marce Posted September 27, 2018 Share Posted September 27, 2018 8 hours ago, fas42 said: What I see are people obsessed with there being technical issues - requiring technical solutions. Ummm ... it doesn't work that way - achieving signal integrity in the analogue sphere isn't like a lovely programming exercise, that you can write a paper about. <Car analogy alert!> Rather, it requires looking under the hood and noting where poor workshop practices have made things far too twitchy - solve those issues, and all the driveability problems just fade away ... https://www.amazon.co.uk/High-Speed-Digital-Design-Semiconductor/dp/0133957241 Link to comment
Popular Post marce Posted September 27, 2018 Popular Post Share Posted September 27, 2018 12 hours ago, Superdad said: Well there is one (rather general) statement that I think most here can agree upon. Nope I disagree, the circuitry and hows it laid out differs for digital, analogue,rf/microwave each has their issues and resolutions. High speed digital is high speed digital whether its audio (though the only high speed digital in Audio is the DDR memory interface, Ethernet and to some extent USB and if a motherboard the various on board busses, all covered in detail) or more taxing designs such as mixed signal boards with multiple high speed ADC/DAC's and some phase array microwave... Mixed signal design and layout is also well documented and again is pretty common in electronics in the wider world, so the interaction between the various sections (Digital, analogue, rf etc.) is again well documented and how to minimise such interactions... gmgraves and Shadders 1 1 Link to comment
gmgraves Posted September 27, 2018 Share Posted September 27, 2018 19 hours ago, fas42 said: We've been here over and over and over again, George . The contact enhancers I tried didn't "solve the problem" - they changed the progession of degradation, and ultimately made it worse - for audio. Which was confirmed by thoroughly cleaning the enhancer gunk off, and immediately listening to a enhancer free, minty fresh connection. Repeated the exercise several times - enhancers like this were then struck off the list of useful tweaks. The contact area has to have sufficent integrity - end of story. I've found solutions which work, so they automatically get used, every time. We've been over this and over this, Frank. With all due respect, you are full of it! George Link to comment
gmgraves Posted September 27, 2018 Share Posted September 27, 2018 On 9/26/2018 at 4:36 AM, pkane2001 said: Except for maybe some quantum states of elementary particles, there is nothing digital in this universe that isn't carried or represented by some analog signal. That's how it's been designed, that's how it works, there's nothing new here. And it's mostly wrong-headed that what makes analog devices sound great will also help digital. These are completely different types of signals, used for different purpose, processed differently, running at different frequencies with a completely different result when subjected to the same set of distortions. That's because the real world is analog. There is no way to express a digital file except through an analog interface. And you are quite correct about it being wrong headed to equate an analog signal with whatever problems and shortcomings it might have with a digital signal. The digital circuitry doesn't care about the analog part, it's just a carrier. AS long as the digital circuitry can SEE the one's and zeros in the analog carrier, it doesn't care. I've seen digital signals that looked so bad, mixed in with noise, the waveforms compromised until the square waves representing each digit looked more like noisy sine waves or triangular wave forms than square wave pulses. Yet the digital receiving circuitry had no problem retrieving them and decoding them perfectly. I was the designer/developer of the original Supertex garage door opener chip. !5 bit, NRZ encoding transmitted over an RF link. We tested that chip under every known condition, and as long as the receiver could "see" the datas stream, it always worked, no matter how nonsensical the transmitted signal looked! pkane2001 1 George Link to comment
Popular Post marce Posted September 27, 2018 Popular Post Share Posted September 27, 2018 I think part of the problem is we look at the "digital waveform" as a voltage, if you look at it as the thing we are actually interested in the rise and fall slopes when all the excitement happens and look at the current pulses as well, you get a different perceptive on what digital transmission is, a monotonic regular current pulse that will result in a monotonic regular pulse that will cause a voltage rise at the receiver causing a defined switch of state... or not. DDR memory is best, never seen square... yet it works reliably. pkane2001 and adamdea 2 Link to comment
Shadders Posted September 27, 2018 Share Posted September 27, 2018 Hi, Seems to be a lot of discussion of analogue and digital. My perspective is that : All circuits are analogue continuous circuits that are designed to process specific classes of signals. So, CMOS logic will process digital, continuous signals, and output digital continuous signals. A comparator will process at its input analogue continuous, or digital continuous signals, but will output digital continuous signals. An opamp as an amplifier will process analogue continuous signals and output analogue continuous signals. An opamp can be used to create a circuit that has hysteresis, so the output is digital continuous. Regards, Shadders. Link to comment
Shadders Posted September 27, 2018 Share Posted September 27, 2018 1 minute ago, marce said: a comparator? Hi, Yes, an opamp specifically designed to be a switching output as opposed to an amplifier (class A/B or B). Some can be open collector too on the output. Regards, Shadders. Link to comment
esldude Posted September 27, 2018 Share Posted September 27, 2018 3 minutes ago, marce said: a comparator? Wrong thread, but how long does it take to burn in a comparator until it functions like a comparator reliably. marce 1 And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. Link to comment
marce Posted September 27, 2018 Share Posted September 27, 2018 You can have fun with them, with a couple and a bit of basic logic you can create a simple high low switch... A 1 bit DAC? Link to comment
esldude Posted September 27, 2018 Share Posted September 27, 2018 1 minute ago, marce said: You can have fun with them, with a couple and a bit of basic logic you can create a simple high low switch... A 1 bit DAC? I remember stringing some together on a multi-level signal to use something like If...then...logic in some liquid level control gear. I didn't recall any burn in or burn out until one took a more or less direct lightning strike. And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. Link to comment
Shadders Posted September 27, 2018 Share Posted September 27, 2018 3 minutes ago, marce said: You can have fun with them, with a couple and a bit of basic logic you can create a simple high low switch... A 1 bit DAC? Hi, Yes, add a counter and you have a SAR ADC. Regards, Shadders. Link to comment
fas42 Posted September 27, 2018 Share Posted September 27, 2018 1 hour ago, gmgraves said: We've been over this and over this, Frank. With all due respect, you are full of it! And you're full of ego, George - if someone doesn't agree with your take on something, they must be wrong - it's remarkable that man has still managed to progress, in spite of the bellowing of the bulls on all sides ... Link to comment
fas42 Posted September 27, 2018 Share Posted September 27, 2018 9 hours ago, marce said: https://www.amazon.co.uk/High-Speed-Digital-Design-Semiconductor/dp/0133957241 Hmmm ... this is purely about digital integrity, when you are pushing the speed hard - zero about "mixed signal". Link to comment
fas42 Posted September 27, 2018 Share Posted September 27, 2018 9 hours ago, marce said: Mixed signal design and layout is also well documented and again is pretty common in electronics in the wider world, so the interaction between the various sections (Digital, analogue, rf etc.) is again well documented and how to minimise such interactions... The trouble is that no-one has documented how "minimal" the interactions have to be in the audio world, to be inaudible - if it don't show up on a CRO, well, that's got to be good enough! Link to comment
Popular Post Ralf11 Posted September 27, 2018 Popular Post Share Posted September 27, 2018 You know, sometimes people just need to have a seal slap them in the face with an octopus Hugo9000, mav52, mansr and 2 others 5 Link to comment
esldude Posted September 27, 2018 Share Posted September 27, 2018 5 minutes ago, Ralf11 said: You know, sometimes people just need to have a seal slap them in the face with an octopus Presumably what you had in mind. fas42 1 And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. Link to comment
Ralf11 Posted September 27, 2018 Share Posted September 27, 2018 yes, but we need to photochop Frank in there Link to comment
kumakuma Posted September 27, 2018 Share Posted September 27, 2018 Just now, Ralf11 said: yes, but we need to photochop Frank in there Which of the three is he? Sometimes it's like someone took a knife, baby Edgy and dull and cut a six inch valley Through the middle of my skull Link to comment
esldude Posted September 27, 2018 Share Posted September 27, 2018 44 minutes ago, Ralf11 said: yes, but we need to photochop Frank in there Does Frank have a kayak? What say you Frank? And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. Link to comment
fas42 Posted September 28, 2018 Share Posted September 28, 2018 Not a water man, I'm afraid - Croc Dundee is more my style ... esldude 1 Link to comment
fas42 Posted September 28, 2018 Share Posted September 28, 2018 For example, here's me working on one of my rigs ... Link to comment
fas42 Posted September 28, 2018 Share Posted September 28, 2018 16 hours ago, marce said: Mixed signal design and layout is also well documented and again is pretty common in electronics in the wider world, so the interaction between the various sections (Digital, analogue, rf etc.) is again well documented and how to minimise such interactions... Sometimes one finds great amusement in what one comes across - just happened to look up Ott's Electromagnetic Compatibility Handbook - and noted the first sentences in the Mixed Signal chaper ... Quote The design and layout of a mixed-signal printed circuit board (PCB) can be a challenging task, the solution to which is not well addressed in most engineering literature. Mixed-signal PCB problems usually involve either one of two situations. One involves digital logic circuits that interfere with sensitive low-level analog circuits [often audio or radio frequency (rf)], and ... Link to comment
marce Posted September 28, 2018 Share Posted September 28, 2018 10 hours ago, fas42 said: Hmmm ... this is purely about digital integrity, when you are pushing the speed hard - zero about "mixed signal". Do a bloody search for mixed signal, like I have said before, there is a lot of information, most boards I do are mixed signal these days. Usually every manufacturer of mixed signal devices (eg. DAC) will have a realm of info on layout, supplies, grounding etc. Read Henry Ott, Ralph Morrison, also understanding the digital side of things would give you an understanding of the issues the digital can cause the analogue side... All mixed signal boards should be segregated, the digital in one section, main supplies in another section away from major signal paths, the analogue in its won area, minimal signal loops, minimal interaction, including importantly power/ground planes inadvertently coupling capacitivley... Link to comment
marce Posted September 28, 2018 Share Posted September 28, 2018 2 hours ago, fas42 said: Sometimes one finds great amusement in what one comes across - just happened to look up Ott's Electromagnetic Compatibility Handbook - and noted the first sentences in the Mixed Signal chaper ... Look at the dates, things move on... Why do you always look for something to support the negative view, why not post some real info on how it cna be done, look for some of the positive information. Jeez if I worked like this I would never get a job done, because a lot look impossible when you start, so you don't go it can't be done, you start with reading the active devices data sheets and planning out the critical signal flows, both local to circuitry and accross the board between blocks of circuitry... You don't look for reasons why it cant be done, that's giving in before you start. Link to comment
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