Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

using pmos based OTA-C (Gm-C) filter as an averager

Status
Not open for further replies.
A

analogturbo

Newbie level 2
Joined
Jun 22, 2010
Messages
2
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,296
I'm designing a pmos based OTA-C filter to be used to average out input values. The issue is: i'm getting correct average value for certain inputs but not for all.

I believe it is due to non constant gm offered by the OTA. Which part of the OTA i should correct.

Its a classic two stage pmos based input differential topology (balanced).

Thanks
 

Re: using pmos based OTA-C (Gm-C) filter as averager

analogturbo said:
I'm designing a pmos based OTA-C filter to be used to average out input values. The issue is: i'm getting correct average value for certain inputs but not for all.

I believe it is due to non constant gm offered by the OTA. Which part of the OTA i should correct.

Its a classic two stage pmos based input differential topology (balanced).

Thanks
Click to expand...

* What means"certain inputs but not for all" ? This sentence has no information at all
* What is the source of your believe? Why is the gm not fixed in your design?
 

Re: using pmos based OTA-C (Gm-C) filter as averager

Thank LvW for your reply.

Inputs are waveform recovered from a source. So when i say certain inputs it means that i applied a waveform V1 i get V1avg_out which is the average value of V1. But when i apply an input V2 or V3 etc... i get Vavg_out which is expected value +/- an offset value of few tens of mV.

As far as gm is concerned i got it wrong previously, i ignored the fact that as the input changes, the gain has to change accordingly.
 

Re: using pmos based OTA-C (Gm-C) filter as averager

analogturbo said:
As far as gm is concerned i got it wrong previously, i ignored the fact that as the input changes, the gain has to change accordingly.
Click to expand...

What does this mean? Do you want or require such a change?
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top