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A five-axis machining center integrates two mechanical models: a three-degree-of-freedom parallel platform and traditional computer numerical control X–Y table. There is a trend for machining centers to be reconfigurable precision hybrid machine tools (RHMTs) for the fabrication of complex and precision products. Most industrial robots have open kinematic chains and serially connected links. A parallel...
Antenna calibration to enhance the channel reciprocity between the uplink and downlink channels is necessary for the practical wireless system operating in the time division duplexing (TDD) mode. This paper investigates on the computation of the antenna calibration coefficients of the cooperative base stations' antennas in the network multiple-input and multiple-output (MIMO) system. An efficient...
As an active scatterometer for the quantitative measurement of precipitation intensity, the spaceborne precipitation radar (PR) can obtain three-dimensional precipitation structure within the observation region. This paper introduces the Ka band precipitation radar (PR-Ka) engineering model and the aerial flight calibration test. Aerial flight calibration test results show that the precision of calibration...
In real environments, channel reciprocity cannot be directly exploited between uplink and downlink in time-division duplex (TDD) due to antenna gain mismatch. Previous work about antenna calibration mainly focused on single cell. This work proposes an adaptive scheme for antenna calibration between two cooperative BSs. The proposed scheme aims at achieving an equal ratio between antenna transmitter...
A new switched-capacitor multiply-by-two amplifier with an accurate gain of two is presented. The proposed architecture requires only one opamp in four phases to generate two effective outputs. It significantly suppresses the gain error due to capacitor-mismatch and also provides a better power efficiency. Monte-Carlo simulation results are presented to confirm the feasibility of this new technique,...
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