I don't think anyone is attacking Richard, just the USPTO. Credit to him for seeing it through and getting it granted.
How would you feel though if you got sued by someone who patented a passive filter topology that likely had significant prior art?
You're right on the other points raised. Especially with the current state of frivolous software patents. There are a lot of companies now that just exist to shake small businesses down.
Uri Geller's Sonning bent spoon sculpture disappears - BBC News He lived not too far from where I do. When he moved out he left a spoon. It was stolen.
Interesting example Scott - it appears he did actually bend the spoon on that show.... as JC has a smoke.
YouTube
IIRC, Feynman has written a chapter about his Geller experience. It never ceases to
amaze me how doggedly some low cult high priests here take refuge to exactly
Feynman to "explain" their imagined effects.
I found the discussion of capacitor decoupling interesting. I think it is true that a lot of older, or recent but poorly executed, audio equipment did not pay a lot of attention to HF decoupling. There would typically be large aluminum electrolytics in the PS and, at best, a few more aluminum electrolytics scattered here and there near different stages. Analysis, including the paper shown earlier, does show extended HF suppression when appropriate small value caps are added very near the load. At some historical point people started talking about this and suggesting improvements, though they sometime ignore the resistance and inductance of PCB traces and wires. Some folks suggest paralleling large numbers of electrolytics (to reduce effective ESR/ESL), others suggest adding parallel low value film caps, either right at the big electros or at the load.
So: Audio Guy says add a small polystyrene cap, because he tried it and it sounded better, or at least different. Having heard a difference or improvement by trying that, he is disinclined to do deeper analysis, and is happy to recommend that others use the same technique. Then Engineer Guy presents analysis and points out that the lead inductance of an axial polystyrene cap would, in that application, swamp the added capacitance and the improved HF performance of the film cap.
The thing to realize is that they can both be right! Compared to a naive PSU implementation, a couple of scattered film caps can improve HF rejection (though axial polystyrenes are likely not the best choice). The change may or may not measure as "better" (implementation dependent) but it may well be audible. OTOH the engineering analysis is right, and it is likely time for a lot of audio desgners/engineers to rethink use of SMD components to minimize series inductance. Dielectrics that are often eschewed in audio signal path may be useful in PS decoupling (I wish Gerhard had also tested some NPO/C0G ceramics in that jig, just for comparison).
So: Audio Guy says add a small polystyrene cap, because he tried it and it sounded better, or at least different. Having heard a difference or improvement by trying that, he is disinclined to do deeper analysis, and is happy to recommend that others use the same technique. Then Engineer Guy presents analysis and points out that the lead inductance of an axial polystyrene cap would, in that application, swamp the added capacitance and the improved HF performance of the film cap.
The thing to realize is that they can both be right! Compared to a naive PSU implementation, a couple of scattered film caps can improve HF rejection (though axial polystyrenes are likely not the best choice). The change may or may not measure as "better" (implementation dependent) but it may well be audible. OTOH the engineering analysis is right, and it is likely time for a lot of audio desgners/engineers to rethink use of SMD components to minimize series inductance. Dielectrics that are often eschewed in audio signal path may be useful in PS decoupling (I wish Gerhard had also tested some NPO/C0G ceramics in that jig, just for comparison).
Wow, what a post! This thread has turned to a better comedy than I have ever expected
I'm glad that you are amused, PMA. It suits you better than your usual disposition. '-)
Today, a fellow engineer who has more degrees in both engineering and physics than most anybody, told me that he acquired a new $13K D-A with a successive approximation converter and a tube output. He is very happy with it. It is certainly out of my league, but I am intrigued. He also wants me to audition the power amp that we both have worked on over the years in his system. It would be a fun ride to his house if he brings the Boxster to pick me up. We shall see. He just retired from a HP-Agilent offshoot designing IC microwave transmitters for cell phones (if I heard him right). Has more than enough money, just got tired of the job, has nice test equipment though. He wants to complete the power amp that he and I worked on over several years, using IC's, a completely new feedback topology, and tracking switching power supplies (Bruno's switching amp modules) that allows more than 300W/channel from a unit that can be hand carried. He experimented with coupling caps and direct connection as well, with this amp. I would like to hear the difference myself if I go to his house. I sort of talked him into servos, but they can be bypassed if necessary, and coupling caps inserted. He has tried my usual best cap selection (REL) but he has also tried other more exotic oil filled caps and finds that they sound 'pleasing', go figure! Yes, there is much more to this audio quality thing that most here will ever know.
Today, a fellow engineer who has more degrees in both engineering and physics than most anybody, told me that he acquired a new $13K D-A with a successive approximation converter and a tube output. He is very happy with it. It is certainly out of my league, but I am intrigued. He also wants me to audition the power amp that we both have worked on over the years in his system. It would be a fun ride to his house if he brings the Boxster to pick me up. We shall see. He just retired from a HP-Agilent offshoot designing IC microwave transmitters for cell phones (if I heard him right). Has more than enough money, just got tired of the job, has nice test equipment though. He wants to complete the power amp that he and I worked on over several years, using IC's, a completely new feedback topology, and tracking switching power supplies (Bruno's switching amp modules) that allows more than 300W/channel from a unit that can be hand carried. He experimented with coupling caps and direct connection as well, with this amp. I would like to hear the difference myself if I go to his house. I sort of talked him into servos, but they can be bypassed if necessary, and coupling caps inserted. He has tried my usual best cap selection (REL) but he has also tried other more exotic oil filled caps and finds that they sound 'pleasing', go figure! Yes, there is much more to this audio quality thing that most here will ever know.
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Creating "sound" is really art. Reproduction of the created sound (we are talking about) is pure science (engineering), nothing else. And it should be based on today's knowledge, not on 40 years old "experiences" and merits.
Unless you look at the impedance right at the load with network analyzer, and the residual ripple (or load induced ripple) with a sprectrum analyzer you are sort of blind when it comes to decoupling and filtering. When offerered to spend $30k on audio measurement equipment most engineers would choose an Audio-Precision rig, actually a good SNA is much more useful and a decent soundcard will allow for "standard" measurements on par with the latest AP if you use some advanced techniques.
Patents like that remind me why my PhD supervisor told me not to take seriously any US patent. He said that they were all regarded as jokes in Europe.Mark Johnson said:
LC traps like that were routinely used in TV circuits since the 1950s (and probably in radar circuits before that). How could a standard textbook circuit be patented? The patent examiner must have been astonishingly incompetent. Maybe he just searched patents for prior art?
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