analogue feedback memory? - Page 1
Forum section: electronics / projects

author: ranch varment
author_rank: Regular Contributor
timestamp: June 21, 2015, 10:56:28 am
content: Is there such a thing as this?

author: tggzzz
author_rank: Super Contributor
timestamp: June 21, 2015, 11:02:27 am
content: Sample and hold

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 21, 2015, 11:47:07 am
content: You could make something like transmission line or acoustic (mercury or otherwise) delay line, with analog feedback to circulate and maintain the data. But after more than a few trips through the line, the signals will be significantly distorted in amplitude (due to loop gain being not exactly 1, or nonlinear distortion), or in time (dispersion -- different propagation rates for different frequency components).To be fair, attempting to conserve all analog quantities would retain a tremendous amount of additional information (the digital equivalent is using multiple levels per symbol, such as from a DAC-ADC pair), so it should be understandable that this is a challenging prospect.The trick there is, if you use a digital method inbetween, you can refresh the analog input state from a digital basis, and convert the analog output plus line errors into a more limited set of digital levels, hopefully the same as what it started with.Tim

author: amyk
author_rank: Super Contributor
timestamp: June 21, 2015, 12:56:51 pm
content: https://en.wikipedia.org/wiki/Bucket-brigade_device

author: ranch varment
author_rank: Regular Contributor
timestamp: June 21, 2015, 11:27:27 pm
content: Thanks for the info.I wasnt even aware it was possible.How many components in one value, doing it like this?

author: dadler
author_rank: Unknown
timestamp: June 21, 2015, 11:32:51 pm
content: Quote from: ranch varment on June 21, 2015, 11:27:27 pmCan you rephrase?BBDs are essentially a delay line of analog voltages, and the chips vary in the number of "buckets" they contain.As for mercury/etc delay lines, you are storing data in physical waves. Not sure how to equate that to your question.

author: ranch varment
author_rank: Regular Contributor
timestamp: June 21, 2015, 11:39:54 pm
content: Its like an analogue delay music/sound engineer effect?

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: June 22, 2015, 01:13:39 am
content: Quote from: ranch varment on June 21, 2015, 11:27:27 pmYou should look into the history of computer memory technologies. They looked at a truly astounding array of physical effects before we learned to make really tiny things in silicon reliably.http://www.computerhistory.org/timeline2014/memory-storage/You'll not only find that people have always been smart, but that in fact you can't even come up with anything they didn't already think of half a century or more ago.The king of the "storage capacity vs. earliness" ratio is this IMO:https://en.wikipedia.org/wiki/IBM_1360The king of the "they must have found a UFO at Roswell after all"https://en.wikipedia.org/wiki/Selectron_tubeThe amount of concepts in there that seem way ahead of their time in there blows my mind...But then again, they had this in WWII:https://en.wikipedia.org/wiki/SIGSALYSo clearly the mathematicians were ahead of the engineers.This is where we are at ~now:

author: LukeW
author_rank: Frequent Contributor
timestamp: June 22, 2015, 06:50:53 pm
content: There are chips like the PT2399 and the Mitsubishi M65830 for audio delay applications such as synchronizing "surround sound", eg. for large-area PA speaker networks.http://sound.westhost.com/project26a.htm

author: dadler
author_rank: Unknown
timestamp: June 22, 2015, 08:29:28 pm
content: PT2399 is a digital delay chip.On guitar pedals, we use analog ICs like the MN3007 BBD, which are true analog bucket-brigade devices.