dsh@csl36h.csl.ncsu.edu (Doug Holtsinger) (11/12/90)
In article kls30@DUTS.ccc.amdahl.com (PUT YOUR NAME HERE) writes: >In article rick@ameristar (Rick Spanbauer) writes: >>If you're having trouble with circuit analysis, I would look for >>weaknesses in either math or physics background. I found that taking > >I had/have trouble with circuit anlysis. I now have a degree in EE >computers of course. I don't have a weakness in calc or physics. >I can handle any calc or physics you give me just fine. Circuit >analysis requires the correct approach. If no one tells you the correct >approach ( a GOOD instructor) you won't do it well. I was never taught >by a good instructor so my circuit analysis skills suck, that's one >reason I like digital design so much, only ones and zeros. Digital design is getting to be much more than just ones and zeros. Just try designing a digital board to run at > 30 Mhz without analyzing board trace delays, or dealing with reflection problems, etc.. IMHO, the time that a student spends in analog circuit classes is time very well spent. >-- >/* -The opinions expressed are my own, not my employers. */ >/* For I can only express my own opinions. */ >/* */ >/* Kent L. Shephard : email - kls30@DUTS.ccc.amdahl.com */ --------------- dsh@csl.ncsu.edu
touch@dsl.cis.upenn.edu (Joe Touch) (11/12/90)
In article <1990Nov12.045429.20147@ncsuvx.ncsu.edu> dsh@csl36h.csl.ncsu.edu.UUCP (Doug Holtsinger) writes: >Digital design is getting to be much more than just ones and zeros. >Just try designing a digital board to run at > 30 Mhz without analyzing >board trace delays, or dealing with reflection problems, etc.. You don't have to get into analog problems to require 'the right approach'. I've seen boards built to 150 Mhz without board trace delay or reflection requiring analog analyis. 'Just ones and zeroes' can be more than enough of a barrier. Just try to design anything with more than a few states. There are issues of state machine minimization, race and hazard detection and elimination, and verification which have nothing to do with analog signals, per se. Good teaching is good teaching, and every subject benefits from such. Joe Touch touch@cis.upenn.edu
dsh@csl36h.csl.ncsu.edu (Doug Holtsinger) (11/13/90)
In article touch@dsl.cis.upenn.edu (Joe Touch) writes: >In article dsh@csl36h.csl.ncsu.edu.UUCP (Doug Holtsinger) writes: > >>Digital design is getting to be much more than just ones and zeros. >>Just try designing a digital board to run at > 30 Mhz without analyzing >>board trace delays, or dealing with reflection problems, etc.. > >You don't have to get into analog problems to require 'the right >approach'. I've seen boards built to 150 Mhz without board trace >delay or reflection requiring analog analyis. Well, the original poster discussed the 'right approach' as it pertains to analog design, not digital design. Your experience at 150 Mhz is not anything like mine at lower frequencies. Sure, you could build a couple of boards with lazy timing, and if it works then you declare that the design is correct. That's not the way it works in the real world - where getting competitive, reliable designs into _mass production_ requires such analysis. My original point was that digital (board) designers who fail to understand analog issues are placing themselves at a severe disadvantage. > >Joe Touch >touch@cis.upenn.edu ---------------- dsh@csl.ncsu.edu
gja@mullian.ee.mu.oz.au (Grenville Armitage) (11/13/90)
In article <32696@netnews.upenn.edu> touch@dsl.cis.upenn.edu (Joe Touch) writes: >In article <1990Nov12.045429.20147@ncsuvx.ncsu.edu> dsh@csl36h.csl.ncsu.edu.UUCP (Doug Holtsinger) writes: >>Digital design is getting to be much more than just ones and zeros. >>Just try designing a digital board to run at > 30 Mhz without analyzing >>board trace delays, or dealing with reflection problems, etc.. >You don't have to get into analog problems to require 'the right >approach'. I've seen boards built to 150 Mhz without board trace >delay or reflection requiring analog analyis. I'd be interested to know how this was done without any reference to the analog nature of signals at such frequencies. Even generalised transmission line theory is based on analog analysis. >'Just ones and zeroes' can be more than enough of a barrier. Just try >to design anything with more than a few states. There are issues of >state machine minimization, race and hazard detection and elimination, ^^^^^^^^^^^^^^^^^^^^^^^^^ >and verification which have nothing to do with analog signals, per se. I should have thought that race and hazard conditions are the outworking of "analog" processes within the "digital" gates. The bottom line is that when you look at things fast enough you'll find a world where signals take whole ranges of values, regardless of whether the circuit is nominally "digital". I think the original posters comments about the world >30Mhz are quite valid. gja
chik@eecg.toronto.edu (Raymond Chik) (11/16/90)
In article <1990Nov12.045429.20147@ncsuvx.ncsu.edu> dsh@csl36h.csl.ncsu.edu.UUCP (Doug Holtsinger) writes: >In article kls30@DUTS.ccc.amdahl.com (PUT YOUR NAME HERE) writes: >>In article rick@ameristar (Rick Spanbauer) writes: >>>If you're having trouble with circuit analysis, I would look for >>>weaknesses in either math or physics background. I found that taking >> >>I had/have trouble with circuit anlysis. I now have a degree in EE >>computers of course. I don't have a weakness in calc or physics. >>I can handle any calc or physics you give me just fine. Circuit >>analysis requires the correct approach. If no one tells you the correct >>approach ( a GOOD instructor) you won't do it well. I was never taught Very true!! I was taught by a very good professor (K.C Smith, if you've ever heard of him) back in my undergraduate circuits course. His innovative way of circuit analysis influenced me a lot and here I am now doing research in Analog IC design. >Digital design is getting to be much more than just ones and zeros. >Just try designing a digital board to run at > 30 Mhz without analyzing >board trace delays, or dealing with reflection problems, etc.. >IMHO, the time that a student spends in analog circuit classes is time >very well spent. > Logic systems that ustilize analog techniques are also becoming popular. Think about Multi-Valued-Logic. And myself has spent some time in looking into possiblity of apply analog technique into new logic gate designs as well.