biasing of analog circuit

F

fz

Guest
Hi all,
I came across a dc biasing problem of a homodyne receiver.
The output of the direct conversion mixer is connected to a VGA. The
first stage of VGA and the output of mixer have different DC biasing
values. I know common source or source follower could be used to shift
the DC bias. But we will lose the flexibility of tuning the biasing of
VGA during experiment.
Is there any other means to bias the VGA in this case?
thanks

fz
 
On Aug 26, 5:40 am, fz <fzhang...@googlemail.com> wrote:
Hi all,
I came across a dc biasing problem of a homodyne receiver.
The output of the direct conversion mixer is connected to a VGA. The
first stage of VGA and the output of mixer have different DC biasing
values. I know common source or source follower could be used to shift
the DC bias. But we will lose the flexibility of tuning the biasing of
VGA during experiment.
Is there any other means to bias the VGA in this case?
thanks

fz
Click to expand...
Dear Fz,

Did you try to ask in the following forums ?
1. http://www.designers-guide.org/Forum/
2. http://www.edaboard.com/viewforum.php?f=88&sid=3c159b2c7f9cdd4ca6c48cd5e380b7d1

I would recommand these links for more design/architecture related
questions.

if you have any troubles running your design under Cadence's DFII then
this is definitelty the right group :)

Good luck !
Riad.
 
On Aug 27, 2:54 am, Riad KACED <riad.ka...@gmail.com> wrote:
On Aug 26, 5:40 am, fz <fzhang...@googlemail.com> wrote:

Hi all,
I came across a dc biasing problem of a homodyne receiver.
The output of the direct conversion mixer is connected to a VGA. The
first stage of VGA and the output of mixer have different DC biasing
values. I know common source or source follower could be used to shift
the DC bias. But we will lose the flexibility of tuning the biasing of
VGA during experiment.
Is there any other means to bias the VGA in this case?
thanks

fz

Dear Fz,

Did you try to ask in the following forums ?
1.http://www.designers-guide.org/Forum/
2.http://www.edaboard.com/viewforum.php?f=88&sid=3c159b2c7f9cdd4ca6c48c...

I would recommand these links for more design/architecture related
questions.

if you have any troubles running your design under Cadence's DFII then
this is definitelty the right group :)

Good luck !
Riad.
Click to expand...
Hi Riad,
Thanks for you suggestion,
I just found this google group is a lot more convenient than those
two.
For those who are also interested in this problem, poojanwagh posted a
very good solution here:
http://www.circuitdesign.info/2008/08/calibrated-level-shifting-circuit/

fz
 
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