Introduction to Signals
1. What is a Signal?
Definition: A signal is a function that represents the variation of a physical quantity with
respect to an independent parameter, typically time or distance.
Mathematical Representation: f(x)=−ax^2+bx+c or f(x) = -ax^2 + bx + c
Example: A person measures the temperature every minute from 9:00 AM to 9:00 PM.
The recorded temperatures can be plotted as a function of time, forming a curve that
represents the signal.
2. Signals in Electrical and Electronics
Electrical Signals: In electrical and electronics, signals often represent the variation of
electrical quantities, such as current or voltage, with respect to time.
Constant Values: If the current or voltage remains constant over time, it is considered a
direct current (DC) and not a signal.
3. Transducers
Definition: A transducer is a device that converts one form of energy to another.
Types:
o Sensor: Converts non-electrical energy (e.g., sound, light, temperature) into an
electrical signal.
o Actuator: Converts electrical signals into non-electrical energy (e.g., sound,
motion).
Example: A microphone (sensor) converts sound into an electrical signal, which is then
amplified and played through a speaker (actuator) to produce sound.
4. Types of Signals
a. Analog Signals
1. What is a Signal?
Definition: A signal is a function that represents the variation of a physical quantity with
respect to an independent parameter, typically time or distance.
Mathematical Representation: f(x)=−ax^2+bx+c or f(x) = -ax^2 + bx + c
Example: A person measures the temperature every minute from 9:00 AM to 9:00 PM.
The recorded temperatures can be plotted as a function of time, forming a curve that
represents the signal.
2. Signals in Electrical and Electronics
Electrical Signals: In electrical and electronics, signals often represent the variation of
electrical quantities, such as current or voltage, with respect to time.
Constant Values: If the current or voltage remains constant over time, it is considered a
direct current (DC) and not a signal.
3. Transducers
Definition: A transducer is a device that converts one form of energy to another.
Types:
o Sensor: Converts non-electrical energy (e.g., sound, light, temperature) into an
electrical signal.
o Actuator: Converts electrical signals into non-electrical energy (e.g., sound,
motion).
Example: A microphone (sensor) converts sound into an electrical signal, which is then
amplified and played through a speaker (actuator) to produce sound.
4. Types of Signals
a. Analog Signals
