Analog Signals
- [Analog Signals and Digital Signals - Javatpoint]
- Overview
Analog signal theory describes how continuous physical quantities, like sound waves or voltage, are represented by signals that vary smoothly and infinitely within a range, mimicking the original data, unlike discrete digital signals.
This theory explains how these real-world variations (amplitude, frequency) are captured and transmitted, such as in old radios or vinyl records, using concepts like voltage/current changes and how they differ from sampled binary data, focusing on their continuous nature and susceptibility to noise.
1. Core Concepts:
- Continuity: Analog signals are continuous in both time and value, meaning they can take on any infinitely small value within their range, like a dimmer switch.
- Analogy: The signal is analogous to the physical phenomenon it represents; for example, a microphone's electrical signal mirrors the continuous pressure changes of a sound wave.
- Representation: Information is encoded in the signal's varying amplitude (height) and frequency (how often it repeats).
- Examples: Sound waves, radio waves, light, temperature, and the hands of an analog clock are classic examples.
2. Key Characteristics:
- Smooth Variation: Produces smooth, curved waveforms (like sine waves) when plotted against time.
- Infinite Values: Can represent infinite gradations of data points.
- Noise Sensitivity: More prone to noise and interference because any added interference becomes part of the signal.
3. Contrast with Digital Signals:
- Analog: Continuous, infinite values, sensitive to noise, smooth curves (e.g., sound waves).
- Digital: Discrete (0s and 1s), finite values, robust to noise, square waves (e.g., computer data).
4. Applications:
- Traditional broadcasting (AM/FM radio, older TV).
- Audio recording (vinyl records, cassette tapes).
- Sensors that measure continuous physical phenomena (thermometers, pressure gauges).
- Analog Signals and Devices
Analog signals are time-varying and are usually limited to a range (such as +12V to -12V), but have an infinite number of values within that continuous range.
Analog signals use a given property of the medium to convey the signal's information, such as an electric current passing through a wire.
The common examples of analog signals are temperature, current, voltage, voice, pressure, speed, etc. The analog signals are used in land line phones, thermometer, electric fan, volume knob of a radio, etc.
In electrical signals, the voltage, current, or frequency of the signal can vary to represent information. Analog signals are often calculated responses to changes in light, sound, temperature, position, pressure, or other physical phenomena.
When plotted on a voltage versus time graph, the analog signal should produce a smooth and continuous curve. There should not be any discrete value changes.
Most basic electronic components - resistors, capacitors, inductors, diodes, transistors, and operational amplifiers (op amps) - are analog in nature. A circuit composed of these components is an analog circuit.
Analog circuits are generally more susceptible to noise, and by "noise" we mean any tiny, unwanted changes in voltage. Small changes in the voltage level of an analog signal can create significant errors in processing.
- Characteristics of Analog Signals
- These electronic signals are time-varying.
- The lowest and highest values, which can be positive or negative.
- It is usually cyclical or acyclical.
- Analog signals are suitable for continuous data.
- Analog signals are not as precise as digital signals.
- It can help you realize natural or physical value.
- Analog signals output in the form of curves, lines, or graphs, so it doesn't make sense to all or anyone.
- Advantages of Analog Signals
Advantages to using analog signals, including analog signal processing (ASP) and communication systems, include the following:
- Analog signals are easier to process.
- Analog signals best suited for audio and video transmission.
- Analog signals are much higher density, and can present more refined information.
- Analog signals use less bandwidth than digital signals.
- Analog signals provide a more accurate representation of changes in physical phenomena, such as sound, light, temperature, position, or pressure.
- Analog communication systems are less sensitive in terms of electrical tolerance.
- Disadvantages of Analog Signals
Disadvantages to using analog signals, including analog signal processing (ASP) and communication systems, include the following:
- Data transmission at long distances may result in undesirable signal disturbances.
- Analog signals are prone to generation loss.
- Analog signals are subject to noise and distortion, as opposed to digital signals which have much higher immunity.
- Analog signals are generally lower quality signals than digital signals.
- The Uses of Analog Signals
Analog signals are commonly used in communication systems that use continuous signals to carry voice, data, image, signal or video information. There are two basic types of analog transmissions, both based on how they condition data to combine the incoming signal with a carrier signal.
The two techniques are amplitude modulation and frequency modulation. Amplitude modulation (AM) adjusts the amplitude of a carrier signal. Frequency Modulation (FM) Adjusts the frequency of the carrier signal.
Just like the human body uses eyes and ears to capture sensory information, analog circuits use these methods to interact with the real world and accurately capture and process these signals in electronic devices.
Analog transfers can be achieved in a number of ways:
- Through a twisted pair or coaxial cable
- Through an optical fiber cable
- Through radio
- Through water
[More to come ...]
