problem with demodulator design?

Status
Not open for further replies.
V

veerubiji

Full Member level 2
Joined
Feb 24, 2011
Messages
122
Helped
3
Reputation
6
Reaction score
3
Trophy points
1,298
Visit site
Activity points
2,301
Hi,

I have the circuit as shown in the below attached image. I am giving 125 KHz(sine) signal through buffer to the switch and at the same time i have 125KHz square wave with 0 to 2.5v to the switch input. I am measuring the voltage at point "Vout". I am getting some glitches or extra peaks when the switch is changing. When the switch going "on"to "off" i have 12v glitch or peak. When switch is going from "off" to "on" then i have small peak. I have attached the image of oscilloscope for clear representation how the signal is look likes.

Can anyone tell me why i am getting those and how to eliminate those?
Images:
https://obrazki.elektroda.pl/6427855200_1373290764.png
https://obrazki.elektroda.pl/1758846300_1373290764.jpg

Thanks in advance.
 

You need to show all part values and connections such as power and ground to the switch on the schematic. Otherwise I'm just guessing.

How did you wire the switch if you don't have a schematic for the circuit?
 

Supposing you left switch unterminated and attaching only oscilloscope probe to it's output may be the reason for those problem you have. Switch capacitance when opened is in range of 30pF and passes signal to output.
Switch must be terminated with proper load impedance.
 


Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…