As I'm having to build a table-top-workshop here from scratch (can't denude my workshop back in the UK), I've been trying out some of the nice USB-based tools you can now get...
Just received an Analog Discovery 2 unit for $279 -
http://store.digilentinc.com/analog-discovery-2-100msps-usb-oscilloscope-logic-analyzer-and-variable-power-supply/ - Farnell have them for about GBP 220
http://uk.farnell.com/digilent/410-321/oscilloscope-usb-2-ch-30mhz-100msps/dp/2528523 .
This is an interesting bit of kit - it's a cooperation between Analog Devices (who do all the signal conditioning and interfacing) and Xilinx, who do the logic, but put together by Digilent, who sell Xilinx development systems... Initially just a reference design, i.e. a technical paper, they realised that they had something pretty neat on their hands, so made it a product.
The design has turned into a really cool bit of kit at a very acceptable price - a full design rationale is available as are all the schematics etc. in the reference manual (also on the Farnell page). Its a really nice unit... Two programmable supplies, 2 waveform generator channels, 16 logic channels. Lots of analog too. 14-bit A/D/A as well, not the usual 12-bit...
Very few compromises have been made - by using 14-bit DACs and ADCs, it compares very favorably with far more expensive units. The software is also extremely stable.
As a small unit to keep with the laptop, there's not a lot to argue about... I keep mine with the laptop at all times. The wiring harnesses are only $10/each, so I leave those attached to the boards I'm working on - the WaveForms (free) software has the concept of projects which contain the configurations of all the devices on the AD2 that you are using for each setup, so switching boards takes literally a minute (or less).
I was using it on the flight from the UK back to the UAE last week - I had my laptop out, a Texas Instruments MSP-EXP430FR5969 development board and the Analog Discovery - 6 hours of uninterrupted development time - USB-powered dev environments are wonderful. No problems from other passengers or the crew - I told the steward in advance I was an EE and that I'd be working on the 'plane - I also made sure to keep any blinking LEDs concealed
I also have the probe expansion board - just sooooooo cute!
- Two-channel USB digital oscilloscope (1MΩ, ±25V, differential, 14-bit, 100MS/s, 30MHz+ bandwidth - with the Analog Discovery BNC Adapter Board
- Two-channel arbitrary function generator (±5V, 14-bit, 100MS/s, 12MHz+ bandwidth - with the Analog Discovery BNC Adapter Board
- Stereo audio amplifier to drive external headphones or speakers with replicated AWG signals
- 16-channel digital logic analyzer (3.3V CMOS and 1.8V or 5V tolerant, 100MS/s)
- 16-channel pattern generator (3.3V CMOS, 100MS/s)
- 16-channel virtual digital I/O including buttons, switches, and LEDs – perfect for logic training applications
- Two input/output digital trigger signals for linking multiple instruments (3.3V CMOS)
- Single channel voltmeter (AC, DC, ±25V)
- Network analyzer – Bode, Nyquist, Nichols transfer diagrams of a circuit. Range: 1Hz to 10MHz
- Spectrum Analyzer – power spectrum and spectral measurements (noise floor, SFDR, SNR, THD, etc.)
- Digital Bus Analyzers (SPI, I²C, UART, Parallel)
- Two programmable power supplies (0…+5V , 0…-5V). The maximum available output current and power depend on the Analog Discovery 2 powering choice:
...250mW max for each supply or 500mW total when powered through USB
...2.1W max for each supply when powered by an auxiliary supply. 700mA maximum current for each supply.
As of March 17th, they have also released a fully-fledged logic analyser version, the Digital Discovery for $199 -
http://store.digilentinc.com/digital-discovery-portable-logic-analyzer-and-digital-pattern-generator/ .
This is an up to 800MHz multi-channel logic analyser & pattern generator for peanuts.
Nick