[Moved]: how to find transfer function for block diagram like that

Status
Not open for further replies.

MahmoudHassan

Full Member level 6
Joined
Oct 4, 2010
Messages
349
Helped
44
Reputation
90
Reaction score
40
Trophy points
1,328
Activity points
3,913
Hello
I am struggling in calculating transfer functions from blocks like that ( I can calculate it using small signal models) but I found papers and projects also calculate transfer functions from block diagram like that
How can I calculate it ?
Best Regards

 

Re: how to find transfer function for block diagram like that

Each transconductor (g_m) is a voltage controlled current source, so using nodal analysis You are able to achieve a transfer function for it in easy way.
 
Re: how to find transfer function for block diagram like that

As an alternative, you simply can apply Blacks formula for the closed-loop gain Acl of feedback systems:

Acl=Af/(1-LG)

with Af=total forward gain (without feedback); LG=Loop gain (negative gain of the whole feedback loop)
 
Re: how to find transfer function for block diagram like that

Each transconductor (g_m) is a voltage controlled current source, so using nodal analysis You are able to achieve a transfer function for it in easy way.
Thanks a lot for your help , really appreciated

Aha great , where is the controller voltage for the input gm1 , I know it is the input voltage but for gmc (in feedback network) where is the controller voltage for this dependent current source ?

- - - Updated - - -

As an alternative, you simply can apply Blacks formula for the closed-loop gain Acl of feedback systems:

Acl=Af/(1-LG)

with Af=total forward gain (without feedback); LG=Loop gain (negative gain of the whole feedback loop)

I will try it mathematically ,
Thanks a lot for your time
really appreciated
 

Status
Not open for further replies.
Cookies are required to use this site. You must accept them to continue using the site. Learn more…