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 …
A speaker is a device that converts electrical signals into actual sound. Speakers accomplish this by using a magnetic reader or antenna to receive an electrical signal from a radio station or magnetic storage device. The magnetic reader is then connected via a wire to an electromagnet that can be turned on and off in …
The Frequency-Hopping Spread Spectrum (FHSS) is a means of transmitting radio signals by shifting a carrier across a number of channels with a pseudorandom sequence that the sending and receiving station knows beforehand. The method is used as a multiple access process in the FH-CDMA (Frequency Hopping Code Division Multiple Access) transmission scheme. What Are …
A photodetector is a device that imprints the image of an object or scene onto a material. Photodetectors are made in various ways and can be used for different purposes. Most photodetectors fall into the phototube, thermal detector, or camera category. These photodetectors are used for communication, navigation, and record keeping. Types of Photodetectors Phototube …
ODU (Out-Door Unit) refers to the set of satellite equipment which is placed outside of the building. The ODU typically includes a satellite dish, a feedhorn, and a LNB (Low Noise Block). In bi-directional satellite systems, the ODU will also include a BUC (Block Up Convertor). The ODU is connected to the IDU (In-Door-Unit) by …
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 …
Resistors can come in different sizes and shapes allowing for different voltages to go through it. However, unless the size of the resistor is large, the code is rarely written on it because it would require very tiny markings. Therefore, a system was developed to use colors to determine the resistor code. In other words, …
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 siemens is the standard unit of electrical conductance. It is the inverse of resistance and is equal to one divided by resistance, or current divided by voltage. One siemens is equal to one ampere per volt. History of the Siemens The siemens was defined at an international conference in 1881, and is named after …