PE #67: System Discretization (I)

In this video we see how to discretize a continuous system. The RC filter is taken as an example. Qspice simulations are shown to illustrate the different ideas. In the second part we will see how to discretize the transfer function of a dc-dc converter.

[@sanjayagrawal6143]

Thanks Sir for educating us.
Best Regards,
Sanjay

[@MarcosAlonsoElectronics]

Thanks for watching

[@zaikindenis1775]

Thank you, very informative!

[@MarcosAlonsoElectronics]

Happy to know. Thanks!

[@MarcosAlonsoElectronics]

All files are available here: github.com/marcosalonsoelectronics/PE-67-68

[@sanjayagrawal6143]

Sir,
Thanks for your videos. We are grateful to you.
I have a query..
Is there difference in Sampling block and ZOH block.
Regards

[@MarcosAlonsoElectronics]

Hello, thanks for your comment
Yes, the sampling block generates a discrete signal from an analog signal. The ZOH block does the reverse function: it generates an analog signal from a discrete signal

[@sanjayagrawal6143]

@@MarcosAlonsoElectronics Thanks Sir

[@bejancornel5224]

Hi Marcos, look at starting with min 17:00, why in the laplace expression the division of exp is made with s*Tsp, and not s only (1-exp(s*Ts))/s as your formula shown in hand calculation?

[@MarcosAlonsoElectronics]

Hello, this is a good question. I tried to explain this at 18:00.
This is because we are including the gain of the sampler too, which is 1/Tsp. Note that when we do the discretization the input is a discrete signal so we do not have to consider the gain of the sampler, but in the simulation circuit at 7:00, the input is the analog signal not the discrete signal. There is a sampling process done by the C++ module. So in the Laplace circuit at 17:00 we have to include the gain of the sampler to have the same gain as in the simulation. Actually, this factor affects only the magnitude of the gain, of course, the phase is the same with or without it.