A discrimination measurement method and demodulation technique for fiber Bragg grating (FBG) sensors were presented using digital filtering technique. The system can control a tunable fiber Fabry-Perot filter with saw...A discrimination measurement method and demodulation technique for fiber Bragg grating (FBG) sensors were presented using digital filtering technique. The system can control a tunable fiber Fabry-Perot filter with sawtooth wave voltage generated by digital clock to interrogate FBG sensors. Using the analogue digital converter (ADC), the reflected FBG signals were sampled with synchronous digital clock. With the aid of digital matched filtering technique, the sampled FBG signals were processed to obtain the maximum signal-to-noise ratio (SNR) and the Bragg wavelength shift from the FBG signals was recovered. The results demonstrate that this system has a scanning range of 1 520 nm-1 575 nm,and the wavelength detection accuracy is less than 2 pm with 1.5 Hz scanning frequency.展开更多
A new method of estimating the frequency-known signals from the strong background noise was presented first. Then the new method was used in the demodulation of the digital frequency modulation (FSK) signals. The new ...A new method of estimating the frequency-known signals from the strong background noise was presented first. Then the new method was used in the demodulation of the digital frequency modulation (FSK) signals. The new demodulation method can complete the demodulation of the FSK signals only with the carrier frequency and without any carrier phase information. The simulation results show that the performance of anti-noise of the new method is better than that of the incoherent demodulation method and the fluctuation of the carrier phase has little effect on the new method. So the new demodulation method has a fine prospect in the practical applications.展开更多
A digital biomedical electrical impedance tomography (EIT) system is developed with the aid of FPGA. The key elements of EIT system are described specifically in the paper. The functions are realized to generate excit...A digital biomedical electrical impedance tomography (EIT) system is developed with the aid of FPGA. The key elements of EIT system are described specifically in the paper. The functions are realized to generate excitation source, switch electrode channels, deal collected signals, demodulate measured voltages etc. The system is tested by a circular tank with 16 stainless electrodes attached around the boundary. The adjacent incentive adjacent measurement mode is adapted to collect boundary voltages of the interesting field. By testing, the system works with 36 dB signal-to-noise ratio (SNR) when 1 mA 100 KHz current is applied into a homogenous tank.展开更多
To solve the difficulty of designing digital impacting filter in the receiver of random-polar modulated Extended Binary Phase Shift Keying with Continuous Phase (CP-EBPSK), a design method based on Quantum-behaved Par...To solve the difficulty of designing digital impacting filter in the receiver of random-polar modulated Extended Binary Phase Shift Keying with Continuous Phase (CP-EBPSK), a design method based on Quantum-behaved Particle Swarm Optimization (QPSO) algorithm is proposed. Firstly, QPSO is introduced elaborately, and the basic flow of QPSO is also given. Then, the demodulation principle of digital impacting filter in the communication system of CP-EBPSK with random-polar is demonstrated, and QPSO is utilized to design the digital impacting filter, which also takes the effect of finite word length into consideration when implemented by hardware. Finally, the proposed method is simulated. Simulation results show that the digital impacting filter designed by new method can derive satisfied demodulation performance.展开更多
Based on the characteristics of field-programmable gate array(FPGA) such as multi-task,high-speed,parallelity,etc,a filtering algorithm is presented to filter the output signal of laser gyr o with high-speed and high ...Based on the characteristics of field-programmable gate array(FPGA) such as multi-task,high-speed,parallelity,etc,a filtering algorithm is presented to filter the output signal of laser gyr o with high-speed and high accuracy.The filter is composed of basic logic cell s,multipliers an d memory inside FPGA.By using an multiplication decomposition method and design ing reliable time-sequence,the filter is realized,which is easy to be transpl anted and of low cost.Furthermore,all the signal demodulation algorithms of t he laser gyr oscope can be integrated in only one FPGA,which reduces the cost and complexity of the system.展开更多
We present an all-digital demodulation system of interferometric fiber optic sensor based on an improved arctangent-differential-self-multiplying(arctan-DSM)algorithm.The total harmonic distortion(THD)and the light in...We present an all-digital demodulation system of interferometric fiber optic sensor based on an improved arctangent-differential-self-multiplying(arctan-DSM)algorithm.The total harmonic distortion(THD)and the light intensity disturbance(LID)are also suppressed,the same as those in the traditional arctan-DSM algorithm.Moreover,the lowest sampling frequency is also reduced by introducing anti-aliasing filter,so the occupation of the system memory is reduced.The simulations show that the improved algorithm can correctly demodulate cosine signal and chirp signal with lower sampling frequency.展开更多
This paper proposes a combination technique of the frequency-domain random demodulation（FRD） and the broadband digital predistorter（DPD）. This technique can linearize the power amplifiers（PAs） at a low sampling ...This paper proposes a combination technique of the frequency-domain random demodulation（FRD） and the broadband digital predistorter（DPD）. This technique can linearize the power amplifiers（PAs） at a low sampling rate in the feedback loop. Based on the theory of compressed sensing（CS）, the FRD method preprocesses the original signal using the frequency domain sampling signal with different stages through multiple parallel channels. Then the FRD method is applied to the broadband DPD system to restrict the sampling process in the feedback loop. The proposed technique is assessed using a 30 W Class-F wideband PA driven by a 20 MHz orthogonal frequency division multiplexing（OFDM） signal, and a 40 W Ga N Doherty PA driven by a 40 MHz 4-carrier long-term evolution（LTE） signal. The simulation and experimental results show that good linearization performance can be achieved at a lower sampling rate with about- 24 d Bc adjacent channel power ratio（ACPR） improvement by applying the proposed combination technique FRD-DPD. Furthermore, the performance of normalized mean square error（NMSE） and error vector magnitude（EVM） also has been much improved compared with the conventional technique.展开更多
基金Doctoral Foundation of Ministry of Education of China (No. 20040056008)
文摘A discrimination measurement method and demodulation technique for fiber Bragg grating (FBG) sensors were presented using digital filtering technique. The system can control a tunable fiber Fabry-Perot filter with sawtooth wave voltage generated by digital clock to interrogate FBG sensors. Using the analogue digital converter (ADC), the reflected FBG signals were sampled with synchronous digital clock. With the aid of digital matched filtering technique, the sampled FBG signals were processed to obtain the maximum signal-to-noise ratio (SNR) and the Bragg wavelength shift from the FBG signals was recovered. The results demonstrate that this system has a scanning range of 1 520 nm-1 575 nm,and the wavelength detection accuracy is less than 2 pm with 1.5 Hz scanning frequency.
基金the National Natural Science Foundation of China (60272077) the Science Foundation of Aeronautics (02F53030).
文摘A new method of estimating the frequency-known signals from the strong background noise was presented first. Then the new method was used in the demodulation of the digital frequency modulation (FSK) signals. The new demodulation method can complete the demodulation of the FSK signals only with the carrier frequency and without any carrier phase information. The simulation results show that the performance of anti-noise of the new method is better than that of the incoherent demodulation method and the fluctuation of the carrier phase has little effect on the new method. So the new demodulation method has a fine prospect in the practical applications.
文摘A digital biomedical electrical impedance tomography (EIT) system is developed with the aid of FPGA. The key elements of EIT system are described specifically in the paper. The functions are realized to generate excitation source, switch electrode channels, deal collected signals, demodulate measured voltages etc. The system is tested by a circular tank with 16 stainless electrodes attached around the boundary. The adjacent incentive adjacent measurement mode is adapted to collect boundary voltages of the interesting field. By testing, the system works with 36 dB signal-to-noise ratio (SNR) when 1 mA 100 KHz current is applied into a homogenous tank.
基金Supported by the National Natural Science Foundation of China (No. 60872075)
文摘To solve the difficulty of designing digital impacting filter in the receiver of random-polar modulated Extended Binary Phase Shift Keying with Continuous Phase (CP-EBPSK), a design method based on Quantum-behaved Particle Swarm Optimization (QPSO) algorithm is proposed. Firstly, QPSO is introduced elaborately, and the basic flow of QPSO is also given. Then, the demodulation principle of digital impacting filter in the communication system of CP-EBPSK with random-polar is demonstrated, and QPSO is utilized to design the digital impacting filter, which also takes the effect of finite word length into consideration when implemented by hardware. Finally, the proposed method is simulated. Simulation results show that the digital impacting filter designed by new method can derive satisfied demodulation performance.
文摘Based on the characteristics of field-programmable gate array(FPGA) such as multi-task,high-speed,parallelity,etc,a filtering algorithm is presented to filter the output signal of laser gyr o with high-speed and high accuracy.The filter is composed of basic logic cell s,multipliers an d memory inside FPGA.By using an multiplication decomposition method and design ing reliable time-sequence,the filter is realized,which is easy to be transpl anted and of low cost.Furthermore,all the signal demodulation algorithms of t he laser gyr oscope can be integrated in only one FPGA,which reduces the cost and complexity of the system.
文摘We present an all-digital demodulation system of interferometric fiber optic sensor based on an improved arctangent-differential-self-multiplying(arctan-DSM)algorithm.The total harmonic distortion(THD)and the light intensity disturbance(LID)are also suppressed,the same as those in the traditional arctan-DSM algorithm.Moreover,the lowest sampling frequency is also reduced by introducing anti-aliasing filter,so the occupation of the system memory is reduced.The simulations show that the improved algorithm can correctly demodulate cosine signal and chirp signal with lower sampling frequency.
基金supported by the National Basic Research Program of China (2014CB339900)the National Hi-Tech Research and Development Program of China (2015AA016801)the National Natural Science Foundation of China (61327806)
文摘This paper proposes a combination technique of the frequency-domain random demodulation（FRD） and the broadband digital predistorter（DPD）. This technique can linearize the power amplifiers（PAs） at a low sampling rate in the feedback loop. Based on the theory of compressed sensing（CS）, the FRD method preprocesses the original signal using the frequency domain sampling signal with different stages through multiple parallel channels. Then the FRD method is applied to the broadband DPD system to restrict the sampling process in the feedback loop. The proposed technique is assessed using a 30 W Class-F wideband PA driven by a 20 MHz orthogonal frequency division multiplexing（OFDM） signal, and a 40 W Ga N Doherty PA driven by a 40 MHz 4-carrier long-term evolution（LTE） signal. The simulation and experimental results show that good linearization performance can be achieved at a lower sampling rate with about- 24 d Bc adjacent channel power ratio（ACPR） improvement by applying the proposed combination technique FRD-DPD. Furthermore, the performance of normalized mean square error（NMSE） and error vector magnitude（EVM） also has been much improved compared with the conventional technique.
