Definition: VCO is an acronym for Voltage Controlled Oscillator. It is a device that produces such an oscillating output signal whose frequency can be regulated or altered by the input dc voltage. In other words, we can say, VCO generates an output signal having an adjustable frequency range that is controlled by the dc input voltage. It is a type of oscillator in which the output frequency obtained is the function of the input signal. Usually, the frequency of an oscillator is … [Read more...] about Voltage Controlled Oscillator (V C O)
Difference Between Single-mode and Multimode Optical Fiber
The major difference single-mode and multimode optical fiber is that in single-mode optical fiber light ray propagates only through a single path. On the contrary, in multimode optical fiber several light rays propagate through the waveguide at the same time. Another crucial difference between single-mode and multimode optical fiber is that single-mode fiber has a smaller core diameter as compared to multimode fiber. We will discuss some other important differences between single-mode and … [Read more...] about Difference Between Single-mode and Multimode Optical Fiber
Bistable Multivibrator
Definition: A type of multivibrator whose output consists of 2 stable states is known as Bistable Multivibrator. The circuit switches from one stable state to the other when an appropriate trigger pulse is applied. In a nutshell, in a bistable multivibrator, one stable state can be maintained until a triggering pulse is provided. It is also known as flip-flop multivibrator because due to applied trigger pulses, multivibrator flip from one stable state. And by applying the next trigger … [Read more...] about Bistable Multivibrator
Monostable Multivibrator
Definition: Monostable Multivibrator is a type of multivibrator that has single stable state. MONO means one thus the name itself indicates one state stable and a quasi-stable state. It is also known as a one-shot multivibrator. Here, a triggering pulse is used in order to have transition from a stable state to quasi-stable state. However, no any triggering pulse is provided to have transition from quasi to a stable state. After a pre-determined time interval, the quasi-state returns … [Read more...] about Monostable Multivibrator
Astable Multivibrator
Definition: An astable multivibrator is a type of multivibrator that does not require a triggering pulse thus, sometimes known as a free-running multivibrator. It necessarily provides square wave as its output. Astable multivibrator is called so because both the states present here are unstable i.e., quasi-stable. This means output swings between 0 and 1 and neither 0 nor 1 is the stable state. Here, the successive transition is made from one quasi-state to other after some pre-decided … [Read more...] about Astable Multivibrator
Multivibrator
Definition: An electronic device that produces a non-sinusoidal waveform as its output is known as a Multivibrator. The generated non-sinusoidal waveforms are basically a square wave, rectangular wave, a triangular wave, sawtooth wave, or ramp wave etc. It is a 2 stage RC coupled amplifier that operates in two modes. The modes are basically termed as states of the multivibrator. Basics of Multivibrator The multivibrator is a switching circuit and its basic configuration is shown … [Read more...] about Multivibrator
Pulse Position Modulation (PPM)
Definition: A modulation technique that allows variation in the position of the pulses according to the amplitude of the sampled modulating signal is known as Pulse Position Modulation (PPM). It is another type of PTM, where the amplitude and width of the pulses are kept constant and only the position of the pulses is varied. Simply put, the pulse displacement is directly proportional to the sampled value of the message signal. To understand the generation of the PPM signal, it is … [Read more...] about Pulse Position Modulation (PPM)
Delta Modulation (DM)
Definition: A modulation technique that converts or encodes message signal into a binary bit stream is known as Delta Modulation. Here only 1 bit is used to encode 1 voltage level thus, the technique allows transmission of only 1 bit per sample. As PCM has the property of converting message signal directly into a sequence of a binary coded pulse, this resultantly increases the bandwidth requirement of the system. So, in order to remove the drawbacks of PCM, delta modulation is … [Read more...] about Delta Modulation (DM)
Pulse Width Modulation (PWM)
Definition: A modulation technique where the width of the pulses of the pulsed carrier wave is changed according to the modulating signal is known as Pulse Width Modulation (PWM). It is also known as Pulse duration modulation (PDM). Basics of Pulse Width Modulation It is a type of Pulse Time Modulation (PTM) technique where the timing of the carrier pulse is varied according to the modulating signal. In pulse duration modulation (PDM), the amplitude of the pulse is kept constant and only … [Read more...] about Pulse Width Modulation (PWM)
Pulse Amplitude Modulation (PAM)
Definition: A modulation technique in which the amplitude of the pulsed carrier signal is changed according to the amplitude of the message signal is known as Pulse Amplitude Modulation (PAM). Simply put, the transmission of data takes place by the variation of the amplitude of pulse according to the modulating signal. Basics of PAM The technique does not show much variation in comparison to continuous wave modulation. The only difference is that the carrier in the pulse modulation … [Read more...] about Pulse Amplitude Modulation (PAM)