• FROM GATES TO FPGA’S – PART 1: BASIC LOGIC

      FROM GATES TO FPGA’S – PART 1: BASIC LOGIC

      It’s time to do a series on logic including things such as programmable logic, state machines, and the lesser known demons such as switching hazards. It is best to start at the beginning — but even experts will enjoy this refresher and might even learn a trick or two. I’ll start with logic symbols, alternate symbols, small Boolean truth tables and some oddball things that we can do with basic logic. The narrative version is found in the video, with a full reference laid out in the rest of this post.Read More »
    • Tech Note on Op-Amps Driving Capacitance

      Tech Note on Op-Amps Driving Capacitance

      A great tech not on OP Amps driving capacitance. http://www.analog.com/library/analogDialogue/archives/31-2/appleng.html Q. How does capacitive loading affect op amp performance? A. To put it simply, it can turn your amplifier into an oscillator. Here's how: Op amps have an inherent output resistance, Ro, which, in conjunction with a capacitive load, forms an additional pole in the amplifier's transfer function. As the Bode plot shows, at each pole the amplitude slope becomes more negative by 20 dB/ decade. Notice how each pole adds as much as -90° of phase shift. We can view instability from either of two perspectives. Looking at amplitude …Read More »
    • New Instrumentation Amp

      New Instrumentation Amp

      We used to build amplifiers for digital scales (weighing Instrumentation)  where we would sample a full scale voltage reference and a ground reference and from there digitally cancel out gain and baseline drift.  Nowadays the amplifier itself can do a lot of this correction.  We used to call these amplifiers “coppers” referring to the processRead More »