It appears that a good analogue design engineer who can design at IC level even can demand a hugh salary - as digital guys are ten a penny. (I don't mean DSP but hardware digital). The higher the frequency the more challenging will be the ADC conversion process for instance.Do they still teach analogue at a high level at Universities? Why the shortage? I expect in an ideal world we would want the whole world to be digital so we can use CMOS and make it cheap as hell but life just isn't like that. Tom
Where have all the analogue men gone?
Started by ●August 16, 2004
Reply by ●August 17, 20042004-08-17
Tom wrote:> It appears that a good analogue design engineer who can design at IC level > even can demand a hugh salary - as digital guys are ten a penny. (I don't > mean DSP but hardware digital). The higher the frequency the more > challenging will be the ADC conversion process for instance.Do they still > teach analogue at a high level at Universities? > Why the shortage? I expect in an ideal world we would want the whole world > to be digital so we can use CMOS and make it cheap as hell but life just > isn't like that. > > > Tom > >Universities are subject to fads; they've been discouraging folk from learning analog for at least 20 years to my knowledge. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com
Reply by ●August 17, 20042004-08-17
Tim Wescott <tim@wescottnospamdesign.com> writes:> Tom wrote: >> It appears that a good analogue design engineer who can design at IC level >> even can demand a hugh salary - as digital guys are ten a penny. (I don't >> mean DSP but hardware digital). The higher the frequency the more >> challenging will be the ADC conversion process for instance.Do they still >> teach analogue at a high level at Universities? >> Why the shortage? I expect in an ideal world we would want the whole world >> to be digital so we can use CMOS and make it cheap as hell but life just >> isn't like that. >> Tom >> > Universities are subject to fads; they've been discouraging folk from > learning analog for at least 20 years to my knowledge.I was, unfortunately, in the first group of people at DeVry back in 1976 which did NOT study tubes. I went back to get my "real" engineering degree from 93 to 97 (University of South Florida, Tampa) and they did teach opamps, transistors, h-parameters, current-mirrors, etc., but I think they were a little less thorough than DeVry was in 1976. -- % Randy Yates % "The dreamer, the unwoken fool - %% Fuquay-Varina, NC % in dreams, no pain will kiss the brow..." %%% 919-577-9882 % %%%% <yates@ieee.org> % 'Eldorado Overture', *Eldorado*, ELO http://home.earthlink.net/~yatescr
Reply by ●August 17, 20042004-08-17
"Tom" <somebody@knowherex.netgx> wrote in message news:<1092709341.909707@ftpsrv1>...> It appears that a good analogue design engineer who can design at IC level > even can demand a hugh salary - as digital guys are ten a penny. (I don't > mean DSP but hardware digital). The higher the frequency the more > challenging will be the ADC conversion process for instance.Do they still > teach analogue at a high level at Universities? > Why the shortage? I expect in an ideal world we would want the whole world > to be digital so we can use CMOS and make it cheap as hell but life just > isn't like that.Well... I took a class on HF analogue electronics some 15 years ago, at a college of engineering. We were handed a HF transistor and was given the task to make a print card, a coil, find some resistors and some other stuff to get this amplifier to work at 800 MHz or so. I did as best I could (which wasn't a lot), I found a capacitor and made a coil to work with it, checking the values with a HF impedance meter. There was supposed to be a resistor in the cirquit (to limit currents?) and I couldn't really find out what value it should have. When I asked the course instructor, he answered "Everybody else used 120 Ohms, I think you should do the same." "Everybody else used". Not a hint of an argument or explanation of why 120 Ohm and not 120 kOhm. No traces of jokes, challenges or sarcasm. Whether I caught a joke or not is immaterial; I decided there and then that analog electronics was too "voodoo-like" for me and not something I wanted to get further involved with. Rune
Reply by ●August 17, 20042004-08-17
Rune Allnor wrote:> "Tom" <somebody@knowherex.netgx> wrote in message news:<1092709341.909707@ftpsrv1>... > >>It appears that a good analogue design engineer who can design at IC level >>even can demand a hugh salary - as digital guys are ten a penny. (I don't >>mean DSP but hardware digital). The higher the frequency the more >>challenging will be the ADC conversion process for instance.Do they still >>teach analogue at a high level at Universities? >>Why the shortage? I expect in an ideal world we would want the whole world >>to be digital so we can use CMOS and make it cheap as hell but life just >>isn't like that. > > > Well... I took a class on HF analogue electronics some 15 years ago, > at a college of engineering. We were handed a HF transistor and was given > the task to make a print card, a coil, find some resistors and some other > stuff to get this amplifier to work at 800 MHz or so. > > I did as best I could (which wasn't a lot), I found a capacitor and made > a coil to work with it, checking the values with a HF impedance meter. > There was supposed to be a resistor in the cirquit (to limit currents?) > and I couldn't really find out what value it should have. When I asked the > course instructor, he answered "Everybody else used 120 Ohms, I think > you should do the same." > > "Everybody else used". Not a hint of an argument or explanation of why > 120 Ohm and not 120 kOhm. No traces of jokes, challenges or sarcasm. > Whether I caught a joke or not is immaterial; I decided there and > then that analog electronics was too "voodoo-like" for me and not > something I wanted to get further involved with. > > RuneAt the transistor level, all circuits are analog. At modern speeds, all traces are transmission lines. Digital engineers need analog savvy in a world where you fell your own trees to make the lumber you need to built something. In the world of lumber yards and giant hardware stores, the distinction between analog and digital is tenable; otherwise not. I didn't go to DeVry, but to RCA Institutes. One of my final exams had a single question: Given these tube characterics* and these power supply voltages, design a 10 KW plate-modulated AM transmitter with 1.000 MHz carrier. Specify the turns ratio of the modulation transformer and the bias supplies for the RF output and class-B audio modulator. Assume 0 dBm audio feed. 2 hours. At home, I made a divide-by-ten with CK721s, resistors, capacitors, and diodes. The same CK721s served in the IF of an AM radio. As for "Let's go digital so we can use CMOS", there are plenty of CMOS op amps. A comparator has analog input and digital output. Tie the output of a CMOS inverter back to its input with a 100K resistor, capacitively couple a signal to the input, and you have a dandy 20 dB audio amplifier. Analog? Digital? At the component level, it's how it's used, not what it is. Jerry _________________________________ * A sheaf of pages of characteristic curves of the tubes to be used for RF output, RF driver, RF oscillator, class-B output and other audio stages. -- ... the worst possible design that just meets the specification - almost a definition of practical engineering. .. Chris Bore ������������������������������������������������������������������������
Reply by ●August 17, 20042004-08-17
"Jerry Avins" <jya@ieee.org> wrote in message news:4122262b$0$5904$61fed72c@news.rcn.com...> Tie the output of a CMOS > inverter back to its input with a 100K resistor, capacitively couple a > signal to the input, and you have a dandy 20 dB audio amplifier.I think I have seen this somewhere before. I assume the output swings about Vcc/2 does it? How good is this sort of amplifier,distortion etc. Tom
Reply by ●August 18, 20042004-08-18
Rune Allnor wrote:> "Tom" <somebody@knowherex.netgx> wrote in message news:<1092709341.909707@ftpsrv1>...snip> > Well... I took a class on HF analogue electronics some 15 years ago, > at a college of engineering. We were handed a HF transistor and was given > the task to make a print card, a coil, find some resistors and some other > stuff to get this amplifier to work at 800 MHz or so. > > I did as best I could (which wasn't a lot), I found a capacitor and made > a coil to work with it, checking the values with a HF impedance meter. > There was supposed to be a resistor in the cirquit (to limit currents?) > and I couldn't really find out what value it should have. When I asked the > course instructor, he answered "Everybody else used 120 Ohms, I think > you should do the same." > > "Everybody else used". Not a hint of an argument or explanation of why > 120 Ohm and not 120 kOhm. No traces of jokes, challenges or sarcasm. > Whether I caught a joke or not is immaterial; I decided there and > then that analog electronics was too "voodoo-like" for me and not > something I wanted to get further involved with. > > RuneThat wasn't analog electronics, that was a (mild epithet) poor instructor. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com
Reply by ●August 18, 20042004-08-18
Jerry Avins <jya@ieee.org> wrote in message news:<4122262b$0$5904$61fed72c@news.rcn.com>...> Rune Allnor wrote: > > Whether I caught a joke or not is immaterial; I decided there and > > then that analog electronics was too "voodoo-like" for me and not > > something I wanted to get further involved with. > > > > Rune> Analog? > Digital? At the component level, it's how it's used, not what it is. > > JerryYou are right, of course. Let me rephrase and say that I decided to focus on the aspects of electronics that thought I had a chance of understanding. And where I had teachers who were capable of teaching. Rune
Reply by ●August 18, 20042004-08-18
allnor@tele.ntnu.no (Rune Allnor) wrote in news:f56893ae.0408172123.392abd25@posting.google.com:> Jerry Avins <jya@ieee.org> wrote in message > news:<4122262b$0$5904$61fed72c@news.rcn.com>... >> Rune Allnor wrote: >> > Whether I caught a joke or not is immaterial; I decided there and >> > then that analog electronics was too "voodoo-like" for me and not >> > something I wanted to get further involved with. >> > >> > Rune > >> Analog? >> Digital? At the component level, it's how it's used, not what it is. >> >> Jerry > > You are right, of course. Let me rephrase and say that I decided to > focus on the aspects of electronics that thought I had a chance of > understanding. And where I had teachers who were capable of teaching. > > Rune >You become the kind of engineer you are because you decide thats what you want to be. I was (am) an analog engineer well before I did my first DSP application. I had exactly one course in DSP in college (1977) and I didn't really understand the material even though I could solve the problems. I decided in school that I wanted to be an analog guy because everyone else was interested in digital stuff. I used to tell my friends that they only had to know two numbers, while I dealt with an infinite number. I once had a business partner who said, I was the only analog engineer without gray hair (unfortunately no longer true). I have always heard that ___________ is a black art. Any area of expertise that you don't understand very well is a black art. Analog guys are out there. Most of us are the gray haired guys lurking in the weeds. If you are a student or a newly minted EE, I would suggest that becoming the analog guy might be a good choice. BTW, today I consider myself a signal processing engineer. DSP & Analog is a very good combination. -- Al Clark Danville Signal Processing, Inc. -------------------------------------------------------------------- Purveyors of Fine DSP Hardware and other Cool Stuff Available at http://www.danvillesignal.com
Reply by ●August 18, 20042004-08-18
Tom wrote:> "Jerry Avins" <jya@ieee.org> wrote in message > news:4122262b$0$5904$61fed72c@news.rcn.com... > >>Tie the output of a CMOS >>inverter back to its input with a 100K resistor, capacitively couple a >>signal to the input, and you have a dandy 20 dB audio amplifier. > > > I think I have seen this somewhere before. I assume the output swings about > Vcc/2 does it? > How good is this sort of amplifier,distortion etc. > > TomWith a series resistor on the input also, feedback makes the output very linear. The intrinsic gain is only between 10 and 30, so reducing it with feedback doesn't leave much. Cascading three CD4049s, feeding back with a 1 meg resistor, and using a 10 K resistor in the input (a 1 muF capacitor gets you down to 16 Hz) makes a dandy 40 dB mike amplifier. Jerry -- ... the worst possible design that just meets the specification - almost a definition of practical engineering. .. Chris Bore ������������������������������������������������������������������������
