Delay line memory

Followup to EEVBLOG's vid on glass ultrasonic delay lines:
• EEVblog #381 - How Do ...
Including storing 32 bits of data with a TV PAL delay line and a few HCMOS gates - memory 1950s style!

[@souzzzzza]

It's because of things like this that i love electrical engineering. Thanks for the video.

[@ET_AYY_LMAO]

Thanks for actually showing the delay line in use! Really amazing!

[@gilgameshismist]

I learned more in the first 5 minutes of this video than in the whole 30 minutes of rambling from the other guy.. Thanks Mike!

[@AntiProtonBoy]

Early calculators also used torsion mode memory, where you have coil of wire, and you send shock waves into the loop (via a torsion force), only to emerge on the other end after some delay. See Monroe Epic 3000 calculators for an example.

[@elboa8]

Thanks Mike. I worked on these for years and never bothered to find out what was happening inside the "glass" block. Very interesting..

[@jjhamblett]

Thanks Mike. You seem to have a natural ability to explain how things work that anyone can follow.

[@joshuaharlow4241]

I have heard an explanation of delay line memory before.... I "got it"... but now I really can "wrap my head around it". Thanks for taking the time to build that up and show us the concept in action. Keep it up!!!

[@nathantrigg5399]

This is the 3rd video on delay line's l've watch. (The best) Thanks for that.

[@Dibblah1900]

As always, very interesting, well explained, in-depth coverage of a subject! Thank you!

[@NanoCottage]

A great explanation, always wondered what they were used for and how they worked.

[@ProtectionDirect]

I have no idea what you're talking about but I've been watching your videos for the last 3 hours. Amazing stuff.

[@DarkInsanePyro]

Thanks Mike for the awesome video. Really enjoyed the attempt at memory implementation at the end.

[@Mark19960]

Excellent Mike. In 20 years servicing consumer electronics where these were used like VCRs and cameras I have actually seen one of these go bad.... the customer dropped their camera and did not obvious damage but they did actually manage to break a delay line.. obviously no fault of the delay line. Other than that they would probably last forever.

[@DJignyte]

That is really cool! Thanks for taking the time to do these video's, Mike. They're quite detailed and rather interesting, keep it up!

[@ZeedijkMike]

It might not have any practical use today but it's still very impressive to see it working.

[@ExStaticBass]

Really cool lad... I would have never thought to use a TV delay line as memory like that or dreamed it would be so stable. I'm glad I subscribed a while ago. I would have missed this...

[@whitcwa]

Imagine how hard it was to build the first oscilloscopes!

[@douro20]

Old electronic desktop calculators often used wire delay lines, which can store more data than a glass delay line.

[@Derundurel]

I'd wondered about that too. Thanks for demonstrating and making it public.

[@CassetteMaster]

Very interesting. I have seen these in old VCRs I took apart and wondered how they worked and what the heck they were!

[@ickipoo]

Another excellent exploration, Mike. Thankyou. Two thumbs up.

[@1ManWrenching]

Absolutely epic demonstration!

[@latasha66]

analog error masking... pure genius.

[@sysmatt]

Incredible Mike! A really great demo. Thanks

[@whitcwa]

The epoxy keeps the waves from spreading out too far by dampening the acoustic waves in areas they shouldn't go. I have replaced many which were used in pro video cameras to create a vertical detail circuit. They had cones etched into the glass (on both sides) where the epoxy dots are. They were also used in NTSC TVs for comb filters and in SECAM TVs for line memory.

[@PodeCoet]

I just read about delay lines the other day, brilliant video!

[@azyfloof]

You've basically made an analogue shift register, sending the output back into the input. Bloody clever! :D Mike mike mike mike.

[@FrankenPC]

THANK YOU! I was just wondering about interference after seeing EEVBLOG's video.

[@gamccoy]

That was a brilliant video. Well done!

[@anthonyj777]

Fascinating stuff! Thanks for the video.

[@TheCrazyInventor]

Good demonstration, thank you for taking the effort to show us. :)

[@shitheadjohnson2797]

adding the computer logic that is reading and writing from it, is the bit that most people dont bother with give up and get an arduino.

[@RandomInsano2]

This is great. Thanks again Mike.

[@Quazzie78]

Fantastic detail and a very interesting use case! Thanks!

[@RamLaska]

Awesome sauce! Fantastic work!!!

[@erlendse]

Really neat, you do a nice job of showing how it works :) I just hope you take the memory idea a bit forward, possible with many delay-lines in series, including drivers e.t.c.

[@Jyaif]

This is so insanely cool

[@truhlikfredy]

MIKE MIKE MIKE MIKE MIKE xD I love it. Can' help every time yours videos are so much more interesting than Daves.

[@mikeselectricstuff]

You'll find one in old PAL TVs, and also some VCRs

[@flatfingertuning727]

Have you tried using a circuit to latch and regenerate pulses? Perhaps use an edge-triggered flop clocked either by the chroma subcarrier or a divided-down version thereof, and feed that through a sequence of four NAND gates, the first two of which take input from a external logic, the third of which accepts chroma subcarrier, and the last of which is simply an inverter? It may be necessary to tweak the timing of the flop to ensure it samples each wave near the peak, but I would think it should be possible, and not overly difficult, to make the circuit so that it could circulate data indefinitely, and it would be interesting to see how many bits it could reliably store. If that worked, it might be interesting to modify the project a little more to implement something like a binary counter or other such logical function.

[@robstorms]

Fantastic Mike !!!

[@nbsr1]

Yup. As much as I like Dave's videos, Mike is in a different league.

[@jix177]

Very good follow up. Thanks for sharing!

[@lolman2008112]

fascinating video, i now understand delay lines...cheers mike!

[@aidanppp]

Good stuff Mike!

[@mikeissweet]

Phenomenal!

[@Jenny_Digital]

@mikeselectricstuff Excellent demonstration. Just one thing though... Do I detect a little bit of sport between you and Dave Jones?

[@mikeselectricstuff]

Minmal effect - hard to hit it at 4.43MHz. Fingers do damp it a bit

[@aptsys]

Indeed, this is proper knowledge rather than Dave's scrambling around on the internet for buzzwords and vague descriptions enough to keep most people happy... ;-)

[@lordchavo]

Actually, truth be told, more interesting than Dave's version :) It's like the continuation, which holds the best part !

[@flubba86]

That was awesome!

[@cos6255]

Nice work!

[@dontbe]

Please remember to tell him its located in a rectangular black plastic box that stands up off the board... you dont see the glass until you open it up!

[@oldevil]

I like your follow up on Daves video, only too bad some viewers are bringing Dave down by saying his videos are boring too long, what are these dad people?I love seeing Daves videos

[@icesoft1]

I was hoping Dave would have done this, but that seems to be more than he'd prefer to screw with. This seems very similar to the old reverb units that used actual springs to presumably get the delay and then fed back into the input through a resistor to get the decay? Is this correct?

[@DIYTAO]

Hi, nice explanation and demo circuilt. Do you have any schematics of the circuilt?

[@Dustycircuit]

Does anyone know a partnr (or link to a store/eBay) for one of the old delaylines Mike was mentioning in the beginning? It would be interesting to do some experiments with. Cheers and thanx for an interesting video Mike!

[@wareb321]

You are a wizard!

[@aliabedi6282]

Do you know what the maximum frequency these delay lines support is? Probably we have to get rid of the long leads.

[@JurekOK]

in the memory case, since you are continously amplify the echo, why does it disapear after several miliseconds? i understand it could get distorted, but why disapear completely? or maybe you are not feeding it back but only reading multiple reflections?

[@technobabble_]

Could you tell us a bit more about the epoxy they put on the glass and what it does and how?

[@jpsousa4]

awesome oscilloscope. what kind is that?

[@Ju00Ls]

Very interesting! many thanks

[@CostaExtranjero]

I wonder how stable would be a clock generator based on a delay line and what would be it's tempco and if it is indeed that low if it could be used to correct the tempco of a crystal...

[@jabramow]

Amazing

[@0MoTheG]

I am sure you could store much more than 64 bit using the proper modulation. Certainly no less than 128 bit assuming only a SNR of 0 dB and 2 MHz usable bandwidth. But likely more than 512 bit.

[@HDXFH]

Cool I got a few of them!!

[@helicoptered]

Yeah, a few... it could be the Mi from Mike and related computer keywords used.. :)

[@nrdesign1991]

7:50 what would happen to the data if you hit the delay line? like snapping a finger against it

[@Tjousk]

Well explained, thanks (:

[@jjoster]

bravo

[@olivercoles87]

Great, thanks!

[@SeanBZA]

How about a spring reverb line, I have one knocking around.

[@paulbendel]

Cool!

[@helicoptered]

Who is dave userbame please?

[@Dustycircuit]

Just found guy on eBay who had a couple. Cheers

[@SuperHddf]

fascinating :::)

[@headsplosive]

eevblog

[@crumplezone1]

Mike have you ever thought about ruling the world ?! :)

[@mikeselectricstuff]

Nope - bored with this now - why don't you try it!

[@aptsys]

Was bored. Now not.