band pass filter signal pics - Electronic Circuits Projects Diagrams Free

MrDEB · 13th April 2008, 07:22 PM

not real sure what I am looking at but pics are of 2 different filters I plan on using for a stereo 10 band equalizer
Using TINA circuit simulation program
Need some help deciphering but THINK the top filter performs better?
note the diode/capacitor transistor circuit is to drive an led display

audioguru · 14th April 2008, 05:47 AM

The top circuit is a simple boost or cut bass tone control, not a bandpass filter. It has a peak detector with the diode.

The bottom circuit is a bandpass filter and you need at least 8 of them. it does not have a peak detector.

Bavananth · 14th April 2008, 07:10 AM

I'm not sure but check with UAF42 (You can get free samples from TI) There you get every filter in single IC. You may have to have three of them cascaded.

Or else you can design your own one using lm324. Application note is attached.

MrDEB · 14th April 2008, 11:44 AM

the top circuit is supposed to be a filter. Found schematic that has 10 of the circuits but different values for the capacitors. valuesfrom 180nf to 360pf.
I will try and find the url.
my big problem is how to read the ossi scope or the siginal analzser graphs.
I want to verify at what frequency each filter operates at.
I only posted 1 of 10 filters.

MrDEB · 14th April 2008, 11:50 AM

url to the 10 band equalizer circuit I am refering to
http://users.otenet.gr/~athsam/EQ_10_band.htm top circuit pic
the second equalizer circuit http://www.uashem.com/index.html?pa=printpage&pid=431
bottom circuit pic

audioguru · 14th April 2008, 05:15 PM

Your first equalizer circuit has two resistors added that are not in my Bauxandall bass tone controls circuit so maybe it is a bandpass filter. It has the same amount of boost and cut which is good.

The second equalizer circuit allows each frequency band to be turned down to zero which is not good. There are many equalizer circuits that use the filters in the feedback of an opamp so that they produce equal amounts of boost and cut.

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14th April 2008, 11:44 AM	(permalink)
MrDEB	the top circuit is supposed to be a filter. Found schematic that has 10 of the circuits but different values for the capacitors. valuesfrom 180nf to 360pf. I will try and find the url. my big problem is how to read the ossi scope or the siginal analzser graphs. I want to verify at what frequency each filter operates at. I only posted 1 of 10 filters.

14th April 2008, 11:50 AM	(permalink)
MrDEB	url to the 10 band equalizer circuit I am refering to http://users.otenet.gr/~athsam/EQ_10_band.htm top circuit pic the second equalizer circuit http://www.uashem.com/index.html?pa=printpage&pid=431 bottom circuit pic

14th April 2008, 05:15 PM	(permalink)
audioguru	Your first equalizer circuit has two resistors added that are not in my Bauxandall bass tone controls circuit so maybe it is a bandpass filter. It has the same amount of boost and cut which is good. The second equalizer circuit allows each frequency band to be turned down to zero which is not good. There are many equalizer circuits that use the filters in the feedback of an opamp so that they produce equal amounts of boost and cut. __________________ Uncle $crooge