There are two types of waveform generators – function generators and arbitrary waveform generators. In this article, we will take a look at their functions and the differences between the two.

In general, both types of waveform generators are very important and useful devices for electronic testing and many other purposes. They are used for example in testing transducers or other machines where you need a stable signal to perform the testing and troubleshooting.

Function generator

Function generators are used to generate basic electrical waveforms for testing electrical equipment. They can produce multiple common waveforms, for example sine, square, triangular, or sawtooth, or pulses. Also, some function generators can generate a DC offset.

What are function generators used for?

You can use function generator to test and repair electronic equipment like amplifiers. They are used for working with analogue circuits.

What is a function generator composed of?

A usual function generator might look something like this:

There are multiple integral parts of every function generator. Firstly, there is the front panel on which all the controls and the display are placed. The size of the device will differ according to the specific type.

The controls usually include power button, setting adjustment knob, other adjustment knobs, wave selection button, digit adjustment buttons and others. There is usually a trigger input, modulation and synchronization signal input, and signal output.

The display might differ in size and resolution according to the type of the device. It shows the settings of the function, for example frequency, amplitude, etc. It also shows the shape of the generated waveform.

There might also be various additional features which depend on the specific type. For example, this generator https://measuritec.com/products/peaktech-p-4055-mv-function-generator-10%C2%B5hz-3-mhz-with-10-w-power-amplifier-remote-control-via-usb or this generator https://measuritec.com/products/peaktech-p-4060-mv-function-generator-10%C2%B5hz-20-mhz-with-10-w-power-amplifier-remote-control-via-usb feature a USB interface. This generator https://measuritec.com/products/siglent-sdg6022x-waveform-function-generator also features a USB host.

Arbitrary waveform generator

Arbitrary waveform generator can generate electrical waveforms, which are then transferred into the device under test. As they go through the device under test, they are measured, and based on the values the proper operation of the device under test is either confirmed or disproven.

Arbitrary waveform generators can generate any defined waveshape, that´s why they are called arbitrary.

What is an arbitrary waveform generator composed of?

A usually arbitrary waveform generator might look something like this:

As you can see, not much difference from the function generator is obvious at first sight.

There are multiple important parts of an arbitrary waveform generator. Firstly, there are numerous controls to set up the device and the size of the waveform, including the power button, function buttons, sleep button, record button etc. Secondly, there is an output channel. Some generators even feature multiple output channels, which is a very handy feature if you need to stimulate multiple machines simultaneously.

For example, this device features two identical output channels: https://measuritec.com/products/siglent-sdg2122x-arbitrary-waveform-generator, just like this one https://measuritec.com/products/siglent-sdg1032x-functional-arbitrary-waveform-generator. However, almost all the modern arbitrary waveform generators feature at least two output channels in their basic gear.

And least but not last, there is a digital monitor to display the waveform, values, and other data. Most importantly, the display shows the picture of the waveform generated, which might be very useful when choosing the waveform from your memory. However, the waveform picture is usually not exact since the generator cannot picture all of the points of the waveform due to insufficient resolution.

Often the display is only black and white but some more advanced generators, like for example this one https://measuritec.com/products/rigol-dg4062-arbitrary-function-generator-with-frequency-range-1-%CE%BChz-60-mhz even feature a coloured display, which can differentiate the waveforms thanks to the different colours. It can help to clear arrangement of the information shown on the display.

Also, the size of the display might differ, which might also contribute to the clear arrangement of the information and the readability of the data. If you are looking for a generator with a very big display, check out this device https://measuritec.com/products/peaktech-4165-1%C2%B5hz-65mhz-arbitrary-waveform-generator-2-channel which has a 10 cm display, or this generator https://measuritec.com/products/peaktech-p4124-waveform-generator with 4´´ HD coloured display.

There is usually an ARB button which can access the arbitrary waveform generator features that function generators don´t have. It is also possible to record the waveform into the internal memory of the generator and later reload the saved values and waveforms. The values of waveforms that the generator can generate might differ according to the type that you are using.

Usually, there are some waveforms built-in to the device that you can choose from which will save you time. However, you can create and define any waveform that you need which is not in the pre-set waveforms.

For example, this device https://measuritec.com/products/rigol-dg4062-function-arbitrary-waveform-generator has 130 pre-set waveforms stored in the memory.

The functions of a function and arbitrary waveform generator can also be combined in one device, like for example this tool https://measuritec.com/products/rigol-dg4062-arbitrary-function-generator-with-frequency-range-1-%CE%BChz-60-mhz which features both function and waveform generator functions. As mentioned in the product´s description, it is possible to generate almost any waveform by using the arbitrary waveform generator mode. Also, it has 150 waveform types stored in the memory, so the work might be even faster and easier.

And if you want ever higher number of pre-set waveforms stored in your memory, take a look at this device https://measuritec.com/products/rigol-dg821-function-arbitrary-waveform-generator-25mhz which features 160 pre-set waveforms. It also offers two-channel operation which is like two independent signal sources.

Some arbitrary waveform generators might also feature additional options, like this one https://measuritec.com/products/peaktech-4125-1%C2%B5hz-25mhz-arbitrary-waveform-generator-2-channel which has a remote control waveform editing function.

How do function and arbitrary waveform generators differ?

In general, it could be said that an arbitrary waveform generator is a specialized type of function generator. It can generate waveforms from a manually entered set of values, something that a basic function generator can´t do.

Function generators can only generate standard functions like sine, square, triangle, sawtooth, pulses, or noise. However, arbitrary waveform generators can generate both periodic and user-defined waveforms of any size. The user can precisely define the waveform that they need to generate. Therefore, arbitrary waveform generators have a wider range of possible use that basic function generators.

Some devices even combine functions and features of multiple tools, like this device https://measuritec.com/products/xds3202a-digital-oscilloscope-data-logger-multimeter-signal-generator-functions-like-n-in-1-200-mhz-and-2gs-s which combines the features and functions of an oscilloscope, data logger, multimeter and signal generator.