How to create a electronic circuit(a function generator) to generate arbitrary waveforms?

Question

I need to generate given functions(for example sin(t) , sin(t)+5 , t+10 ) using electronic components including microcontrollers. Any type of IC or an electronic component can be used. Please help me with this? (schematic diagram, procedure and referance). The final output should be able to be observed using an oscilloscope.

Answer 1

I'm in the process of creating one of these devices for educational use, right now.



Aside from the usual recommendations of using one of the various "function generator" chips that exist, or using a bog standard DAC and driving it from tables, you might want to look up Walsh functions. There's a great book on the topic by Henning F. Harmuth called "Sequency Theory: Foundations and Applications," 1977.



You might also look up articles on synthesizers, since they have been using Walsh functions in the past and there is a lot of practical information available there. Benjamin Jacoby also wrote a nice, short article on using these. It's called "Walsh Functions" and I've provided a link, below.



The huge advantage for Walsh functions is that they work with square waves which are easily generated by digital I/O pins.



Just another path you might consider, among the usual and more obvious recommendations.

Answer 2

Here's one way http://www.instructables.com/id/Arbitrary-waveform-generator/ Basically you need a microcontroller (pic chip, microprocessor), and a DAC. The wave table is held in ROM or can be calculated.

Answer 3

You could use a function generator chip that will provide sine, square, triangle, waveforms over a wide frequency range.



Another method is a micro-controller driving an (perhaps internal) DA converter. The microcontroller can provide a stream of numbers to the DAC to produce any waveform desired, within the limits of the microcontrollers speed and memory and the DAC resolution.



You need to write specs as the first step. Such as waveforms, amplitude and frequency range, accuracy, noise, etc.