My first ever engineering job was at a company that made RF over fibre optic equipment. If you've ever watched satellite TV, or driven through a tunnel and still had GPS signal, the RF signal for that was probably passed over a fibre optic. Since they support frequencies of over 4GHz it's all done totally analogue - the laser amplitude is modulated by the RF itself. Somehow, it works.
That can't possibly work for GPS. You've fixed the relative timing delays of the various satellites to be equal to what they are at the RF recieving station so your GPS should always say you are at the location of the radio receiver. Or is that good enough here?
not to be confused with the other RF over fibre optic, where you send an RF signal and it somehow ends up at the other end just like visible/near visible light would. Magic
Hey joeofloath , I need some help with this optical transmission through rf thing , what's the best thing I can do to learn , and any Elmer's into this type of thing.
Love it. One idea I had to work around the retimer - modulate the TOSLINK signal with OOK (or more generally, FSK) so you have a carrier signal of several MHz that would be in spec for those devices.
@@flyinginthedark6188 "On the wire" is very subjective. Standard TOSLINK doesn't even run on the wire - it's modulated onto an optical signal, and that optical carrier itself already has some frequency.
In some subway systems, mobile phone reception is implemented by having the RX/TX equipment in some cabinet, and then the tunnel just has dumb antennas that receive/relay the signal they see via fiber optics. That's done because maintenance in the tunnel would be too hard, or there is no space. Berlin has such things. Probably there are some old one sold off at some time?
remote radio heads are really common these days. It's also convenient for antennas on buildings, since it allows you to put a lot of the stuff in a box outside the building on the ground (or inside but more accessible than on the roof), run power and high speed data up to the remote heads and antennas. Means you have to put people on the roof a lot less often, and the distance from RF Frontend to antenna is minimized, which is especially critical for 5G FR2 (which should never have been deployed anyways but that's a different topic)
There's no discrete antennas in the excellent Prague metro coverage but a leaky cable, a coax cable with slits in the sheathing running between the stations
In general in tunnels they use a leaky coaxial cable with cuts in the outer shell, one cable can be used for multiple frequencies at the same time, and this also works in turn's
Hey all the smart people on this comment thread , where can I learn this stuff , or something like that , I got a pred problem in my area and I have a idea on what to do . But need to learn some more or have someone to talk to when I can't figure stuff out , like I'm experimenting with my hack rf and GNU and forgot how to activate my hackrf 😂 , I did have it working and now when I made my own flow I can't remember what I did to get it working on the script I deleted already 😢😢😢
I'd imagine the EEPROMs existed primarily as a simple and mandatory thing to store info on the module's capable link speeds. Then people like Cisco likely thought up of using extra space for vendor info.
Yeah, the thing about YOLOing FM is that the first thing almost any modern FM receiver does (after the frequency discrimination) is to put the input signal into an AGC and then amplify it up until it's a nice square wave so that it can just count the zero crossings. So if your medium is turning it into a square wave for you... it's not really that bad.
There are Optical Talk Sets available, meant for installation technicians. They do voice over single mode fiber. Not sure if they do Ethernet like encoding, some digital mode or analog audio in AM/FM. This is even less bandwidth than TOSLINK.
Cool experiment! I work with Fiber daily and know how niche it is. Glad to see fiber content on YT! You can do really cool stuff with fiber optics. Thinklogical has the most impressive devices and solution applications in my opinion (but im biased). It's insane to play with raw uncompressed 8k video over 0.5km over OM4 or 100km over OS2 where the delay is only perceivable on the nano/micro level. Not to mention how MM is nearly indestructible now and the crazy stuff in R&D.
I was recently looking into this for a thing to help me and my entrepreneurs find the correct fiber. We have our own (as in my employer) fiber network with the longest being 100km. We have almost no WDM, and we have no amplifiers. Everything that is not used is dark fiber and available for lab 🙂 This really got me excited.
I built something similar to this... for FTTH tracing. At the moment im using a cheap SFP switch with 8 ports.. but wanted to cost-optimize it by using a low cost microcontroller or similar and use 1Mbps or something similar to send "IDs" down the fiber. I was using bidi-optics so you can test strand by strand..
Just as a side note: FM over optic is quite doable. I've worked in the field myself, distributing a mix of QUAM256 CableTV and FM Radio over up to 100km of fiber. After 100km the signal gets kinda mushy due to dispersion and after 150km it's definitely game over. But it works. And quite good I might add. It's a really easy way to distribute TV over large networks, which is why they use it everywhere. Also keeps the traffic off the infrastructure, our QUAM256 signal had the equivalent of 3GBit's of data in it!
TOSLINK maxes out at 125 mbit/s. They just don't allow it in consumer stuff because studios think people are going to be ripping DTS-HD and Atmos audio from it (even though MakeMKV exists).
That's a lot of Mbit/s to be making with an LED. Just because professional equipment exists that can do it doesn't mean consumer equipment is physically capable of doing that, apart from being restricted by logic and arbitrary limitations. Optocouplers often top out at like 150 khz.
@@timramichSome situations between a pure consumer space and high end professional space would really benefit from that kind of toslink compatibility, like low budget pro audio in small clubs/venues. Behringer's line of x32 mixers use AES50 over shielded cat 5. Traditionally this is been a weak point in many low end professional audio setups. For some reason nobody has been able to really figure out so far, Even though the mixing consoles use regular ethernet transceivers on the AES ports, It is imperative that the shield along the cable is terminated onto the metal sleeve of the ethercom connector at both ends of the cable. This is contrary to the standard implementation where the shield is terminated at one end of the cable only. All of this weird electrical compatibility nonsense would have been a non-issue had they just gone with an LED blinking into a glass tube. Or Barringer could have just put the same transceivers that they put into the Midas m32 consoles that work over standard unshielded cat 5 just fine But I guess that would make the x32 cost more??
Speaking of dailup over fibre, work (an electrified railway) runs low speed serial over fibre links (I assume with a handful of abstraction layers) because while the speed is over kill it makes life much easier from an efi and electrical perspective.
A student radio at Lodz University of Technology used this technology around 2006 as their STL (studio-transmitter-link). No SFP's back then - they used an old set of MDX 10Mbit mediaconverters as the base if I recall correctly. It could have been ADAT actually...
If there's a small amount of people in the game, the missing and misleading chip markings aren't doing anything to confuse each other, they all know exactly what everyone else is doing. This is predominantly a barrier to a new guy coming along and going "i can do same thing but cheaper".
I would suggest Teletype as a good candidate for wasting bandwidth (well and its already digital!). Transatlantic is demanding as EU used to use 50Bd Teletype where US used 45.45Bd (synchronized to mains frequency)...
In reality, it could be possible to see gravity waves with those signals on optical wires. They shift in time, when a big enough gravity wave hits the earth.
he should hook up some vintage manual Morse key to the transatlantic optical cable and have someone on the other end listen to the Morse code signal with a vintage speaker/headphone and manually decode the URL to the particular music video
I don't know if this was just dumbed down on purpose, or if there is a fundamental lack of understanding. Multimode uses LEDs. It bounces the light off the walls with total internal reflection. Singlemode uses lasers (coherent light). The thinner core and coherent light mean the light travels straight through the fiber. It does not get transmitted via total internal reflection (until the fiber is bent below its minimum bend radius, but that's not normal mode of operation).
@@timramich ok , do you have a recommendation how to learn this stuff, this could be used for any signal , could you see the different frequency range or pick up stray transmissions .
Your simplification is as wrong as the one you are trying to correct. Single mode vs multimode has nothing to do with the sources. If you shine any light into a single mode fiber, it will still transmit just a single mode, because electromagnetically this is the only mode that can propagate. Modern multimode will also often use lasers because its too much of a pain in the ass to modulate LEDs at 25 gigabit.
The production of this convention is just flawless...
My first ever engineering job was at a company that made RF over fibre optic equipment. If you've ever watched satellite TV, or driven through a tunnel and still had GPS signal, the RF signal for that was probably passed over a fibre optic. Since they support frequencies of over 4GHz it's all done totally analogue - the laser amplitude is modulated by the RF itself. Somehow, it works.
That can't possibly work for GPS. You've fixed the relative timing delays of the various satellites to be equal to what they are at the RF recieving station so your GPS should always say you are at the location of the radio receiver.
Or is that good enough here?
@petergerdes1094 that's good enough - it's used more for timekeeping than for location. Lots of road and rail systems use GPS for time sync.
not to be confused with the other RF over fibre optic, where you send an RF signal and it somehow ends up at the other end just like visible/near visible light would. Magic
@@petergerdes1094 Nerds fact-check Commentors! 8-D
Hey joeofloath , I need some help with this optical transmission through rf thing , what's the best thing I can do to learn , and any Elmer's into this type of thing.
Toslink or FM-over-long-haul-fibre loop echo guitar pedal when? Like a tape loop echo, but with flashy lights!
Love it. One idea I had to work around the retimer - modulate the TOSLINK signal with OOK (or more generally, FSK) so you have a carrier signal of several MHz that would be in spec for those devices.
But then it won't be toslink on the wire anymore, so you can't claim the world record for this
@@flyinginthedark6188 "On the wire" is very subjective. Standard TOSLINK doesn't even run on the wire - it's modulated onto an optical signal, and that optical carrier itself already has some frequency.
In some subway systems, mobile phone reception is implemented by having the RX/TX equipment in some cabinet, and then the tunnel just has dumb antennas that receive/relay the signal they see via fiber optics. That's done because maintenance in the tunnel would be too hard, or there is no space. Berlin has such things. Probably there are some old one sold off at some time?
remote radio heads are really common these days.
It's also convenient for antennas on buildings, since it allows you to put a lot of the stuff in a box outside the building on the ground (or inside but more accessible than on the roof), run power and high speed data up to the remote heads and antennas. Means you have to put people on the roof a lot less often, and the distance from RF Frontend to antenna is minimized, which is especially critical for 5G FR2 (which should never have been deployed anyways but that's a different topic)
There's no discrete antennas in the excellent Prague metro coverage but a leaky cable, a coax cable with slits in the sheathing running between the stations
In general in tunnels they use a leaky coaxial cable with cuts in the outer shell, one cable can be used for multiple frequencies at the same time, and this also works in turn's
That's just how cell had been done since 4g. The BBUs are put in a rack and the RRHs get power and fiber and just output the rf signal.
Hey all the smart people on this comment thread , where can I learn this stuff , or something like that , I got a pred problem in my area and I have a idea on what to do . But need to learn some more or have someone to talk to when I can't figure stuff out , like I'm experimenting with my hack rf and GNU and forgot how to activate my hackrf 😂 , I did have it working and now when I made my own flow I can't remember what I did to get it working on the script I deleted already 😢😢😢
I'd imagine the EEPROMs existed primarily as a simple and mandatory thing to store info on the module's capable link speeds. Then people like Cisco likely thought up of using extra space for vendor info.
Yeah, the thing about YOLOing FM is that the first thing almost any modern FM receiver does (after the frequency discrimination) is to put the input signal into an AGC and then amplify it up until it's a nice square wave so that it can just count the zero crossings. So if your medium is turning it into a square wave for you... it's not really that bad.
Laser Disc stored the signal as digitally stored FM. Same pits and lands style as CDs, but for storing a analogue signal.
What a great talk.
absolutely wild. I just started digging into this a few weeks ago. I hope he will publish more technical details so I can reproduce this!
There are Optical Talk Sets available, meant for installation technicians. They do voice over single mode fiber. Not sure if they do Ethernet like encoding, some digital mode or analog audio in AM/FM. This is even less bandwidth than TOSLINK.
Cool experiment! I work with Fiber daily and know how niche it is. Glad to see fiber content on YT!
You can do really cool stuff with fiber optics. Thinklogical has the most impressive devices and solution applications in my opinion (but im biased). It's insane to play with raw uncompressed 8k video over 0.5km over OM4 or 100km over OS2 where the delay is only perceivable on the nano/micro level. Not to mention how MM is nearly indestructible now and the crazy stuff in R&D.
I was recently looking into this for a thing to help me and my entrepreneurs find the correct fiber. We have our own (as in my employer) fiber network with the longest being 100km. We have almost no WDM, and we have no amplifiers. Everything that is not used is dark fiber and available for lab 🙂
This really got me excited.
I built something similar to this... for FTTH tracing. At the moment im using a cheap SFP switch with 8 ports.. but wanted to cost-optimize it by using a low cost microcontroller or similar and use 1Mbps or something similar to send "IDs" down the fiber. I was using bidi-optics so you can test strand by strand..
@garci66 I want to be able to generate 270Hz, 1KHz, 2KHz for example. Then I could id fibers without unplugging patch cords.
This was a really fun video!
Kindof disappointed there wasn't a toslink over transatlantic fiberoptic cable section in there.
Didn't you watch until the end on why this is most likely not possible these days?
Excellent presentation, engaging, interesting and funny!
NSA: “what weird signal is this?”
Definitely UTP
Just as a side note: FM over optic is quite doable. I've worked in the field myself, distributing a mix of QUAM256 CableTV and FM Radio over up to 100km of fiber. After 100km the signal gets kinda mushy due to dispersion and after 150km it's definitely game over. But it works. And quite good I might add.
It's a really easy way to distribute TV over large networks, which is why they use it everywhere. Also keeps the traffic off the infrastructure, our QUAM256 signal had the equivalent of 3GBit's of data in it!
This is definitely one way to send mixed signals via fibre optic cable :D
TOSLINK maxes out at 125 mbit/s. They just don't allow it in consumer stuff because studios think people are going to be ripping DTS-HD and Atmos audio from it (even though MakeMKV exists).
Which is endlessly frustrating. I would really love to TOSLINK all of the things in my audio setups.
@javaguru7141 I think HDMI put a nail in its coffin. The market largely said it wanted one cable for everything.
That's a lot of Mbit/s to be making with an LED. Just because professional equipment exists that can do it doesn't mean consumer equipment is physically capable of doing that, apart from being restricted by logic and arbitrary limitations. Optocouplers often top out at like 150 khz.
@@SianaGearz Meanwhile SFP28 optics are doing 25 gigabits with LEDs.
@@timramichSome situations between a pure consumer space and high end professional space would really benefit from that kind of toslink compatibility, like low budget pro audio in small clubs/venues. Behringer's line of x32 mixers use AES50 over shielded cat 5. Traditionally this is been a weak point in many low end professional audio setups. For some reason nobody has been able to really figure out so far, Even though the mixing consoles use regular ethernet transceivers on the AES ports, It is imperative that the shield along the cable is terminated onto the metal sleeve of the ethercom connector at both ends of the cable. This is contrary to the standard implementation where the shield is terminated at one end of the cable only. All of this weird electrical compatibility nonsense would have been a non-issue had they just gone with an LED blinking into a glass tube. Or Barringer could have just put the same transceivers that they put into the Midas m32 consoles that work over standard unshielded cat 5 just fine But I guess that would make the x32 cost more??
Had to check the playback speed settings.
We need to get acoustic couplers working through optic lines!
Speaking of dailup over fibre, work (an electrified railway) runs low speed serial over fibre links (I assume with a handful of abstraction layers) because while the speed is over kill it makes life much easier from an efi and electrical perspective.
Cars also prefer MOST for all sorts of things for two reasons, EMI resilience and weight, that plastic optic fibre weighs a LOT less than copper.
A student radio at Lodz University of Technology used this technology around 2006 as their STL (studio-transmitter-link). No SFP's back then - they used an old set of MDX 10Mbit mediaconverters as the base if I recall correctly. It could have been ADAT actually...
If there's a small amount of people in the game, the missing and misleading chip markings aren't doing anything to confuse each other, they all know exactly what everyone else is doing. This is predominantly a barrier to a new guy coming along and going "i can do same thing but cheaper".
They make LVDS experimenter boards, I have always wanted to get one to drive an SFP+ but never have the time...
Someone needs to make a tier of rickroll 😂 at this point to put more effort in we’d need to carve a giant scale LP into the Martian soil.
If toslink works, I wonder if ADAT would? It's higher data rate, but uses the same cables.
I would suggest Teletype as a good candidate for wasting bandwidth (well and its already digital!). Transatlantic is demanding as EU used to use 50Bd Teletype where US used 45.45Bd (synchronized to mains frequency)...
That was a funny one!
Gravity waves, shift every signal sligtly in time!
In reality, it could be possible to see gravity waves with those signals on optical wires. They shift in time, when a big enough gravity wave hits the earth.
So if you really want, you can very easily replace toslink with just fiber and sfp on both ends
What? No discussion about EDFA vs Raman optically pumped amplifiers?
PTP master clocks in SFP
he should hook up some vintage manual Morse key to the transatlantic optical cable and have someone on the other end listen to the Morse code signal with a vintage speaker/headphone and manually decode the URL to the particular music video
should have tried with DAT signal from pro audio equipment...
RFO: some customer was trying to send toslink over a dark fiber...
I don't know if this was just dumbed down on purpose, or if there is a fundamental lack of understanding. Multimode uses LEDs. It bounces the light off the walls with total internal reflection. Singlemode uses lasers (coherent light). The thinner core and coherent light mean the light travels straight through the fiber. It does not get transmitted via total internal reflection (until the fiber is bent below its minimum bend radius, but that's not normal mode of operation).
This is quantum entanglement basically, I need some help learning this , anyone know any Elmer's.
@medude1987 It has nothing to do with anything quantum. This is all wave-based stuff, not particles.
@@timramich ok , do you have a recommendation how to learn this stuff, this could be used for any signal , could you see the different frequency range or pick up stray transmissions .
Your simplification is as wrong as the one you are trying to correct. Single mode vs multimode has nothing to do with the sources. If you shine any light into a single mode fiber, it will still transmit just a single mode, because electromagnetically this is the only mode that can propagate. Modern multimode will also often use lasers because its too much of a pain in the ass to modulate LEDs at 25 gigabit.
@JorenVaes Pain in the ass to modulate an LED that fast 🤣 even though a laser diode starts as an LED 🤣
I wonder if we could send morse code down the fibre......
Why wonder?
@kreuner11 because Morse code would be the lowest possible bitrate way to send data, so it would be funny.
@@varno no, not sending anything at all would be the lowest possible bitrate of 0 bits per infinite time
@@gorak9000that's cheating though, you have to send _something_ for it to count :D
Morse code is easily learned. This young chap is obviously from another dimension to normal people.
this is funny
Its 62,5 um not 62um
Multimode sfp modules are cheapter than single mode modules.