# help on frequency formula

Discussion in 'General Electronics Chat' started by joe99641, Nov 11, 2007.

1. ### joe99641 Thread Starter New Member

Nov 9, 2007
2
0
Could somebody out there help with this, I am trying to figure out what the following letters stand for in this formula, they are Wc, s, j ; the formula is
LP=Wc^4/(Wc^2+1.414*Wc*s+s^2)^2 I also have the following information
Wc=j*2*pi*Fc, Fc=crossover Frequency, s=j*2*pi*F, F=frequency in Hz.
Any comments would be appreciated, Thanks

2. ### hgmjr Moderator

Jan 28, 2005
9,030
214
the W is actually the greek letter omega $\omega$

$\omega = 2\pi*f$ where f equals frequency.

$\omega_{c}$ Most likely this is being used to represent the corner frequency of a filter.

The variable s = j$\omega$

LP stands for lowpass. This indicates to me that the expression you have is the transfer function for a lowpass filter.

Further to my earlier comments, the coefficients that appear in the denominator of the expression would lead me to conclude that the expression is for a 2-pole Butterworth Low Pass filter.

hgmjr

Nov 9, 2007
2
0