A digital signal-processing instrument for impedance measurement (original) (raw)

DSPIC-Based Impedance Measuring Instrument

Metrology and Measurement Systems, 2011

An implemented impedance measuring instrument is described in this paper. The device uses a dsPIC (Digital Signal Peripheral Interface Controller) as a processing unit, and a DDS (Direct Digital Synthesizer) to stimulate the measurement circuit composed by the reference impedance and the unknown impedance. The voltages across the impedances are amplified by programmable gain instrumentation amplifiers and then digitized by analog to digital converters. The impedance is measured by applying a seven-parameter sine-fitting algorithm to estimate the sine signal parameters. The dsPIC communicates through RS-232 or USB with a computer, where the measurement results can be analyzed. The device also has an LCD to display the measurement results.

Implementation of DSP based algorithms for impedance measurements

ICSPC 2007 Proceedings - 2007 IEEE International Conference on Signal Processing and Communications, 2007

In this paper, two DSP based algorithms are implemented for impedance measurements. The algorithms (the sevenparameter sine-fitting algorithm and the ellipse fitting algorithm) are implemented and tested in a commercial DSP kit. The complete system is used to compare the algorithms by measuring 105 different impedances, using the four-wire impedance measurement method. The strategic selection of appropriate reference impedances, intrinsic to the impedance measurement method, is also described. The results of each algorithm are compared in terms of speed and accuracy. This is the ground work for a portable DSP based impedance measurement device to be implemented in specifically designed hardware.

Impedance measuring system based on a dsPIC

2010

This paper describes a device based on a dsPIC (Digital Signal Peripheral Interface Controller) as a processing unit, capable of making impedance measurements at multiple frequencies. A DDS (Direct Digital Synthesizer) stimulates the measurement circuit composed by the reference impedance and the unknown impedance. The voltage across the impedances is amplified by programmable gain instrumentation amplifiers and then digitized by analog to digital converters. To measure the impedance, a seven-parameter sine-fitting algorithm is used to estimate the sine signals across the impedances. The dsPIC is connected through RS-232 to a computer where the user can view the measurement results.

Impedance Measurement With Sine-Fitting Algorithms Implemented in a DSP Portable Device

IEEE Transactions on Instrumentation and Measurement, 2000

The development and implementation of a digitalsignal-processor (DSP)-based portable impedance-measurement instrument is described. The circuit sinewave stimulus is generated by the device using a direct digital synthesizer at the desired measurement frequency. The sine is applied to a reference impedance in series with the unknown impedance. Two analogto-digital converters (ADCs) acquire multiple samples of the two sine voltages, which are transmitted to the DSP. Sine-fitting algorithms determine the sine amplitudes, phases, dc components, and frequency. With these values and the reference-impedance values, the unknown impedance amplitude and phase are determined. Amplifiers, which are included in the device, extend the ADCs' input range, while a digital potentiometer enables the adjustment of the reference impedance to improve accuracy.

Application of compensation techniques in a dsPIC based impedance measuring system

2011 IEEE EUROCON - International Conference on Computer as a Tool, 2011

A dsPIC (Digital Signal Peripheral Interface Controller) based impedance measuring system was developed and implemented. The system measures the impedance's amplitude and phase at the desired frequency using a sine-fitting algorithm running on the dsPIC and the results are sent to a personal computer using an USB or RS-232 connection. The measurement results are also shown in an LCD included in the device. This paper describes the system and details the OPEN and SHORT compensation techniques used to correct the measurements obtained with the device.

A multi-chanel electrical impedance meter based on digital lock-in technology

Pollack Periodica, 2019

The presented multichannel measuring system working on various frequencies is suitable either for electrical impedance spectroscopy or tomography. The authors of this paper have developed the complete measurement system and a graphical user interface platform. The accuracy of impedance amplitude and phase are 1 ppm and 0.01 o , respectively. The basic instrument works with 8 channels and can be expanded to 64 channels with the application of multiplexing or multiple parallel connected instruments in the same system.

Impedance Measurements using Analog to Digital Converters and Ellipse Fitting Signal Processing Algorithms

In this paper, the measurement of impedances using analog to digital converters and ellipse fitting signal processing algorithms is described. The robustness of this new method makes it specially suited for low frequency impedance measurements (up to 1 MHz) in portable DSP based instruments. Previous methods relied on sine-fitting algorithms to estimate the sine parameters together with the signal frequency. These were iterative algorithms where convergence is not assured and they can be a significant computational burden requiring more processing capabilities in the instrument. With ellipse fitting, the frequency is not estimated and the algorithm is not iterative.

Embedded System for Impedance Measurement

2016

The purpose of this paper work is to design and implementation of an embedded system for impedance measurement. This system is design by using the impedance converter integrated circuit AD5933 which gives the real and imaginary value for measuring the impedance. The system combines an on-board frequency generator with build in 12-bit, 1 MSPS, analog-to-digital converter (ADC). There is built in frequency generator allows an external complex impedance to be excited with a known frequency. The response signal from the device testing under test (DUT) is sampled by the on-board ADC and a discrete Fourier transform (DFT) is processed by an onboard DSP engine. The DFT algorithm returns a real (R) and imaginary (I) data word at each output frequency as the real and imaginary register contents, which can be read from the serial I2C interface. The Arduino mega board microcontroller (ATmega2560) maintains control of the AD5933 via the I2C-compliant serial interface protocol. The impedance mea...