With the continuous development of PRCPM detctor, the accuracy and data transmission rate are increasingly required, so the detctor needs a higher rate of pseudorandom code to *** paper designs a high speed pseudorand...
详细信息
ISBN:
(纸本)9781665467520
With the continuous development of PRCPM detctor, the accuracy and data transmission rate are increasingly required, so the detctor needs a higher rate of pseudorandom code to *** paper designs a high speed pseudorandom code source based on Cyclone 10 GX FPGA and the dynamic reconfiguration of the Nios II processor, its output signal frequency can reach up to 12.5GHz, and supports the dynamic reconfiguration of frequency and m sequence order.
pseudorandom code error of GNSS signal could degrade user receiver’s data demodulation and ranging performance, it is usually caused by unexpected behaviour within the logic circuits of navigation sig
pseudorandom code error of GNSS signal could degrade user receiver’s data demodulation and ranging performance, it is usually caused by unexpected behaviour within the logic circuits of navigation sig
In this pilot study, a novel and minimalistic Brain Computer Interface (BCI) based wheelchair control application was developed. The system was based on pseudo-random code modulated Visual Evoked Potentials (c-VEPs). ...
详细信息
ISBN:
(纸本)9781424492701
In this pilot study, a novel and minimalistic Brain Computer Interface (BCI) based wheelchair control application was developed. The system was based on pseudo-random code modulated Visual Evoked Potentials (c-VEPs). The visual stimuli in the scheme were generated based on the Gold code, and the VEPs were recognized and classified using subject-specific algorithms. The system provided the ability of controlling a wheelchair model (LEGO (R) MINDSTORM (R) EV3 robot) in 4 different directions based on the elicited c-VEPs. Ten healthy subjects were evaluated in testing the system where an average accuracy of 97% was achieved. The promising results illustrate the potential of this approach when considering a real wheelchair application.
With the rapid development of 5G communication, crossly-polarized transmitting and receiving scalable channels have received wide attention. We conduct an in-depth analysis of the 5.8 GHz horizontal and vertical cross...
详细信息
With the rapid development of 5G communication, crossly-polarized transmitting and receiving scalable channels have received wide attention. We conduct an in-depth analysis of the 5.8 GHz horizontal and vertical crossly-polarized electromagnetic (EM) wave propagation and propose a novel test scheme for the feature of the particular EM wave propagation. The scheme acquires the channel characteristics and the interchannel coupling interference strength by transmitting and receiving pseudorandom codes and analyzing the fuzzy function of the corresponding noise-like signals. We then optimize the pseudorandom codes with parallel pseudorandom sequence generation method based on Hash function, greatly reducing calculation time. The transceiver's mode adopts time division duplexing and chooses the pseudorandom codes as the system transceiver's pseudorandom codes. The fuzzy function analysis and processing are performed by a MATLAB code and we can clearly obtain pin-shaped fuzzy images and coupling interference between crossly-polarized channels.
A calibration technique has been developed and tested for scales with an irregular structure typical for absolute angular sensors based on pseudorandom codes. Experimental calibrations were at the level of +/- 2.2 ...
详细信息
A calibration technique has been developed and tested for scales with an irregular structure typical for absolute angular sensors based on pseudorandom codes. Experimental calibrations were at the level of +/- 2.2 '' with an uncertainty of +/- 0.5 '', typical for the measuring and diagnostic installation AE.1686 used in this study. The reliability of the calibration results for irregular scales is confirmed by the identity of the resulting curves when compared with the calibration curve of the regular scale formed on another radius in a single technological cycle together with one of the controlled irregular scales.
In the design of unmanned aerial vehicle (UAV) communication systems, orthogonal frequency division multiplexing (OFDM) is a commonly used communication technology. An efficient channel estimation and equalization alg...
详细信息
In the design of unmanned aerial vehicle (UAV) communication systems, orthogonal frequency division multiplexing (OFDM) is a commonly used communication technology. An efficient channel estimation and equalization algorithm is required to recover the amplitude, phase, and frequency of the signal in OFDM systems. At present, the more precise channel estimation method is based on the pilot. However, its spectrum utilization is relatively low. Therefore, this paper presents the design of a new pilot based on the LS channel estimation, which extends the role of the traditional pilot and improves the utilization of the spectrum. In addition to the channel estimation and equalization, the new pilot can also be utilized for ranging. Simulation results show that the proposed scheme can achieve both channel estimation and communication ranging functions by using the new pilot, and it outperforms the conventional method in channel estimation performance. The proposed method can complete ranging when the bit error rate (BER) is above 0 dB. Moreover, compared with the traditional channel estimation, it reduces the requirement for SNR by about 1 dB under the same BER.
Compared with the traditional electronic line delay, the optical fiber delay line has the advantages of small size, light weight, wide bandwidth, low loss, and strong anti-interference *** optic transmission delay mea...
详细信息
ISBN:
(纸本)9781510661905;9781510661912
Compared with the traditional electronic line delay, the optical fiber delay line has the advantages of small size, light weight, wide bandwidth, low loss, and strong anti-interference *** optic transmission delay measurement technology has a wide range of applications in early warning, communications, navigation, ranging, remote mapping, etc. Traditional optical methods of measuring time intervals can achieve a high degree of accuracy, but they are complex to use, difficult to set up, susceptible to interference, have a limited measurement range and are expensive. Time interval measurement methods for electrical signals can be broadly classified into two categories: analogue and digital. With the continuous development of semiconductor technology and the increasing maturity of digital circuit technology, digital methods now have an increasingly wide range of practical applications, not only because analogue methods are very sensitive to ambient temperature, but also because they require relatively long conversion times, are susceptible to external disturbances and are difficult to integrate. Correlation detection is a very common method for processing signals in the time domain, and is used in correlation detection, delay measurement and signal identification.
An estimation method of pseudo-random (PN) codes in the periodic long code direct sequence spread spectrum signals using a pair of spreading code and scrambling code [i.e. long scrambling code direct sequence spread s...
详细信息
An estimation method of pseudo-random (PN) codes in the periodic long code direct sequence spread spectrum signals using a pair of spreading code and scrambling code [i.e. long scrambling code direct sequence spread spectrum (LSC-DSSS)] is investigated in this study. Via the investigation of properties of triple correlation function (TCF) of m-sequences, the existence of common peaks in the TCFs of different m-sequences is proved, and the corresponding relationship between common peaks and primitive polynomials is further investigated. Four theorems are proposed as supplements of triple correlation theory and a novel estimation algorithm of the PN codes in LSC-DSSS signals is put forward on the basis of the theorems. With certain carrier frequency and chip rate of spreading code, this algorithm first eliminates the influence of information codes through delay-and-multiply operation. Then the TCF of signal is calculated, and the two PN codes in signal are successfully estimated finally by searching and using the common peak coordinates in the TCF. Simulation results show that the proposed algorithm exhibits excellent performance in estimating PN codes in LSC-DSSS signals.
This study presents the signal processing techniques applied on a 9.4/18.8 GHz harmonic radar, which is used to investigate behaviours of small insects such as bees, beetles and butterflies. It is still a challenge to...
详细信息
This study presents the signal processing techniques applied on a 9.4/18.8 GHz harmonic radar, which is used to investigate behaviours of small insects such as bees, beetles and butterflies. It is still a challenge to achieve high accuracy and long detection range simultaneously in a harmonic pulse radar system. The authors combine the spread spectrum technology with the classic pulse harmonic radar system to overcome the dilemma between accuracy and detection range. The processing gain of the pseudo-random code from the spread spectrum technology is used to increase the sensitivity and makes the system able to detect the signal with the weak power strength below the system noise level. To eliminate the effect caused by the local leakage, the signal-processing method provided to cancel the leakage through applying the symmetric property of the autocorrelation function of the pseudo-random code. In the field tests, the proposed system achieves a 60 m detection range within 1 m ranging accuracy by using 1.75 W transmitting power corresponding to 40.430 dBW equivalent-isotropically radiated power (EIRP). It is estimated to extend to at least 900 m detection range by using a 3 kW transmitting power corresponding to 72.771 dBW EIRP.
Based on the requirement of improving the detection capability of laser detector, the pseudorandom code may be adopted as the transmitting code of a laser detector. The auto correlation and the anti-jamming characteri...
详细信息
ISBN:
(纸本)9780769535043
Based on the requirement of improving the detection capability of laser detector, the pseudorandom code may be adopted as the transmitting code of a laser detector. The auto correlation and the anti-jamming characteristics of the pseudorandom code are analyzed at first. Because the emitting power of a laser is reduced greatly where the journey of the pseudorandom code is longer than one, the pseudorandom code should be modulated. On the basis of the foregoing analyses, a new method of pseudorandom code generating and modulating using complex programmable logic device is studied in this paper. The auto correlation characteristic of the modulated pseudorandom code is discussed by simulation method at last. The result shows that the pseudorandom sequence has excellent anti-jamming capability, and the modulated sequence still possesses well the auto correlation characteristic. The theoretic foundation is provided for designing and improving the detecting capability of the laser detector.
暂无评论