DPScope - Low-Cost USB Oscilloscopes
DPScope II
Disclaimer: The author of these pages does not assume any responsibility whatsoever regarding the
design, construction or use of the described circuit. The author cannot be held responsible for any
damage to persons or property connected with the described design. This includes (but is not limited
to) damage to you or your computer, fitness for a specific task, and specified performance.
If you
soldering. Never apply any voltage exceeding 20V to the oscilloscope inputs.

Copyright Notice: Circuit schematics, layout files, PC software etc. on this siteare intended for use with
our DPScope only. The only exception to this is their use (or use of portions of them) for private,
non-commercial projects.
Any commercial use is strictly prohibited without explicit, prior, written
consent by us. That means that you can't for example sell or even distribute your own version of
oscilloscope which runs with our PC software, or sell any instrument, circuit or kit whose design is
substantially based on the DPScope schematic and/or layout without prior permission from our side.
The DPScope II builds on our experience with the original DPScope, but improves it in several key areas.
We completely redesigned both the analog and the digital section from ground up to achieve more than
twice the sample rate and analog bandwidth, 100x faster and much smoother datalogger mode, 4x longer
records, added AC coupling, spectrum measurements, fully automated gain and offset compensation, a
programmable clock (quare wave) output, and so on.

Safety is also a big concern of ours. While we do not recommend applying voltages exceeding 20V to the
scope inputs, we took care in layout and component selection to ensure the scope inputs will withstand at
least 100V indefinitely, and short electrostatic discharges up to much higher levels. The inputs are
protected with fast Schottky diodes that will effectively clamp any overvoltage (e.g. electrostatic discharges)
to prevent damage to the instrument or to the computer attached to it.

The DPScope II has all the features you'd expect from a good entry-level oscilloscope (see also the
full list
of specifications for details):

  • Two input channels, with selectable AC or DC coupling; many of the low-end scopes on the
    market have only a single channel which makes them little more than a toy - too often you need to
    display one signal with respect to an other (e.g. clock vs. data) and or trigger on a signal different to
    the one you want to look at. Many do not offer built-in AC coupling either.

  • Triggering on either channel, rising or falling edge or both (selectable), or free running.

  • Pre-trigger capability to see what happened before and at the trigger event.

  • Datalogger mode (roll mode) to visualize and record slower changing signals (actually, up to 1000
    samples/sec so you can e.g. log thing happening at power supply frequencies).

  • Approx. 2.5 MHz analog bandwidth easily covers the typical applications in a hobby environment
    - things like audio (0 - 20 kHz), ultrasound (< 200 kHz) and infrared (38 kHz), servo motor control (a
    few kHz), common data transmission protocols (RS-232, CAN, I2C, SPI, one-wire).

  • Sample rate up to 50 million samples/sec - the sample rate must be about 10x the analog
    bandwidth to allow meaningful display without very advanced filtering.

  • Spectrum Analyzer functionality (real-time Fast Fourier Transformation) so one can look at things
    like distortion in an audio amplifier. Fully automated spectrum and distortion measurements are
    part of the software!

  • Fast and smooth acquisition - shows the signals "as they happen", with a screen update rate up to
    40 frames/sec.

  • Wide input range (from Millivolts to several 10 Volts).

  • Low-cost so every student or hobbyist can afford one.

  • Small and easy to use so even a user without much experience with oscilloscope gets a quick
    start, and compact so it doesn't use much desk space.

  • Uses USB to connect to a computer as well as for power supply.

If all of that got you all excited, check out the
"Buy It" section where you can order the scope fully assembled
and tested.

For questions, suggestions, feedback etc. please do not hesitate to
contact us.