Jerry Avins <jya@ieee.org> wrote in message news:<4030e68b$0$3080$61fed72c@news.rcn.com>...> machines weren't fast enough to work in real time. Mechanical things > move slowly on scales used by computers.Some do and some don't. MEMS are a good example of mechanical parts that move very fast mostly because of their scale however. There is also people trying to build nanotechnology mechanical devices that will move very very quickly.> A machine part moving at 600 > ft/sec seems frighteningly fast. Nevertheless, an interrupt service that > needs 100 microseconds is completed before the part has moved 3/4 inch. > The "latest and greatest" processors of the time (80186) were much > faster than my Z-80s. Expressing time as the distance moved by a > standard bridged my client's understanding gap. To have a common > measure, I adopted the approximate speed of sound in air, roughly 330 > meter/sec. Using that that scale, a microsecond translates to .013 inch. > Perspective is good. Most people have a better feel for the size of an > inch than for the duration of microsecond.I have noticed that most people who talk about their embedded processing or realtime work at timing the flight time of sound, which moves about a foot in a millisecond, think of 100 microseconds as a short period of time. Those of us who work with timing light, which travels about a foot in a nanosecond, and need to measure in small fractions of a nanosecond think of 100 microseconds as a long period of time. But if I talk about that stuff most of the people who are thinking of sound speed realtime will think that I meant milli or microseconds when I talk about processing things at light speed.> Aside from your taking metaphor (which I tend to use freely) more > literally than I intended, I don't see the underlying problem that you > want to address. Where have I failed? What do you believe I did wrong?You stated that I had confused you with someone else and that I was mixed up. You were wrong about that and mixed up. Recall that I quoted Charles Moore a number of years ago saying that 'The speed of light used to seem fast.' That was back when we were pushing 10GHz external timing in .8u. With today's technology the numbers are much more impressive. Where you failed was in validity of your comments that I was the one who was confused and mixed up because I remembered that you were working with the tecnnology that you have told us that you work with. But if you can't remember what you posted in December I should accept that you were just confused then too. If I 'mixed you up' the mixup was in your mind. Sorry if I mixed up your mind. I did not mixup who you were in my mind as you stated back then. Best Wishes
DSP book recommendations
Started by ●February 1, 2004
Reply by ●February 16, 20042004-02-16
Reply by ●February 16, 20042004-02-16
Jeff Fox wrote:> Jerry Avins <jya@ieee.org> wrote in message news:<4030e68b$0$3080$61fed72c@news.rcn.com>... > >>machines weren't fast enough to work in real time. Mechanical things >>move slowly on scales used by computers. > > > Some do and some don't. MEMS are a good example of mechanical parts > that move very fast mostly because of their scale however. There is > also people trying to build nanotechnology mechanical devices that > will move very very quickly.Jeff, Some of the machines I built assembled TV sets and coordinated the assembly lines that carried the parts. Another applied tape to what would become the corners of corrugated cartons. The challenge was to locate the tape to within 1/64th inch with an applicator that has significant but constant delay, while the product conveyor speed varied from a crawl to 50 ft/sec. Yet another assembled the caddies for 12-inch video disks. ...> I have noticed that most people who talk about their embedded processing > or realtime work at timing the flight time of sound, which moves about a > foot in a millisecond, think of 100 microseconds as a short period of time. > Those of us who work with timing light, which travels about a foot in a > nanosecond, and need to measure in small fractions of a nanosecond think > of 100 microseconds as a long period of time. But if I talk about that > stuff most of the people who are thinking of sound speed realtime will > think that I meant milli or microseconds when I talk about processing > things at light speed.I try to use tools appropriate to the task.>>Aside from your taking metaphor (which I tend to use freely) more >>literally than I intended, I don't see the underlying problem that you >>want to address. Where have I failed? What do you believe I did wrong? > > > You stated that I had confused you with someone else and that I was > mixed up. You were wrong about that and mixed up. Recall that I > quoted Charles Moore a number of years ago saying that 'The speed of > light used to seem fast.' That was back when we were pushing 10GHz > external timing in .8u. With today's technology the numbers are > much more impressive. > > Where you failed was in validity of your comments that I was the > one who was confused and mixed up because I remembered that you > were working with the tecnnology that you have told us that you > work with. But if you can't remember what you posted in December > I should accept that you were just confused then too. > > If I 'mixed you up' the mixup was in your mind. Sorry if I mixed > up your mind. I did not mixup who you were in my mind as you > stated back then.As I wrote, I don't recall out exchange. If I told you that I thought you confused me with someone else, it was likely that you had attributed to me words that someone else had written. It is also possible that you so misconstrued what had meant that I didn't recognize what you had made of it. If so, then the failure to communicate might have been mine. Let's either review the whole thread by email, or drop it. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●February 17, 20042004-02-17
"Jeff Fox" <fox@ultratechnology.com> wrote in message :> Best WishesFor some reason, I don't think he means it. Rick Armstrong (note: reply address is bogus)
Reply by ●February 17, 20042004-02-17
Rick Armstrong wrote:> "Jeff Fox" <fox@ultratechnology.com> wrote in message : > >>Best Wishes > > > > For some reason, I don't think he means it.It's sad, but I'm sure he does. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
