Types of Function Generators

We categorize the Function Generators depending on the kind of waveform they generate are:

• Analog function generators
• Digital function generators
• Arbitrary waveform generators

Analog Function Generators

As the name suggests analog function generators are specifically used for generating analog signals. Analog signals are continuous function signal in the time domain which can take infinite number of values in a given range. An Analog function generator generates simple waveforms of varying magnitudes and frequencies that repeat over a period of time. These generators use signal generator circuit and an electronic oscillator for generation of signal. Let us see how it works to generate output waveform

• It mainly consists of an oscillatory circuit which generates fundamental waveforms like sine wave. Operational amplifiers or PLL can be used for implementing this circuit.
• The next part involves waveform shaping which is done using a comparator circuit and a reference voltage for comparison.
• Now a frequency control knob is used in the function generator to control the frequency of signals being generated. This can also be done by using capacitor or resistances. Then ,we change the gain to modify the amplitude of wave.
• Now function selector switch helps us to select the type of waveform we need and then signal goes through a final amplifier for matching. The output is shown.

Digital Function Generators

As the name suggests digital function generators are specifically used for generating digital signals. Digital signals are signals which have discrete values in a certain given range this means they can only take finite number of values. A Digital function generator generates simple waveforms of certain magnitude. These generators use digital technology for generation of signal. They mostly use direct digital synthesis, DDS for this. Let us see how it works to generate output waveform:

• The primary step involved is generation of a digital waveform which is converted to analog format using a digital-to-analog converter (DAC). The quantized values are converted to continuous values.
• The DAC controls the quality of signal by determining the sampling rate and resolution. This is directly linked to the accuracy of waveform.
• The generator allows users to control the properties of wave by allowing them to set them using buttons, knobs, a touchscreen, or software control via a computer.
• Then the random pulse is modulated by Digital function generator by managing frequency/phase of the generated waveform. Frequency sweeping is also performed.
• Synchronization of waveform is done and triggering options can be provided for initiating waveform at certain time instants. Then generated signal is passed through amplifier and shown using screen.

Arbitrary Waveform Generators

This generator has a prefixed list of waveforms that it can generate. In addition to this ,it can generate arbitrary waveforms by controlling the frequency of waveform, the amplitude and offset and basic distortion of waveform. It is popular mainly because of its stability and its great ability to switch almost instantaneously between Voltage levels. It is mainly used in power electronics to generate random signals with high frequency response.

Let us see how it works to generate output waveform

• Arbitrary Waveform Generator uses for generating a user defined waveform. Complex waveforms are stored in the memory of AWGs.
• AWGs used interpolation techniques to create a specific and well-defined waveform. This is done by reconstructing the waveform with high fidelity.
• The DAC controls the quality of signal by determining the sampling rate and resolution. This is directly linked to the accuracy of waveform.
• Synchronization of waveform is done and triggering options can be provided for initiating waveform at certain time instants.
• Filters are employed to remove any unnecessary element form signal and the amplification is done for the last time before sending the output pulse on the screen.

In the field of electronics engineering, scientists and researchers often require signals that can be fed as an input to various devices which can later test their devices on these signals. Devices like modulators, filters, and analog-to-digital convertors require some input signals and other signals for testing. You will wonder what researchers do to get these signals. The answer to this is Function Generator. These are the devices that can generate different types of signals each representing different functions. These can be trigonometric signals, square functions, or any other necessary function. In this article we will see what is a function generator, we will also see the block diagram of a function generator and understand its working through it.