An RF bandpass filter with a Q-enhancement active inductor is presented. The design technique for a tunable Q-enhancement CMOS active inductor operating in the wide RF-band is described. Moreover,issues related to noi...An RF bandpass filter with a Q-enhancement active inductor is presented. The design technique for a tunable Q-enhancement CMOS active inductor operating in the wide RF-band is described. Moreover,issues related to noise and stability of the active inductor are explained. The filter was fabricated in 0.18μm CMOS technolo- gy,and the circuit occupied an active area of only 150μm ×200μm. Measurement results show that the filter centered at 2. 44GHz with about 60MHz bandwidth （3dB） is tunable in center frequency from about 2.07 to 2. 44GHz. The ldB compression point is - 15dBm while consuming 10. 8mW of DC power,and a maximum quality factor of 103 is attained at the center frequency of 2.07GHz.展开更多
The loss mechanisms of different passive devices （on-chip inductors and capacitors） on different substrates are analyzed and compared. OPS （oxidized porous silicon） and HR （high-resistivity） substrates are used ...The loss mechanisms of different passive devices （on-chip inductors and capacitors） on different substrates are analyzed and compared. OPS （oxidized porous silicon） and HR （high-resistivity） substrates are used as low-loss substrates for on-chip planar LPF （low pass filter） fabrication. For the study of substrate loss, a planar coil inductor is also designed. Simulation results show that Q （the quality factor） of the inductor on both substrates is over 20. Measurements of the LPF on OPS substrate give a - 3dB bandwidth of 2.9GHz and a midband insertion loss of 0.87dB at 500MHz. The LPF on HR substrate gives a - 3dB bandwidth of 2.3GHz and a midband insertion loss of 0.42dB at 500MHz.展开更多
In this paper,we investigate the matched filter based spectrum sensing in a more reasonable cognitive radio(CR) scenario when the primary user(PU) has more than one transmit power levels,as regulated in most standards...In this paper,we investigate the matched filter based spectrum sensing in a more reasonable cognitive radio(CR) scenario when the primary user(PU) has more than one transmit power levels,as regulated in most standards,i.e.,IEEE 802.11 Series,GSM,LTE,LTE-A,etc.This new multiple primary transmit power(MPTP) scenario is specialized by two different targets:detecting the presence of PU and identifying the power level.Compared to the traditional binary sensing where only the presence of PU is checked,SU may attain more information about the primary network(making CR more "intelligent") and design the subsequent optimization strategy.The key technology is the multiple hypothesis testing as opposed to the traditional binary hypothesis testing.We discuss two situations under whether the channel phase is known or not,and we derive the closed form solutions for decision regions and several performance metrics,from which some interesting phenomenons are observed and the related discussions are presented.Numerical examples are provided to corroborate the proposed studies.展开更多
Since the gas infrared absorption spectrum source intensity of several in a thousand, it is even less linewidth is only several nanometers occupying the than the noise of light source. The signal of gas absorption is ...Since the gas infrared absorption spectrum source intensity of several in a thousand, it is even less linewidth is only several nanometers occupying the than the noise of light source. The signal of gas absorption is submerged in the noise, so it is impossible to measure the concentration of gas with spectrum absorption directly. According to the principle and parameters of difference absorption system of CH4 gas, a detection circuit consisted of the lock-in amplifier is designed. The experiment results indicated that the detection circuit can satisfy the demand of the whole system, and the limit concentration is 150×10^-6.展开更多
Distribution systems operators are often confronted with declined power quality, which can cause substantial economical losses. The problem analyzed in paper concerns thyristor controlled direct current motor used for...Distribution systems operators are often confronted with declined power quality, which can cause substantial economical losses. The problem analyzed in paper concerns thyristor controlled direct current motor used for ski-lift in ski resort as a source of disturbances with negative impact on sensitive electric equipment, which is then unable to operate correctly. To solve mentioned problems, series of measurements of voltage quality parameters were carried out according to the respective valid standards. Crucial power quality parameters necessary for parallel power active filter design were then analyzed. Power active filter compensates power factor and filters characteristic current harmonics. After power active filter was put into operation, power quality problems were eliminated. Payback period is estimated up to four years.展开更多
文摘An RF bandpass filter with a Q-enhancement active inductor is presented. The design technique for a tunable Q-enhancement CMOS active inductor operating in the wide RF-band is described. Moreover,issues related to noise and stability of the active inductor are explained. The filter was fabricated in 0.18μm CMOS technolo- gy,and the circuit occupied an active area of only 150μm ×200μm. Measurement results show that the filter centered at 2. 44GHz with about 60MHz bandwidth （3dB） is tunable in center frequency from about 2.07 to 2. 44GHz. The ldB compression point is - 15dBm while consuming 10. 8mW of DC power,and a maximum quality factor of 103 is attained at the center frequency of 2.07GHz.
文摘The loss mechanisms of different passive devices （on-chip inductors and capacitors） on different substrates are analyzed and compared. OPS （oxidized porous silicon） and HR （high-resistivity） substrates are used as low-loss substrates for on-chip planar LPF （low pass filter） fabrication. For the study of substrate loss, a planar coil inductor is also designed. Simulation results show that Q （the quality factor） of the inductor on both substrates is over 20. Measurements of the LPF on OPS substrate give a - 3dB bandwidth of 2.9GHz and a midband insertion loss of 0.87dB at 500MHz. The LPF on HR substrate gives a - 3dB bandwidth of 2.3GHz and a midband insertion loss of 0.42dB at 500MHz.
基金supported in part by the National Basic Research Program of China(973 Program)under Grant 2013CB336600the Beijing Natural Science Foundation under Grant 4131003+1 种基金the National Natural Science Foundation of China under Grant{61201187,61422109}the Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions under Grant YETP0110
文摘In this paper,we investigate the matched filter based spectrum sensing in a more reasonable cognitive radio(CR) scenario when the primary user(PU) has more than one transmit power levels,as regulated in most standards,i.e.,IEEE 802.11 Series,GSM,LTE,LTE-A,etc.This new multiple primary transmit power(MPTP) scenario is specialized by two different targets:detecting the presence of PU and identifying the power level.Compared to the traditional binary sensing where only the presence of PU is checked,SU may attain more information about the primary network(making CR more "intelligent") and design the subsequent optimization strategy.The key technology is the multiple hypothesis testing as opposed to the traditional binary hypothesis testing.We discuss two situations under whether the channel phase is known or not,and we derive the closed form solutions for decision regions and several performance metrics,from which some interesting phenomenons are observed and the related discussions are presented.Numerical examples are provided to corroborate the proposed studies.
基金Doctorate Foundation of Hebei Province(03547020D) Natural Science Foundation of Heilongjiang Province(F0312)
文摘Since the gas infrared absorption spectrum source intensity of several in a thousand, it is even less linewidth is only several nanometers occupying the than the noise of light source. The signal of gas absorption is submerged in the noise, so it is impossible to measure the concentration of gas with spectrum absorption directly. According to the principle and parameters of difference absorption system of CH4 gas, a detection circuit consisted of the lock-in amplifier is designed. The experiment results indicated that the detection circuit can satisfy the demand of the whole system, and the limit concentration is 150×10^-6.
文摘Distribution systems operators are often confronted with declined power quality, which can cause substantial economical losses. The problem analyzed in paper concerns thyristor controlled direct current motor used for ski-lift in ski resort as a source of disturbances with negative impact on sensitive electric equipment, which is then unable to operate correctly. To solve mentioned problems, series of measurements of voltage quality parameters were carried out according to the respective valid standards. Crucial power quality parameters necessary for parallel power active filter design were then analyzed. Power active filter compensates power factor and filters characteristic current harmonics. After power active filter was put into operation, power quality problems were eliminated. Payback period is estimated up to four years.
