Pocket Oscilloscope Review Roundup

We put three miniature oscilloscopes to the test

4 min read
Pocket Oscilloscope Review Roundup

Ever knelt behind a home-theater receiver, tangled in wires, trying to figure out why nothing’s coming out of the stereo speakers? Is the cable bad? Is the cable box even putting out the digital audio signal? Oh, if only you could whip out a scope from your pocket and check. As it turns out, you can. Here’s a look at three pint-size oscilloscopes.

Perhaps the most ambitious pocket scope yet attempted, the DSO Quad (left), from Seeed Studio, is smaller than a smartphone. It offers four input channels (two analog, two digital), a gorgeous, high-contrast, active-matrix color screen, and measurements galore. Peak-to-peak voltage, duty cycle, frequency—you name it and this scope will measure it. That is, once you calibrate the thing! The Quad comes completely uncalibrated, requiring you to adjust tiny trimmer capacitors and perform a multistep firmware voltage calibration as well.

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From WinZips to Cat GIFs, Jacob Ziv’s Algorithms Have Powered Decades of Compression

The lossless-compression pioneer received the 2021 IEEE Medal of Honor

11 min read
Photo of Jacob Ziv
Photo: Rami Shlush

Lossless data compression seems a bit like a magic trick. Its cousin, lossy compression, is easier to comprehend. Lossy algorithms are used to get music into the popular MP3 format and turn a digital image into a standard JPEG file. They do this by selectively removing bits, taking what scientists know about the way we see and hear to determine which bits we'd least miss. But no one can make the case that the resulting file is a perfect replica of the original.

Not so with lossless data compression. Bits do disappear, making the data file dramatically smaller and thus easier to store and transmit. The important difference is that the bits reappear on command. It's as if the bits are rabbits in a magician's act, disappearing and then reappearing from inside a hat at the wave of a wand.

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