Patent RS-20060558-A (RS)
Title: Digital analyst of complex periodic and nonharmonic ac signals
Inventor: PETROVIC PREDRAG
IPC: G01R19/00
Filed: 2006-10-09
Abstract: Digital analyst of complex and nonharmonic AC signals according to the invention, represents a new solution which using a micro-processor, memory circuits (two SRAM circuits), and connecting in a new way and LCD display (LM032L) to display calculated and unknown parameters (amplitude and a phase) of voltage and current signals, to represent measured effective values of voltage and electricity in the system under consideration, i.e. measured active power on loading and frequency of carrying signal in non-harmonic conditions, carrying out processing and display of results in the conditions where processing of complex periodic alternating signals is carried out. Processing is based on a completely new algorithm, by means of analythical expressions deducted, which enables the processing possible in a real time. Representation is selected using keys TASTER 1-8 to choose a desired listing of the processing results. Microprocessor is over lines /OE and/ WR for permission and reading and entry of data and through eight data lines (LCD_DATA) connected to a display (LM032L), and through sixteen address lines (AD 0: 15) and sixteen data lines (D 0:15) to RAM memory. Device sends data on recalculated parameters of signal and measured values of electric values to the supervisory computer which can be networked through the lines RX and TX. Switching to a separate operating mode, digital analyst provides processing of signals having both interharmonics and subharmonics as a nonharmonic components, all on the grounds of accurate identification of required number of samples of the signal and distance between two consecutive samples of the signal. There is also a completely new algorithm and processing steps or processing procedure for this type of processing. Digital analyst represents a completely new solution for a digital system for acquisition of alternating signals, in the process of processing known values of integral input voltage and current signals are used. Complete control and all required recalculations are carried by a microprocessor PIC17C44 produced by Microchip. Possibility for realization of a highfrequency and accurate digital analyst (which can be used as a spectral analyst) as well, and which can be used for different sorts of measuring and control, and calibration of other less accurate instruments, as well. A special significance is the fact that such an instrument is not accomplished neither in this country nor anywhere else in the world. Price of such an instrument would be very low because of the simplicity of usable hardware in its accomplishment. Herewith defined are all required conditions for specific types of processing offered by a digital analyst according to the invention. High level of synchronization with a measured signal is achieved. Synchronization with measured signal is achieved by means of a simple circuit and counting resources of the microprocessor itself. Device is equipped with a serial connection by means of which it can be network connected to the supervisor computer, and therewith into a larger integrated information system. Errors in transmission are controled and detected by Cyclic Redundancy Check.