Short Circuit Time Constants (SCTC) Use of Pole Instead of Zero

[Shadders]

Hi,
I have been examining Open Circuit Time Constants (OCTC) from a text book, and then the next section is on Short Circuit Time Constants (SCTC). For SCTC, the discussion is on the lower frequency cut off due to the zeros, and refers to a text (book) that I don’t have.

I am unsure why, but the book text than refers to the zeros as poles. I searched and located this text :

https://inst.eecs.berkeley.edu/~ee105/fa14/lectures/Lecture15-Short Circuit Time Constant (SCTC).pdf

This text too refers to the lower frequency cut off as poles. I can see how if you move lower in frequency, that the zero can be considered a pole, i.e. reversal of frequency ‘f’.

Apart from that, why are zeros called poles in the texts ?

Thanks and regards,
Shadders.

 

[yagizhanugur]

Hi,
I have been examining Open Circuit Time Constants (OCTC) from a text book, and then the next section is on Short Circuit Time Constants (SCTC). For SCTC, the discussion is on the lower frequency cut off due to the zeros, and refers to a text (book) that I don’t have.

I am unsure why, but the book text than refers to the zeros as poles. I searched and located this text :

https://inst.eecs.berkeley.edu/~ee105/fa14/lectures/Lecture15-Short Circuit Time Constant (SCTC).pdf

This text too refers to the lower frequency cut off as poles. I can see how if you move lower in frequency, that the zero can be considered a pole, i.e. reversal of frequency ‘f’.

Apart from that, why are zeros called poles in the texts ?

Thanks and regards,
Shadders.

Gain equals 0db in lower frequency. So it behaves like a pole in a particular way. But still have differnces. But in this method zeros can be accepted as poles.

 

[Shadders]

Gain equals 0db in lower frequency. So it behaves like a pole in a particular way. But still have differnces. But in this method zeros can be accepted as poles.

Hi,
I understand from a qualitative approach that a low frequency "knee" can be seen as a pole if the frequency is reversed. What i was looking for is the mathematics behind why a zero can be represented as a pole.

I do have a text (Analysis and Design of Analog Integrated Circuits) which has some text on this, but it is built on a lot of the work already covered in the book - i was looking for a quick explanation. Thanks,

Regards,
Shadders.

 

[Shadders]

Hi,
As an update, the equation provided was not derived - and was referred to another book. It seems that whether the pole has a negative or positive slope, it is still a pole, and the equation represented the low frequency behaviour only.

Regards,
Shadders.