# Low-High Pass Filter

Discussion in 'Electronics Homework Help' started by pianolife, Nov 15, 2012.

1. ### pianolife

3
0
Nov 15, 2012
Dear Members of ElectronicsPoint, I'm studying Audio Engineering, but Electronics is my weakest point.
I need to do some homework about High and Low Pass filter, and I need your help.

1)Design first order low-pass and high-pass filters with a -3dB cut-off frequency ( ωC) = 10^4radians/sec, which use a 1KΩ resistor.
2) From your knowledge of the source impedance of the SG (50Ω), decide which sinusoidal output would be the best to use in this experiment.
3) Sketch both circuits in your log book.
4) Derive the transfer function H(j ω) for these filters in complex number form.
5) Look up or derive the expressions for |H(j ω)| and argH(j ω). Note |H(j ω)| = Vo/Vin
6) How you will convert the time difference between two sine waves as observed on the ! ʻscope into a !phase difference?
7) What is the value of the roll-off for first order filters and why are they called first order?

Sorry for the massive post, but I'm really stuck on this subject. I hope that someone can help me.

Thank you very much.

All the best

2. ### Laplace

1,252
185
Apr 4, 2010
A first-order filter will comprise a single resistor and single capacitor. Nothing more complex seems to be necessary here. Don't know what Q#2 is supposed to mean, possibly since I don't know what sinusoidal outputs are available.

3. ### pianolife

3
0
Nov 15, 2012
I guess it's referred to the frequency, since this is the only thing we can change about the sinusoidal wave.

Thank you so much