A 1-GHz 64-Channel Cross-Correlation System for Real-Time Interferometric Aperture Synthesis Imaging

We present a 64-channel 1-bit/2-level cross-correlation system for a passive millimeter wave imager used for indoor human body security screening. Sixty-four commercial comparators are used to perform 1-bit analog-to-digital conversion, and a Field Programmable Gate Array (FPGA) is used to perform the cross-correlation processing. This system can handle 2016 cross-correlations at the sample frequency of 1GHz, and its power consumption is 48.75 W. The data readout interface makes it possible to read earlier data while simultaneously performing the next correlation when imaging at video rate. The longest integration time is up to 68.7 s, which can satisfy the requirements of video rate imaging and system calibration. The measured crosstalk between neighboring channels is less than 0.068%, and the stability is longer than 10 s. A correlation efficiency greater than 96% is achieved for input signal levels greater than −25 dBm.

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MEMS Seismic Sensor with FPAA Based Interface Circuit for Frequency-Drift Compensation using ANN

International Journal of Reconfigurable and Embedded Systems (IJRES) ◽

10.11591/ijres.v6.i2.pp120-126 ◽

2018 ◽

Vol 6 (2) ◽

pp. 120

Author(s):

Ramesh Pawase ◽

N.P. Futane

Keyword(s):

Frequency Drift ◽

Ann Model ◽

Interface Circuits ◽

Interface Circuit ◽

Analog To Digital ◽

Significant Power ◽

Development Platform ◽

Analog To Digital Conversion ◽

Field Programmable ◽

Minimum Block

<p>Electrochemical MEMS seismic sensor is limited by its non-ideality of frequency dependent characteristics hence interface circuits for compensation is necessary. The conventional compensation circuits are limited by high power consumption, bulky external hardware circuitry. In these methods digital circuits are also limited by inherent analog to digital conversion and vice versa which consumes significant power, acquires more size and limits speed. A Field programmable analog array (FPAA) overcomes these limitations and gives fast, simple and user friendly development platform with less development speed comparable to ASIC. Recently FPAA becoming popular for rapid prototyping. The proposed system presents FPAA (Anadigm AN231E04) based hardware implementation of ANN model. Using this FPAA based compensation circuit, the error in frequency drift have been minimized in the range of 3.68% to about 0.64% as compared to ANN simulated results in the range of 23.07% to 0.99 %. This single neuron consumes of power of 206.62 mW. and has minimum block wise resource utilization. The proposed hardware uses all analog blocks which remove the requirement of ADC and DAC reducing significant power and size of interface circuit. This work gives the SMART MEMS seismic sensor with reliable output and ANN based intelligent interface circuit implemented in FPAA hardware.<strong></strong></p>

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Symmetric Multistep Methods Revisited: II. Numerical Experiments

International Astronomical Union Colloquium ◽

10.1017/s0252921100031602 ◽

1999 ◽

Vol 173 ◽

pp. 309-314 ◽

Cited By ~ 3

Author(s):

T. Fukushima

Keyword(s):

Multistep Methods ◽

Computational Time ◽

Integration Time ◽

Implicit Methods ◽

Symmetric Methods ◽

Celestial Bodies ◽

The Stability ◽

Predictor Corrector ◽

Symmetric Multistep Methods ◽

Integration Errors

AbstractBy using the stability condition and general formulas developed by Fukushima (1998 = Paper I) we discovered that, just as in the case of the explicit symmetric multistep methods (Quinlan and Tremaine, 1990), when integrating orbital motions of celestial bodies, the implicit symmetric multistep methods used in the predictor-corrector manner lead to integration errors in position which grow linearly with the integration time if the stepsizes adopted are sufficiently small and if the number of corrections is sufficiently large, say two or three. We confirmed also that the symmetric methods (explicit or implicit) would produce the stepsize-dependent instabilities/resonances, which was discovered by A. Toomre in 1991 and confirmed by G.D. Quinlan for some high order explicit methods. Although the implicit methods require twice or more computational time for the same stepsize than the explicit symmetric ones do, they seem to be preferable since they reduce these undesirable features significantly.

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