Self Organizing Maps (SOM) technique was developed in 1982 by a professor, Tuevo Kohonen. Professor Kohonen worked on auto-associative memory during the 1970s and 1980s and in 1982 he presented his self-organizing map algorithm. SOMs are named as “Self-Organizing” because no supervision is required. Self-organizing maps learn on their own through unsupervised competitive learning. They … Read more
In the previous article, we had learned about Kalman filter. As Kalman filter assumes linear system but finds greatest applications in non-linear systems. Kalman filter assumes an approximate solution, describe the deviations from the reference by linear equations. Kalman filter has issues of divergence also. When the error covariance matrix Pk computed by the Kalman filter … Read more
The Kalman filter is a recursive state space model based estimation algorithm. In other words, it is an optimal recursive data processing algorithm. Kalman filter is also called as the Predictor-Corrector algorithm. This filter is named after Rudolph E. Kalman, who in 1960 published his famous paper describing a recursive solution to the discrete data … Read more
A sensor is basically a device that converts the physical parameter (for example, viscosity, temperature, blood pressure, light intensity, humidity, speed, etc.) into a signal(may be electrical or non-electrical quantity) which can be easily measured. For example, let us consider an electrical resistance temperature element. Here the measurand is the temperature which is being sensed … Read more
A sensor producing an electrical output, when combined with some interfacing hardware is termed to be an intelligent sensor. Intelligent sensors are also called smart sensors, which is a more acceptable term now. Sensors + Interfacing hardwares = Smart sensors This type of sensor is different from other types of sensors because it carries out … Read more
In many applications such as audio applications, it is useful to represent a signal in terms of sample values taken at appropriately spaced intervals. The signal can be reconstructed from the sampled waveform by passing it through an ideal low pass filter. In order to ensure a distortionless reconstruction, the original signal must be sampled … Read more
So far we have seen different types of pulse modulation. In this article, we are going to talk about Pulse Code Modulation (PCM). Pulse Code Modulation (PCM) Pulse Code Modulation (PCM) is a different type of pulse modulation because it is a digital process. Though it uses sampling techniques. The PCM generator produces a series of … Read more
In this article, we will learn about Pulse Time Modulation. In the previous article, we had learned about pulse amplitude modulation. In Pulse Time Modulation, the timing characteristics such as width, position, and frequency are varied with the amplitude of the input signal. So, Pulse Time Modulation are of three types i.e. Pulse Width Modulation (PWM) Pulse Position … Read more
Pulse Amplitude Modulation (PAM) is a type of pulse modulation in which the signal is sampled at regular intervals, with each sample proportional to the amplitude of the signal at the time of sampling. There are two types of Pulse Amplitude Modulation Single polarity PAM Double polarity PAM Single polarity PAM In this type of PAM, … Read more
There are some simple relations between currents and voltages of different branches of an electrical circuit. These relations are determined by some elementary laws that are known as Kirchhoff laws or more exactly Kirchhoff Current and Voltage laws. These laws are first derived by Gustave Robert Kirchhoff and therefore these laws are also called as Kirchhoff … Read more
