# Peak detector using a digital potentiometer

#### sebathn

Joined Apr 26, 2018
2
Hi all,
Any input will be much appreciated. Im trying to build up a project from the Subject for school purpose.
The specifications would be:
Gain Range -> 20dB
BW: KHz,MHz
Linearity : 1-2 V

Could you please let me know what components would be most appropriate for this scenario?
Im using LTSpice as an simulator if I could find components that could be imported into this in order to make the analysis would be awsome.

#### Attachments

• 41.9 KB Views: 16

#### MrAl

Joined Jun 17, 2014
6,963
Hi,

I guess you want to adjust the gain for various input signals?
Check the frequency response of your digital pot to see if it can handle the frequency you want.

It's a little unclear however what kind of control law you want to use here, as we see the ADC connected directly to the pot, which doesnt tell us what you really expect to get out of this system.
This is not just a negative feedback system, it's an autonomous variable gain negative feedback system. That is very different from just an ordinary feedback system.

#### ericgibbs

Joined Jan 29, 2010
9,346
hi sebathn,
Please post your LTS asc file, together with any non standard models.
E

#### sebathn

Joined Apr 26, 2018
2
Hi all,
I`m trying to build an AGC

I would use an PGA instead of digi potentiometer ; that gives the signal to an Peak detector from whom the signal is passed trough an ADC and given the command back to the PGA.
Attached are individual blocks of those above (in LTSpice) - problem is I do not know how to "add" them into one functional schematic. (from this would I would build more specifications etc.)
I want to build the project using ICs - if you could recomand me some it would be awesome.

Sebastian

#### Attachments

• 10.1 KB Views: 1
• 10.9 KB Views: 2
• 12 KB Views: 1