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

Author(s):  
Kyohei Suto ◽  
J. T. Sri Sumantyo ◽  
V. C. Koo ◽  
M. Y. Chua ◽  
W. G. Cheaw
2005 ◽  
Vol 23 (1) ◽  
pp. 39-46
Author(s):  
◽  
La Hoz ◽  
◽  

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.


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

2012 ◽  
Vol 195-196 ◽  
pp. 205-211
Author(s):  
Wei Qi ◽  
Qing Chang ◽  
Lv Qian Zhang ◽  
Yuan Yu

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.


1993 ◽  
Vol 94 (3) ◽  
pp. 1752-1752
Author(s):  
Kazushige Yamamoto ◽  
Osamu Yanaga
Keyword(s):  

2013 ◽  
Vol 722 ◽  
pp. 260-264
Author(s):  
Xue Fei Gao ◽  
Yong Li An

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.


2007 ◽  
Vol 17 (02) ◽  
pp. 631-639 ◽  
Author(s):  
SHUIFA SUN ◽  
SAM KWONG

In this letter, a signal processor based on the bistable aperiodic stochastic resonance (ASR), that can be used to detect the base-band binary pulse amplitude modulation (PAM) signal transmitting over an additive white Gaussian noise (AWGN) channel, is studied. The principle of the ASR signal processor is analyzed and the information capacity of such a communication system is evaluated by the Bit Error Ratio (BER) and the bit rate, according to the well-known Shannon information theory. The roles played by the noise on this capacity are analyzed. It is observed that keeping the bit rate unchanged we can neither decrease BER nor increase the bit rate and keep BER unchanged by adjusting the density of the noise. Simulation results also agree well with this observation. In addition, a statistical method to improve the performance of the system is proposed with theory and experiment.


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