Recover Digisign Time with airSlate SignNow

Recover digisign time

the last point in the topic of sampling regards the timing of the sampling so um we have discussed the channel nyquist theorem which said that the maximum frequency must be less or equal than half of the sampling frequency and in a real system you choose an analog to digital converter which has a sampling frequency of close to the maximum signal which you want to process yeah this is again a reason of reducing reducing cost so faster analog to digital converters are generally more expensive and so you try to reduce the cost by reducing the sampling frequency and by this you probably reach a point where your maximum signal is very close to half of the something frequency like shown here in this example and in the upper diagram we have a perfect sampling so it's very optimal we always hit the maxima of our input function here so we use a sinusoidal function here which is a monochromatic signal and now the frequency of our monochromatic signal is exactly half of the sampling frequency yeah so this is a boundary case but it's good to describe the issue so here in the upper diagram our timing is optimal but the sampling clock is normally not adjusted to our input signal so it might happen that the sampling log does not perfectly hit the maxima of the signal so we get this sampling points and now the digital system does not see the green line which is the original signal and our digital signal only sees the red sampled data and now it assumes that it has this function here yeah this has two problems so the first problem is that the amplitude is a bit lower so there is the amplitude is decreased and there's a time shift here so a phase shift um and the female gnome that is observed here is called the timing error so we have a time timing error but in this case the signal is a bit weaker but it can still be decoded by the digital processing system but um this case is not optimal but then we have a case where it is impossible to decode the signal so now the timing error is so huge that we hit the zero crossings of the signal and the sampled enquenty signal would be constantly zero so after the analog to digital conversion there is there is no signal so we can say that this sampling clock is now orthogonal to our input signal again i write this down no also gunality will come across several times throughout the lecture so here the consequence is that there is no signal at the output so what we need to do is to adjust the phase of the sampling clock so that we get the optimal case so we need to adjust the face of the sampling clock so we need some kind of controller which detects that we for example...