Radio Frequency (RF) switch circuit is the basic part of microwave devices and systems. The non-linearity distortion figure is necessary in the field of large dynamic range of signal. This letter analyzes the basic sw...Radio Frequency (RF) switch circuit is the basic part of microwave devices and systems. The non-linearity distortion figure is necessary in the field of large dynamic range of signal. This letter analyzes the basic switch circuit and its inter-modulation, and studies in detail the measurement methods and systems of RF switch intercept point. It has provided cascaded simulation testing methods, which can accurately measure the PF switch, of which the second or third order intercept point value is above 75dB and 60dB, respectively. As the testing results are consistent with the theoretical analyses, it proves that the validity of the method satisfies the requirements of large scaled linearity measurement in engineering.展开更多
Wideband multiple-input multiple-output (MIMO) channel measurements were performed at5.25GHz in the hotspot environment in Beijing.The propagation mechanism was line-of-sight and ob-structed-line-of-sight (LOS/OLOS) i...Wideband multiple-input multiple-output (MIMO) channel measurements were performed at5.25GHz in the hotspot environment in Beijing.The propagation mechanism was line-of-sight and ob-structed-line-of-sight (LOS/OLOS) in the outdoor scenario.Using a large amount of estimated angle ofdeparture (AoD) and angle of arrival (AoA) results,the cumulative distribution functions (CDFs) of di-rectional spread (DS) are extracted,which illustrate that the spatial dispersion is quite significant at bothends due to the low antenna height of base station and rich scatterers.The average power azimuth spec-trum (PAS) is found to be well fitted with a Laplacian function.In addition,the non-isotropic property ofspatial correlation is investigated,and the average envelop correlation over arbitrary antenna spacing pro-vides the correlation distance to facilitate the MIMO optimization and deployment in the outdoor hotspotenvironment.展开更多
In order to accurate measure micro displacement, the paper presents an accurate measuring system of distributed micro displacement. The system uses a linear CCD and FPGA and network communication technology to realize...In order to accurate measure micro displacement, the paper presents an accurate measuring system of distributed micro displacement. The system uses a linear CCD and FPGA and network communication technology to realize data acquisition and remote transmission. The test results show that the system can support 16 line array CCD test node to measure the micro deformation of the one- dimensional, the CCD data transmission rate is 3200 frames/s, node data transmission distance is greater than 200 m, and measurement accuracy is 500 micron.展开更多
This paper introduces the choices of the technology solutions pertinent to the industrial standard of Chinese communications industry, YD/T 1591 Technical Requirements and Test Method of Charger and lnterface for Mobi...This paper introduces the choices of the technology solutions pertinent to the industrial standard of Chinese communications industry, YD/T 1591 Technical Requirements and Test Method of Charger and lnterface for Mobile Telecommunication Terminal Equipment, as well as its development and revision process. It also elaborates the technology contents for Recommendation of Improving the Standard ITU-TL.1000.展开更多
文摘Radio Frequency (RF) switch circuit is the basic part of microwave devices and systems. The non-linearity distortion figure is necessary in the field of large dynamic range of signal. This letter analyzes the basic switch circuit and its inter-modulation, and studies in detail the measurement methods and systems of RF switch intercept point. It has provided cascaded simulation testing methods, which can accurately measure the PF switch, of which the second or third order intercept point value is above 75dB and 60dB, respectively. As the testing results are consistent with the theoretical analyses, it proves that the validity of the method satisfies the requirements of large scaled linearity measurement in engineering.
基金the National High Technology Research and Development Programme of China(No.2006AA01Z258)
文摘Wideband multiple-input multiple-output (MIMO) channel measurements were performed at5.25GHz in the hotspot environment in Beijing.The propagation mechanism was line-of-sight and ob-structed-line-of-sight (LOS/OLOS) in the outdoor scenario.Using a large amount of estimated angle ofdeparture (AoD) and angle of arrival (AoA) results,the cumulative distribution functions (CDFs) of di-rectional spread (DS) are extracted,which illustrate that the spatial dispersion is quite significant at bothends due to the low antenna height of base station and rich scatterers.The average power azimuth spec-trum (PAS) is found to be well fitted with a Laplacian function.In addition,the non-isotropic property ofspatial correlation is investigated,and the average envelop correlation over arbitrary antenna spacing pro-vides the correlation distance to facilitate the MIMO optimization and deployment in the outdoor hotspotenvironment.
文摘In order to accurate measure micro displacement, the paper presents an accurate measuring system of distributed micro displacement. The system uses a linear CCD and FPGA and network communication technology to realize data acquisition and remote transmission. The test results show that the system can support 16 line array CCD test node to measure the micro deformation of the one- dimensional, the CCD data transmission rate is 3200 frames/s, node data transmission distance is greater than 200 m, and measurement accuracy is 500 micron.
文摘This paper introduces the choices of the technology solutions pertinent to the industrial standard of Chinese communications industry, YD/T 1591 Technical Requirements and Test Method of Charger and lnterface for Mobile Telecommunication Terminal Equipment, as well as its development and revision process. It also elaborates the technology contents for Recommendation of Improving the Standard ITU-TL.1000.
