QPSK (Quadrature Phase Shift Keying) is a phase modulation algorithm. Phase modulation is a frequency modulation version where the carrier wave’s phase is modulated to encode bits of digital information in each phase change. The “PSK” in QPSK refers to the use of Phased Shift Keying. Phased Shift Keying is a form of phase modulation …
Pulse position modulation is a signal modulation technique that allows computers to share data by measuring the time each data packet takes to reach the computer. It is often used in optical communication, such as fiber optics, in which there is little multi-pathway interference. Pulse position modulation exclusively transfers digital signals and cannot be used …
A thyristor is a solid state semiconductor device that consists of four alternating layers of N-type and P-type material. Many sources consider thyristors to be the same as Silicon Controlled Rectifiers (SCRs). In some cases they are defined as a large group of devices – the eligibility criterion being that the device should consist of …
VSAT (Very Small Aperture Terminal) is basically a two-way satellite ground station with a less than 3 meters tall (most of them are about 0.75 m to 1.2 m tall) dish antenna stationed. The transmission rates of VSATs are usually from very low up to 4 Mbit/s. These VSATs’ primary job is to access the …
A projector lamp is used to transfer an image from a multimedia projector onto a larger screen. Earlier halogen bulbs were used for many years for projection purposes, but were discontinued as halogen produced a yellow tone on the images. A projector lamp relies on an intense light bulb, called a metal halide bulb, to …
Rainfade refers to a phenomenon that occurs during strong rain or snowfall in which satellite signals are prevented from reaching their destination. Rainfade may also refer to extensive cloud cover, strong winds, or any other environmental effect that distorts a satellite broadcast, but is most often observed during rainfall. Rainfade may also refer to the …
MSK (Minimum Shift Keying) is a type of continuous frequency shift modulation that is used to transfer radio signals from satellites and radio broadcasting to mobile devices and vice versa. Unlike other forms of frequency modulation, MSK produces a half sine wave that limits problems associated with non-linear distortion. What is GMSK? GMSK (Gaussian Minimum …
Pulse Width Modulation, abbreviated as PWM, is a method of transmitting information on a series of pulses. The data that is being transmitted is encoded on the width of these pulses to control the amount of power being sent to a load. In other words, pulse width modulation is a modulation technique for generating variable …
Low Earth Orbit (LEO) refers to a satellite which orbits the earth at altitudes between (very roughly) 200 miles and 930 miles. Low Earth Orbit satellites must travel very quickly to resist the pull of gravity — approximately 17,000 miles per hour. Because of this, Lowe Earth Orbit satellies can orbit the planet in as …
A Ham radio antenna tower is usually a metal tower that hams use to support their antennas. There's also an interesting story behind birth of the terms Ham or amateur radio. The actual signification of the term 'ham' was lost but there are several theories that explain its provenience. For example some say it was …