[time-nuts] Chinese Scopes

[Marvin Gozum]

Sorry john, that's more what I meant, by accuracy and precision I imply its faithful to the signal you choose to examine, free of artifacts induced by the scopes timebase or vertical amp, but with DSOs its limited by Nyquist sampling rules.

Thus, sampling rate is as important a feature as a scopes rated bandwidth.  For best results, its should be 10x the analog bandwidth.  Below it, one has to beware of artifacts, it worsens as the ratio signal bandwidth/ sampling rate < 10.


At 14:32 04/16/2012, time-nuts-request at febo.com wrote:
------------------------------
Message: 2
Date: Mon, 16 Apr 2012 10:59:16 -0700 (PDT)
From: "J. Forster" <jfor at quikus.com>
To: "Discussion of precise time and frequency measurement"
        <time-nuts at febo.com>
Subject: Re: [time-nuts] Chinese Scopes (was: Re: LORAN-C at MIT)
Message-ID: <56387.12.6.201.2.1334599156.squirrel at popaccts.quikus.com>
Content-Type: text/plain;charset=iso-8859-1

> At eevblog.com forum Chinese scopes are a daily discussion for over 3
> years.
>
> In summary, in the <= 100 MHz level they are ...
...snip...
>... less.  The criteria for rating them are
> measurement accuracy and precision, UI, construction quality and tech
> support.

Measurement accuracy is a ruse, IMO. I don't care if a 'scope is
"accurate". I want the waveform to be a faithful representation of the
electrical behaviour of the circuit, free oif sampling artifacts and
aliasing.

If I want to accurately measure a voltage, I'll use a differential
comparator or DVM. Anything timing, an appropriately gated counter.

Some years ago Tektronix had a digital camera package with RS-170 output
and some aardvaark frame grab board for a PC and a SW package. It was
designed to do waveform measurement.

I would actually like to know why many seem to feel that a 500 MHz analog
'scope is not "good enough" for what you really do in your lab?

The more I hear about 40 GSps or whatever 'scopes, the more I'm convinced
it's like comparing car engines or top speed. So, I have a car that'll do
160 MPH and yours will do 172? So what? Can you use it? No.

YMMV,

-John


Best Wishes,


Marv Gozum, Philadelphia Pa

[ sent via Outlook webApp]