An optimized method is presented to design the down scalers in a GHz frequency synthesizer. The down scalers are comprised of dual modulus prescaler （DMP） and programmable ＆ pulse swallow divider,different methods ...An optimized method is presented to design the down scalers in a GHz frequency synthesizer. The down scalers are comprised of dual modulus prescaler （DMP） and programmable ＆ pulse swallow divider,different methods of high frequency analog circuit and digital logical synthesis are adopted respectively. Using a DMP high speed, lower jitter and lower power dissipation are obtained,and output frequency of 133.0MHz of the DMP working at divide-by-8 shows an RMS jitter less than 2ps. The flexibility and reusability of the progrs, mmable divider is high;its use could be extended to many complicated frequency synthesizers. By comparison,it is a better design on performance of high-frequency circuit and good design flexibility.展开更多
Dual-modulus prescalers （DMP） for RF receivers are studied. An improved D-latch is proposed to increase the speed and the driving capability of the DMP. A novel D-latch architecture integrated with ‘OR＇ logic is p...Dual-modulus prescalers （DMP） for RF receivers are studied. An improved D-latch is proposed to increase the speed and the driving capability of the DMP. A novel D-latch architecture integrated with ‘OR＇ logic is proposed to decrease the complexity of the circuit. A divided-by-16/17 DMP for application in a digital video broadcasting-terrestrial receiver is realized with a TSMC 0.18μm mixed-signal CMOS process. The programmable ＆ pulse swallow divider in this receiver is designed with a 0.18μm CMOS standard cell library and realized in the same process. The measured results show that the DMP has an output jitter of less than 0.03% and works well with the programmable ＆ pulse swallow divider.展开更多
In order to clarify the natures of a rotating stall cell, the experimental investigation was carried out in a high specific-speed diagonal flow fan. The pressure field on the casing wall and the velocity fields at the...In order to clarify the natures of a rotating stall cell, the experimental investigation was carried out in a high specific-speed diagonal flow fan. The pressure field on the casing wall and the velocity fields at the rotor inlet and outlet were measured under rotating stall condition with a fast response pressure transducer and a single slant hot-wire probe, respectively. The data were processed using the “Double Phase-Locked Averaging (DPLA)”technique, which enabled to obtain the unsteady flow field with a rotating stall cell in the relative co-ordinate system fixed to the rotor. As a result, the structure and behavior of the rotating stall cell in a high specific-speed diagonal flow fan were shown.展开更多
A portable dual-channel digital/analogue hybrid lock-in amplifier（LIA） is developed,and its amplitude detection error is less than 10% when the signal-to-noise ratio（SNR） is larger than-12 d B.Then,a differential ...A portable dual-channel digital/analogue hybrid lock-in amplifier（LIA） is developed,and its amplitude detection error is less than 10% when the signal-to-noise ratio（SNR） is larger than-12 d B.Then,a differential mid-infrared methane（CH4） detection device is experimentally demonstrated based on a wideband incandescence wire-source and a multi-pass spherical reflector.The experiments are carried out to obtain the sensing performance of the device.With the absorption length of only ~4.8 cm,the limit of detection（Lo D） is about 71.43 mg/m3,and the detection range is from 0 mg/m3 to 5.00×104 mg/m3.As the concentration gets larger than 714.30 mg/m3,the relative detection error falls into the range of-5%—＋5%.Two seven-hour-measurements are done on the CH4 samples with concentrations of 1.43×103 mg/m3 and 4.29×103 mg/m3,respectively,and the results show that the maximum relative error is less than 5%.Because of the cost effective incandescence wire-source,the small-size and inexpensive dual-channel LIA,and the small-size absorption pool and reflector,the developed device shows potential applications of CH4 detection in coal mine production and environmental protection.展开更多
文摘An optimized method is presented to design the down scalers in a GHz frequency synthesizer. The down scalers are comprised of dual modulus prescaler （DMP） and programmable ＆ pulse swallow divider,different methods of high frequency analog circuit and digital logical synthesis are adopted respectively. Using a DMP high speed, lower jitter and lower power dissipation are obtained,and output frequency of 133.0MHz of the DMP working at divide-by-8 shows an RMS jitter less than 2ps. The flexibility and reusability of the progrs, mmable divider is high;its use could be extended to many complicated frequency synthesizers. By comparison,it is a better design on performance of high-frequency circuit and good design flexibility.
文摘Dual-modulus prescalers （DMP） for RF receivers are studied. An improved D-latch is proposed to increase the speed and the driving capability of the DMP. A novel D-latch architecture integrated with ‘OR＇ logic is proposed to decrease the complexity of the circuit. A divided-by-16/17 DMP for application in a digital video broadcasting-terrestrial receiver is realized with a TSMC 0.18μm mixed-signal CMOS process. The programmable ＆ pulse swallow divider in this receiver is designed with a 0.18μm CMOS standard cell library and realized in the same process. The measured results show that the DMP has an output jitter of less than 0.03% and works well with the programmable ＆ pulse swallow divider.
文摘In order to clarify the natures of a rotating stall cell, the experimental investigation was carried out in a high specific-speed diagonal flow fan. The pressure field on the casing wall and the velocity fields at the rotor inlet and outlet were measured under rotating stall condition with a fast response pressure transducer and a single slant hot-wire probe, respectively. The data were processed using the “Double Phase-Locked Averaging (DPLA)”technique, which enabled to obtain the unsteady flow field with a rotating stall cell in the relative co-ordinate system fixed to the rotor. As a result, the structure and behavior of the rotating stall cell in a high specific-speed diagonal flow fan were shown.
基金supported by the National Natural Science Foundation of China(No.61307124)the Changchun Municipal Science and Technology Bureau(No.14KG022)the Education Department of Jilin Province in China
文摘A portable dual-channel digital/analogue hybrid lock-in amplifier（LIA） is developed,and its amplitude detection error is less than 10% when the signal-to-noise ratio（SNR） is larger than-12 d B.Then,a differential mid-infrared methane（CH4） detection device is experimentally demonstrated based on a wideband incandescence wire-source and a multi-pass spherical reflector.The experiments are carried out to obtain the sensing performance of the device.With the absorption length of only ~4.8 cm,the limit of detection（Lo D） is about 71.43 mg/m3,and the detection range is from 0 mg/m3 to 5.00×104 mg/m3.As the concentration gets larger than 714.30 mg/m3,the relative detection error falls into the range of-5%—＋5%.Two seven-hour-measurements are done on the CH4 samples with concentrations of 1.43×103 mg/m3 and 4.29×103 mg/m3,respectively,and the results show that the maximum relative error is less than 5%.Because of the cost effective incandescence wire-source,the small-size and inexpensive dual-channel LIA,and the small-size absorption pool and reflector,the developed device shows potential applications of CH4 detection in coal mine production and environmental protection.
