 Hello everyone. I am Mr. Praveen Ellapa Kumbar. Today we want to see earth station. The learning outcome of this topic is at the end of the session student will be able to explain the concept of earth station. The contents of this topics are introduction. We want to see the what is the means of the earth station. Then after we want to see the earth station architecture and after that one in detail we see the RF section and the baseband section and after that one we want to see the earth station desired consideration. So first one introduction. So here we want to see what is the means of the earth station. So earth station is a collection of equipment that installed on the earth surface that enables the communication over one or more satellites. So earth stations are typically owned by the company that receiving the data from the satellites network. So earth station must operate within the certain specified parameters to maintain the networks stability. So earth stations are a part of a satellites network ground segment. It consists of all earth stations operating in a satellite system. This can be concerned to the end users equipment directly or via terrestrial network. Though the actual architecture of an earth station depends on the application. So we see we want to see earth station architecture. So this is a general purpose earth station architecture. But this earth station will be different for depending upon the applications. So this is a generalized diagram of the earth station. So basically earth station consists of baseband section, RF section and the third one is support facilities. And the user is always connected to the baseband section with the help of the terrestrial interface. So in the baseband section, the baseband section consists of baseband processing circuits, modulator and the demodulator. This modulator for the transmitting side and demodulator for the receiving side. In the RF section, there are two parts. One is uplink and second one is downlink. For the uplink it consists of upconverter, high power amplifier and antenna consists of transmitter as well as the receiver. For the uplink it consists of transmitter. In the downlink it consists of receiver part of the antenna, low noise amplifier and the downconverter. So these are the support facilities. In the support facilities, environment conditioning, monitoring and control of the satellite, the power supply for the earth station. So the major components of an earth station include RF section, baseband equipment and the terrestrial interface. So the earth station has a certain support facilities such as power supply unit with adequate backup, monitoring and control equipment and the thermal and environment conditioning unit. So we want to see the in details RF section. So this diagram shows the RF section. In this RF section, this is called as a uplink channel and this one is called as a downlink channel. Uplink channel consists of upconverter and from that upconverter it provides to the high power amplifier and from that it will give to the antenna of the transmitter part. So antenna consists of the transmitter as well as the receiver part. So in the downlink channel, the receiver part that will give one to the low noise amplifier and that given to the downconverter. So this is a downlink channel. So this is the overall generalized diagram of the RF section. Now the RF section interface with the modem subsystem of the baseband section. The job of the upconverter, the present in the RF section is the uplink channel is to upconvert the baseband signal to the desired frequency. The upconverter signal is then amplified to the desired level before it is fed to the feed system for subsequent transmission to the intended satellite. Similarly, a no noise amplifier amplifies the weak signal received by the antenna. So the amplified signal is then down converted to the IF frequency that is called as intermediate frequency level before it is fed to the modem in the baseband section. The antenna feed system provides the necessary aperture illumination. So antenna introduce the desired polarization and also provides the isolation between the transmitted and the received signals. So now we want to see the baseband section. So in that baseband section the baseband processing circuit the baseband processing circuit connected to the modulator and the demodulator. Now we want to see the detail information about the baseband section. The baseband section performs the modulation and the demodulation functions. So the modulation and the demodulation function with the specific equipment required. Equipment required depending upon the modulation techniques and the multiple access method employed. So for that one we want to see one example. In that example two-way digital communication link we want to consider and for that two-way digital communication link the baseband section would comprise of a digital modem and here we use the time division multiplex techniques. So the baseband section input output is connected to the terrestrial network through a suitable interface known as a terrestrial interface. The terrestrial network could be a fiber optic cable link or microlink or a combination of these two. So the complexity of an earth station architecture depends upon the application. So for example a tvro earth station would be the less complex than the fss earth station interconnecting last traffic nodes. So now we want to see earth station design consideration. So for the design of an earth station it is generally a two-step process. The first step is identification of a earth station requirement specification and the second step is identifying the most cost-effective architecture that achieves the desired specification. So the requirement specification affecting the design of an earth station include types of a service offered that is fixed satellite service broadcast satellite service and the mobile satellite service. So communication requirements that is communication means telephony that data we want to transmit that television that we want to see that etc this related to the communication requirement are required baseband quality at the destination and system capacity and reliability. The major system parameters relevant to the earth station design includes transmitter ERP ERP means effective isotropic radiated power and the receiver figure of merit that is G by T ratio. Now my transmitter ERP is required at the transmitter side receiver figure of merit is considered at the receiver side. So system noise and interface will allowable tracking error. So first we want to see effective isotropic radiated power that is ERP. So ERP gives the combined performance of the HPA that is high power amplifier and the transmitting antenna. So the ERP that is effective isotropic radiated power is the product of the HPA that is high power amplifier at the antenna and the gain of the transmitting antenna. The ERP is expressed in the decibels. ERP now when we measure in terms of a dB then it is the sum of power output of HPA and the gain of the transmitting antenna in dB. So ERP is defined for both the earth station transmitting antenna as well as satellite transmitting antenna. It is important to note that ERP is always measured at the antenna. So some satellite operates have the practice of taking space loss in account while publishing the satellite footprint maps of their users. Footprint means the satellite's range. Now we want to see receiver figure of merit that is G by T ratio. So receiver figure of merit is indicative of how the receiving antenna performs together with the receiving electronics to produce useful signal. The figure of merit is defined as the parameter called G by T ratio which is the ratio of receiving antenna gain to the system noise temperature. So G by T is expressed in decibel per Kelvin. So G by T ratio of the earth station may be enhanced by increasing the receiving antenna gain and lowering the noise temperature. So the references for this topic is thank you.