It's for a school project I'm currently working on, from research a OTRA can realize any nth order transfer function by selecting admittance branches. I would like some help in calculating the admittance values for a High Pass filter using the OTRA.I'm not aware of any compelling reason to do this. OTRA filter blocks cannot be cascaded to make higher order filters so their performance would be limited to a single stage. Capacitors and inductors work in filters because of their effect on voltage, not current. I'm note even sure there is a filter theory that works with a current to voltage converter. Do you know something that I missed?
I'll take your word for all that. Might I suggest you invest in the free simulator LTspice from Analog Devices. There are two main reasons:It's for a school project I'm currently working on, from research a OTRA can realize any nth order transfer function by selecting admittance branches. I would like some help in calculating the admittance values for a High Pass filter using the OTRA.
Not sure what you mean here. The way i understand them is they can be used similar to any op amp. The only difference is conceptual, but then again we can think of an ordinary op amp in the same way where we analyze more from a current standpoint than a voltage standpoint (ie the current from input to output is equal to the current from the very input to the op amp input).I'm not aware of any compelling reason to do this. OTRA filter blocks cannot be cascaded to make higher order filters so their performance would be limited to a single stage. Capacitors and inductors work in filters because of their effect on voltage, not current. I'm note even sure there is a filter theory that works with a current to voltage converter. Do you know something that I missed?
The OTRA takes a current and puts a voltage out. So you can't directly take that voltage output and run it to a current input. Not directly at least.Not sure what you mean here. The way i understand them is they can be used similar to any op amp. The only difference is conceptual, but then again we can think of an ordinary op amp in the same way where we analyze more from a current standpoint than a voltage standpoint (ie the current from input to output is equal to the current from the very input to the op amp input).
Capacitors work on voltage differences but if you have a voltage output and more or less current input and the input is at virtual ground, the capacitor is going to pump current into the input terminal due ot the change in voltage on the output, just like a regular op amp except now the input is at virtual ground no matter what the output is (ie it does not depend on the topology anymore to maintain a virtual ground). So the only difference i think is what forces the virtual ground, the output or the op amp internal design. This makes me think we can use one almost the same way we use any other op amp, which of course means we should not have much trouble cascading stages for a more complex response.
What method he wants to use here though i dont know...choose admittance branches...he will have to elaborate. Maybe he means choose branches to add to the circuit based on individual admittance and known behavior of such branches, which is a very simple technique. Cant be sure until he replies though.
Yeah but you almost never do that anyway, except in the case of a voltage follower you always use resistor(s) between output and input, and that allows you to calculate the voltage input op amp the same way you calculate the current input op amp, because they both can be viewed as having current inputs. The difference there is that the voltage input op amp has the currents go AROUND the op amp while the current input op amp has the currents going INTO the op amp also to going around.The OTRA takes a current and puts a voltage out. So you can't directly take that voltage output and run it to a current input. Not directly at least.
by Jake Hertz
by Jake Hertz
by Jake Hertz