Base current is recombination in the base, it has shot noise plus any excess noise from the recombination process (that's why base current almost always has more 1/f than the voltage noise). Remember the signal is on top of the DC base current which is typically in the uA region 10^13 carriers per second, separating out a noise mechanism for the signal current makes no sense at all. No Maxwell's demons allowed.
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Or, you are trying to be too smart sometimes.
If i write an article or a test report, than it would be a comprehensive description of the test objectives, the methods, the gear used, the data and the statistical analysis and the conclusions drawn.
That takes something around 5-12 pages (sometimes even more) and if i release this report then i consider it as published.
As i did post over the years comments on our tests (or test results) and sometimes did post an incomprehensive description of a test, i do not consider these tests as published, something other users might have read.
@ jneutron,
thanks for the guidance to the papers, i´ve found these at Malcom´s webpage.
BTW, very nice solution with the CVR!
@ ScottWurcer,
That´s the reason why a negative control must be included in a test like that.
But to exclude a test result as an outlier, just due to statistical reasoning is very dangerous, when you are trying to find out if "at least someone could detect a difference" .
Wrt to the -100dB of a 2mV amplitude- shouldn´t the number be a bit more around 1.8 * 10^6 electrons per second at max, and of course varying with time while following the waveforim?
thanks for the guidance to the papers, i´ve found these at Malcom´s webpage.
BTW, very nice solution with the CVR!
@ ScottWurcer,
That´s the reason why a negative control must be included in a test like that.
But to exclude a test result as an outlier, just due to statistical reasoning is very dangerous, when you are trying to find out if "at least someone could detect a difference" .
Wrt to the -100dB of a 2mV amplitude- shouldn´t the number be a bit more around 1.8 * 10^6 electrons per second at max, and of course varying with time while following the waveforim?
While one should not use those test signals to prove that digital audio is flawed, it is still very useful to test with artificial one sample impulse (for example) or other violating signals as long as nobody ensures that these waveforms will not occur in music files.
Digital audio (Nyquist frequency limited) is "perfect" only in theory. The real digital audio deals with non-ideal anti-aliasing filters, non-ideal A/D and D/A converters regarding linearity, non-ideal converters regarding several kinds of jitter, non-ideal sampling etc. etc. Digital audio is thus flawed both by principle (frequency limited and resolution limited) and by non-ideal realization of every of its parts.
There is a good reason why 'classic' analog audio such as the Blowtorch and Vendetta (phono) are still around, used and discussed, even years after the last one was produced.
I keeps people 'honest' about what is audible and what is not. Without SELECTED vinyl records or analog master tapes as an occasional reference, we forget the goal that we are attempting to design towards. We 'wallow' in TV sound, convenient portable players, digital based FM transmission, and even CD's, which while sometimes very good, are seldom perfect. It can be a shock that reminds us of something we have overlooked, like fast food compares to haute cuisine.
Many here are happy with 'fast food' and consider 'better' as a waste of money. And so it goes!
I keeps people 'honest' about what is audible and what is not. Without SELECTED vinyl records or analog master tapes as an occasional reference, we forget the goal that we are attempting to design towards. We 'wallow' in TV sound, convenient portable players, digital based FM transmission, and even CD's, which while sometimes very good, are seldom perfect. It can be a shock that reminds us of something we have overlooked, like fast food compares to haute cuisine.
Many here are happy with 'fast food' and consider 'better' as a waste of money. And so it goes!
Absolutely. Time can be quantified more precisely than any other of the observable physical phenomena that make up the base SI units of measurement, commonly to parts in 10^-14. There are realizations down into parts in 10^-16.
A stable and repeatable resistance with achievable uncertainties in the parts per billion range is good enough in my book to be considered constant for a measureable physical quantity. Once you leave the realm of super low temperatures and super high magnetic fields though it is as they say, all relative.
Dave
In common case we speak of R=dV/dI, where all variables are complex. Hence no Ohm's law violation in the nature, if measured quantities are infinite small. However, infinite small in nature is another can of warms, that opens on territory of different models of physical reality. But for engineering calculations in audio design I believe we can firmly rely on Ohm's law.
Scott,
You are welcome to redefine Ohm's law just call it something else.
According to Georg Simon Ohm the ratio of V/I is a constant. That is defined as the Ohmic resistance. When it is not constant it is considered Non-Ohmic or nonlinear.
Specifically Ohm showed that the length of a poorly conducting wire was directly proportional to the current through it for a fixed voltage.
That idea of V/I being constant was big news at the time. It was initially considered a fallacy! Only when it was accepted as accurate did it allow a great deal of other work to come to fruition.
Prior to the acceptance of Ohm's law Barlow's law was considered the correct approach!
ES
Let's talk about laws of Nature, definitions, and terms as 3 different things. Presence of the term Non-Ohmic means that we have to apply Ohm's law in accordance with complexity and non-linearity of resistances. I don't remember such term in Russian education, so probably in Russia Ohm's law is always true, before we come to the territory where quantum physics rules.
No, YOU are welcome to redefine the concept of resistance. The fact that a resistor has a TC does not violate Ohms Law. Recounting the machinations of 19th century scientists has some amusement value but we have moved on, maybe you should visit Warehouse 13 (lots of fun).
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Scott,
Have you ever bothered to read a translation of the paper? Maybe even a history of why it was so controversial?
Do you understand that Ohm actually was wrong in his conclusion!!! He used thermocouples to provide the test voltage as a voltaic pile did not give him consistent results. He missed the concept of the internal resistance of the voltage source or the burden of the meter.
Just about everyone understood that voltage and current varied with the connection quality. Ohm is the guy who said the V/I curve is constant.
Starting around 1850 is when the term Non-Ohmic came into use as folks found that under some conditions the V/I curve was not constant.
One of the uses of jargon is to separate the uninitiated from the illuminati.
A resistor TC does not violate Ohms law except when there is enough self heating to change the actual value, which is just about always. Resistors keep coming closer to following the "Law" but the reality is that the mathematical model is just a model and is limited by how complex it can get.
Thanks! I always wondered where the different corners might come from.
Sometimes there's a pearl in this pile of * thread.
regards, Gerhard
Scott,
Can't you keep your posts in order? Revising them after a response is a bit confusing as to the order of the logic.
if you don't understand the context or history of a development you not only don't appreciate what a breakthrough was or is, but you also miss the faulty reasoning that fought it. And to paraphrase; if you don't learn the prior faulty reasoning you are doomed to repeat it.
ES
Sure, and nothing is violated then.
We have to distinguish secondary school approach (R = V/I) from scientific approach.
Now, we have the 4'Th thing to separate from Laws of Nature, Definitions, and Terms: it is models that were changing with schools and ages.
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