Sallen Key Low Pass Filter, bandpass filter

[Maglatron]

From what I understand it is still possible to use the TL074's

 

[bertus]

Hello,

Yes, The point called REF is the virtual ground.
All points called REF are connected together.
The ground is lifted to about hlf the powersupply.

Bertus

 

[Maglatron]

that easy, just connect the points called ref, for the virtual, and then what about the part in the red box

 

[bertus]

Hello,

The circuit in the red box, is the circuit to create the REF voltage.
On the input of that opamp there is a voltage divider that creates half the powersupply.
The opamp is used as buffer.

Bertus

 

[Maglatron]

can I use the TL074 for the buffer, and I think I understand it, do you use the same 12v going into the filters op-amps as the input for the buffer and then connect the refs together as you said before? also can you use this buffer for all of the filters or do you need to create a buffer for each filter that's been made? because I ordered quad op-amps to cater for the 4 op amps in each filter but now there is a 5th op-amp for the buffer

 

[Maglatron]

I ordered quad op-amps to cater for the 4 op amps in each filter but now there is a 5th op-amp for the buffer

do I need to make this buffer circuit for every filter also or can I use the the one buffer circuit for all of the reference ground on each and every filter as I will be using the same 12v source or all of the filters

 

[Maglatron]

I ordered quad op-amps to cater for the 4 op amps in each filter but now there is a 5th op-amp for the buffer
do I need to make this buffer circuit for every filter, also or can I use the the one buffer circuit for all of the reference ground on each and every filter as I will be using the same 12v source or all of the filters
On the input of that opamp there is a voltage divider that creates half the powersupply. (would this be 6v)
The opamp is used as buffer. so the reference voltage (is 6v at virtual ground) and the actual ground connects through the buffer to ground so positive (12v for positive)(ref gnd 6v) and ground(0v for negative) and for the buffer circuit can I still use the TL074

 

[bertus]

Hello,

No, one buffer is likely enough for several filters.

Bertus

 

[Maglatron]

Nice one bertus and can I use one of the TL074's

 

[Maglatron]

and this is accurate?

positive (12v for positive)(ref gnd 6v) and ground(0v for negative)

 

[Maglatron]

the reference voltage (is 6v at virtual ground) and the actual ground connects through the buffer to ground

this correct too??

 

[Maglatron]

No, one buffer is likely enough for several filters.

16 filters??

 

[Maglatron]

so can I use one of the TL074's for the buffer circuit?

 

[Maglatron]

I have the paper now so am going to commence in designing all of the required frequency filters what should thee gain of the passband be?

 

[Maglatron]

is gain the ratio of the input frequency to the output frequency?

 

[Maglatron]

in the filter tool nothing changes when I alter the gain?

 

[Maglatron]

is gain the ratio of the input frequency to the output frequency?

found the answer "The gain is simply the ratio of the output voltage over the input voltage."

 

[Maglatron]

just to clarify and make crystal clear what are these parameters you can set in the red box

 

[Maglatron]

what are the differences do ie changing -3 dB to -6 dB in the pass band, changing the stopband from -40 to -10 what will be the real world effects?
And what would be better for what I'm trying to do eg filter sound waves

 

[Maglatron]

you make no sense