 Welcome to this session. Today we want to study Waste Agile Sideband Transmission. The learning outcome of this topic is at the end of this session student will be able to explain the concept of Waste Agile Sideband Transmission. The contents of this topic is first introduction. Video signal is formed modulating components and the rest of the signal. Out of that one first one is modulating components having the very low frequency and it rise to sidebands very close to the carried frequency. Sidebands are difficult to remove by physically releasable filters. Thus it is not possible to fully suppress one complete sideband in the case of television signal. Therefore the low video frequency contains the information of the picture. Completely suppress the lower sideband would result in distortion at this frequencies. This distortion is seen by this eye. It is called as Seamer in the reproduced picture. Therefore only part of the lower sideband is suppressed. Means here you cannot suppress fully lower sideband. You suppress only the few parts of the lower sideband. Because if you suppress the fully lower sideband that type of a filter we cannot be designed or we cannot be offered. Therefore the radiated signal now become as upper sideband and carrier and wastages. This wastages is formed as removal of a lower sideband and which is to be removed that part and remaining that part is called as a wastages part. Therefore now the signal is ready for radiation and transmission. The transmitted signal now contains upper sideband, carrier signal and wastage signal. This pattern of a transmission of the modulated signal is known as wastages sideband or FIC transmission. In the 625 line system which we use in India that is a 625 line system that is a frequency up to 0.75 megahertz in the lower sideband are fully radiated. Therefore the net result become for transmission or whichever radiated signal is normal double side transmission for the lower video frequencies and the main body of the picture information. The main body of the picture information means that it contains the message and the normal double sideband transmission means it contains upper sideband and the lower sideband having the removal part of that one and remaining part. Now recall wait for pause the video for few minutes and think on this question and write down answering your book. Is it possible to terminate the bandwidth of a signal abruptly at the age of the sideband? The answer is no because filter design is difficult, standard filter design is difficult. That's why we cannot bandwidth of a signal abruptly at the age of the sideband. We cannot terminate. Therefore an attenuation slope of 0.5 megahertz will be required. A loss in horizontal detail is occur if attenuation slope were not allowed at any distortion at the higher frequency end then only horizontal loss will happen. Since the high frequency components of the video modulation determines the amount of horizontal details in the picture. Now this figure shows total channel bandwidth using wasteage lower sideband. This figure shows 625 line system of the wasteage sideband. Now wasteage sideband means what we can understand with the help of this diagram. See there are two parts of the upper sideband. This one is upper sideband. One is a lower sideband and now we transport the full upper sideband. No problem and for the wasteages means for the saving the bandwidth we remove the parts of LSB. We cannot remove the full part because that type of a filter we cannot design. That's why we remove the lower part of the LSB. Therefore the total now become as total channel will become as 7 megahertz. Now in the previous lecture we studied the total requirement for that one 11 megahertz. Now we reduce that one up to 7 megahertz. Now this graph is drawn amplitude versus frequency. Now this LSB. Now if you observe this diagram the total channel bandwidth is 7 megahertz. Up to that one the picture carrier is at present 5.5 megahertz and the sound carrier is present at the 0.5 megahertz and the guardband is 0.25 megahertz. In this way the total channel bandwidth requirement is what 7 megahertz and we save 4.25 megahertz in this band space. Now figure one illustrates the saving of band space which results from wasteages sideband transmission. The picture signal is occupy a bandwidth of 6.75 megahertz instead of 11 megahertz. Now the second part is transmission efficiency. The total power that is developed and edited at the transmitter. The total power is equal to carrier power plus the power in the two sideband. Means total power is equal to the summation of carrier power plus the power in the two sideband means upper sideband as well as lower sideband. Therefore the above equation becomes as Pt is equal to that is a total power is equal to PC that is carrier power plus the power in the two sidebands that is in upper sideband power in the upper sideband and the power in the lower sideband. Now put that values of the carrier power and two sideband power that equation one become now as Pt is equal to EC square by 2R plus M square EC square by 8R plus M square EC square by 8R means here this is what carrier power this is what upper sideband this is a lower sideband power. Where EC by root 2 is the RMS value of the sinusoidal carrier view. R is the resistance in which the power is dissipated. The equation 2 can be now simplified as in terms of we simplify that equation to PC. PC means power in carrier then therefore the above equation to become as Pt is equal to PC plus M square by 4 PC plus M square by 4 PC. Now again we simplify this equation then the equation become as Pt is equal to PC in bracket 1 plus M square by 2. Now if we keep the constant the carrier power then the transmitted power Pt is purely depend on this M, M means modulation index. Now as M increases this transmission power increases the maximum value of M is 1 this value of M is range between 0 to 1. Now we suppose if we calculate the maximum transmitted power then the value of M is also what maximum by because the transmitted power is directly proportional to the M and if M is equal to 1 then the power at that time transmitted power is high. From equation 3 PC remains constant but Pt depends on the value of the modulation index M. Total modulating voltage is equal to the square root of the sum of the squares of the individual modulating voltage. From the equation 3 at 100 percent modulation M is equal to 1 the transmitted power attains the maximum possible value. Therefore when you put the M is equal to 1 that above equation become as transmitted power maximum is equal to 1.5 PC carrier power where the power contained in the two side band has a maximum value of 50 percent of the carrier power. So the carrier component is redundant. In the transmission when we calculate then 72 percent of the total power that is related in the double side band and full carrier wave in the AM system that is full carrier wave is called as A3 modulation. Now economy can be affected if the carrier power is suppressed and not be transmitted. Suppression of a one side band result in more economy and also house the bandwidth requirement for transmission as compared to A3. SSB single side band is used to save the power and bandwidth in mobile communication system and SSB is used in mainly in the telemetry, radio navigation and military application also. In all the TV systems we use full carrier is radiated and we use wastage and side band transmission is used in for TV transmission. Now complete channel bandwidth. The sound carrier is positioned at the extremity of the full radiated upper side band. The sound carrier is 5.5 megahertz away from the picture carrier. Since it makes for minimum interference between the two signals that's why it always keep away from 5.5 megahertz away from the picture carrier. The frequency spectrum is equal to plus or minus 75 kilowatts. The hard band will require 0.25 megahertz therefore total channel bandwidth for the TV system is 7 megahertz and in the previous lecture we studied the total bandwidth required is when we not using the wastage side band 11.25 megahertz but when we use the wastage side band for the transmission of a television we require only 7 megahertz. Therefore the band space we saved with the help of when we transmit in the wastage side band then 11.25 megahertz minus 7 megahertz equal to 4.25 megahertz. That means we save 4.25 megahertz that much amount we want to save in the for the transmission in the TV signal. Now we take an example here. This example we now studied the example of different countries we use different countries and out of that of the first countries which was India in India we use this signal that we show this CCIR TV channel sideband spectrum and see is the color sub carrier frequency this type of a total channel bandwidth use of in India we use. This graph is drawn amplitude versus the frequency and if you observe this diagram it will start from the zero the picture is start from the zero frequency and it will reach up to the picture information is up to in between 5.5 megahertz and the color sub carrier is in between the 4 to 5 megahertz and this is sound which is present at a 5.5 and south signal sideband we require for in India this is 150 kilohertz therefore total channel width when we use wastage side band requirement is 7 megahertz in the India we use and this is a lower sideband 1.25 megahertz and this is a 1.25 we use lower sideband for in India. Now again for the UK there is again 625 line system for the TV channel standards we use but here total channel bandwidth for the UK is 8 megahertz out of that one 6 megahertz is used for the picture transmission and the color subcarrier is present at 4 to 5 megahertz this upper picture sideband required is 5.5 megahertz 0.75 this megahertz separation here guardband is 0.25 megahertz and this again wastage LSB we require here lower picture sideband is 1.75 megahertz this is a example where we use in UK this is a example we use in America that is 525 line system TV channel standards here again it will shows the diagram amplitude versus the frequency here we use total channel bandwidth is 6 megahertz out of that one 4.5 megahertz is used for the picture and color subcarrier present at the from 0 to 3.58 megahertz and this is a sound carrier is present at 4.5 to 4.75 megahertz and this is sound signal spectrum total is 75 kilohertz is required in America this 0.25 megahertz is used for guardband in this America and the remaining part 0 to 1.25 is required for lower sideband we use this type of pictures in America so in this way we studied the example in India in UK and in America and the requirement of a different bandwidth is for different countries different and we studied with the help of this diagram this sideband spectrum of two adjacent channels of the lower which of band of television section is allocation is shown here this is a one band one channel for and this is a bandwidth channel three these are separated by this guardband and we draw this graph amplitude versus the frequency this is a first band channel and this is second band channel we transmitted one after the other and these two are separated with help of this guardband is shown and requirement of this total channel bandwidth is 7 megahertz including the guardband the references for this topic is thank you