Hi. ANyone knows about a digitally controlable potentiometer that has a wide bandwidth. It's for a portable-scope project so I would need a bandwidth something like 20MHz minimum. Do anyone knows if its a good idea to use the digital pot in the feedback loop of a inverting-amp (op-amp). Will my signal still be clean. Well thanks
Take a common 100 Ohm potentiometer and attach a step motor to it.
Bad idea. Digital pot is RC-RC-RC-RC.... Stability and response will be problematic and varying with gain.
The design of the scope front end amps is not trivial and requires a great deal of experience.
Vladimir Vassilevsky DSP and Mixed Signal Design Consultant
On Jan 22, 11:25=A0am, " snipped-for-privacy@gmail.com" wrote: > Hi. ANyone knows about a digitally controlable potentiometer that has > a wide bandwidth. It's for a portable-scope project so I would need a > bandwidth something like 20MHz minimum. Do anyone knows if its a good > idea to use the digital pot in the feedback loop of a inverting-amp > (op-amp). > Will my signal still be clean. > Well thanks
Maybe these guys have something you could use.
I used the AD603 10 years ago and it did everything AD said it would
GG
These pieces seem quite interesting. But since it's a portable scope, I only use 3.3v powered devices and many of this amps require 5 or
12v. So I'm thinking about an analog multiplexer that could handle wide bandwidths and a set of non-ajustable amps. Still, if someone has another idea please tell me. Thanks Joey Caron
Use a programmable gain broadband amplifier.
-- Paul Hovnanian mailto:Paul@Hovnanian.com ------------------------------------------------------------------ Experience is the worst teacher. It always gives the test first and the instruction afterward.
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