Definition: Companding is a technique of achieving non-uniform quantization. It is a word formed by the combination of words compression and expanding. Companding is done in order to improve SNR of weak signals. We know if the characteristics of the quantizer is non-linear then it causes the step size to be variable despite being constant then it is known as non-uniform quantization. As we know in non-uniform quantization, the step size varies according to the signal level.If the signal … [Read more...] about Companding
Wavelength Division Multiplexing (WDM)
Definition: WDM is a short form used for Wavelength Division Multiplexing. It is a technique in which signals of different wavelength are multiplexed together in order to get transmitted over an optical link. The concept of WDM was arrived in 1970. It is an analog multiplexing technique used in fiber optic communication. Here, optical signals of multiple wavelengths are transmitted using a fiber link. Basically, the technique acts in a way that signals get combined using a multiplexer … [Read more...] about Wavelength Division Multiplexing (WDM)
Beat Frequency Oscillator (BFO)
Definition: Beat Frequency Oscillator or BFO is an oscillator that produces a sinusoidal signal of the variable audio frequency range. It provides such a frequency that can be varied over a very large range. BFO was invented in 1901 by Reginald Fessenden. It is among the most common type of oscillator that can generate a signal of variable frequency at its output. Block Diagram and Working of Beat Frequency Oscillator The figure below represents the block diagram of a BFO:Here as we can … [Read more...] about Beat Frequency Oscillator (BFO)
Phase Shift Oscillator
Definition: Phase shift oscillators are the oscillators that generate a stable sinusoidal signal at the output. Basically, the circuit has, an amplifier unit like transistor or op-amp along with a feedback network comprising of resistors and capacitors. Thus, is also known as RC phase shift oscillator. The RC network is present in the feedback path is connected in ladder fashion thus also known as ladder RC phase shift oscillator. We know for an RC circuit; the output voltage leads the input … [Read more...] about Phase Shift Oscillator
Zero Crossing Detector
Definition: An op-amp detector that has the ability to detect the change from positive to negative or negative to a positive level of a sinusoidal waveform is known as a zero crossing detector. More specifically, we can say that it detects the zero crossing of the applied ac signal. It is basically a voltage comparator whose output changes when the input signal crosses the zero of the reference voltage level. Thus it is named so. It is also known to be a square wave generator as the … [Read more...] about Zero Crossing Detector
Relaxation Oscillator
Definition: A relaxation oscillator is basically a non-linear oscillator that has the ability to generate a non-sinusoidal periodic waveform at its output. Such as triangular wave, square wave etc. These are also known as non-sinusoidal waveform generators. A relaxation oscillator operates in such a way that it generates oscillations by charging the capacitor and quickly discharging it after attaining a pre-determined threshold voltage. The figure below will help you to understand the … [Read more...] about Relaxation Oscillator
Anderson’s Bridge
Definition: Anderson’s Bridge is an AC bridge that determines the self-inductance of an inductor in the circuit. This bridge offers highly accurate output and is an advancement of Maxwell’s inductance capacitance bridge. By Anderson's bridge, one can measure inductance by utilizing other circuit components like resistors and capacitor. In Maxwell’s bridge, the inductance is calculated by comparing it with a standard variable capacitance. In this article, we will discuss the construction, … [Read more...] about Anderson’s Bridge
Potentiometer
Definition: Potentiometer is an instrument that is used the determine the potential (voltage) between two points by performing a comparison with a known voltage. Basically, in order to do so, a manual variation in resistance is performed so as to control the current flow thereby determining the required voltage. Potentiometers are normally abbreviated as POT and are nothing but variable resistors that measures the emf between two existing points. The circuit of a potentiometer provides the … [Read more...] about Potentiometer
Phase Modulation (PM)
Definition: Phase modulation is another type of angle modulation in which the phase of the carrier wave is changed according to the amplitude (magnitude) of the message (modulating) signal. In phase modulation of an analog signal, the phase change is a continuous back and forth movement. While in case of digital signal there exist an abrupt change in the phase of the carrier signal. The phase modulation of the digital signal is generally known as phase shift keying. The process of phase … [Read more...] about Phase Modulation (PM)
Frequency Modulation (FM)
Definition: A category of angle modulation in which the frequency of the carrier wave is changed according to the amplitude of the message signal is known as frequency modulation. It is abbreviated as FM and is a widely used analog modulation technique. One can modulate a signal by varying the amplitude of the carrier signal according to the message signal, which we commonly knew as amplitude modulation (AM). The implementation of AM is simple. However, it possesses various … [Read more...] about Frequency Modulation (FM)