Re: Which USB scope is the best deal?
- From: bill.sloman@xxxxxxxx
- Date: Mon, 02 Jul 2007 15:43:55 -0700
On Jul 2, 5:05 pm, linnix <m...@xxxxxxxxxxxxxxxxxx> wrote:
On Jul 2, 6:06 am, bill.slo...@xxxxxxxx wrote:
On Jul 2, 2:42 am, linnix <m...@xxxxxxxxxxxxxxxxxx> wrote:
On Jul 1, 4:58 pm, bill.slo...@xxxxxxxx wrote:
On Jul 2, 12:28 am, Joerg <notthisjoerg...@xxxxxxxxxxxxxxxxxxxxx>
wrote:
Hello Folks,
When looking at that market there is a myriad of options. Which one is
the best from a price performance point of view? Does anyone have good
experience with a particular model?
USB, 2-Channel, 500MS/sec or more would be nice. SW-FFT, decent doc
capabilities, the usual. If it needs a separate supply that's fine.
I don't need it in the lab so much but more on the road. Noise hunting
etc. I wish someone would also make a somewhat decent spectrum analyzer
for USB but that market still looks totally untapped.
There comes a point in most people's lives where the lower back doesn't
want to schlepp heavy lab gear or you run the chance of not being able
to move the next day.
About five years ago I used one of Pico Technology Ltd's slow PC-based
scopes - 12-bits at up to 7kHz - which plugged into the parallel port.
Farnell still stocks something like it - the ADC42 (order code
318-0827, 134 euro).
It worked fine, and the software that came with it was fair easy to
use, and didn't crash.
Farnell now carries a bunch of their faster USB-based scopes, with
sampling rates up to 200Msamples/sec. The A/D converters are strictly
8-bit parts. Prices run from 600 euro to 1200 euro depending on speed.
Farnell also stock two Picoscope Oscilloscope/Spectrum analysers
offering a 12-bit A/D sampling at up to 50 or 100Msamples/sec, the
ADC-212/50 and the ADC-212/100. They plug into the parallel port can
cost 700 euro and 950 euro respectively.
But they don't meet the requirements.
The "requirements" appear to be a wish list, rather than non-
negotiable constraints, and I mentioned where the units I put forward
fell short of the requirements.
Why do you think it is necessary to waste bandwidth by reposting this
information?
Because your suggestion is off-base, he asked for 500 MSPS USB and you
suggested 100 MSPS parallel port.
Grow up. Note that the Picoscope wb-sited that I posted includes two
devices - the 5203 and the 5204 offering 1Gsample/sec and a USB
interface. Both are expensive, and Farnell doesn't stock them (which
may mean that Picoscope can't make them in volume, which might - in
turn - have something to do with the yield on the A/D converters being
used).
You can get a reasonable A2D
converter (in price and power consumption) for 200 MSPS. But for
500MSPS (as requested by OP) or beyond, it's ridiculously expensive
and hot (in power).
The "ridiculousness" of the price depends on the application, which
Joerg didn't spell out. There other aspects of A/D performance which
can also be important in some applications, but since Joerg was asking
about units that he could buy rather than devices that he could use to
build his own, this isn't all that relevant to this thread.
Cost of the chip is definitely relevant to the devices available on
the market. If it can be made with reasonable price, it will be
available.
Dream on. USB-oscilloscopes aren't high volume products. They have to
use chips that are predominantly made for other, larger, markets.
These chips aren't always reliably available to low volume
manufacturers - if the main market takes off the low volume
manufacturers find themselves with six month delivery times. I can
still remember buying up the last 36 of a particular single chip
processor available from Dutch distributors for my ex-employer in the
UK, when Volkswagen had bought up every one that Siemens was producing
for the next six months ...
--
Bill Sloman, Nijmegen
.
- References:
- Which USB scope is the best deal?
- From: Joerg
- Re: Which USB scope is the best deal?
- From: bill . sloman
- Re: Which USB scope is the best deal?
- From: linnix
- Re: Which USB scope is the best deal?
- From: bill . sloman
- Re: Which USB scope is the best deal?
- From: linnix
- Which USB scope is the best deal?
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