# Post History

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**#3: Question closed**

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**#2: Post edited**

Meaning of complex frequency

- If we have a LC high pass filter the transfer function H(s) becomes:
**![](https://physics.codidact.com/uploads/9ebwwQ7uz2nhUmVCM8WQow4u)**- If we solve for s to find a pole of the transfer function we get:
**![](https://physics.codidact.com/uploads/YFvV7yjmhDkMFSb1XatGiyxD)**~~In the case of a sinusoidal input signal =~~**s**= j**ω -> ω = 1/**sqrt**(LC)**~~But in a case of a signal which may not be sinusoidal s can be a complex number and the result of this is that the pole exists at a complex frequency.But what physical meaning does a complex frequency have?~~

- If we have a LC high pass filter the transfer function H(s) becomes:
**$$ H(s) = \cfrac{sL}{sL + \cfrac{1}{sC}} $$**- If we solve for s to find a pole of the transfer function we get:
**$$ s = j \cfrac{1}{\sqrt{LC}} $$**- In the case of a sinusoidal input signal =
**$ s**= j**\omega \rightarrow \omega = \cfrac{1}{\**sqrt**{LC}} $** - But in a case of a signal which may not be sinusoidal s can be a complex number and the result of this is that the pole exists at a complex frequency.

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**#1: Initial revision**

Meaning of complex frequency