Modern digital oscilloscopes question

Mon Dec 12, 2011 7:32 pm   

Hello

I worked in a place that gave me access to budget, non memory 20MHz CRT
scopes - I no longer work there. They were perfect for my needs.

Six years on and I find I need an oscilloscope, the market seems to have
changed. Are those cheap digital models any good?

I need reasonable Y sensitivity (5mV/div), up to 5MHz, storage would be
nice, it's not for radio work.

I found things like this...

http://www.rapidonline.com/Tools-Equipment/Uni-T-UTD2000-series-2-Channel-digital-storage-oscilloscopes-400399/?sid=2e6f6286-b98a-4994-b9ce-0631e8fc6b4d

Decent for the money? Or to be avoided?

John

Mon Dec 12, 2011 9:48 pm   

On 12/12/2011 1:32 PM, eatmorepies wrote:


Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

Mon Dec 12, 2011 10:14 pm   

"eatmorepies"


** Not so good for service work, particularly audio service.

If you like using analogue scopes, stick with one.

Analogue scopes are easy to use and tell you no lies.

The opposite is true for digital ones.



.... Phil

Mon Dec 12, 2011 10:59 pm   

On 13/12/2011 4:32 AM, eatmorepies wrote:

UNI-T is nice for a Chinese brand. You are aware that the basic 25Mhz
model is only good to about 5Mhz for digital (a 5Mhz square wave being
made up of a 5Mhz fundamental plus odd order harmonics. 25Mhz only
allows the first two harmonics, giving you a wonky square wave but it is
OK for basic stuff if you know what your looking for)


Lots of people like this scope:

http://www.saelig.com/product/PSPC017.htm


Have a look at these. They seem to meet your spec and give a bit more.


http://www.dealexcel.com/ut2062ce-digital-storage-oscilloscope-60mhz-color-screen_p332.html

http://www.dealexcel.com/ads1042c-digital-storage-oscilloscope-40mhz-500mss-usb_p650.html

http://www.dealexcel.com/mini-digital-storage-color-oscilloscope-handheld-scope-ds-203-nano-black_p19554.html

--
We have failed to address the fundamental truth that endless growth is
impossible in a finite world.

Mon Dec 12, 2011 11:41 pm   

On Mon, 12 Dec 2011 18:32:21 -0000, "eatmorepies"
<jckipper_at_lineone.net> wrote:



My regular scope is a Rigol DS1052E. It's great. The going price is
around $340.

I'd never go back to an analog scope or a VTVM.

John

Mon Dec 12, 2011 11:51 pm   

On 12/12/2011 5:41 PM, John Larkin wrote:

Hey, wait a minute. I've bought two Simpson VTVMs in the last year.
(Mostly for the nice analogue displays, admittedly. Analogue is nice
for temperature-control loops and other things that change on the time
scale of 100 ms to 10 s or thereabouts.)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

Tue Dec 13, 2011 4:42 am   

"George Herold"

Yeah but an analog 'scope can't average.

** So fucking what ?

Put that together with the digital filters on the front end of the
Rigol

** Shame there are no analogue ones.

Shame how the scope keeps showing things that are not at the input - like
aliasing products, noise and signals that have stopped seconds ago.

These are fatal flaws in audio servicing.


.... Phil

Tue Dec 13, 2011 5:01 am   

On 12/12/2011 10:27 PM, George Herold wrote:

My TDS744A has a 1 mV/div range, which is still useful at 500 MHz BW.
Cost about two low-end Rigols' worth.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

Tue Dec 13, 2011 5:08 am   

"George Herold"


I'll post some 'scope shots tomorrow.


** FFS dickwad - I own a bloody Rigol !!!



Oh I agree, But the cost would be out of control.


** Not to mention the scope would then finally,y actually have
INTENTIONALLY varying bandwidth with sweep setting.

This is the biggest LIE about DSOs and why analogue scopes are SOOOOO much
better for troubleshooting analogue circuits.




Oh DSO's aren't for every task.


** FFS read the bloody CONTEXT !!

Here it is again - you RETARDED BIRD BRAIN !!


" I need reasonable Y sensitivity (5mV/div), up to 5MHz, storage would be
nice, it's not for radio work.

** Not so good for service work, particularly audio service.

If you like using analogue scopes, stick with one.

Analogue scopes are easy to use and tell you no lies.

The opposite is true for digital ones."



.... Phil

Tue Dec 13, 2011 5:27 am   

On Dec 12, 5:41 pm, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:

I like my Rigol, but to be honest I use the cheap TEK (1001B?) more
often.

I've got an old analog TEK that I'd like to bring back to life!
Not great speed, but it's got a 1mV/div input range that I used.

DSO's mostly suck at low sensitivity.... JL build's his own input
stages, I assume.

George H.

Tue Dec 13, 2011 5:36 am   

On Dec 12, 4:14 pm, "Phil Allison" <phi...@tpg.com.au> wrote:

Yeah but an analog 'scope can't average.
Put that together with the digital filters on the front end of the
Rigol
and it's a pretty nice tool for finding signals.

George H.

Tue Dec 13, 2011 5:59 am   

On Dec 12, 10:42 pm, "Phil Allison" <phi...@tpg.com.au> wrote:

I'll post some 'scope shots tomorrow.
Averaging is very useful, for all sorts of things.
Average 256 signals and if you trigger it right your noise goes down
by
a factor of 16! You can see all sorts of 'little crap' that way.

Oh I agree, But the cost would be out of control. I haven't looked
closely at the
Rigol's digital filters, there may be some flaws. You just need to
know the limits of your tools.


Oh DSO's aren't for every task. For what I do it's useful.

George H.

Tue Dec 13, 2011 6:14 am   

On Dec 12, 11:01 pm, Phil Hobbs
<pcdhSpamMeSensel...@electrooptical.net> wrote:

Ahh, OK, then most cheap DSo's stink at low sensitivity.

How much for a new one?

George H.

Tue Dec 13, 2011 6:19 am   

On Dec 12, 11:08 pm, "Phil Allison" <phi...@tpg.com.au> wrote:

OK sorry, As Phil point's out I've forgotten the start of this
thread.

George H.

Tue Dec 13, 2011 2:40 pm   

On Mon, 12 Dec 2011 18:32:21 -0000, "eatmorepies"
<jckipper_at_lineone.net> wrote:


<Shameless plug>
How about a cheap analog scope, supplemented by a
ridiculously-cheap (US$29) Windows sound card scope for
audio work?

Sound cards don't do DC (without mods or external help), but
the "audio" range keeps creeping up... these days you can
get to nearly 96 kHz (192 kHz sample rates) even on cheap
built-in sound chipsets.

With the proper software (hint, hint!) you can get fancy
triggering, including negative trigger delay, hysteresis,
hold-off, etc. You can get real-time FFT spectrum analysis
(with optional peak tracking), and color spectrograms.

Synchronous waveform averaging allows stupendous noise
reduction... you can easily extract signals that were
totally buried in noise. See for example:
<http://www.daqarta.com/dw_wavg.htm>

Best of all, you get a signal generator that can create
almost any signal you want, with modulation including AM,
FM, PM, Burst, and Sweep on up to 4 independent streams per
stereo output channel. It can drive all your tests, and
provide the sync for the averaging as well. See:
<http://www.daqarta.com/dw_gen,htm>

(Actually, the generator is free. Even if you stick with
only an analog scope, or a cheap DSO, you will find plenty
of uses for the signal generator.)

Lots of other features, like a frequency counter that can
read low frequencies quickly with high precision (due to
reciprocal period methods). True RMS measurements. Sound
level (SPL) meter (if you have a calibrated microphone).
Histograms, including post-stimulus time histograms.

The $99 Pro version allows you to write macros to run
automated test sequences, allows custom spectrum response
limits for pass/fail production testing, and supports remote
control from custom software.

Best regards,


Bob Masta

DAQARTA v6.02
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, FREE Signal Generator
Pitch Track, Pitch-to-MIDI
Science with your sound card!