi-stable oscillator circuit. The oscillator also comprises an impedance network 201, a buffer amplifier 203 and an AGC amplifier 204. When a load imparted to the surface of the resonator is less than a pre-determined threshold value the oscillator circuit oscillates at the resonant frequency of the quartz resonator. When the load imparted to the surface is greater than the threshold value the oscillator circuit oscillates at a free-running frequency set by the impedance network. Bi-stable switching of the circuit oscillation frequency (fig.3) is indicative of the load crossing the predetermined threshold value. The frequency switching can easily be detected without the use of accurate frequency measurements.

Temperature compensated crystal oscillator, printed-circuit board, and electronic device

Abstract: A temperature compensated crystal oscillator includes an oscillation circuit including a crystal oscillator; a variable capacitor inserted in series in the oscillation circuit; a thermosensitive circuit element whose resistance value changes in accordance with a temperature of the crystal oscillator, the thermosensitive circuit element being formed on the crystal oscillator by vapor deposition; and a correction circuit configured to correct capacitance of the variable capacitor based on a current value that is used when applying current to the thermosensitive circuit element.