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.

i need to detect the peak to peak value of a sine wave

Status
Not open for further replies.

royvincent

Member level 2
Joined
Jan 28, 2010
Messages
52
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,288
Location
India
Activity points
1,610
peak detection

i need to detect the peak to peak value of a sine wave. i have some circuits, but the problem is the required bandwidth is 10Hz-200KHz and none has worked out properly. NEED HELP URGENTLY.....

PLEASE.
 

peak detection

have u tried the calibration?is it ok if you detect +ve peak and display 2 times which assumes -ve peak same as positive?
 

Re: peak detection

ya, its enough to find only the positive peak value and get it multiplied with 2.

my main problem is, the circuits i tried is having capacitors to hold the peak value. but at high frequencies its not getting enough time to charge completely:cry: so the voltage across the capacitor is not the actual peak value. how much ever time i give, its not getting charged completely at high frequencies. i think this capacitor need to be eliminated. any idea how to do it?
 

Re: peak detection

200 kHz isn't actually a very high frequency. Classical peak detector circuits can handle it with sufficient fast OPs. In any case,
you have to be aware of non-ideal circuit properties, so the design has to start with - besides operation frequency - a specification
of relative and absolute error and acceptable droop.
 

peak detection

For fast peak detects, I quite like the dual opamp circuit:

11_1271664488.gif


Keith.
 

Re: peak detection

I just tried with my circuit but used faster op amp. also switched the capacitor 2 or 3 times while going from low to high frequency. now things are working perfectly...:D

surely i will try your circuit also....

THANKS
 

peak detection

Peak detects are quite demanding of opamp performance, particularly slew rate.

Keith.
 

Re: peak detection

Ya, slew rate was a problem for me.
 

Re: peak detection

The second circuit, that was the thing i said i tried.... But earlier tried with a very ordinary op amp... now ok.

THANKS EVERYBODY.
 

peak detection

The problem with the simpler circuits is the output sits at the negative rail so when a pulse comes along it has a long way to get to the peak value. The dual opamp version I posted holds the output one diode volts drop below the input so the output hasn't got as far to go when a peak comes along, so the slew rate requirement is less.

Keith.
 

Re: peak detection

ok, will surely try it... and see the difference.
 

Hi, What OP AMPs did you end up using if I might ask?

John
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top