# Signal excited by square wave

• faen
In summary, the frequency components observed in the output of a linear system excited by a symmetric square wave include the fundamental frequency and its harmonics, with a decrease in amplitude as the frequency increases. However, in a non-linear system, the fundamental and harmonic components can be affected by amplitude and frequency changes, particularly due to the presence of a diode.

## Homework Statement

11. What kind of frequency components can be observed in the output if a linear system is excited by a symmetric square wave?

12. What kind of frequency components can be observed in the output if a non-linear system is excited by a symmetric square wave?

I have no idea

## The Attempt at a Solution

Well, all I was given to answer this problem was the following wikipedia page about Fourier transforms http://en.wikipedia.org/wiki/Fourier_transform. I still feel that I am not sufficiently informed to answer these questions.

faen said:

## Homework Statement

11. What kind of frequency components can be observed in the output if a linear system is excited by a symmetric square wave?

12. What kind of frequency components can be observed in the output if a non-linear system is excited by a symmetric square wave?

I have no idea

## The Attempt at a Solution

Well, all I was given to answer this problem was the following wikipedia page about Fourier transforms http://en.wikipedia.org/wiki/Fourier_transform. I still feel that I am not sufficiently informed to answer these questions.

Well, what is the frequency spectrum of a symmetric square wave? What harmonics are present, and how do they fall off with frequency?

When you have a linear system, what does that mean in terms of how it can affect the fundamental and the harmonic components?

And if you have a non-linear system (think of a diode in the circuit), what can you say about what can happen to the fundamental and the harmonics, in terms of amplitude and frequency effects?

## 1. What is a square wave signal?

A square wave signal is a type of signal that alternates between two fixed voltage levels at regular intervals, creating a waveform that resembles a square. It is a type of periodic waveform and is commonly used in electronics and digital signal processing.

## 2. How is a square wave signal generated?

A square wave signal is typically generated using a square wave generator, which is an electronic circuit that produces a square wave output. This can also be achieved through software or programming by controlling the voltage levels of a digital signal.

## 3. What are the characteristics of a square wave signal?

A square wave signal has a fixed frequency and amplitude, with a 50% duty cycle (equal time in high and low voltage states). It is a symmetrical waveform, meaning that the rising and falling edges are equal and the amplitude remains constant during each cycle.

## 4. What are the applications of square wave signals?

Square wave signals are commonly used in digital communication systems, such as Ethernet and USB, as well as in electronics testing and measurement. They are also used in audio and video equipment, as well as in power supplies and inverters.

## 5. How does a square wave signal differ from a sine wave signal?

A square wave signal differs from a sine wave signal in terms of its shape and frequency components. A sine wave has a smooth, curved shape and contains only one frequency component, while a square wave has a sharp, angular shape and contains multiple frequency components due to its rapid changes in voltage levels.