Recommendation on o'scope for working with ADI 's DSPs

"Chris Carlen" <crcarle@BOGUS.sandia.gov> wrote in message
news:c2qjj2016vj@enews2.newsguy.com...
> Ian Buckner wrote:
> > I'll try and explain the HP54100D specs.
> >
> > The front end of the 54100 has a sample and hold that is _very_
fast,
> > together with trigger circuitry that is good for up to 1GHz
signals.
> > The following ADC only samples at 40MHz rates.
> >
> > For non-repetitive signals, Nyquist dictates that anything above
20MHz
> > will be aliased by the ADC, so the spec says for that mode
_usable_
> > bandwidth of 4MHz (a substantial factor below Nyquist, so the
> > waveforms
> > are "clean"). There's lots more bandwidth there, just not usable.
> >
> > If the signals are repetitive, i.e. you can get a stable trigger,
then
> > the scope
> > can locate the input samples in time to 10psec with respect to the
> > trigger
> > point. That allows the scope to slowly (at 40MHz rate) build up
the
> > waveform on the screen. In this mode the full S/H bandwidth can be
> > used
> > without aliasing, and you get 1GHz bandwidth.
>
>
> Excellent explanation.
>
> For this reason, the scope is great for analog work, and not to my
> liking for digital.  That is because digital involves lots of
> single-shot events that you want to be able to capture.  So I'd much
> rather have a sampling rate > bandwidth scope for digital.
>
> I'd go for the TDS350 to get the maximum bandwidth of the fast
sampling
> scopes (200MHz > 60MHz) and live with the limited memory until I
could
> afford an upgrade to a deeper memory scope.
>
Thanks for the compliment.

High bandwidth real time acqisition is certainly very useful for
non-repetitive signals and single shot events. However, the bandwidth
available with the techniques used in the 54100 are significantly
higher than available with real time acquisition.

This is useful in high speed digital work for examining the quality
of the signal (eye opening, rise and fall times, overshoots, rise/fall
delay discrepancies etc).

The OP was surprised at the discrepancy between a real time bandwidth
of 4MHz compared to a repetitive acq bandwidth of 1GHz - I have
an even more extreme example on my bench. 30kHz sample rate,
50GHz repetitive bandwidth (not strictly true, I changed the
connectors
to something more sane, so it only goes to 25GHz or so now).
Yes, that was kilo and Giga.

Regards
    Ian

"Jaime Andres Aranguren Cardona" <jaime.aranguren@ieee.org> wrote in message
news:14a86f87.0403101441.726f2aa8@posting.google.com...
> Hi,
>
> Maybe this should be crossposted to other newsgroups, but I don't know
> which ones.
>
> I need your recommendation for buying a digital oscilloscope mainly
> for use with ADI DSPs (I mention that because of the SPORTs and link
> ports), and also general digital design. All of these instruments are
> to be bougth used, but functional.
>
> The choices are:
>
> - HP/Agilent 54100D
> *1 GHz bandwidth/10 ps resolution
> *40 megasample/second digitizing rate
> *10 bits vertical resolution with averaging
> *1k memory per channel
> *Two vertical input channels and two trigger inputs, each selectable
> for high, low, don't care.
> *In addition to triggering on entering or exiting the specified
> pattern, it can be set to trigger when a specified pattern is present
> for less than or greater than a specified duration, from 10 nS to 5
> Seconds.
> *Can be set to trigger on an edge of either polarity on any one of the
> four inputs.
> *Four HP 54002A pods included

I have a 54110D scope.
Make sure to get a set of ear muffs / protectors.
Fans are rather nosiy.
(share the same enclosure and power supply as 54100)
Rather large for desktop use, need a large lab style bench.

I only have 1 HP 54002A pod.
Have used mine on any thing faster than 200MHz

Works well.

sure you have the specs correct ?
http://www.testequip.com/sale/used/catalogs//HP/1992/138.pdf
http://www.testequip.com/sale/used/catalogs//HP/1992/140.pdf

> - Tektronix TDS350
> Signal Acquisition System
> * Bandwidth: 200 MHz
> * Sample Rate: 1 GS/s on each channel
> * Channels: two identical channels, each with invert function
> * Sensitivity: 2 mV to 10 V/div
> * Vertical Resolution: 8 bits (256 levels over 10.24 vertical
> divisions)
> Time Base System (Main and Delayed)
> * Time/Division Range: 2.5 ns - 5 s/div
> * Record Length: 1000 sample points per channel
> Triggering System (Main Only)
> * Triggering Types: Edge, Video
> Automatic Measurements
> Option 14 (I/O Interface): Computer Interface and Hardcopy Capability
> * GPIB (IEEE-488.2) Programmability
> * RS-232 Interface Programmability
> * Video Output
> * Hardcopy Port - Centronics-type parallel or RS-232
> * Graphics Interface File Formats - Interleaf (.img), TIFF, PCX (PC
> Paintbrush), BMP (Microsoft Windows), and Encapsulated Postscript
> (EPS)
> * Printer Formats - ThinkJet, DeskJet, LaserJet, Epson (9 & 24 Pin),
> Seiko DPU 411/II, DPU 412.  DC power provided for Seiko printers
>
> - Tektronix TDS2002
> * 60 MHz Bandwidth * Sample Rate 1 GS/s * 2 Channels * Color Display *
> CompactFlash Mass Storage Option with TDS2MEM Module * Autoset Menu
> with Waveform Selection * Probe Check Wizard To Ensure Correct Probe
> Usage * Context-sensitive Help * Dual Time Base * Advanced Triggers,
> including Pulse Width Trigger and Line-Selectable Video Trigger * 11
> Automatic Measurements * Multi-language User Interface * Waveform and
> Setup Memories * FFT Standard on All Models
>
> My main doubt is about the "1 GHz bandwidth/10 ps resolutio, 40
> megasample/second digitizing rate" of the HP 54100D against the
> "Bandwidth: 200 MHz, Sample Rate: 1 GS/s on each channel" of the Tek
> TDS350. What is better?
>
> What would you recommend me, guys??
>
> Regards,
>
> JaaC

I would probably try and get something a bit more recent.

Some of the new mid range Tek scopes can be had for
quite a reasonable price even here in Australia.

If your a uni student have a chat with the distributor
as some will give student / academic discounts.

Can't try renting them first ?



Alex