A Tektronix TDS 684B Oscilloscope Uses CCD Analog Memory

Introduction I have a Tektronix TDS 684B oscilloscope that I bought cheaply at an auction. It has 4 channels, 1 GHz of BW and a sample rate of 5 Gsps. Those are respectable numbers even by today’s standards. It’s also the main reason why I have it: compared to modern oscilloscopes, the other features aren’t nearly as impressive. It can only record 15k samples per channel at a time, for example. But at least the sample doesn’t go down when you increase the number of recording channels: it’s 5 Gsps even all 4 channels are enabled. I’ve always wondered how Tektronix managed to reach such high specifications back in the nineties, so in this blog post I take a quick look at the internals, to figure out how it works, and do some measurements along the signal path. The TDS600 Series The first oscilloscopes of the TDS600 series were introduced around 1993. The last one, the TDS694C was released in 2002. The TDS684 version was from sometime 1995. The ICs on my TDS684C have date codes from a ... Read full article.