 Hello friends, myself Ilya Arsandane, assistant professor from Department of Electronics, Walshan Institute of Technology, Solapur. Today we are going to see the topic MATV and CATV systems from the subject audio-video engineering. So what are the learning outcomes from this topic? At the end of this topic students are able to explain the concept and modifications in standard television system to achieve MATV and CATV systems. Also they can explain the working principle of MATV and CATV systems. So first what is meant by MATV? The full form of MATV is master antenna system television. So introduction to MATV it is basically known as master antenna TV system. The purpose of MATV system is to deliver a strong signal that is which is above 1 millivolt from one or more antennas to every television receiver connected to the same system. The basic application of MATV systems are it is used in hotels, motels, schools, apartment buildings and so on. In this one or in this system one or more antennas are usually located on rooftop then the number depending on available telecast and their direction. Hence the number of antennas which are attached or connected to this type of system generally depends upon the availability of telecast and the direction in which they are going to be used. So this is the block diagram for MATV. As you can see there are different antennas over here which are connected then there is a balloon by which the antennas are connected and then there is a hybrid system which is a linear mixer. Then the pre-amplifier is there distribution amplifier splitter and then there are different transmitters TR 1, 2 and 3, 4, 5 and 6 and these are the receivers. So this system basically over here that is from TR or television receiver to the splitter is known as distribution system from the splitter to the pre-amplifier it is known as signal processing system and then from the pre-amplifier or above the pre-amplifier towards the antennas it is known as antenna system. So this is the block diagram of MATV. So what or how does the MATV work? In this one or more antennas are usually located on rooftop the number of antennas generally depend upon the availability of telecast and their direction. Each antenna is properly oriented so that all stations are received simultaneously or synchronously. In order to make convenient match between the coaxial transmission line and components these are synchronized. MATV systems are designed to have an impedance of 75 ohm as most of the antennas have 300 ohm impedance. Hence a balloon is used to convert that particular 300 ohm impedance of an antenna to 75 ohms. Antenna output is then fed into a 4-way hybrid converter. A hybrid is basically a signal combining linear mixer which provides suitable impedance matching to prevent development of standing wave. The output of this hybrid feed is then given to a distribution amplifier via a pre-amplifier. The function of these two amplifiers is to raise the signal amplitude to a level so as to overcome the losses of the distribution system. The output from the distribution amplifier is then given or fed to the splitters through coaxial trunk lines. So what is a splitter? A splitter is a resistive inductive device which provides trunk line isolation and impedance matching. Coaxial distribution line then carries television signals from the output of splitters to point of delivery called as subscriber tap-off. Taps can be transformer coupled capacitive type of coupling or these are in the form of resistive pads. So this is the working. These taps look like AC outlets but are normally mounted in the wall. The wall taps may be obtained, may have a impedance of 300 ohm output which can be of 75 ohm output with a dual one. The preferred method is to use 75 ohm type which provides a proper impedance matching and which is done by a matching transformer. The matching transformer is usually mounted at the end at the end that is at the antenna terminals of the receiver and will have a VHF output and a UHF output. The improper lines improper terminated lines will develop a standing wave hence the end of each 75 ohm distribution cable is terminated with a 75 ohm register called as a terminator to avoid the standing wave pattern. Generally the standing wave pattern can introduce losses of the information. So this is all about the working of MATV. Similarly this is the block diagram for CATV. So here as you can see it consists of FM band amplifier then there are different televisions which are having UHF and VHF antenna systems then there is a local programmer which is given to a TV modulator then there is a combining network through coaxial cable the output or TV signals are given to amplifier equalizer where preemphasis and deemphasis of signal takes place then there is a distribution amplifier which gives the output to splitter and then there are register with a terminator register of 75 ohm. So these are the tap-off points these are the amplifiers and the trunk lines next these are the amplifiers and the translators or it is also known as head end which provides the input to the CATV system. So the working of community antenna system is the signal from various TV channels are processed in the same manner as we have seen in MATV system. A CATV system can be combined with a MATV system that means we can use MATV as the base and then on that particular MATV setup we can put forth the CATV system. When UHF reception is to be provided in addition to VHF for this case the signal from each UHF channel is processed by a translator that means a UHF signal is converted into VHF1. A translator is a frequency converter which is which uses a super heterodyne UHF which uses a super heterodyne type of UHF converter which provides UH which converts UHF channel frequencies down to VHF channel. Translation here translation is advantages as CATV system operates in length coaxial cables and transmission loss through these cables is much greater at UHF than VHF frequencies. Hence a translator is used for conversion for converting UHF frequencies into VHF frequencies in CATV. As in the case of MATV various inputs including those from translators are combined in suitable mixer. Hence the output of the mixer or the combiner is generally called as the high-end system. The CATV output from the combining network are fed to the trunk cables through broadband distribution amplifier. The trunk cables generally carry these signals from the antenna site to the utilization site or to the subscribers for thousands of kilometers. The cables which are used are feeder type hence feeder amplifier are used at several points to overcome progressive signal attenuation or progressive signal losses which occur due to the cable. As the cable losses are greater at higher frequencies higher frequencies high in high band equalizers are provided with amplifiers and signal splitters. An equalizer or it is also known as tilt controller which consists of a band pass filter is used to adjust the frequency response. Hence the output of the the output of controller is then given which the output of controller gives a relatively low frequency loss so that the output from the amplifiers or splitters have uniform relative amplitude response across the entire VHF band. The signal distribution from the splitters to tap off points is done through multi-core coaxial cables which is same as that of MATV systems. The signal level provided to a television receiver is order of 1.5 millivolt whereas in MATV system it is of order of 1 millivolt. This level is used generally because this provides good quality reception without causing any radiation problems from the CATV systems and without any interference from the other installation or other services. So this is the working for CATV systems. So these are the references. Most of the parties for MATV and CATV system is covered in monochrome and color television systems by R.R. Gulati. Thank you for watching the video.