Balder W. Holst

Hello there!

My name is Balder and this is my personal website. Here i write down what i learn to maybe help others some day. For now i will just act like people are reading my articles, and make them for fun.

This website has three main sections:

I write these articles for fun, and even though i try to make sure that they are correct, i am not a perfect human and there are sure to be mistakes. Below is a list of most recent articles in all categories.

Recent Posts

Window Functions

Window Functions When you multiply in the time domain, you fold in the frequency domain. We therefore want our window function to be as narrow as possible. Ideally window should resemble the Unit Sample in the frequency domain. Effects on Filters Filters dampening will also depend on the window function used. If we assume an ideal filter, the transition from amplification of $1$ to amplification of $0$ with have the same width of the main lobe of the window function.

0001/01/01 · Notes

z-transformation

z-transformation $$z = e^{j\omega T}$$ When we sample a signal, be may get poles repeated up and down the imaginary axis. The z-transformation solves this by wrapping the imaginary axis around the unit circle of the z-plane. $$ X(z) = \mathcal{Z}{x(t)} = \sum_{n=0}^{\infty} x(n)z^{-n} $$ $X(z)$ converges (is stable) if $|x| < 1$. Zero points in the center only alter the phase, not the amplitude. Transfer Function $$H(z) = \frac{Y(z)}{X(z)}$$ $X(z)$: Input sequence $Y(z)$: Output sequence

0001/01/01 · Notes

Ækvivalente Kredsløb

Ækvivalente Kredsløb Kredsløb med samme $I/V$ egenskaber. Typer Thevenin Ækvivalens Norton Ækvivalens

0001/01/01 · Notes