Shot noise can be observed in variety of materials, devices and systems. Let us consider one of the simplest examples from physics: noise generated by trapping and detrapping of a single charge carrier.

Last time we have moved away from mathematical abstraction of point events by considering pulses of finite duration. Yet the theory we have derived in the earlier post did not fully match the simulated power spectral density. In this post we will see that the discrepancy close to the Nyquist frequency arises due to the observations being made in discrete time.

The following video by prof. Ali Hajimiri discusses various types of noises often seen in physical systems. I have found it and watched it in preparation to our previous post on shot noise. I believe some of our readers may find it interesting too.

In the last few posts we have looked at spectral densities of a select point processes. In those posts we have represented events as points on the time axis. Such approach is just an approximation, which is valid when the duration of events is negligible, but it is not always so. When the events have finite duration, but the process is otherwise identical to the Poisson process, we obtain a peculiar type of noise known as the shot noise.

I have also attended couple of conferences in the end of October. At International Conference on Noise and Fluctuations I got asked a question the gist of which was what would change in my model, if inter-event times would be normally distributed. I would expect that, in the particular case I was talking about, little would change, but let us make sure of that. In this post, we will take a look at point process, and we will revisit a more complicated topic I talked about later on.