On Thu, Aug 2, 2012 at 7:03 PM, Yigit Turgut wrote: >> I have a microwave prescaler which runs to 12GHz. It has flip-flops in >> it which are being clocked by the input frequency. However, it is very >> different from typical CMOS logic because the input and output logic >> levels are much smaller and the output doesn't switch very "hard" ON >> even when clocked at moderate frequencies. I say this because the >> output is not very rich in harmonics when I view it on a 21GHz >> spectrum analyzer. > > Sounds cool, which methodology did you follow while building the prescale= r ? I didn't build it - it is a building-block which I purchased to use in a larger device that I am building. The prescaler is part number FPS-8-12 and is sold by a guy on eBay calling himself "RFBay". He has his own site, too: http://www.rfbay.com/ I have not taken it apart but I think that it is based on an IC from Hittite Microwave, the HMC363 http://www.hittite.com/products/view.html/view/HMC363 This IC uses Indium Gallium Phosphide (InGaP) heterojunction bipolar transistors (HBT). >> What do you mean by "non-contact magnetic gates"? >> > > Imagine there are two coils (very rough example but same principle) > and we apply a potential to first coil's terminals and a potential > will be measured in secondary coil's terminals. Since the magnetic > field will propagate at the speed of light, only capacitive behavior > will effect the response time. Am I missing something here ? You are basically correct but I do not see how that device could be called a gate. It sounds like just a transformer. I would say that a gate must have gain. The simplest device that could be called a gate would be an amplifier with saturation limits on the output which can be reached without degrading the frequency response too much. If this is a non-inverting amplifier, then it is a digital buffer. If it is inverting, it is a digital inverter. For CMOS, the saturation limits come just from the supply rails. For bipolar transistor logic, saturating the BJTs causes charge storage effects that slow down the switching action, so various other means of output clipping were used, like Schottky diode clamps (as in 74Sxx and 74LSxx logic) and the use of differential amplifiers whose output swing was limited without saturating the transistors themselves (ECL is an example of this). Sean --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .