a computer is a machine which is able to maximum things like playing games ,google
its uses are :
1.it is used in banks
i don't know answer
coherent transmissions are transmissions where the receiver knows what type of data is being sent. coherency implies a strict timing mechanism, because even a data signal may look like noise if you look at the wrong part of it. in contrast, noncoherent receivers don't know exactly what are looking for, and therefore noncoherent communication systems need to be far more complex (both in terms of hardware and mathematical models) to operate properly.
section will talk about coherent receivers, first discussing the "simple receiver" case, and then going into theory about what the optimal case is. once we know mathematically what an optimal receiver should be, we then discuss two actual implementations of the optimal receiver.
it should be noted that the remainder of book will discuss optimal receivers. after all, why would a communication's engineer use that is less than the best?