Inverting Sallen-Key low pass filter

I ended up talking electronics to all of them. My physical chemistry classes did include thermodynamics, and it took me longer than usual - not all that long - to get my head around that, but when both your parents have bachelors degrees in chemistry, you do hit the ground running.

My only post-doc supervisor finally made Fellow of the (British) Royal Society a few moths ago, and he is a physical chemist/photochemist. As a post-doc I built some electronics for him and his graduate students, and rather more after I'd moved into industry, strictly as hobby projects.

I can't remember the exact name of the class, but the book is Van Trees "Detection Estimation, and Modulation Theory".

In one of the homework problems it has you derive Kalman filtering from basic principles. In another, Kalman-Bucy filtering.

I still get occasional contracts to do weird stuff at the intersection of communications and metrology that I wouldn't be able to touch if it weren't for that class. In fact, I'm working on one right now.

Awesome! thanks. If I ever have any metrology/ communications problems you'll be the first one I contact. (Don't hold your breathe.)

I did see this Ladyada, Paul Horowitz video today, where he talks about AoE3.. fun stuff, Appendix I is about TV, digital TV looks like white noise compared to the old analog AM ... sad news for SETI, unless someone is trying to communicate.

George H.

Yup. I was listening to some SETI guys talking and they were all over the notion of detecting alien broadcasts because they'd be narrow band -- we only started in on narrow-band RF comms in 1915; it's only been 100 years and we're going more and more to spread spectrum.

Assuming that the little green men out there are basically like us, that's a pretty small window of time to catch them in the act.

(and for all we know, narrow band RF signals means "we're tasty and defenseless right now!" to someone out there).

Happily, the narrow-band period of signalling tasty and defenseless seems t o have taken more than 100 years to get to anybody hungry and offensive-min ded.

Maybe some Dubbya-equivalent in a nearby star-system is arguing that we alr eady have weapons of mass-destruction, and needed to be pacified before we get bigger ones. If they can measure our atmospheric CO2 levels they will h ave already worked out that we are dangerously irresponsible.

}snip{

Increasing CO2 levels are the only option to be able to keep feeding our growing population. ;-)

joe

Until the population crash that's going to happen when our agriculture - de pendent on specific plants carefully selected over ten thousand years of re gular interglacial weather - collapses when our plants decide they don't li ke the new climate.

I'm probably going to be dead before it gets interesting, but while your ig norance doesn't guarantee that you are young - Jamie is both elderly and il l-informed - it seems likely that you might have to cope with it.

Personally I think that there are three possibilities:

2: We're about as interesting to the ones out there as a 1st grader is to a 6th grader

And Slowman is insane. Don't feed the troll. ...Jim Thompson

Graduate quantum field theory (relativistic quantum mechanics). The class wasn't the very hardest, except that the guy who cajoled me into taking it in the first place bailed out after a couple of months, leaving me with no study partner. Having a wife and daughter, I needed to graduate ASAP, so I had to bail too. (He's now the beam-time czar at Brookhaven.)

A pity--it was a great class.

Cheers

Phil Hobbs

Or, as seems most likely,

1. As expected from Einstein's causality argument, there really is no way to accomplish FTL travel, and sending an object interstellar distances on organism-relevant time scales requires converting a major fraction of its mass into energy.

Cheers

Phil Hobbs

That could be.

I think if we want to better dodge mass extinction events than we can now

-- even ones not of our own creation -- we want to spread off the planet. If we could colonize an asteroid and power it from fission I'm pretty sure we could get someplace interesting on a species-relevant time scale if not an organism-relevant one, thus dodging even more mass extinction events.

True, but as we're finding out on a daily basis, there's lots of planets out there. Really, really, lots.

If nothing else, modesty would insist that we're not unique.

Heaven help us, but there's probably another Slowman out there >:-} ...Jim Thompson

Whereas you can find pond scum like Jim Thompson in any sewage farm anywhere around the world.

My feeling is that there aren't any hard classes, just a some badly taught classes.

Some stuff - like thermodynamics and relativistic quantum mechanics - is hard to teach well, because it does require the student to learn an unusual way of looking at the problems involved, but good teachers can do it.

Egomaniac teacher go out of their way to make it hard, because they look cleverer that way.

I hope not!

Jamie

George H.