ANALOG SIGNALS

Analog signals are continuous signals that represent physical measurements, such as sound, light, temperature or pressure. They are characterized by a continuous range of values and their amplitudes, frequency and phase can vary continuously over time.

There are several types of analog signals and by waveform are; sine, square, saw tooth and rectangular analog wave signals.

A sine analog signal also known as a sinusoidal signal is a continuous signal that represents a pure tone or a single frequency. The waveform of a sine signal is a smooth, continuous curve that oscillates between positive and negative values. Sine signals are used in many applications this includes; sine waves are used to analyze and design AC circuits, sine waves are used as carriers in modulation schemes such as AM, FM etc.

A square analog signal also known as a binary signal (0 or 1, true or false etc.). The waveform of a square signal is a rectangular waveform with flat top and bottom section. Square waves are used in many applications this includes; square waves are used in digital modulation schemes such as ASK (amplitude shift keying) and FSK (frequency shift keying), square waves are used in switching power supplies etc.

A saw tooth analog signals also known as a saw tooth wave is a signal that increases linearly from a minimum value to a maximum value and then suddenly returns to the minimum value. The wave form of a saw tooth signal is a ramp like wave form with a sharp transition at the end of each cycle. Saw tooth waves are used in many applications this includes; saw tooth signals are used in sweep generators for frequency analysis, saw tooth signals are used in audio effects such as distortion and fuzz etc.

A rectangular analog signal also known as a rectangular wave is a signal that has constant amplitude for a certain period of time and then suddenly changes to a different amplitude for another period of time. The waveform of a rectangular signal is a rectangular waveform with a flat top and bottom sections. Rectangular analog signals are used in many applications, this includes; rectangular signals are used in digital modulation schemes such as ASK and FSK, rectangular signals are used in radar systems to determine the range and velocity of targets etc.

The advantages of analog signals are; analog signals can represent a wide range of values making them suitable for applications where high fidelity is required, such as audio and image processing. Analog signals can be processed using simple analog circuits, which are often less expensive and more efficient than digital circuits. Analog signals can be processed in real time, making them suitable for applications where speed is critical such as audio and video processing. Analog signal is a natural fit for real world quantities such as sound, light and temperature as nature is inherently analog. Analog signals has lower bandwidth requirement and no quantization errors induced.

The disadvantages of analog signals are; analog signals are susceptible to noise which can degrade their quality and accuracy. Analog signals can attenuate over long distances making them weaker and more prone to errors. Analog signals have a limited dynamic range, which means they can only represent a certain range of values. Analog signals are difficult to process, store or copy without loss. Analog signals are very difficult to encrypt or compress. Analog signals equipment are prone to wear and drift especially in mechanical and electronic equipment. It is difficult to multiplex many analog signals efficiently.

The application of analog signals is as follows; analog signals are used in audio equipment such as microphones, speakers and headphones. Analog signals are used in image capture devices such as cameras and scanners. Analog signals are used in medical equipment such as ECG machines, EEG machines and blood pressure monitors. Analog signals are used in industrial control systems to control processes such as temperature, pressure and flow rate. Analog signals are used in industrial sensors, analog computers, broadcasting, telephone land lines and a host of other equipment.

The future of analog signals is based on the advances and development of the following technologies; while analog signals are still widely used, there is a growing trend towards using digital signal processing (DSP) techniques to process analog signals. Advances in analog to digital converters (ADC) are enabling faster and more accurate conversion of analog signals to digital signals. The growing demands of IoT devices are driving the need for analog signals to be used in applications such as sensor networks and wearable devices. However analog signals will still remain king in the following, sensor and devices with low power and cost. As digital systems become more prevalent the need to integrate analog signals with digital systems to form an hybrid system will grow.

 

SOURCES:

• Signals, systems and transforms by Charles L. Phillips, John M. Parr and Eve A. Riskin.
• Signals and systems by Alan V. Oppenheim and Alan S. Willsky.
• Fundamentals of signals and systems by Michel Roger,Benoit Feyel and Lousis Le Blond.
• Communication system by Simon Haykin.
• Analog and digital electronics by B.R. Gupta.