analog function-generator

Download Analog function-generator

Post on 20-Jun-2015




1 download

Embed Size (px)



2. MUHAMMAD AMEER MOHAVIABS(ELECTRONICS ENGINEERING)BALOCHISTAN UNIVERSITY OF INFROMATIONTECHNOLOGY ENGINEERING AND MANAGEMENTSCIENCES, QUETTA, PAKISTAN. 3. 1. INTRODUCTION2. OPERATING PRINCIPLE3. CIRCUIT DIAGRAM4. WORKING OF CIRCUIT5. Applications 4. A function generator is a piece of electronictest equipment used to generate electricalwaveforms. These waveforms can be eitherrepetitive, or single-shot (once only) inwhich case some kind of triggering source isrequired (internal or external). The resultantwaveforms can be applied to a device undertest and analyzed as they progress throughthe device, confirming the proper operationof the device or pinpointing a fault in it. 5. An electronic instrument which generatesperiodic voltage or current waveforms thatduplicate various types of well-definedmathematical functions. The simplestfunction generator usually generates acombination of square waves, triangularwaves, and sine waves. A typical function generator can providefrequencies up to 20 MHz. 6. The ICL8038 is a function generator chip, capable ofgenerating triangular, square , sine, pulse andsawtooth waveforms . From these sine, square &triangular wave forms can be made simultaneously. There is an option to control the parameters likefrequency, duty cycle and distortion of thesefunctions. This is the best function generator circuit for abeginner to start with and is of course a must on thework bench of an electronics hobbyist. The circuit here is designed to produce waveformsfrom 20Hz to 20 kHz 7. The circuit needs a dual power supply. A +15 -15power supply as shown in the circuit is enough forthe purpose. The frequency of the output wave form can beadjusted using R7.It must be a 100K Log POT. The duty cycle can be adjusted using R3 , a 1KPOT. The distortion of the wave form can be adjustedusing R5 , a 100K POT. Square, triangle & sine waveforms can beobtained simultaneously at pins 9,3,2respectively. 8. Square, sine and triangle waves are producedusing an LM348 and passive components. TheLM348 is a quad operational amplifier ICpackage; that is, it contains four separateopamps all in the one IC. They are marked A,B, C & D in the schematic diagram 9. A pseudo or imitation sine wave is producedby a wave shaping circuit. A diode is a non-linear device. As the potential differenceacross it increases the current rises in thecharacteristic way. This circuit joinstogether this characteristic curve to producean approximation to a sine wave. Two diodeshave been joined together as a series pair inorder to provide a higher amplitude thanwould be obtained using only a single diode 10. One opamp (LM324:D) is used. The voltagelevel to pin 13 is set by the resistor dividerpair R1 and R2. The input to pin 12 dependson two things; firstly the potential of pin 14,and secondly, the voltage output of opamp Cat pin 8. When the input at pin 13 is higherthan the input at pin 12 the output goes low.If it is lower then the output goes high.Switching back and forth between the twostates causes a square wave to be produced.The time constant (R4+R5)C2 determines thefrequency. 11. Function Generators are used indevelopment, testing and repair ofelectronic equipment, e.g. as a signal sourceto test amplifiers, or to introduce an errorsignal into a control loop They are generally used in designing, testing,troubleshooting, and repairing electronic orelectroacoustic devices; though they oftenhave artistic uses as well.. A device such asan oscilloscope is then used to measure thecircuits output. 12. There are many different types of signalgenerators, with different purposes andapplications (and at varying levels of expense); ingeneral, no device is suitable for all possibleapplications. Another type of function generator is a sub-system that provides an output proportional tosome mathematical function of its input; forexample, the output may be proportional to thesquare root of the input. Such devices are used infeedback control systems and in analog computers Technology Behind Multi-InstrumentSynchronization 13. Semiconductor Characterization Ultrasonic Phase Array Testing Disk Array Configuration Response testing using squarewaves, pulses, and noise.