Mobile Satellite Service (MSS) is a type of mobile telephone service that depends on portable terrestrial satellites rather than fixed terrestrial satellites that are also known as cell phone towers. Portable terrestrial satellites are similar to cell phone towers, but can be mounted on moving vehicles such as cars, ships, and airplanes, and individual users …
Intersymbol interference is a signal distortion in telecommunication. One or more symbols can interfere with other symbols causing noise or a less reliable signal. The main causes of intersymbol interference are multipath propagation or non-linear frequency in channels. This has the effect of a blur or mixture of symbols, which can reduce signal clarity. If …
The symbol rate is the rate of state changes on a communications circuit. If a circuit can carry two tones per second, the circuit has a symbol rate of two. Circuits then use different modulation techniques to carry multiple bits per symbol. If the circuit is limited to two different tones, the first tone can …
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 …
Reed-Solomon is an algorithm for Forward Error Correction (FEC). Reed-Solomon was introduced by Irving S. Reed and Gustave Solomon of MIT Labs in Polynomial Codes Over Certain Finite Fields, which was published in the Journal of the Society for Industrial and Applied Mathematics in 1960. Reed-Solomon does not specify a block size or a specific …
A retrograde orbit is an orbit where the satellite travels in an East to West direction instead of the common West to East orbit. The normal West to East orbits are known as prograde orbits. Retrograde orbits are uncommon due to the much higher velocities necessary for successful launch and the associated higher costs. During …
MCPC stands for Multiple Channel Per Carrier. MCPC is a form of satellite transmission where each carrier is utilized to transmit multiple channels. MCPC transmits multiple video or audio channels on one carrier by utilizing Time Division Multiplexing (TDM). The alternative to MCPC is SCPC (Single Channel Per Carrier). MCPC is used much more than …
Before you ask what an LNB tester is, you should know what an LNB is. An LNB is the receiving end of a satellite dish. LNB stands for low noise blocker; it is a device that essentially does what it says. It blocks low noise (frequencies) in order to receive higher frequencies in which satellite …
S band is a frequency range from approximately 2 to 4 GHz. S band is used for Digital Audio Radio Satellite (DARS) satellite radio systems such as Sirius XM Satellite Radio. Sirius XM uses frequencies between 2,320.00 and 2,332.50 MHz, and also between 2,332.50 and 2,345.00 MHz. S band is also used by many weather, …
A transponder is an automatic electronic monitoring or control device that receives, cross-examines, amplifies and retransmits the arriving signal. It is primarily implemented in wireless communication. The word ‘Transponder’ itself is a combination of two words; transmitter and responder (occasionally abbreviated to TPDR, TR, XPNDR, and XPDR). A transponder works by receiving a signal on …