Function Generator: Features & Applications

Features of Function Generators

A function generator is a signal source that can produce different types of waveforms as its output signal. The most common output waveforms are: sine waves, square waves and triangular waves. Furthermore, some function generators also produce sawtooth, pulse and non-symmetrical square waves. A typical frequency range for function generators is 0.01 Hz to 3 MHz.

A number of function generators have the capability of generating two different waveforms simultaneously (from different output terminals). This feature can be of great help when two generated signals are needed for a specific application. For example, by providing a square wave for linearity measurements in an audio-system, a simultaneous sawtooth output may be used to drive the horizontal deflection amplifier of an oscilloscope, providing a visual display of the measurement result.

Some function generators are capable of phase locking an external signal source. One function generator may be used to lock a second function generator, and the two output signals can be displaced in phase by an adjustable amount. Additional, one function generator may be phase locked to a harmonic of the sine wave of another function generator. By the adjustment of the phase and the amplitude of the harmonics, almost any waveform may be produced by the summation of the fundamental frequency generated by one function generator and the harmonics generated by the other function generator.

The block diagram below, illustrates the key components of a function generator:

Generally, the major components of a function generator are: Schmitt trigger, integrator, sine-wave converter, and an attenuator. The Schmitt trigger converts a slowly varying input signal to a square wave signal. This square wave signal is available at the output and it is also connected to the integrator as an input through a potentiometer (R). The potentiometer is used to adjust the frequency of the output signal. The frequency range is adjusted by selecting a suitable capacitor connected in the integrator circuit. The sine wave converter is a six-level (or more) diode-resistor loading circuit.

Applications of Function Generators

Function generators are used in different types of applications, for example they are used in: design, training, product testing in manufacturing, bench calibration, repair, laboratory, education and research.

Function generators are key equipment for an electronic laboratory as they are used to generate signals for testing different types of analog and digital systems (amplifiers, filters, digital circuits, etc.) during the design in addition to troubleshooting the same.

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