Research and test of the adaptive quadrature demodulation technology for silicon micro-machined gyroscope

A program of adaptive quadrature demodulation is proposed to supply the gaps in the traditional analog detection technology of a silicon micro-machined gyroscope (SMG). This program is suitable for digital phase locked loop (DPLL) drive technology that proposed in other papers. In addition the program adopts an adaptive filtering algorithm, which selects the in-phase and quadrature components that are outputs of the DPLL of the SMG's drive mode as reference signals to update the amplitude of the in-phase and quadrature components of the input signal by iteratively. An objective of the program is to minimize the mean square error of the accurate amplitudes and the estimated amplitudes of SMG's detection mode. The simulation and test results prove the feasibility of the program that lays the foundation for the further improvement of the SMG's system performance and the implementation of the SMG system's self-calibration and self-demarcation in future.

Broadband ADCP digital signal processing based on CIC filter banks

The acoustic Doppler current profilers(ADCP)as a new type of flow measuring equipment,can measure the flow velocity of the channel section directly.ADCP has the advantages of short measuring time and wide measuring range.The traditional ADCP processing system uses analog method to realize demodulation and filtering,which will introduce extra errors.While digital processing system will greatly increase the computation and slow down the speed of data processing.To solve this problem,an efficient real-time broadband ADCP digital signal processing system is proposed based on the low computational cascade integrator comb(CIC)cascade and interpolated second-order polynomial(ISOP)filter banks.The digital in-phase and quadrature(IQ)demodulation,CIC filter banks,and complex autocorrelation operation steps are cascaded with a pipelined method in the system,which greatly improves the system operating speed while avoiding the high memory occupation of non-real-time systems.

An efficient quadrature demodulator for medical ultrasound imaging

Quadrature demodulation is used in medical ultrasound imaging to derive the envelope and instantaneous phase of the received radio-frequency(RF) signal.In quadrature demodulation,RF signal is multiplied with the sine and cosine wave reference signal and then low-pass filtered to produce the base-band complex signal,which has high computational complexity.In this paper,we propose an efficient quadrature demodulation method for B-mode and color flow imaging,in which the RF signal is demodulated by a pair of finite impulse response filters without mixing with the reference signal,to reduce the computational complexity.The proposed method was evaluated with simulation and in vivo experiments.From the simulation results,the proposed quadrature demodulation method produced similar normalized residual sum of squares(NRSS) and velocity profile compared with the conventional quadrature demodulation method.In the in vivo color flow imaging experiments,the time of the demodulation process was 5.66 ms and 3.36 ms,for the conventional method and the proposed method,respectively.These results indicated that the proposed method can maintain the performance of quadrature demodulation while reducing computational complexity.

A low power, low noise figure quadrature demodulator for a 60GHz receiver in 65-nm CMOS technology

This paper presents the design of a low power （LP） and a low noise figure （NF） quadrature demodula- tor with an on-chip frequency divider for quadrature local oscillator （LO） signal generation. The transconductance stage of the mixer is implemented by an AC-coupled self-bias current reuse topology. On-chip series inductors are employed at the gate terminals of the differential input transconductance stage to improve the voltage gain by enhancing the effective transconductance. The chip is implemented in 65-nm LP CMOS technology. The demod- ulator is designed for an input radio frequency （RF） band ranging from 10.25 to 13.75 GHz. A fixed LO frequency of 12 GHz down-converts the RF band to an intermediate frequency （IF） band ranging from DC to 1.75 GHz. From 10 MHz to 1.75 GHz the demodulator achieves a voltage conversion gain （VCG） ranging from 14.2 to 13.2 dB, and a minimum single-sideband N F （SSB-NF） of 9 dB. The measured third-order input intercept point （lIP3） is -3.3 dBm lbr a two-tone test frequency spacing of 1 MHz. The mixer alone draws a current of only 2.5 mA, whereas the complete demodulator draws a current of 7.18 mA from a 1.2 V supply. The measurement results for a frequency divider, which was fabricated individually, prior to being integrated with the quadrature demodulator, in 65-rim LP CMOS technology, are also presented in this paper.

Improvement of signal processing in Coriolis mass flowmeters for gas-liquid two-phase flow

As an increasingly popular flow metering technology,Coriolis mass flowmeter exhibits high measurement accuracy under single-phase flow condition and is widely used in the industry.However,under complex flow conditions,such as two-phase flow,the measurement accuracy is greatly decreased due to various factors including improper signal processing methods.In this study,three digital signal processing methods—the quadrature demodulation(QD)method,Hilbert method,and sliding discrete time Fourier transform method—are analyzed for their applications in processing sensor signals and providing measurement results under gas-liquid two-phase flow condition.Based on the analysis,specific improvements are applied to each method to deal with the signals under two-phase flow condition.For simulation,sensor signals under single-and two-phase flow conditions are established using a random walk model.The phase difference tracking performances of these three methods are evaluated in the simulation.Based on the digital signal processor,a converter program is implemented on its evaluation board.The converter program is tested under single-and two-phase flow conditions.The improved signal processing methods are evaluated in terms of the measurement accuracy and complexity.The QD algorithm has the best performance under the single-phase flow condition.Under the two-phase flow condition,the QD algorithm performs a little better in terms of the indication error and repeatability than the improved Hilbert algorithm at 160,250,and 420 kg/h flow points,whereas the Hilbert algorithm outperforms the QD algorithm at the 600 kg/h flow point.

A 1.2-V CMOS front-end for LTE direct conversion SAW-less receiver

A CMOS RF front-end for the long-term evolution（LTE） direct conversion receiver is presented.With a low noise transconductance amplifier（LNA）,current commutating passive mixer and transimpedance operational amplifier（TIA）,the RF front-end structure enables high-integration,high linearity and simple frequency planning for LTE multi-band applications.Large variable gain is achieved using current-steering transconductance stages.A current commutating passive mixer with 25%duty-cycle LO improves gain,noise and linearity.A direct coupled current-input filter（DCF） is employed to suppress the out-of-band interferer.Fabricated in a 0.13-μm CMOS process,the RF front-end achieves a 45 dB conversion voltage gain,2.7 dB NF,-7 dBm IIP3,and ＋60 dBm IIP2 with calibration from 2.3 to 2.7 GHz.The total RF front end with divider draws 40 mA from a single 1.2-V supply.