Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic 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.

Register Log in

Band pass filter caught local FM station, how come?

Status
Not open for further replies.

magnetra

Full Member level 5
Joined
Apr 21, 2005
Messages
265
Helped
10
Reputation
20
Reaction score
7
Trophy points
1,298
Location
27.45N, 85.20E KTM, NP
Activity points
3,390
Interference or what?

I had a bizzare experience today. I was testing a simple band pass filter in the lab. I had connected the output to a speaker. As I was setting up the ckt for testing, I hear the local FM station in the speaker. I was loud and clear. I couldn't believe it. How can that happen. The FM station's antenna is very close to my lab, but that doesn't explain how the FM signal got demodulated and got onto my speaker. Any explanations as to what might have happened? Or any one with a similar experience??

Magnetra
 

fasaghandis

Member level 5
Joined
Jul 10, 2002
Messages
81
Helped
1
Reputation
2
Reaction score
0
Trophy points
1,286
Location
tehran
Activity points
638
Re: Interference or what?

Look at the FM demodulatores. In this circuits, at first FM signal diferentated by mean of a RC circuit and then a push detector is used for extraction of signal from the amplitude. So you must search for such procedure in your setup.
regards
 

magnetra

Full Member level 5
Joined
Apr 21, 2005
Messages
265
Helped
10
Reputation
20
Reaction score
7
Trophy points
1,298
Location
27.45N, 85.20E KTM, NP
Activity points
3,390
Interference or what?

Yea that could be the explanation. My ckt had lots of RC combination. So that might have worked as demodulator.
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top