Oscilloscope

An oscilloscope (often abbreviated o'scope or scope) displays signal voltages as a 2-D graph, usually as voltage (vertical axis) as a function of time (horizontal axis).

The probe of a o'scope is held against, or is clipped to, the metal wire carrying the signal of interest.

A dual-trace o'scope has 2 probes, so 2 different signals can be seen -- so not only the shape of the signal can be seen, but also the exact time from events on one signal to events on the other signal.

techniques

Sometimes one wants to look at a 8-bit data bus -- typically one uses a "logic analyzer" to look at lots of time-aligned digital signals. For a given number of signals to look at, oscilloscopes (which show the true analog waveform) are much more expensive than logic analyzers (which only show if a digital waveform is hi or low, above or below the logic threshold). Many people buy both a (dual-trace) o'scope and a 16-trace logic analyzer, which together have a total cost less than one true 8-trace o'scope.

... more techniques ...

open source oscilloscopes

Of course, you have to already have a working o'scope in order to build and test another o'scope, making this the same sort of chicken-and-egg problem as the RepRap project, the GCC project, and other projects David Cary finds interesting.

open source oscilloscope: BitScope

• $550 BS100U: 2 analog inputs + 8 digital inputs, optically isolated, from BitScope Designs (MetaChip Pty. Ltd.) [1]. ("Scopal" third-party software is available[2]). (open hardware).

open source oscilloscope: the MultiAnalyser

Some people on the PIClist have been discussing designing an open-source oscilloscope.

• I think initial discussions occured on the "[EE scope project anyone?"] thread [3] at PIClist.
• Later discussion moved to the "MultiAnalyser" group at Yahoo

are these open-source?

(FIXME: get sampling rate and resolution)

• K3PTO http://www.qsl.net/k3pto/ 8 bit
• Massmind: "SX based O’Scope" by Alberto Geraci of BTX Sistemas
• Sourceforge: xoscope is a digital oscilloscope using input from a sound card or EsounD and/or a ProbeScope/osziFOX and will soon support Bitscope hardware.
• Baudlineis a signal analyzer designed for scientific visualization, using input from recorded data files or from a sound card.
• "PIC12F675 Oscilloscope"
• "DIY HACK - Make your own Oscilloscope"

some low-cost oscilloscopes

some low-cost oscilloscopes, in no particular order. ... it would be nice to mention # of analog input channels, # of digital input channels, whether it can be used under Linux, does it have output channels ... price should (?) include 2 analog probes, ... is it open hardware? ... anything else?

• price name comments
• $250 VT DSO-2810F,2x100MHz, with a Multi-Instrument Standard software license, which converts a PC into oscilloscope, spectrum analyzer, multimeter, signal generator, data logger...it also supports sound card (both MME driver and ASIO driver), NI DAQmx cards, etc. [4]
• $150 Poscope basic 2 from PoLabs PoLabs, 2 analog channels, 16/8 digital channels, PC USB oscilloscope, spectrum analyzer, chart recorder, pattern generator, logic analyzer, PWM/ square generator
• $420 PicoScope 2202 from Pico Technology([5])([6])([7])
• $200 Hantek DSO-2090 USB PC Oscilloscope [8]
• $380.00 DSO2250 100MHz PC-SCOPE 250MS/s [9]
• CAN 219.99 Syscomp Electronic Design DSO-101 [10] (Syscomp supports the "The Open Instrumentation Project" [11])
• EUR 427 ETC s.r.o. M520 Oscilloscope [12]
• $222 ANT8 : 8 Channel Logic Analyzer (EasySync)[13]
• $200 PS40M10 : Swordfish Hand-Held Instrument (1 channel) USB (EasySync)
• $220 DS1M12 : Stingray Multi-Function Instrument (2 channel) USB (EasySync)
• under $600 : Jameco has some actual stand-alone oscilloscopes for under $600.
• under $200 : Carl's Electronics has some stand-alone and PC-hosted (parallel port?) oscilloscopes for under $200.[14]
• $170 HobbyLab USB oscilloscope [15]
• $500 DS1022C : 2 Channel, 25 MHz Rigol Technologies Inc.[16]
• $999 CS320A Cleverscope [17] (has a discussion forum[18])
• $167 DrDAQ "data logger" (parallel port) from Pico Technology [19]
• $970 NI USB-5132 : USB digitizer from National Instruments [20]
• $139 Parallax USB Oscilloscope 2 analog inputs + trigger; 1 MS/s [21]
• $170 PC USB Oscilloscope DiSco (HobbyLab, LLC). 2 analog inputs ( 200 KHz ) + 16 digital inputs (or 8 digital inputs + 8 digital outputs). [22]
• $150 ST16B 10 MHz stand-alone oscilloscope, 2 analog inputs [23]
• $190 VEPCS100 ( PCS100 ) - PC Based Oscilloscope; 1 analog input ( 12 MHz ); optically isolated from PC [24]
• $950 DSO-8502 USB Oscilloscope, 2 analog inputs (250MSa/s) + external trigger; 1 digital output (trigger out); buffer: 512K points/ch.[25]
• $799 DSO-8202 USB Oscilloscope, 2 analog inputs (200MSa/s) + external trigger; 1 digital output (trigger out); buffer: 128K points/ch.[26]
• $108 LabJack U3 USB data acquisition and control device, 16 analog inputs ( 12 bit, 2.5 KSa/s at 12 bit resolution, 50 KSa/s at 8 bit resolution), buffer: 984 samples, 2 analog outputs, digital outputs [27]

FIXME: Measurement Computing has some wireless and USB analog DAQ instruments -- add to the above list.

FIXME: DATAQ Instruments, Inc. has some USB and Ethernet analog DAQ instruments -- add to the above list.

FIXME: DesignNotes.com, Inc. has some USB and handheld LCD o'scopes from Velleman: Velleman oscilloscopes -- add to the above list.

EasySync[28] is a distributor of RockyLogic's ANT8/etc products.

Test Equipment Solutions Today, Inc.[29] is a distributor of Rigol's DVM and oscilloscope products.

When you search eBay for oscilloscope, you might find some good deals.

further reading

• other good equiptment to buy when getting started

external links

• Keith has made a list of "PC USB logic analyzers that cost under $1000."[30], some of which can be used as an o'scope. Should I use the same $1000 price cut-off for the above list? Or perhaps double or halve it?
• Brooke Clarke has posted a list of "PC based Oscilloscopes"
• Wikipedia: oscilloscope
• Other discussions of "Cheap digital storage oscilloscope"
• The Ganssle Group reviews Inexpensive USB Scopes and Logic Analyzers
• Massmind: Tools lists a few sources for a variety of tools used in electronics: o'scopes, logic analyzers, meters, waveform generators, etc.
• Slashdot: "Cheap PC Oscilloscopes - Any Recommendations?"
• Slashdot: "Building a Cheap Oscilloscope Using Your PC?"
• ePanorama.net: "Using PC as a measurement instrument" (FIXME: anything we should add to the above list?)

---