In this task your teacher want you work as you would in any work situation Your filter can be made by combining the correct low-pass and high-pass filter. If you use opamps you can connect the output of one "stage" to the input of the other stage. Look at the link I gave you. That can be a big help in your task. And also remember Google is your friend https://www.google.com/search?q=band+pass+filter
Also I hope you understand that we will help with giving a nudge in the correct direction. But we will not do all the work for you. Being an engineer is much the same as being an explorer. Go exploreing do not just sit on your thumbs because your books do not give you a ready made solution

He is describing a Cascade Bandpass Filter. Such bandpass filter has three blocks:
Low Pass Filter
High Pass Filter
Amplifier

The Low Pass and High Pass provide the passband that you need (300 Hz to 3100 Hz), their Gain is 1 (unity gain) so they provided no amplification. Amplifier provides the Gain of 10 that you need.

I assume the 100 kOhm specified after the Gain of 10 is for Amplifier. So. You know the Gain, you know input resistance (Ri), you can now find feedback resistance (Rf). With these three values you have your Amplifier designed. The amplifier is ready. Now do the Low Pass and High Pass.

Also. We could assume that 100 kOhm input resistance is for all the blocks. This will help us calculate capacitors we need for the Low Pass and High Pass blocks.

 

thank you guys for help

i will start on the project if i stuck in something i will come and ask for an advice

all the info u mentioned is useful

it's just that i don't understand this subject a lot

thanks all

 

"...it's just that i don't understand this subject a lot "



Io0oty_dxb, you have the task to design a bandpass filter based on a (uncomplete) specification.
You should know that filter design in general is a very challenging task because you have a lot of options (active/passive, many different circuit topologies, different approximations (Butterworth, Chebyshev,...), different impedance niveaus).
Thus, it is necessary to know the options you have.
In most cases, you have to find a trade-off between several (sometimes conflicting) requirements (circuit complexity, reliability, exactness, sensitivity to passive tolerances, sensitivity to opamp non-idealities, parameter tuning, component spread,etc... )
Therefore, based on your task - may I give you some general hints?

For an active opamp based band pass you have - in principle - two different options:

1.) Cascade of lowpass and high pass (Two opamp stages),
This alternative is appropriate in case of a relatively large bandwidth - as in your case with two real poles.
The necessary gain can be implemented into the active low pass or high pass stage (or distributed). Thus, no separate gain stage is necessary.

2.) Band pass (direct realization) with only one single stage (perhaps, in addition, a separate stage for gain requirements).
Here, you have the choice between several circuit topologies (multi-feedback, Sallen-Key, GIC, integrator-based like KHN).
Designing such a filter requires knowledge of the corresponding transfer function (if you make no use of filter design software).
In any case, I would recommend to make use of design software (which is available for free).
__________________

Because you are required to design an "opamp band pass filter" (task description) I would assume that your teacher expexts a filter as described above under point 2.) - however, of course the cascade of lowpass and highpass could be seen also as a solution which meets his task description.

Some further questions?

LvW