I remember in the days of modems we used to use a 511 bit pseudo-random error pattern to test data links. If you listened to it on the line, it was a surprisingly repetetive sound compared to real random data. So I can see how you'd "hear" patterns in data this way.
While I agree that we are able to see patterns and automatically expand, rescale, and focus on anomolies with our eyes, I don't beleive the same is true with our ears. They are much more 2d(or arguably, 1d) and are thus easily outdone by relatively unsophisticated algorithms.
I used to work in radiopaging sending digital data packets and during development would often say or hear "there was something wrong with that packet". We were rarely, if ever, wrong.
Most people who use(d) modems will have had a "that didn't sound right" moment.
Very much so, I used to deal with multisite modems on a polling system and got to know when there was something wrong on the line by the sounds. For instance, you could teell how many sites were responding, or if one was retransmitting a lot.
While Selinz may be sceptical, just as your eyes will register small changes in what you see, so the ear can distinguish small changes or patterns in modulated data. I can see how that could be used to find patterns or other irregularities in data - it would only give you a starting point for further investigation but you could get through a lot of data quickly.
old-time computer folks used to debug with an AM radio next to their system. Back in those days, clocks used to be in the hundreds of kilohertz, and you could hear the program flow (loops, jumps, interrupts) in the buzz on the corresponding AM frequency.
Good comment przemek. And folks still use the AM radio technique. Put it near the AC service panel of a house and see (hear) if any x10, etc. devices are wired somewhere and perhaps therefore interfering with some other system. Turn off individual breakers to isolate and find.
Power supply designers use touch all the time to tell if things are running hot. Low voltage circuits, of course. And sight, smell, and hearing give a quick indication that an electrolytic is in backwards. Or, what is left of it was in backwards. If something is hot, we can often tell by the smell if it's a semiconductor or a resistor.
Evaluating data by sound , smell, or touch is indeed a very good method, particularly when the required results are qualitative, such as "good or bad". But it calls for skilled personal judgement and so it would not be found acceptable by that segment of managers who strongly want to eliminate the need for such skills in the name of uniformity. Think ISO9000 and similar policies.
But listening is still a very handy way to detect problems, beyond any doubt.
Agreed, by ISO9000, and even good solid logic, measurements must be done by instumentation. But a first cut, fire it up, qualitative run can use all the senses. And when something goes wrong, a good nose or ear is often the first indication. On a power supply, the first indication of a failure is sometimes that loud popping sound, flash of light, and acrid smell. Of course, if that's the case, the fact that the product no longer works makes it obvious.
Agreed! Experienced power electronics engineers use all their senses to detect anomalous circuit operation, and hearing is very important. A circuit that is slightly unstable, say, only during a step change in either input or output, often has a distinctive change in noise, in many cases a "chirp", that indicates that some control loops are not quite happy. Back in the days before deep memory scopes I relied on this to detect stability problems. Even today a keen ear can often detect a problem long before someone relying on a scope image.
Off-peak power: here in Australia, one can hear the high-freq signals sent by the power supply authorities to turn off-peak relays on and off. Some times (older) equipment malfunctioned due to this signal, and the best test we had was to plug in a particular soldering iron and just listen for the distinctive "off-peak" sound....
Another example - switching power supplies - sometimes a a faulty SMPSU will emit audible "chirps" or a usually supersonic oscillation will become audible - many's the time I've used that as a diagnostic.
I was called in once by a power supply company that had a conducted emissions EMC problem on a new PSU. I tested one and emissions were some dB's above the limit. I then asked to test the PSU they submitted for testing. It was below the limit. But I then took the lid off and I new straightaway why it had passed. I could hear that it was unstable and this was conveniently spreading the emissions spectrum. I cured the marginal stability problem but had to add an extra filter.
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