‫No, we'll discuss the pulse shipping to combat the inter symbol interference due to melting pot.
‫Now, for example, currently in order to represent one, we are using this square pulse.
‫But if instead of using these square bottles, we use these sink bottles.
‫Who represent the one, for example?
‫This is a sync pulse that that is representing one.
‫And then when we are sending the next symbol after time capital city.
‫This is the second symbol or the second sinc palace.
‫That is Foo's could represent the second one.
‫And then we will have the third.
‫Symbol would represent it as the sync pulse here.
‫OK, so now, for example, at the receiver, if we sample these symbols at these points.
‫We can see that at this point, the first symbol has maximum value.
‫While the other two symbols are zero, at this point, the second symbol has the maximum value.
‫While the other two symbols are zero.
‫And at this point, this symbol as the maximum value while the other two symbols are zero.
‫So using the sync pulses, we can considerably reduce the inter symbol interference.
‫And here, if we see the if we represent the sync pulse in the frequency domain, we can see that this
‫is the bandwidth of the signal pulse, which is equal to one over hoopy.
‫So the minimum bandwidth that is required in order to transmit a single US symbol are a signal without
‫inter symbol interference.
‫This minimum bandwidth is one over pooty.
‫However, using the sync pulses have certain disadvantage and the disadvantage is that, for example,
‫if the clock are dissembling, clock at the receiver is not accurate.
‫For example, if we sample at this point are.
‫Then what would happen is that at this point, we can see that we are having considerable interference
‫from the second symbol.
‫And at this point also we can see that this signal is not here.
‫This symbol is not at its peak value, and we are suffering from the interference from this second symbol.
‫So there is inter symbol interference.
‫If the clock of the receiver is has some jitter in it or if there is distortion in the channel, in
‫that case, these symbols would be distorted.
‫And even if the sampling clock is correct, there would be inter symbol interference.
‫And this inter symbol interference is caused due to the fact because of these side loops.
‫They that considerably stronger.
‫So we can see their distinct policies suffer from the problem of the inter sambal interference due to
‫the sensitivity to their timing error are due to the bad channel conditions that lead to the distortion
‫of these symbols.
‫Now, the solution to this problem is to juice the raised co-sign policies and indeed is co-sign policies.
‫We have a unique factor, which is also called as the pulse shipping factor.
‫Smaller.
‫The then small.
‫Ah ah.
‫This pulse shipping factor is zero.
‫These is cosine.
‫Pulses are sync pulses.
‫That means they have stronger side lobes.
‫When we see in the time domain and in the frequency domain for ory's equal to zero, we have we require
‫minimum bandwidth, which is Vanover budy and this is the minimum bandwidth that is required for the
‫sync pulses.
‫Now when we change the shipping factor two out is equal to zero point five.
‫In that case, we can see that decide Laub have reduced.
‫But on the other hand, we can see that the bandwidth that is required by assemble it is increased by
‫50 percent.
‫And when we change this pulse shipping factor, whose small R is equal to one.
‫In that case, we can see that these side lobes have tremendously reduced, but the bandwidth or the
‫excess bandwidth that is required.
‫It has increased by hundred percent.
‫So here we had the minimum bandwidth and this excess bandwidth is almost a hundred percent more so.
‫Now, suppose we are using orders equal to one.
‫And this symbol represents one.
‫And then we are sending another symbol for one here.
‫So in that case.
‫If this is the correct sampling point and add the receiver instead of this point, we sample it at this
‫point.
‫In that case, we can see that there is very less inter symbol interference due to the first symbol
‫to the second symbol.
‫So are in other are in the second case, if, for example, there is a distortion in the channel and
‫we are.
‫Sampling at the correct time, but these symbols are distorted.
‫Even then, the entire symbol interference from this first symbol would be less because these side lobes
‫are smaller.
‫Four are is equal to one.
‫So we adjust this pulse shipping factor are as a function of the channel conditions.
‫If the channel conditions are very good, then we would use these are as equal to zero.
‫In that case, we require minimum bandwidth for the symbol.
‫We don't require any excess bandwidth.
‫Excess bandwidth is zero.
‫And if the channel conditions degrade, there are multi pots and there is.
‫I say we increase the R is equal to, for example, zero point five.
‫In that case, we can see that we require 50 percent excess bandwidth.
‫But.
‫We can reduce these, I'd say, but if the channeler conditions are very bad, then we would lose out
‫as equal to one.
‫In that case, we would require a hundred percent taxes, bandwidth, but the eyesight would be reduced
‫because of the smaller sideburns.
‫So that's how we reduce the ISI in all communication are the inter symbol in the in interference in
‫our communication by adjusting the.
‫While shipping fact that small R as a function of these general conditions.