A 37. 5 MHz differential complementary metal oxide semiconductor （CMOS） crystal oscillator with low power and low phase noise for the radio frequency tuner of digital radio broadcasting digital radio mondiale （DRAM...A 37. 5 MHz differential complementary metal oxide semiconductor （CMOS） crystal oscillator with low power and low phase noise for the radio frequency tuner of digital radio broadcasting digital radio mondiale （DRAM） and digital audio broadcasting （DAB） systems is realized and characterized. The conventional cross-coupled n-type metal oxide semiconductor （NMOS） transistors are replaced by p-type metal oxide semiconductor （PMOS） transistors to decrease the phase noise in the core part of the crystal oscillator. A symmetry structure of the current mirror is adopted to increase the stability of direct current. The amplitude detecting circuit made up of a single- stage CMOS operational transconductance amplifier （OTA） and a simple amplitude detector is used to improve the current accuracy of the output signals. The chip is fabricated in a 0. 18- pxn CMOS process, and the total chip size is 0. 35 mm x 0. 3 mm. Under a supply voltage of 1.8 V, the measured power consumption is 3.6 mW including the output buffer for 50 testing loads. The proposed crystal oscillator exhibits a low phase noise of - 134. 7 dBc/Hz at 1-kHz offset from the center frequency of 37. 5 MHz.展开更多
Combining oven controlled technique,digital compensation,high-resolution frequency difference measurement and self-calibration technique,a new design method of precise oven controlled crystal oscillator（OCXO） is pro...Combining oven controlled technique,digital compensation,high-resolution frequency difference measurement and self-calibration technique,a new design method of precise oven controlled crystal oscillator（OCXO） is proposed.Fine compensation is made in the vicinity of the crystal temperature inflection point by using the non-real-time temperature compensation strategy,and self-calibration system is integrated in the crystal.The method improves the digital compensated phase noise,simplifies the traditional OCXO development system,reduces the cost and shortens the developing cycle.Experiment results show that with a standard reference signal and self-calibration updated data,the oscillator can work stable and achieve its best performence.The performance index of crystal oscillator had an improvement with one to two orders of magnitude on the basis of original technical index.The method is widely used in the improvement of high-end crystal oscillator and atomic clock.展开更多
The design procedure of a CMOS process integrating Colpitts cr ystal oscillator is described in detail by using the tools of Matlab and advanced design system (ADS). The small-signal analysis is performed both in the ...The design procedure of a CMOS process integrating Colpitts cr ystal oscillator is described in detail by using the tools of Matlab and advanced design system (ADS). The small-signal analysis is performed both in the viewpoint of negative resistance and positive feedback. The analysis of condition for reliable start-up of oscillation and design guides for low phase noise is introduced. The measured phase noise is ?172dBc/Hz@10 kHz and the power dissipation is 0.36 mW at power supply 3V.展开更多
This paper presents a 25-MHz fully-integrated digitally controlled crystal oscillator（DCXO） with automatic amplitude control（AAC）.The DCXO is based on Colpitts topology for one-pin solution.The AAC circuit is intr...This paper presents a 25-MHz fully-integrated digitally controlled crystal oscillator（DCXO） with automatic amplitude control（AAC）.The DCXO is based on Colpitts topology for one-pin solution.The AAC circuit is introduced to optimize the phase noise performance.The automatic frequency control is realized by a 10-bit thermometer-code segmental tapered MOS capacitor array,ensuring a～35 ppm tuning range and～0.04 ppm frequency step.The measured phase noise results are-139 dBc/Hz at 1 kHz and-151 dBc/Hz at 10 kHz frequency offset,respectively.The chip consumes 1 mA at 1.8V supply and occupies 0.4 mm^2 in a 0.18-μm CMOS process.展开更多
The wide-field electromagnetic method is widely used in hydrocarbon exploration,mineral deposit detection,and geological disaster prediction.However,apparent resistivity and normalized field amplitude exceeding 2048 H...The wide-field electromagnetic method is widely used in hydrocarbon exploration,mineral deposit detection,and geological disaster prediction.However,apparent resistivity and normalized field amplitude exceeding 2048 Hz often exhibit upward warping in data,making geophysical inversion and interpretation challenging.The cumulative error of the crystal oscillator in signal transmission and acquisition contributes to an upturned apparent resistivity curve.To address this,a high-frequency information extraction method is proposed based on time-domain signal reconstruction,which helps to record a complete current data sequence;moreover,it helps estimate the crystal oscillator error for the transmitted signal.Considering the recorded error,a received signal was corrected using a set of reconstruction algorithms.After processing,the high-frequency component of the wide-field electromagnetic data was not upturned,while accurate high-frequency information was extracted from the signal.Therefore,the proposed method helped effectively extract high-frequency components of all wide-field electromagnetic data.展开更多
In this paper, we analyze and design a new type of servo system with noninteger voltage controlled crystal oscillator （VCXO） for rubidium atomic frequency standard （RAFS）, which does not require fractional frequen...In this paper, we analyze and design a new type of servo system with noninteger voltage controlled crystal oscillator （VCXO） for rubidium atomic frequency standard （RAFS）, which does not require fractional frequency synthesizer. By the estab- lishment of the loop equations with noises and drifts, we prove that all the components of the loop can affect its performance in- dex, and in which, RAFS long-term frequency stability is mainly determined by frequency multiplier, quantum system, and servo amplifier; the short-term one is mostly decided by VCXO. Owing to the elimination of the frequency synthesizer and its additive mixing unit, we can reduce phase noise and stray of the servo sys- tem, and it is favorable for miniaturizing the RAFS system. In addition, we adopt some targeted optimization measures to im- prove the frequency stability index. The good short-term fre- quency stability index is also validated by the test results.展开更多
基金The National Natural Science Foundation of China(No. 61106024)the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20090092120012)the Science and Technology Program of South east University (No. KJ2010402)
文摘A 37. 5 MHz differential complementary metal oxide semiconductor （CMOS） crystal oscillator with low power and low phase noise for the radio frequency tuner of digital radio broadcasting digital radio mondiale （DRAM） and digital audio broadcasting （DAB） systems is realized and characterized. The conventional cross-coupled n-type metal oxide semiconductor （NMOS） transistors are replaced by p-type metal oxide semiconductor （PMOS） transistors to decrease the phase noise in the core part of the crystal oscillator. A symmetry structure of the current mirror is adopted to increase the stability of direct current. The amplitude detecting circuit made up of a single- stage CMOS operational transconductance amplifier （OTA） and a simple amplitude detector is used to improve the current accuracy of the output signals. The chip is fabricated in a 0. 18- pxn CMOS process, and the total chip size is 0. 35 mm x 0. 3 mm. Under a supply voltage of 1.8 V, the measured power consumption is 3.6 mW including the output buffer for 50 testing loads. The proposed crystal oscillator exhibits a low phase noise of - 134. 7 dBc/Hz at 1-kHz offset from the center frequency of 37. 5 MHz.
基金Supported by the National Natural Science Foundation of China (10978017)the Open Fund of Key Laboratory of Time and Frequency Primary Standards (CAS)+2 种基金the Postdoctoral Grant of China (94469)the Basic and Advanced Technology Research Foundation of Hennan Province (122300410169)the Fundamental Research Funds for the Central Universities
文摘Combining oven controlled technique,digital compensation,high-resolution frequency difference measurement and self-calibration technique,a new design method of precise oven controlled crystal oscillator（OCXO） is proposed.Fine compensation is made in the vicinity of the crystal temperature inflection point by using the non-real-time temperature compensation strategy,and self-calibration system is integrated in the crystal.The method improves the digital compensated phase noise,simplifies the traditional OCXO development system,reduces the cost and shortens the developing cycle.Experiment results show that with a standard reference signal and self-calibration updated data,the oscillator can work stable and achieve its best performence.The performance index of crystal oscillator had an improvement with one to two orders of magnitude on the basis of original technical index.The method is widely used in the improvement of high-end crystal oscillator and atomic clock.
文摘The design procedure of a CMOS process integrating Colpitts cr ystal oscillator is described in detail by using the tools of Matlab and advanced design system (ADS). The small-signal analysis is performed both in the viewpoint of negative resistance and positive feedback. The analysis of condition for reliable start-up of oscillation and design guides for low phase noise is introduced. The measured phase noise is ?172dBc/Hz@10 kHz and the power dissipation is 0.36 mW at power supply 3V.
基金Project supported by the National Natural Science Foundation of China(No.60876019)the National S&T Major Project of China(No. 2009ZX0131-002-003-02)+1 种基金the Shanghai Rising-Star Program,China(No.09QA1400300)the National Scientists and Engineers Service for Enterprise Program,China(No.2009GJC00046).
文摘This paper presents a 25-MHz fully-integrated digitally controlled crystal oscillator（DCXO） with automatic amplitude control（AAC）.The DCXO is based on Colpitts topology for one-pin solution.The AAC circuit is introduced to optimize the phase noise performance.The automatic frequency control is realized by a 10-bit thermometer-code segmental tapered MOS capacitor array,ensuring a～35 ppm tuning range and～0.04 ppm frequency step.The measured phase noise results are-139 dBc/Hz at 1 kHz and-151 dBc/Hz at 10 kHz frequency offset,respectively.The chip consumes 1 mA at 1.8V supply and occupies 0.4 mm^2 in a 0.18-μm CMOS process.
基金Project(42004056)supported by the National Natural Science Foundation of ChinaProject(ZR2020QD052)supported by the Natural Science Foundation of Shandong Province,ChinaProject(2019YFC0604902)supported by the National Key Research and Development Program of China。
文摘The wide-field electromagnetic method is widely used in hydrocarbon exploration,mineral deposit detection,and geological disaster prediction.However,apparent resistivity and normalized field amplitude exceeding 2048 Hz often exhibit upward warping in data,making geophysical inversion and interpretation challenging.The cumulative error of the crystal oscillator in signal transmission and acquisition contributes to an upturned apparent resistivity curve.To address this,a high-frequency information extraction method is proposed based on time-domain signal reconstruction,which helps to record a complete current data sequence;moreover,it helps estimate the crystal oscillator error for the transmitted signal.Considering the recorded error,a received signal was corrected using a set of reconstruction algorithms.After processing,the high-frequency component of the wide-field electromagnetic data was not upturned,while accurate high-frequency information was extracted from the signal.Therefore,the proposed method helped effectively extract high-frequency components of all wide-field electromagnetic data.
文摘In this paper, we analyze and design a new type of servo system with noninteger voltage controlled crystal oscillator （VCXO） for rubidium atomic frequency standard （RAFS）, which does not require fractional frequency synthesizer. By the estab- lishment of the loop equations with noises and drifts, we prove that all the components of the loop can affect its performance in- dex, and in which, RAFS long-term frequency stability is mainly determined by frequency multiplier, quantum system, and servo amplifier; the short-term one is mostly decided by VCXO. Owing to the elimination of the frequency synthesizer and its additive mixing unit, we can reduce phase noise and stray of the servo sys- tem, and it is favorable for miniaturizing the RAFS system. In addition, we adopt some targeted optimization measures to im- prove the frequency stability index. The good short-term fre- quency stability index is also validated by the test results.
