My scope only goes down to 10mV/div. How do I scope signals around 200uV between 800Khz and 100Mhz? If there an amplifier I can buy? If possible I want to dodge making an amp.
I got this problem due to the small signals off a LISN network for EMI compliance.
Bummer :( I thought if I could get the signal big enough for the scope I could use the FFT feature built in. Or if there's a dominant signal, I could just look at the waveform.
About the Highland amp.... Noise spec: 5mV RMS into 50ohm load. Gain@50ohm: 50X
So
Vout = Vin X Gain = 250uV X 50 = 12.5mV
I think I'm going to see 5mVRMS of noise added to 12.5mVRMS of signal(mostly 800Khz squarewave).
I don't think I'll be able to pick out what I want just by looking at the waveform. Butttt.. DSOs have averaging features :) So I might be able to see through the noise.
Why are there no prices on your web site? I hate that. Does your pricing compete with mini circuits? I've got a couple of their ZFL-500's which I think only cost ~$60 or so. (0.05 to 500 MHz.)
Marketing wants to harvest contact info and feed that to the reps. So stuff like manuals and pricing require filling out the form. I fought to keep the form minimal.
No, we don't compete with m-s, in products or pricing. The J750 is $750... I wonder how that happened.
We're time-domain people, so don't think in s-params. I can't even measure them.
Yeah. We're erratic about that.
Not here. Both input connectors are hard grounded. The zero pot is just a DC offset adjust, for nulling photodiode leakages and such.
It's really pretty simple, two opamps and some power supplies.
ftp://jjlarkin.lmi.net/J750.gif
As I said, it was born as a layout exercize. My layout guy quit, and The Brat wanted to take over, so I needed something that could be done in the roughly 1 week overlap.
Probably your best bet, though, is to use a mixer to downconvert a small part of that range to a more convenient frequency with limited bandwidth, and amplify that smaller bandwidth.
In the RF world the practice (including what we do) is to provide a feedthru capacitor as the power pin and a ground stud; that apparently gets you out of having to provide a power supply. :-)
Ah, gotcha -- I was thinking "MMIC amp" rather than "op-amp."
The letter in a product name corresponds to a product line, and to the first two digits of a drawing number.
V = 22 = VME P = 23 = benchtop/rackmount instruments J = 21 = small boxes, mostly photonics T = 28 = bigger boxes M = 32 = CAMAC, mostly gone by now
and a bunch of others for OEMs and weird stuff.
For example,
V490 is a VME module.
22D490-A is the rev A pcb design
22S490-A is the schematic
22A490-2A is an actual product, dash 2 version, V490-2 to the customer
22A490.2A is the BOM (ascii MAX file) for above
22E492-B is rev B of the firmware
22C493-D is rev D of the FPGA
The BOM ties all the various bits together for a given deliverable.
Yeah, I hate having to solder the power supply connections on those things.
These are real opamps, which gets us DC coupling and relatively precise gains. MMICS are actually, usually, terrible from a quantitative standpoint: gain accuracy, actual impedances, frequency rolloff.
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
Me too. I suspect they think a lot of the alternatives wouldn't be as good when, in actuality, in many cases it probably just wouldn't matter. E.g., use an RCA connector for power (I'd suggest BNC or SMA -- and I have seen BNCs used for power on infrequent occasion -- but I wouldn't want Joerg to come after me for the extra cost involved :-) ), solder down some chip caps ASAP and OK, it's not quite as good as a capacitive feedthru, but probably hard to see the difference below a few GHz or so.
...and leave the solder-on terminals there for people who are just going to put it all in a bigger box anyway...
Ah, they should appeal to the "negative feedback is baaddd" audiophool crowd then. Hmm... that sounds like a good product -- a 3GHz headphone amplifier!
I imagine somebody somewhere has taken a MMIC amp and closed a loop around it.
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