BandPass using single supply opamp????

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Elits

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Hi all,
1. i want to know how to filter the noise of square wave (50kHz)? because when i use Bandpass for sinusoidal wave , my square wave was differentiated (HPF) and Integrated (LPF).
2. How to make bandpass using single supply Opamp (LM324)? is the configuration same if we use double supply opamp? I want to make bandpass (100Hz-14kHz) for audio but using single supply opamp..

please help me
Thanks

Elits
 

To eliminate the square 50Hz, you must remember the componets of this signal:

at 50Hz, 3*(50Hz), 5*(50Hz), 7*(50Hz) . . . . . . . . . .

You must use a notch filter and take decide how many harmonics you want to eliminate.

Example 2 harmonics, an you fl < 50Hz and fh > 350Hz
and use a 3rd order filtersand take care that those frequencies stays on the reject band.
 

Of course you can build circuits with opamps and supply them of a single supply rail ..
The trick is that instead of using 0V as reference, as is the case with dual-supply, you will need to reference inputs to 1/2 Vcc, and between stages you will need to use coupling capacitors ..

A bandpass filter for that range (100Hz - 14kHz) can be build of connected in series (cascade) high-pass (100Hz) and low-pass (14kHz) filters ..
Below is an example of single supplied LPF + HPF ..

If you would like to read more on the single supply of opamps issue here is the link:
"A Single-Supply Op-Amp Circuit Collection"
One of the biggest problems for designers of op-amp circuitry arises when the circuit must be operated from a single supply, rather than ±15 V. This application note provides working circuit examples.
Click to expand...
**broken link removed**

Regards,
IanP
 

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