Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

LPF->BPF transform, strange result

Status
Not open for further replies.

Eugen_E

Full Member level 6
Joined
Nov 29, 2004
Messages
383
Helped
44
Reputation
86
Reaction score
11
Trophy points
1,298
Location
Romania
Activity points
2,862
Hello,

To transform a LPF to BPF, the following frequency transform is made:

ω=(1/w) ( (f/f0) - (f0/f) )

ω is related to the generic LPF prototype filter, so ωc = 1.
For the BPF with a bandwidth f1...f2:
w is the fractional bandwidth: w=(f2-f1)/f0.

Suposing a zero is added at ωz, what is the corect resulting fz for the BPF?
Solving the transform equation gives two fz values, negative and positive.

E.g.:

w=0.05
f0=2GHz
ωz=2

Gives: fz= -1902MHz or fz=2102MHz

Which one is correct?
In an EM simulation of the filter I got fz=2106MHz, and in a lumped component linear circuit simulation I have fz=1904MHz.

Thanks
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top