A Method for Obtaining Constant Envelope Quadrature Modulation System Base-Band Signal

2012 ◽  
Author(s):  
Wei Xue ◽  
Dafeng Zhao
Keyword(s):  
Quadrature Modulation ◽  
Constant Envelope ◽  
Base Band ◽  
Band Signal

scholarly journals A procedure to correct the effects of a relative delay between the quadrature components of radar signals at base band

2005 ◽  
Vol 23 (1) ◽  
pp. 39-46
Author(s):  
◽  
La Hoz ◽  
◽  
Keyword(s):  
Radar Data ◽  
Center Frequency ◽  
Digital Receiver ◽  
The Real ◽  
Incoherent Scatter ◽  
Singular Region ◽  
Analysis Strategies ◽  
Relative Delay ◽  
Base Band ◽  
Band Signal

Abstract. The real and imaginary parts of baseband signals are obtained from a real narrow-band signal by quadrature mixing, i.e. by mixing with cosine and sine signals at the narrow band's selected center frequency. We address the consequences of a delay between the outputs of the quadrature mixer, which arise when digital samples of the quadrature baseband signals are not synchronised, i.e. when the real and imaginary components have been shifted by one or more samples with respect to each other. Through analytical considerations and simulations of such an error on different synthetic signals, we show how this error can be expected to afflict different measurements. In addition, we show the effect of the error on actual incoherent scatter radar data obtained by two different digital receiver systems used in parallel at the EISCAT Svalbard Radar (ESR). The analytical considerations indicate a procedure to correct the error, albeit with some limitations due to a small singular region. We demonstrate the correction procedure on actually afflicted data and compare the results to simultaneously acquired unafflicted data. We also discuss the possible data analysis strategies, including some that avoid dealing directly with the singular region mentioned above.

scholarly journals A Pan-Function Model for the Utilization of Bandwidth Improvement and PAPR Reduction

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yidong Xu ◽  
Wei Xue ◽  
Wenjing Shang
Keyword(s):  
Attenuation Factor ◽  
Average Power ◽  
Quadrature Modulation ◽  
Phase Shift Keying ◽  
Function Model ◽  
System A ◽  
Constant Envelope ◽  
Quadrature Phase ◽  
Shift Keying ◽  
Simulation Results

Aiming at the digital quadrature modulation system, a mathematical Pan-function model of the optimized baseband symbol signals with a symbol length of4Twas established in accordance with the minimum out-band energy radiation criterion. The intersymbol interference (ISI), symbol-correlated characteristics, and attenuation factor were introduced to establish the mathematical Pan-function model. The Pan-function was added to the constraints of boundary conditions, energy of a single baseband symbol signal, and constant-envelope conditions. Baseband symbol signals with the optimum efficient spectrum were obtained by introducing Fourier series and minimizing the Pan-function. The characteristics of the spectrum and peak-to-average power ratio (PAPR) of the obtained signals were analyzed and compared with the minimum shift keying (MSK) and quadrature phase-shift keying (QPSK) signals. The obtained signals have the characteristics of a higher spectral roll-off rate, less out-band radiation, and quasi-constant envelope. We simulated the performance of the obtained signals, and the simulation results demonstrate that the method is feasible.

scholarly journals Base-band Signal Processing of Narrow MUSE.

1991 ◽  
Vol 45 (6) ◽  
pp. 737-746
Author(s):  
Seiichi Gohshi ◽  
Makoto Tadenuma ◽  
Minoru Honda ◽  
Kiyotaka Okada ◽  
Kazumasa Enami
Keyword(s):  
Signal Processing ◽  
Base Band ◽  
Band Signal

Development of SAR base-band signal processor using FPGA and onboard PC

2014 ◽  
Author(s):  
Kyohei Suto ◽  
J. T. Sri Sumantyo ◽  
V. C. Koo ◽  
M. Y. Chua ◽  
W. G. Cheaw
Keyword(s):  
Base Band ◽  
Band Signal ◽  
Signal Processor

An Improved Re-Sampling Interpolation Algorithm for Base-Band Signal Shaping Filtering

2012 ◽  
Vol 195-196 ◽  
pp. 205-211
Author(s):  
Wei Qi ◽  
Qing Chang ◽  
Lv Qian Zhang ◽  
Yuan Yu
Keyword(s):  
Spread Spectrum ◽  
Communication Systems ◽  
Dynamic Environment ◽  
Software Radio ◽  
Wireless Communication Systems ◽  
Interpolation Filter ◽  
Shaping Filter ◽  
Band Power ◽  
Base Band ◽  
Band Signal

Research on shaping filtering algorithms in wireless communication systems has important practical value. Based on the digital base-band shaping filter, which is widely used in the area of software radio, an improved re-sampling filtering algorithm is proposed in this paper. By the design of truncated raise cosine filter, the continuous sequence of digital spread-spectrum signal can be restored. The piecewise parabola interpolation filter is established to carry out the signal re-sample, and the Farrow implementation structure is adopted to reduce the calculation cost. The algorithm is validated through the experiment using simulated and true signals respectively, which demonstrate that not only the out band power of frequency division multi signals can be effectively suppressed, but also the steadiness of re-sampling signals is improved during the dynamic environment.

2FSK Signal Generator Based on AT89C51 Microcontroller

2013 ◽  
Vol 722 ◽  
pp. 260-264
Author(s):  
Xue Fei Gao ◽  
Yong Li An
Keyword(s):  
Second Order ◽  
Signal Generator ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Output Side ◽  
Base Band ◽  
Band Signal

In order to simplify the devices used for generating the 2FSK signal, a 2FSK signal generator based on AT89C51 microcontroller is proposed in this paper. A digital base band signal is inputted to the microcontroller through one of I/O ports. Then microcontrollers program is executed, which are designed for generating PWM signals according to the sine waveforms corresponding with 2FSK signals required. Consequently, an appropriate PWM signal is outputted from another I/O port. This PWM signal is sent into a simple second order passive low-pass filter, and the 2FSK signal can be obtained on the output side of the filter. The 2FSK signal generator makes full use of the resources of the microcontroller, and as a result, it is simple, easy to use, economical and reliable.

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