High Quality White Noise Gen
in [Design]
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From: Richard Henry on 8 Jun 2010 17:26 On Jun 8, 11:20 am, Bill Sloman <bill.slo...(a)ieee.org> wrote: > On Jun 8, 4:01 pm, John Larkin > > > > <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > > On Tue, 8 Jun 2010 04:47:14 -0700 (PDT),Bill Sloman > > > <bill.slo...(a)ieee.org> wrote: > > >On Jun 7, 6:06 pm, John Larkin > > ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > > >> On Mon, 7 Jun 2010 08:41:20 -0700 (PDT),Bill Sloman > > > >> <bill.slo...(a)ieee.org> wrote: > > >> >On Jun 7, 3:55 pm, John Larkin > > >> ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > > >> >> On Mon, 7 Jun 2010 02:16:57 -0700 (PDT),Bill Sloman > > > >> >> <bill.slo...(a)ieee.org> wrote: > > >> >> >Modern wines are often made to be instantly drinkable. This doesn't > > >> >> >mean that they can't get better with age, but many don't. If the wine- > > >> >> >maker has a gas-chromatograph - ideally with a tandem mass- > > >> >> >spectrometer as a detector - they can have a very clear idea of what > > >> >> >their wine tastes and smells like, and the good ones know how to > > >> >> >create an attractive mixture of sensations, and have a pretty good > > >> >> >idea of how that mixture will change and develop with time, > > > >> >> Can a GC tell that the vines grew in water that had been filtered > > >> >> through glacial gravel, slate and shale? > > > >> >Beats me. Why not ask a wine-maker? In theory, the mineral content of > > >> >the water could influence the volatile organic compounds that give > > >> >wine its odour and flavour, but I'd be surprsied if the comment was > > >> >much more than decorative verbiage. > > > >> In other words, delusional fat-headedness. There's a lot of that going > > >> around. He should be careful about chewing on rocks... it's bad for > > >> your teeth. > > > >It's not all delusional fat-headedness, though publicists do latch > > >onto to some of the more impressionistic terms as a basis for the > > >inevitable chunks of decorative verbiage. > > > >There are wine-tasting terms that most people understand - "slatey" > > >and "grassy" comes to mind - even though the connection between the > > >word and the flavour is somewhat arbitrary. My wife describes > > >particular wines as "pink" by which she seems to mean having a high > > >concentration of a particular floral ester. If we had a GC we could > > >probably tell you which floral ester. > > > >People - like you - who don't pay much attention to what they are > > >drinking, and don't develop a vocabulary of terms that allow them to > > >talk about the differences between particular wines, defensively > > >devalue the comments of those who have tasted a wide variety of wines > > >and can articulate the differences between them. > > > Right. Fatheads. Hilarious failures in double-blind tests. > > Fatheads do fail ludicrously on double-blind tests, but blind tasting > is popular amongst wine buffs, and some people do remarkably well. > Some of their success has nothing to do with the taste and smell of > the wine - one of my wife's colleagues paid particular attention to > the shapes of the bottles, which provide useful extra information and > someone who knows what the wine merchants have been pushing in the > week or so before a wine tasting can have a pretty fair idea of what > might being offered at a blind tasting - but people who know wine can > get a lot from the aroma and taste. > If not aroma and taste, what are they judging for? > > > > >> >The GC can detect what you can smell, with somewhat more > > >> >discrimination, allowing a more rational approach to wine-making than > > >> >was possible in previous centuries, not that the more subjective > > >> >approach couldn't produce great wines. > > > >> So the GC knows more about what wines I like than I do? > > > >The GC doesn't know anything. The wine-makers who look at the results > > >of gas chromatic analysis of their wines (and those of others) know a > > >great deal more about wines than you do, and - given a short list of > > >wines that you do like - and could probably predict what other wines > > >you would like a great deal more reliably than you could. > > > >> No, thanks. The Bandit tastes great. > > > >If enough people share your opinion, it will get to be expensive and > > >hard to find, and you would want to find something that tastes similar > > >and is less widely known. If you could describe what it tastes like in > > >terms that a wine critic or a a good wine merchant could understand, > > >the process of finding an alternative would be easier. > > > No, There are lots of inexpensive, great-tasting wines. Cynthia, the > > wine buyer down at Canyon Market, puts out stacks of good, cheap > > stuff. > > There are lots of inexpensive good-tasting wines. "Great" implies > something more, and great wines don't stay cheap and available for > very long. The invisible hand of the market guarantees that. Cynthia > will tell you all about it if you ask her nicely. > > -- > Bill Sloman, Nijmegen
From: krw on 8 Jun 2010 18:11 On Tue, 8 Jun 2010 14:26:10 -0700 (PDT), Richard Henry <pomerado(a)hotmail.com> wrote: >On Jun 8, 11:20�am, Bill Sloman <bill.slo...(a)ieee.org> wrote: >> On Jun 8, 4:01�pm, John Larkin >> >> >> >> <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> > On Tue, 8 Jun 2010 04:47:14 -0700 (PDT),Bill Sloman >> >> > <bill.slo...(a)ieee.org> wrote: >> > >On Jun 7, 6:06 pm, John Larkin >> > ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> > >> On Mon, 7 Jun 2010 08:41:20 -0700 (PDT),Bill Sloman >> >> > >> <bill.slo...(a)ieee.org> wrote: >> > >> >On Jun 7, 3:55 pm, John Larkin >> > >> ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> > >> >> On Mon, 7 Jun 2010 02:16:57 -0700 (PDT),Bill Sloman >> >> > >> >> <bill.slo...(a)ieee.org> wrote: >> > >> >> >Modern wines are often made to be instantly drinkable. This doesn't >> > >> >> >mean that they can't get better with age, but many don't. If the wine- >> > >> >> >maker has a gas-chromatograph - ideally with a tandem mass- >> > >> >> >spectrometer as a detector - they can have a very clear idea of what >> > >> >> >their wine tastes and smells like, and the good ones know how to >> > >> >> >create an attractive mixture of sensations, and have a pretty good >> > >> >> >idea of how that mixture will change and develop with time, >> >> > >> >> Can a GC tell that the vines grew in water that had been filtered >> > >> >> through glacial gravel, slate and shale? >> >> > >> >Beats me. Why not ask a wine-maker? In theory, the mineral content of >> > >> >the water could influence the volatile organic compounds that give >> > >> >wine its odour and flavour, but I'd be surprsied if the comment was >> > >> >much more than decorative verbiage. >> >> > >> In other words, delusional fat-headedness. There's a lot of that going >> > >> around. He should be careful about chewing on rocks... it's bad for >> > >> your teeth. >> >> > >It's not all delusional fat-headedness, though publicists do latch >> > >onto to some of the more impressionistic terms as a basis for the >> > >inevitable chunks of decorative verbiage. >> >> > >There are wine-tasting terms that most people understand - "slatey" >> > >and "grassy" comes to mind - even though the connection between the >> > >word and the flavour is somewhat arbitrary. My wife describes >> > >particular wines as "pink" by which she seems to mean having a high >> > >concentration of a particular floral ester. If we had a GC we could >> > >probably tell you which floral ester. >> >> > >People - like you - who don't pay much attention to what they are >> > >drinking, and don't develop a vocabulary of terms that allow them to >> > >talk about the differences between particular wines, defensively >> > >devalue the comments of those who have tasted a wide variety of wines >> > >and can articulate the differences between them. >> >> > Right. Fatheads. Hilarious failures in double-blind tests. >> >> Fatheads do fail ludicrously on double-blind tests, but blind tasting >> is popular amongst wine buffs, and some people do remarkably well. >> Some of their success has nothing to do with the taste and smell of >> the wine - one of my wife's colleagues paid particular attention to >> the shapes of the bottles, which provide useful extra information and >> someone who knows what the wine merchants have been pushing in the >> week or so before a wine tasting can have a pretty fair idea of what >> might being offered at a blind tasting - but people who know wine can >> get a lot from the aroma and taste. >> >If not aroma and taste, what are they judging for? The three 'C's. Clarity, Cost, and Condesention.
From: Bill Sloman on 8 Jun 2010 19:11 On Jun 9, 12:11 am, "k...(a)att.bizzzzzzzzzzzz" <k...(a)att.bizzzzzzzzzzzz> wrote: > On Tue, 8 Jun 2010 14:26:10 -0700 (PDT), Richard Henry <pomer...(a)hotmail.com> > wrote: > > > > >On Jun 8, 11:20 am,Bill Sloman<bill.slo...(a)ieee.org> wrote: > >> On Jun 8, 4:01 pm, John Larkin > > >> <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > >> > On Tue, 8 Jun 2010 04:47:14 -0700 (PDT),Bill Sloman > > >> > <bill.slo...(a)ieee.org> wrote: > >> > >On Jun 7, 6:06 pm, John Larkin > >> > ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > >> > >> On Mon, 7 Jun 2010 08:41:20 -0700 (PDT),Bill Sloman > > >> > >> <bill.slo...(a)ieee.org> wrote: > >> > >> >On Jun 7, 3:55 pm, John Larkin > >> > >> ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > >> > >> >> On Mon, 7 Jun 2010 02:16:57 -0700 (PDT),Bill Sloman > > >> > >> >> <bill.slo...(a)ieee.org> wrote: > >> > >> >> >Modern wines are often made to be instantly drinkable. This doesn't > >> > >> >> >mean that they can't get better with age, but many don't. If the wine- > >> > >> >> >maker has a gas-chromatograph - ideally with a tandem mass- > >> > >> >> >spectrometer as a detector - they can have a very clear idea of what > >> > >> >> >their wine tastes and smells like, and the good ones know how to > >> > >> >> >create an attractive mixture of sensations, and have a pretty good > >> > >> >> >idea of how that mixture will change and develop with time, > > >> > >> >> Can a GC tell that the vines grew in water that had been filtered > >> > >> >> through glacial gravel, slate and shale? > > >> > >> >Beats me. Why not ask a wine-maker? In theory, the mineral content of > >> > >> >the water could influence the volatile organic compounds that give > >> > >> >wine its odour and flavour, but I'd be surprsied if the comment was > >> > >> >much more than decorative verbiage. > > >> > >> In other words, delusional fat-headedness. There's a lot of that going > >> > >> around. He should be careful about chewing on rocks... it's bad for > >> > >> your teeth. > > >> > >It's not all delusional fat-headedness, though publicists do latch > >> > >onto to some of the more impressionistic terms as a basis for the > >> > >inevitable chunks of decorative verbiage. > > >> > >There are wine-tasting terms that most people understand - "slatey" > >> > >and "grassy" comes to mind - even though the connection between the > >> > >word and the flavour is somewhat arbitrary. My wife describes > >> > >particular wines as "pink" by which she seems to mean having a high > >> > >concentration of a particular floral ester. If we had a GC we could > >> > >probably tell you which floral ester. > > >> > >People - like you - who don't pay much attention to what they are > >> > >drinking, and don't develop a vocabulary of terms that allow them to > >> > >talk about the differences between particular wines, defensively > >> > >devalue the comments of those who have tasted a wide variety of wines > >> > >and can articulate the differences between them. > > >> > Right. Fatheads. Hilarious failures in double-blind tests. > > >> Fatheads do fail ludicrously on double-blind tests, but blind tasting > >> is popular amongst wine buffs, and some people do remarkably well. > >> Some of their success has nothing to do with the taste and smell of > >> the wine - one of my wife's colleagues paid particular attention to > >> the shapes of the bottles, which provide useful extra information and > >> someone who knows what the wine merchants have been pushing in the > >> week or so before a wine tasting can have a pretty fair idea of what > >> might being offered at a blind tasting - but people who know wine can > >> get a lot from the aroma and taste. > > >If not aroma and taste, what are they judging for? > > The three 'C's. Clarity, Cost, and Condesention. Condescension. In fact, blind tasting of wines is aimed at identifying the wine being tasted. Which grape it was made from, which country it was grown in, which area in that country, which year? Some wines are easier than others. Bordeaux from the Margaux area has a characteristic scent of violets which even quite unsophisticated palates can detect. http://www.thebordeauxcellar.co.uk/page8.htm -- Bill Sloman, Nijmegen
From: JosephKK on 9 Jun 2010 07:46 On Wed, 2 Jun 2010 10:37:12 -0700 (PDT), George Herold <gherold(a)teachspin.com> wrote: >On Jun 2, 10:55 am, John Larkin ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> On Wed, 2 Jun 2010 07:32:55 -0700 (PDT), George Herold >> >> >> >> >> >> <gher...(a)teachspin.com> wrote: >> >On Jun 1, 5:51 pm, John Larkin >> ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> >> On Tue, 1 Jun 2010 11:35:59 -0700 (PDT), George Herold >> >> >> <gher...(a)teachspin.com> wrote: >> >> >On May 31, 12:56 pm, John Larkin >> >> ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> >> >> On Mon, 31 May 2010 12:23:10 GMT, jimsl...(a)esterlux.com (Jim Slone) >> >> >> wrote: >> >> >> >> >What are the best options for high quality audio white noise >> >> >> >generation? >> >> >> >> >I have been using generic diodes and reversed biased transistors. Then >> >> >> >someone mentioned there are special parts available with better >> >> >> >characteristics. >> >> >> >> >Can anyone please give me a pointer? >> >> >> >> >Jim Slone >> >> >> >> You can buy noise diodes from lots of people... just google <noise >> >> >> diode> >> >> >> >Does anyone know what makes a high price "noise diode" any better than >> >> >your garden variety Zener? >> >> >> Probably a very small junction area (for low capacitance, high current >> >> density) and maybe some doping profile. Not a power device! >> >> >> Regular zeners get spikey and asymmetric and sort of oscillate at low >> >> current. You can get noise diodes that behave at low currents. >> >> >> >> If you want really flat, really gaussian noise, a mathematical random >> >> >> stream (single-bit) or random word (dac) generator is probably best. >> >> >> See AoE for details. >> >> >> >> For audio, it doesn't matter much. A 10-volt zener biased at a few mA >> >> >> is fine. >> >> >> >Yup, and if the voltage asymmetry is a problem you can add the signal >> >> >from two diodes, one biased from the positve supply and the other from >> >> >the negative. (Though I've never tried this trick.) >> >> >> Or sum the signals from a bunch of them. Central limit theorem. >> >> >Well that is not going to get rid of the voltage asymmetery. >> >> >If you need real Gaussian noise you can look at the shot noise from a >> >photodiode illuminated by an LED. Gives you noise ~100 times bigger >> >than the johnson noise of the sense resistor. (Assuming a 5 Volt DC >> >drop across R). But this has one big drawback. It's very sensitve to >> >vibrations. >> >> Shot noise is the ultimate asymmetric waveform. It's made of >> single-photon unidirectional spikes. If it manages to be Gaussian, >> it's because a lot of asymmetric signals are being summed. Central >> limit theorem. >> >> http://en.wikipedia.org/wiki/Illustration_of_the_central_limit_theorem >> >> John- Hide quoted text - >> >> - Show quoted text - > >Hmmm, you are right.... I still don't think that summing the voltage >noise from a bunch of unipolarized zeners is going to get rid of the >voltage assymetry. But I'd be happy to be wrong too. Have you ever >tried this? It would be simple enough to put 5 or 6 together and see >what the output looks like. (As long as you don't mind my summing >with an opamp)... Maybe I can find some 'fun' time on Friday. > >George H. Actually differencing them in twos, then summing seems more likely to reduce the asymmetry.
From: JosephKK on 9 Jun 2010 07:51
On Wed, 02 Jun 2010 10:46:33 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Wed, 2 Jun 2010 10:37:12 -0700 (PDT), George Herold ><gherold(a)teachspin.com> wrote: > >>On Jun 2, 10:55 am, John Larkin >><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >>> On Wed, 2 Jun 2010 07:32:55 -0700 (PDT), George Herold >>> >>> >>> >>> >>> >>> <gher...(a)teachspin.com> wrote: >>> >On Jun 1, 5:51 pm, John Larkin >>> ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >>> >> On Tue, 1 Jun 2010 11:35:59 -0700 (PDT), George Herold >>> >>> >> <gher...(a)teachspin.com> wrote: >>> >> >On May 31, 12:56 pm, John Larkin >>> >> ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >>> >> >> On Mon, 31 May 2010 12:23:10 GMT, jimsl...(a)esterlux.com (Jim Slone) >>> >> >> wrote: >>> >>> >> >> >What are the best options for high quality audio white noise >>> >> >> >generation? >>> >>> >> >> >I have been using generic diodes and reversed biased transistors. Then >>> >> >> >someone mentioned there are special parts available with better >>> >> >> >characteristics. >>> >>> >> >> >Can anyone please give me a pointer? >>> >>> >> >> >Jim Slone >>> >>> >> >> You can buy noise diodes from lots of people... just google <noise >>> >> >> diode> >>> >>> >> >Does anyone know what makes a high price "noise diode" any better than >>> >> >your garden variety Zener? >>> >>> >> Probably a very small junction area (for low capacitance, high current >>> >> density) and maybe some doping profile. Not a power device! >>> >>> >> Regular zeners get spikey and asymmetric and sort of oscillate at low >>> >> current. You can get noise diodes that behave at low currents. >>> >>> >> >> If you want really flat, really gaussian noise, a mathematical random >>> >> >> stream (single-bit) or random word (dac) generator is probably best. >>> >> >> See AoE for details. >>> >>> >> >> For audio, it doesn't matter much. A 10-volt zener biased at a few mA >>> >> >> is fine. >>> >>> >> >Yup, and if the voltage asymmetry is a problem you can add the signal >>> >> >from two diodes, one biased from the positve supply and the other from >>> >> >the negative. (Though I've never tried this trick.) >>> >>> >> Or sum the signals from a bunch of them. Central limit theorem. >>> >>> >Well that is not going to get rid of the voltage asymmetery. >>> >>> >If you need real Gaussian noise you can look at the shot noise from a >>> >photodiode illuminated by an LED. Gives you noise ~100 times bigger >>> >than the johnson noise of the sense resistor. (Assuming a 5 Volt DC >>> >drop across R). But this has one big drawback. It's very sensitve to >>> >vibrations. >>> >>> Shot noise is the ultimate asymmetric waveform. It's made of >>> single-photon unidirectional spikes. If it manages to be Gaussian, >>> it's because a lot of asymmetric signals are being summed. Central >>> limit theorem. >>> >>> http://en.wikipedia.org/wiki/Illustration_of_the_central_limit_theorem >>> >>> John- Hide quoted text - >>> >>> - Show quoted text - >> >>Hmmm, you are right.... I still don't think that summing the voltage >>noise from a bunch of unipolarized zeners is going to get rid of the >>voltage assymetry. But I'd be happy to be wrong too. Have you ever >>tried this? It would be simple enough to put 5 or 6 together and see >>what the output looks like. (As long as you don't mind my summing >>with an opamp)... Maybe I can find some 'fun' time on Friday. >> >>George H. > >The math says it must be so. Still, the sum would converge to Gaussian >faster if half of the lopsided signals were inverted. And that is where you tripped yourself up. Sums of lopsided signals are still lopsided. Differences may work better. > >Zener noise gets more symmetric at higher currents. 10 mA is usually >OK for a small 10-volt zener. Direct from the nature of the I-V curve. > >I sometimes generate Gaussian-distributed numbers by summing a bunch >of RAN() calls, which are uniform on [0,1]. Six to ten works well, and >the crest factor is finite and known. > >John > |