 Hello friends. Myself, Aaliyah Ahsanjane, assistant professor from Department of Electronics, Walchen Institute of Technology, Solapur. So today, we are going to see the topic, satellite television system from the subject audio-video systems. So first, what are the learning outcomes of this topic? At the end of this topic, students are able to understand the need of modern television systems. Next, the working principle of satellite system. Next, to analyze trans-receiver subsystems for satellite communication. So basically, this is the satellite communication system, which generally consists of a satellite and there are two antennas which are at the earth station. This is the transmitting antenna and this is the receiving antenna. Generally, the transmitting antenna transmits the information towards the satellite and then the satellite processes this information and it resents to the receiving antenna at the earth station. So basically, the transmitting frequency is generally known as the uplink frequency and the retransmitted frequency sent from the satellite to the earth station antenna is generally known as the downlink frequency. The uplink frequency generally ranges from 5.9 to 6.4 GHz and the downlink frequency generally ranges from 3.7 to 4.2 GHz. So basically, here the satellite has two antennas. One of them is the receiving antenna and the other one is the transmitting antenna. It also consists of solar panels, which it consists of solar panels, which accumulates the solar sun rays and then these are generally used for charging of the batteries which are in the satellite. So satellite system generally consists of the transmitting station which sends the RF waves to the satellite. Generally, microwave frequencies are used which are of band, which are having a band of 3 GHz to 30 GHz. Here as this is the long distance communication, here atmosphere does not act as a barrier that is abstraction or it does not absorbs or deflects any RF waves which consist of the information. As we have seen the transmitting frequency is generally known as uplink frequency and the frequency which is received by satellite and it sends the other frequency with information is generally known as the downlink frequency. These two frequencies are different from each other, so these are different from each other hence to avoid the interface between the two frequencies during the communication. The bandwidth allotted for uplink and downlink frequency is of about 500 MHz. The frequencies which are generally used in satellite communication, the uplink frequency is the frequency which is used for transmission of signal from earth station to the satellite. Downlink frequency is the reverse that is it is the frequency which is used for transmission of signals from satellite to the earth station receiver. Uplink frequency is different from downlink frequency for the following reasons. The satellite transmitter generates a signal that would jam its own receiver if uplink and downlink frequencies are shared on the same frequency bandwidth that is there is an interference between the uplink and downlink frequencies whenever the same frequencies are used for transmission and reception of information in satellite communication. Frequency band separation allows the same antenna to be used for both receiving and transmitting hence it simplifies the satellite hardware both receiving and transmitting here comes the concept of trans receiving antenna that is a same antenna can be used for receiving as well as transmitting the signal to overcome the above problems. Satellite repeaters are used with some form of frequency translation before amplification hence uplink frequency is different for downlink frequency at higher frequencies attenuation is more hence more power will be required for signal transmission. As we know that at frequency attenuation is frequency attenuation is directly proportional to the frequency range hence more power is required for the signal transmission. Hence to ensure that it reaches the destination with required minimum power. That means whenever the signal is transmitted from earth station to towards the satellite it is ensured that the power which has been increased in the transmitting signal this power makes the signal to reach to its destination that is towards the satellite with its minimum power. Higher power requirements generally involve the use of high power amplifiers with high ratings and heat sinks. This increases the weight and power supply ratings which does not make any difference but however the satellite however for the satellite this will result in higher power consumption which results in avoidable inefficiency. So satellite TV system generally consists of these blocks. So this is the block diagram for satellite television system here as you can see the uplink signal is of 5.9 to 6.4 gigahertz this signal consists of the main information this is given to the input filter then it is again given to the 6 gigahertz amplifier where the power amplification of this signal takes place and it is then later given to the mixer where it is mixed with 2.2 gigahertz local oscillator frequency and which acts as the carrier frequency and here the process of modulation takes place and then it is given to the 4 gigahertz of amplifier. Here again the power amplification takes place and then it is given to a transponder. Now the transponder generally consists of three major blocks first input multiplexer second TWT amplifier and third one is output multiplexer input multiplexer multiplexes all the incoming signal and then it gives to the TWT amplifier where the traveling wave tube amplifier generally amplifies this signal in terms of microwave frequencies and then it is given to the output multiplexer where these signals are given to the single antenna this antenna then transmits to the earth station this is then goes to the downlink signal which is of 3.7 to 4.2 gigahertz generally the transponder is nothing but it is a part of a satellite that means this is the part of the earth station and this is the part of earth station or the receiving station and the transponder is nothing but the antenna which is used in the satellite. So it generally uses k band of signal which is of 11 to 12 gigahertz which is used for the transmission of signal then a low noise block is used which down converts the signal for the transmission and then an L band tuner is used for selecting the desired transponder channel. Basic elements of earth station generally these include the generally these include first this is the switch second modulator up converter standby chain and then HPA that is high power amplifier and then there is a switch which is then given to the antenna and this part is generally the transmitting part whereas this down part is nothing but the receiving part here the baseband signals are given to the baseband interconnection panel which is then given to the switch which acts as a multiplexer then a modulator is used for the modulation of these signals up converter this is generally used for increasing the power of the signal and then high pass high power amplifier generally this is used for the amplification of the signals where the power of the signal is increased and then it is again given to the switch where the switch again converts these signals into a single signal and this is then later transmitted by the antenna during the reception this antenna receives the signal these signals are given to the switches and to a low noise amplifier then a divider is used for the division of original information from the carrier signal or original signal original information signal from the carrier signal here the carrier signal is given to the standby chain down converter generally demodulates the down converter generally cuts down the power of the signal which is been received and then it is given to the demodulator where the signal is demodulated and again it is given to the switch this which this later gives the signal main information signal to the baseband interconnection panel so basic elements of earth station generally includes the transmitting part and the receiving part so here you can differentiate these two signals these two sections by HPA and low noise amplifier here a divider is used here a switch is used here a modulator is used that is during the transmitter demodulator is generally used at the receiving side so these are the basic elements of earth station and working so assignments so these are the two important questions for you people first discuss the frequency concept used in satellite communication second discuss the satellite television system so these are the references for you people these are the reference books satellite communication third edition by Dennis Roddy composite satellite and cable television systems by RR Gulati and fundamentals of multimedia and this is a research paper a single chip universal digital receiver with 480 megahertz intermediate frequency input so this is the reference paper for you people thank you for watching the video