The above circuit illustrates several low noise techniques as applied to a low phase noise crystal oscillator. Ablno series is designed with high q, 3rd overtone crystal resonators. Hence vcos with low phase noise have to be designed to meet stringent communications standards. In this situation, the crystal should be presented with impedance that doesnt. Reducing phase noise degradation due to vibration of. The ox175 is a low phase noise, highfrequency ovenized crystal oscillator in a 28 x 38 mm package.
Reducing phase noise degradation due to vibration of crystal. The oscillator transistor q104 is cutoff most of the time except for a short period at the peak of the crystal current waveform. In the case of a crystal oscillator, the filter consists of the crystal. An oscillator circuit can be a combination of an amplifier with gain a j. The design and implementation of a pierce low phase noise. Oscillators theory and practice ed messer ki4nna october 2009 rev b. Using the 16 mhz crystal oscillator nxp semiconductors. A discrete, low phase noise, 125 mhz crystal oscillator. The phase noise of the 50mhz colpitts crystal oscillator is simulated by the agilent. Low noise oscillator design and performance michael m. Butler oscillator circuit provided by steven swift, p. Crystal oscillator vcxo, phase detector, and loop filter. Crystal is the common term used in electronics for the frequencydetermining component, a wafer of quartz crystal or ceramic with electrodes connected to it.
Quartz crystal oscillator circuits design handbook, available. Ndk has developed an ultralow phase noise 10mhz crystal oscillator nh40m40la for use in measuring instruments. Experimental results show that it is feasible to design low phase noise crystal. This can be analysed by matching the slopes of the real phase noise plot to those shown in the idealised phase noise plot of fig. Xtal oscillator design the design of a xtal oscillator is very similar to a normal. Design and characterization of low phase noise microwave. Oscillator basics and lownoise techniques for microwave oscillators and vcos ulrich l. Oscillator design considerations for lowcurrent applications. An oscillator is a circuit capable of maintaining electric oscillations. Likewise, if a design requires a small crystal package, an oscillator design that will drive a high esr crystal is needed, increasing the.
Numerous practical examples are demonstrated and validated with computer. The crystal oscillator s output is fed to the system pll as the input refe rence. A number of low phase noise commercial designs are available, along with their phase noise specifications. The oscillator has a noise floor of 176dbchz, and typical adev below 5e12 for t0.
Based on the literature, the circuit structure of the currentreused oscillator has lower power consumption compared to that of the conventional lcvco. If cl is too low, the actual frequency will be higher than the target frequency, and vice versa. Crystals oscillators realtimeclocks filters precision. Design and characterization of low phase noise microwave circuits.
Oscillators tuned oscillators untuned oscillators rc oscillators. The vco is the major contributor to the pll output phase noise outside the pll loop bandwidth. To a large extent, these parameters are determined by the crystal resonator, which has very accurate and stable resonant frequency and a quality factor over 10,000, enabling the. This solution represents a good compromise among low phase noise performance, circuit complexity, and cost. Based on this conclusion, phase noise of a pierce crystal oscillator is simulated and analyzed by the agilent advanced design system. Outline characterization of vcos oscillators rc lc relaxation oscillators ring. By discarding the implicit assumption of time invariance underlying many other approaches, this model is capable of making quantitative predictions of the phase noise and jitter of different types of oscillators. The oscillator transistor q104 is cutoff most of the time. In the above circuit, thecrystal resonatorx1 acts as a par allel circuit of a shunt capacitance c0 and the series circuit of an inductance, a capacitance and a resistance, the equivalent. The analysis and design of a 50mhz colpitts low phase noise. Low noise oscillator design the hewlett packard archive. Mani mina, major professor robert weber jaeyoun kim iowa state university.
Blileys robust quartz crystal oscillators incorporate the most advanced low power, low phase noise, and gsensitivity technology to maintain frequency stability in even the toughest environments. Cdce6214q1 crystalbased oscillator design application report snaa331december 2019 cdce6214q1 crystalbased oscillator design haozheng abstract the lowpower clock generator cdce6214q1 incorporates a crystaldriver circuit that can drive an external crystal resonator xtal. Often a simple calibration procedure is used to set the xtal frequency to within the desired range and a simple lookup table is used to adjust it. A more accurate term for it is piezoelectric resonator. New qenhanced planar resonators for low phasenoise radio frequency oscillators by morteza nick a dissertation submitted in partial fulfillment of the requirements for the degree of doctor of philosophy electrical engineering in the university of michigan 2011 doctoral committee professor amir mortazawi, chair professor kamal sarabandi. Impact of ultralow phase noise oscillators on system performance ramon m. Design procedures related to crystal input are explained in this. At the core of apis designs is our ceramic based resonator circuitry exhibiting very.
Niknejad university of california, berkeley eecs 242 p. Analysis and design of low phase noise crystal oscillators. Poor availability of low c l crystals may make selection of a crystal with a higher c l necessary, at the cost of increased oscillator current. This article has explained the primary design considerations for a simple crystal oscillator. A programmable crystal oscillator pcxo is a combined pll a.
The low temperature coefficient of crystals also proves critical in most applications. This application note introduces the pierce oscillator basics and provides guidelines for the oscillator design. Design complexity low high low integration high low high jitter filter no yes discrete yes integrated. A voltagecontrolled crystal oscillator vcxo is used. All modeling for this assignment was done using python packages numpy, scipy and. Topics relevant in other types of radio systems, such as phase noise of crystal oscillator circuits, are not limiting factors in ism radios and are not discussed. Region c of figure 1 is called white noise or broadband noise.
The simulated phase noise results are reduced by adjusting circuit parameter. Design a crystal oscillator to match your application. Reducing phase noise degradation due to vibration of crystal oscillators by cory lee nelson a thesis submitted to the graduate faculty in partial fulfillment of the requirements for the degree of master of science major. To a large extent, these parameters are determined by the crystal resonator, which has very accurate and stable resonant frequency and a quality factor over 10,000, enabling the design of very low phase noise sources. In some applications, processors or asics integrate the phase detector and charge pump within the ic so that only a. The phase noise is similar to the best oscillators by wenzel associates, inc which are claimed to be the best in the industry with phase noise down to 180dbchz at 20 khz. Design of lowphasenoise cmos ring oscillators circuits. But the performance of rfmicrowave frequency synthesizers is often tied to a lowerfrequency reference oscillator, such as an ovencontrolled crystal oscillator ocxo, and great effort is often required to produce a microwave frequency synthesizer with low phase noise. Design of low phase noise and low power modified current. This paper describes the design and implementation of low phase noise 10mhz crystal oscillators using sc cut crystal resonators which are being used as part of the chain of a local oscillator. The oscillator design generates low frequency and phase jitter, which is recommended for usb operation. A discrete, low phase noise, 125 mhz crystal oscillator for the. Extremely lowphasenoise saw resonators and oscillators.
Fundamentals of crystal oscillator design electronic design. Txp type possessed the advantages over arbitrary frequency, rapid development and low phase noise. The analysis and design of a 50mhz colpitts low phase. Clean, quiet frequency synthesizers are essential for modern communications systems.
Ultralow phase noise 10mhz oven controlled crystal. The design of low noise oscillators offers a new timevariant phase noise model. Txp type products provide 3 types of logic outputs to choose from, namely lvcmos singleended output, lvpecl and lvds differential output. Tuning range, tuning gain and phase noise are the important characteristics of a vco. Dear all, which part number would you recommend for the lowest phase noise crystal oscillator design. The oscillator phase noise characteristics will dominate the entire system performance and spending a few more dollars on the oscillator can boost a.
Likewise, if a design requires a small crystal package, an oscillator design that will drive a high esr crystal is needed, increasing the necessary oscillator current. New qenhanced planar resonators for low phasenoise radio. The oscillator must get the proper amount of attention during the design phase, well before moving to manufacturing, to avoid the nightmare scenario of products being returned from the field. Blileys robust quartz crystal oscillators incorporate the most advanced lowpower, low phase noise, and gsensitivity technology to maintain frequency stability in even the toughest environments. This product is the same size as conventional ndk low phase noise crystal oscillator 40 x 40. Ndk has developed an ultra low phase noise 10mhz crystal oscillator nh40m40la for use in measuring instruments. The 16 mhz crystal oscillator module is designed to handle offchip crystals that have a frequency of 4. Api technologies, a leading manufacturer of standard and custom saw oscillators, combines low phase noise, excellent frequency stability and rugged construction in a lineup of cost effective saw oscillator solutions. Yan wang, ying cui, shiyi xu school of electrical engineering and information, southwest petroleum university, no.
All oscillators use positive feedback of one form or another. For very low drive levels the esr can befor very low drive levels, the esr can be. This oscillator is an experiment that i made to improve my own understanding of sideband noise in oscillators. A discrete solution is preferable when the lowest possible jitter and best possible phase noise are required. Cdce6214q1 crystalbased oscillator design 1 introduction. While helping to understand phase noise and jitter of highperformance oscillators, this paper also examines the. We always strive to maintain the lowest size, weight, power, and cost swapc. Q2 also saturates during part of the cycle and the crystal current is poorly controlled. The ocxo is designed to be used in aerospace applications. Ttl gate crystal oscillator one of many single and dual gate implementations. Design techniques employed in vectron low noise l2 crystal oscillators limit this to a very low, often insignificant, value. Phase noise measured using an api technologies crystal oscillator at 25c. Impact of ultralow phase noise oscillators crystek.
Crystal oscillator an overview sciencedirect topics. A crystal oscillator is an electronic oscillator circuit that uses a piezoelectric resonator, a crystal, as its frequencydetermining element. Low oscillator phase noise is a necessity for many receiving and transmitting. New qenhanced planar resonators for low phasenoise. The transistor should have very low 1f noise datasheets dont provide this data.
Reference oscillator phase noise, in conjunction with the. To do this but trading with gain, in the series resonant circuits use a large inductor, and in parallel circuits use a large capacitor. Download rf and microwave transistor oscillator design ebook free in pdf and epub format. Lf and is expressed in dbc dbs down from the carrier fig. In other words, crystal oscillators have found new importance for their low phase noise in addition to their longterm frequency stability. A design of the prototype 120 mhz pierce crystal oscillator is presented and the experiments are carried out. The oscillator will use either 3rd or 5th overtone at approx. Topics relevant in other types of radio systems, such as crystal oscillator phase noise, arent limiting factors in.
However shunting r4 with a 100uh inductor to reduce the dc gain from base to collector of q1 may be useful in that it reduces the flicker phase phase noise of q1. The ox175 is a member of the ox17 oscillator series. Crystal oscillators crystal oscillators phase locked loops phase locked loops. Ultralow phase noise 10mhz oven controlled crystal oscillator ocxo with nearcarrier noise of 115 dbchz nihon dempa kogyo co. If the application requires a more accurate clock, the mcu series 0 or wireless mcu series 0 devices include two crystal oscillators, the low frequency crystal oscillator lfxo and the high frequency crystal oscillator hfxo. This contribution is devoted to design guidelines for selecting the low. This paper describes the design and implementation of low phase noise 10mhz crystal oscillators using sc cut crystal resonators which are being used as part of the chain of a. Part of the difficulty is that device noise undergoes multiple frequency translations to. A low noise 14 mhz crystal oscillator with phase noise.
Cerda vice president of engineering, crystek corporation 12730 commonwealth drive, fort myers, fl 339 abstract. Rules for designing a low phase noise voltage controlled oscillator vco. By discarding the implicit assumption of time invariance underlying many other approaches, this model is capable of making quantitative predictions of the phase noise and jitter of. Ultralow phase noise 10mhz crystal oscillators white rose. The analysis and design of a 50mhz colpitts low phase noise crystal oscillator. Lee, member, ieee, and ali hajimiri, member, ieee abstract linear timeinvariant lti phase noise theories provide important qualitative design insights but are limited in their quantitative predictive power. Read rf and microwave transistor oscillator design online, read in mobile or kindle. Noise in region b of figure 1, called 1f noise, is caused by semiconductor activity. Pdf this paper describes the design and implementation of low phase noise 10mhz crystal oscillators using sc cut crystal resonators. The term reference implies high frequency accuracy, stability, and low phase noise. Reac 30nov2009 dhn integrated circuit design 23 crystal tuningcrystal tuning crystals arecrystals are tuned to a particularto a particular. Suppose a 100mhz crystal oscillator signal spectrum in the region around f100hz is flickeroffrequency with. Some designs prefer nec cels ne688xx family for the low 1f. This unit is equipped with the cheapest possible standard crystals.
New qenhanced planar resonators for low phase noise radio frequency oscillators by morteza nick a dissertation submitted in partial fulfillment of the requirements for the degree of doctor of philosophy electrical engineering in the university of michigan 2011 doctoral committee professor amir mortazawi, chair professor kamal sarabandi. Tuning gain and noise present in the control signal affect the phase noise. Led d1 ensures that the emitter currents of q1, and q2 have a low tempco. Ultra low phase noise 10mhz oven controlled crystal oscillator ocxo with nearcarrier noise of 115 dbchz nihon dempa kogyo co. The design is based on a microcoaxial resonator and silicon bipolar transistor. The major challenge lies in the design of fully integrated low phase noise and low power of voltage controlled oscillators vcos that simultaneously have a wide tuning range. A low noise 14 mhz crystal oscillator with phase noise 180.
429 441 431 1311 165 819 1600 1317 977 1508 283 813 538 1683 1564 188 196 1511 1595 721 759 615 1018 1446 858 897 1075 331 1315 96 825 294 196 658 1395 1451