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Oscilloscope / Data-Acquisition Research

Saturday 10 September 2011 at 10:44 pm. Used tags: , , , ,

So, my trusty Tektronix 475 oscilloscope is dead.  

It powers up, the various mode switches toggle the corresponding lamps, etc. but there is no output on the display.  No amount of fiddling with the intensity/focus/beam-finder knobs will show any sort of trace on the screen.   Something in the internal signal path is dead.

While I am looking to see if it is repairable, I am also asking myself the various questions of how I could replace it. Here's my analysis so far...

To begin with, I started by looking at these as the critical factors:

  • Analog only, or Digital Logic capable?  (thinking digital logic analysis is a minimum at this point)
  • Standalone (Benchtop) device or PC-Integrated?  (portability would be nice, but can't argue against dedicated device)
  • Number of Analog Inputs & Max. Signal Bandwidth  (minimum 2 inputs, would like to have 100Mhz+)
  • Number of Digital Inputs & Max. Sample Rate  (minimum 8 line input, would like to have 100MS/s+)

And additional criteria for PC-Integrated models:

  • Is the hardware design open?
  • Is the software 100% open source?
  • Is the software multi-platform?  (Linux, Mac, Windows, others.)
  • Interface options (USB? Ethernet? other?)

Note: I actually apply these PC-integration criteria to just about every peripheral device or product I purchase.  I would prefer if every device I buy from a mouse to a printer, (or whatever!) could also come with the hardware design plans, schematics, and firmware source.  It would make life so much easier to support those devices on the range of systems I have.


Stand-alone Options:

Model Open
HW?
Open
SW?
Plat-forms Inter-faces #In
Analog
#In
Digital
Band-width Samples
/Sec.
Approx. ($USD) Incl. Probes Notes
 
JYE tech http://www.jlectronique.org/jlectronique/
JYE Tech 062 DSO YES YES - 1 - 20MHz - $48 Yes  

Can be purchased either assembled or kit from Seeed Studios.

 

I've received advice that having a dedicated/benchtop unit is handy because it instantly powers on and you don't need to worry about software configuration, and since I think there is something to be said for a dedicated device, I am researching which devices would meet my needs, and also trying to determine if any of the "pro" benchtop units, could potentially be picked up for cheap in the used market:

  • HP/Agilent 167x series (1671D, 1670G, etc.)
  • HP/Agilent 166x series (1664A, etc.)
  • HP/Agilent 165xx mainframe series (16500, with 16550A, 16531A, etc. options cards)
    (HP Mainframe units have HP-IB interface, as well as TP-Ethernet so you can connect from a PC and control/monitor the system remotely over X-windows or transfer plots over FTP/NFS.) 
  • Tektronix TLA 704 (what? runs embedded Windows 98? i wouldn't buy that!)
  • Tektronix TLA 520
  • Tektronix TLS 216 

I will be doing further research here to see what is available used, but still in the "hobbyist" price range.

 

PC-Integrated Options (Scope w/ Logic Analysis):

Model Open
HW?
Open
SW?
Plat-forms Inter-faces #In
Analog
#In
Digital
Band-width Samples
/Sec.
Approx. ($USD) Incl. Probes Notes
 
Bitscope http://www.bitscope.com/  
    
BS325  YES YES Linux,
Mac, Win
USB, Ethernet 4 8 100MHz 40MS/s $800
$935 
No
Yes 
[1]
[2]
[3]
[7]
Comments: The only scope option with an open hardware design & good open source software.  Combines 4 functions (scope, Logic, spectrum, waveform gen.) and is very attractively priced for everything you get in the one box.  I wish the samples/second was a bit higher than 40MS/s.
 
Cleverscope http://www.cleverscope.com/
CS320A  No No Win  USB, Ethernet 2 -- 100MHz  -- $1199 Yes [4]
[5]
[6]
[8] 
                       
CS328A No No Win Usb, Ethernet 2 8 100MHz 100MS/s $1359 Yes [4]
[5]
[6]
[8]
Comments: Compared to Bitscope, the Cleverscope unit has a much higher digital probe sample rate (100MS/s over 40MS/s) but while the hardware looks nice, the hardware design is proprietary, the software is not open source, and it only supports the Windows platform, AND it's a lot more expensive.  Not a contender.
 
SyscompDesign (Circuitgear) http://www.syscompdesign.com/
CGR-101 No Yes Linux,
Mac, Win
USB 2 8 2MHz 20MS/s $189
$220 
No
Yes 
[2]
[3]
[9]

Comments: The Circuitgear 101 has open-source software support, and supports all three platforms, so I might consider it even without having an open hardware design. And, SyscompDesign Supports the Open Instrumentation Project.

The speed is so slow!  2Mhz analog and 20MS/s digital won't meet my needs. :(

 
PoLabs http://www.poscope.com
PoScope Mega1 No No Win USB 2 16 1MHz 1MS/s $212 Yes [1]
[2]
[3]
Comments: PoScope is lower on my list than the Circuitgear.  Closed-source and proprietary software, supports only a closed-source and proprietary operating system (Windows only) and is far slower as well: 1Mhz Analog and 1MS/s digital.  Pretty bad specs to be that slow.
 
Link Instruments http://www.linkinstruments.com/
MSO-28 No No Win USB 2 8 60MHz 200MS/s $325 Yes

[1]
[2]
[3] 

Comments: I like seeing the 200MS/s sample rate on digital logic, but other than that, it's a closed-source proprietary device and only supports Windows, so I can't use it.

 
Elan Digital Systems http://www.elandigitalsystems.com/
USB-SCOPE50 No YES Linux,
Mac, Win 
USB 1 1 75MHz 50MS/s $295 Yes

[1]

Comments: Modular stacking approach means you can use up to 4 devices at once, but that adds up in cost if you need that.  Overall, supported by LGPL/GPL software and looks very portable if you need a 1-channel device.

Companion products from Elan include Function Generator, Clock Generator, and Pulse/Clock Counter.

Designed/sold in the UK, but can be purchased in the US through Synchrotech.

 
USBee http://www.usbee.com/
USBee AX No No Win  USB 1 8 8MHz 24MS/s $545 Yes

[1]

Comments: The hardware looks nice, but the bandwidth and sample rates are a bit slow. (They do offer more capable units which are more expensive.)

They officially only support Windows, although there are some code samples on discovering and initializing the device from any operating system, if you wanted to develop your own Linux or Mac support  While it might be a fun and interesting project for me to develop the Linux drivers for these, I'm interested in having one work out of the box for now.

One thing that IS really cool about their existing application suite is the number of protocol decoders they have, including USB on the wire, but you have to run Windows to run their software suite.

Notes:
[1] = Includes Logic Analyzer, SPI, I2C, UART, etc. 
[2] = Includes Spectrum Analyzer
[3] = Includes Waveform Generator
[4] = Includes Waveform Generator, costs extra $300
[5] = Linux Support under development http://www.cleverscope.com/forum/viewtopic.php?id=260
(but not open source??)
[6] = Uses NI (National Instruments) VISA daq drivers (closed, proprietary)
[7] = Ethernet option is extra $50
[8] = Ethernet option is extra $150

 

Logic-Analysis only (no-scope) options:

Model Open
HW?
Open
SW?
Plat-forms Inter-faces #In
Analog
#In
Digital
Band-width Samples
/Sec.
Approx. ($USD) Incl. Cables Notes
 
ChronoVu http://www.chronovu.com/
LA-8 Kit Deluxe No No Linux,
Mac, Win 
USB -- 8 -- 100MS/s $189 Yes

[1] 

Comments: No oscilloscope, spectral analysis, or waveform generation function.  This one is multi-platform, but not open-source.

 
Saleae http://www.saleae.com/
Logic16 No No Linux,
Mac, Win 
USB -- 16 -- 12.5MS/s - 100MS/s $299 Yes

[1] 

Comments: No oscilloscope, spectral analysis, or waveform generation function.  This one is multi-platform, but not open-source.

Max samples/sec varies based on #pins sampled. 2 pins = 100MS/s, 16 pins = 12.5MS/s max.

 
Dangerous Prototypes http://dangerousprototypes.com/docs/Main_Page#Projects

Bus Pirate v3.5 YES YES Linux,
Mac, Win 
USB -- 2? -- 12.5MS/s - 100MS/s $27
$32
No
Yes 

[1] 

Comments: No generic multi-channel digital logic analysis, but more of a 2-wire CAN protocol type analyzer.  This little unit would be very flexible and useful in hacking on MIDI circuits, small arduino serial interface projects, etc. but not usable for tracing 8-bit data lines on micro-processors circuits.

Dangerous Prototypes makes the PCB, but the buyer purchases the components and assembles the unit. You could also purchase a pre-assembled Bus Pirate v3 unit from Seeed Studios.

 
Open Workbench Logic Sniffer YES YES Linux,
Mac, Win 
USB -- 32 -- 100MS/s - 200MS/s $50
$66 
No
Yes 

[1] 

Comments: This one is definitely capable of multi-channel logic analysis.  It is the hardware that enables the SUMP software client to do the analysis.  The SUMP software is Java-based, and uses the RXTX library (host-device communications) for broad cross-platform support.

The Sniffer has external Trigger IN and also Trigger OUT to external devices.  I don't know yet how this could work with a digital storage oscilloscope, but presumably could be made to slave the scope to a set of logic.

Dangerous Prototypes makes the PCB, but the buyer purchases the components and assembles the unit. You could also purchase a unit pre-assembled (recommended) from Sparkfun (US), GadgetFactory (US), or Seeed Studios (China).

Notes:
[1] = Includes Logic Analyzer, SPI, I2C, UART, etc. 

References:

I found these pages to be extremely valuable references:

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