[time-nuts] adjustable gain/offset amplifiers

Lux, James P (337C) james.p.lux at jpl.nasa.gov
Fri Jul 24 20:00:39 UTC 2009


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of J. Forster
Sent: Friday, July 24, 2009 11:35 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] adjustable gain/offset amplifiers

Hi Jim,

A couple of thoughts:

Tektronix made a TM500 Op-Amp module that would do what you want
functionally, but I don't know about the BW.

>>> the venerable (and discontinued) AM502 that plugged into the TM500 series racks. And what I was actually thinking when I set out on this quest, having used them in the 70s.  Turns out that they only have 1 MHz BW (the SRS SIM983 is essentially an improved AM502, functionally, and works the same.. shared power supply cage, etc.)

If you are interested, there is a NIM and CAMAC Yahoo Group. It's pretty
new. CAMAC is more likely to have such a thing than NIM, since it's a much
newer standard. You should also check other vendors, like Canberra. There
is a guy in New Mexico (?) that specializes in used modules and cages and
has a very extensive web site listing modules.

>>> oetech.com  is the guy.  This is for work, so we can buy/rent new, if it exists. I'll check Berkeley Nucleonics and Canberra.. good hint.

Strain gage stuff is usually very low level and is often set up for full
bridges. Wide band is not usually required as the measurements are mostly
static or low bandwidth.

>> that's what I noticed.

You might want to look at Instrumentation Amp ICs from Analog Devices or
others. They have a gain set resistor, + and - inputs with typically hi-Z
and very, very good CMRR.

>> that's the fallback.. but I wanted to just buy a box with nice knobs, a power supply, etc., rather than engage in a development project.  Already got too many little unlabeled boxes with trimpots, some opamps, and unlabeled power connectors.. If someone sold a few thousand dollar box that does this, then I don't have to rummage through the cabinets, reverse engineer the design, etc.  

Thanks
Jim
> I'm looking for some amplifiers with adjustable gain (say from 0 to 5) and
> offset (say +/- 5V) for general benchtop use (e.g. you have some widget
> you want to test as a replacement, but the original device had different
> input ranges, and before you go redesign the rest of the circuit..) with
> at least 10 MHz BW.
>



More information about the time-nuts mailing list