What is a Signal Generator and How is it Used?

Product testing and software debugging are two of the biggest challenges that embedded systems engineers face when creating a new product. To help streamline the process, embedded systems developers must invest in various types of electronics testing equipment that provide clear and concise feedback and insight into product performance. Logic analyzers and protocol analyzers are two of the most popular debugging tools for embedded systems, but there's another versatile tool that can be deployed in a variety of electronics testing applications: a signal generator.

A signal generator is a diagnostic testing device for electronic systems that functions by producing an electrical signal according to user specifications. There are many kinds of signal generators - five in total - with each type offering unique advantages and applications based on its capabilities to generate signals of varying characteristics. In this blog piece, we'll take a look at what exactly signals generators are and how they're used to measure the performance of electronic products.

What is a Signal Generator? 

A signal generator is an electronic device that generates either analog or digital electronic signals. The signal produced by a signal generator can be calibrated according to user specifications and adjusted on the basis of its frequency, impedance, waveform, modulation, and output voltage. Signal generators are used to test electronic devices and instruments in a variety of applications, and as a result, there are several different types of signal generators:

Oscillators

An electronic oscillator is classified as a signal generator. It produces a periodic, oscillating low-frequency electronic signal that may be analog or digital (sine wave signal or square wave signal). Oscillators are a typical component in processor chips or microcontrollers where they provide clocking for digital devices.

Standard Signal Generators

Standard signal generators are often used to measure the functional properties and performance of electronic devices such as radio receivers. They generate analog electrical signals across a wide range of power output levels and waveform variations (modulations).

Frequency Synthesizers

Frequency synthesizers take a single input frequency and generate electric signals across a wide range of frequencies according to programmed logic. They are used in many types of electronic devices, including telephones, televisions, and global positioning systems (GPS).

Pulse Generators

A pulse generator is a piece of electronic test equipment that generates rectangular pulses. Pulse generators are similar to function generators, but are used in projects that involve digital circuits while function generators are used with analog circuits.

Random Noise Generators

Random noise generators can do some very interesting things. The purpose of a random noise generator is to generate random electrical signals. Instead of generating an electrical signal according to user specifications, a random noise generator produces a random signals within parameters that are set by the user. A random noise generator can be used to measure noise figure and frequency response for an electronic device, or even to generate random numbers.

How Does a Signal Generator Work?

The five types of signal generators mentioned above have one core aspect in common: they are all used to produce electric signals. However, each type is unique in the types of signals that it is capable of producing, and therefore, in its testing applications. An electric signal can be described as a voltage whose value changes over time according to a function specified by the user. 

A signal generator, when used to test an electronic device, is typically deployed in conjunction with some kind of measurement device. The signal generator is used to produce an electric signal, known as the input signal, that will elicit a response, known as the output signal, from the device under test. The output signal will be received by a measurement device like a protocol analyzer or logic analyzer, enabling the developer to see whether the expected output was, in fact, received. If the device responds as expected, the test was passed. Otherwise, the developer will have to further investigate the anomalous or unexpected behavior of the device.

Today's signal generators are designed with an intuitive user interface that makes it easy to adjust target variables based on project requirements. A series of knobs and switches on the face of the signal generator allows users to adjust the type of waveform, voltage level, frequency, signal inversion, and other characteristics. 

Different Types of Signal Generators

When we presented five categories of signal generators earlier in this piece, we included several signal-emitting devices alongside the standard signal generators that are used in electronics testing. Within the category of standard or "general purpose" signal generators, we can further divide signal generators into three sub-types: analog and vector (also called digital) signal generators and digital pattern generators.

Analog Signal Generator

An analog signal generator is a device whose construction is based on the sine wave oscillator. This device was also the first product ever sold by the Hewlett-Packard company in 1939. The term "analog" refers to the types of waveforms that can be produced by this device: continuous and sinusoidal. Analog signal generators effectively produce signals in the audio and radio frequency ranges and are effective for measuring sound distortion and other properties of electronic devices.

Vector Signal Generator

While analog signal generators are still in use, vector signal generators represent the next stage in the evolution of this technology. Vector signal generators are used to measure and test digital communications systems that can no longer be tested properly with analog equipment. They can generate digitally modulated radio signals across a variety of formats.

Digital Pattern Generator 

A digital pattern generator is a useful diagnostic tool for embedded systems engineers programming projects with I2C, SPI, or USB communication protocols. Digital pattern generators produce logic signals - square-shaped waveforms that represent ones and zeroes with changes in voltage level. Digital pattern generators can be deployed in testing applications for embedded systems and digital integrated circuits.

Conclusion

A signal generator allows embedded systems engineers to produce an electric signal according to their exact specifications and use it as an input signal to measure the response and performance of any electronic device. However, embedded systems developers will still need the right measurement tool to effectively capture and record the response from their device for function validation and performance verification.

That's where Total Phase comes in: our Beagle I2C/SPI Protocol Analyzer is the ideal bus monitoring tool for use with your chosen signal generator. You'll gain complete insight into the performance of your embedded system with real-time data capture and display, making it easy to measure performance and identify errors.

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