www.ijsret.org 797 International Journal of Scientific Research Engineering & Technology (IJSRET), ISSN 2278 – 0882 Volume 3, Issue 4, July 2014 Signal Generation and Measurement Using ARM7 Controller Santosh Shanbhag 1 , Ravi Talawar 2 , Dr.Indumathi T.S 3 1 P.G. Student, Dept. of DECS, VTU, CPGS, Bangalore. Email Id:santoshanbhag@gmail.com 2 Asst. Professor, Dept. of DECS, VTU, CPGS, Bangalore. Email Id: talawar.ravi@gmail.com 3 Professor & Chairmen, Dept. of DECS, VTU, CPGS, Bangalore. Email Id: vtucpgsb@gmail.com ABSTRACT Cathode Ray Oscilloscope is most versatile and widely used instrument in the sciences, medicine, engineering, and telecommunications industry. The Cathode Ray oscilloscope is used for variety of purpose such as detecting wave form, frequency, and time period. A signal generator is a device which produces simple repetitive waveforms and such devices contain an electronic oscillator, a circuit that is capable of creating a repetitive waveform. The most common waveforms are sine wave, saw tooth, step pulse, square, and triangular waveform. The goal of this project is to design a signal generator and a digital oscilloscope with 20 kHz bandwidth. The signal generator and digital oscilloscope that is used in laboratory cost ten to twelve thousands. The motivation of this project is to produce an affordable, easy to make a signal generator and an oscilloscope for students or other engineers who cannot afford to buy a manufacturer’s oscilloscope. The project consists of two parts: Signal generator and Digital Oscilloscope. A single ARM7 controller is used in the project which acts like master brain of the system. At a time a single functionality works and is based on mode selected by the user. Keywords-ARM7 Controller, Oscilloscope, Signal Generator 1. INTRODUCTION Measurement defined as the process of determining the amount or capacity by comparison with accepted standards of the systems units being used. The major parts of electrical experimentation are signal generation and measurement. CRO used for signal measurement and function generator used for signal generation. There are different types of function generators and CROs available in the market. CROs used in any field where a parameter can be converted into a proportional voltage for observation example meteorology biology and medicine. They are Dual beam CRO, Dual trace CRO, Analog & Digital Storage Oscilloscopes, VLF Sampling Oscilloscope, and Digital readout oscilloscope. Depending upon the application we use various CROs. Function generators produce different waveforms of adjustable frequency. The common output waveforms are sine square, triangular and saw tooth waves. The frequency may be from a fraction of Hertz to several hundred kHz. The main drawback with the signal generators and CRO is cost, compatibility and portability. The main purpose is to reduce the hardware cost to minimum and portability. ARM7 based LPC2148 flash version, is a high-performance FLASH micro controller provide highest design flexibility. It has 512 Kbytes of FLASH program memory, 2Kbytes of data memory and 368 bytes of RAM. Performance FLASH micro controller provides highest design flexibility. It has 512 Kbytes of FLASH program memory, 2Kbytes of data memory and 368 bytes of RAM [8]. 2. BACK GROUND MATH This paper relies on oscillation principle and sampling a waveform and then reconstructing it. The wave form generated must be repetitive and hence undammed oscillation is needed. The Shannon sampling theorem, which states that samples must be taken at a rate greater than twice the maximum frequency of the original signal (or at the Nyquist rate)[1], is used so that no aliasing occurs. Aliasing occurs when a signal gets under sampled; a waveform of lower frequency will get reconstructed instead of the correct higher frequency signal. Since the project aimed at designing a digital oscilloscope with 20 kHz bandwidth, the sampling rate is always set higher than 40 kHz (the oscilloscope functions correctly at a maximum frequency of 20 kHz). The analog signal is converted into digital signal by using analog to Digital converter. The conversion involves quantization, small error will encounter. An ADC performs the conversions periodically. An ADC may also provide an isolated measurement such as an electronic device that converts an input