Crystek claims I've wondered how useful a 100 GHz sampling oscilloscope can be. It's
Probably bragging rights. The cables and connectors will cost a fortune.
Another potentially huge market is automobile Long Range Radar at 77 GHz.
That's my next target after 50 GHz.
BTW, I found another source of 50 GHz cable. Thor Labs is now the cheapest vendor:
I thought you were looking for coaxial cable that needed to pass DC to
50GHz. Automotive radar lives at 76 to 81 GHz where the transmission lines do not need to pass lower frequencies. So, 77 GHz waveguide (WR12) and coax transitions should work. From what I've seen from Ti, there isn't any coax or waveguide being used except in test fixtures and maybe evaluation boards. All the RF is on the same PCB as the antenna array with microstrip transmission lines. However, the array is used for beam forming and steering, where all the transmission lines between the RF sources and antennas must be phase matched. The built in calibration helps reduce the phase matching problem, but doesn't eliminate it. Phase matching is possible on a PCB or machined metal substrate, but far more difficult and expensive for individual coax cables or waveguides at the level of precision needed. 77GHz = 3.9mm wavelength where 1 degree = 0.01 mm = 10 micrometers or microns Therefore, I don't think you'll see any coax cables running at 77 GHz in auto radar products.Reminder: RF is magic.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
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Only in the Arthur C. Clarke sense that any sufficiently advanced technolog y is indistinguishable from magic until you have mastered the technology.
Somebody who wanted a transmission line section whose length could be smoot hly varied over 3.9mm with a resolution of better than 10 microns could get one made if they had access to sufficiently skillful and ingenious mechani cal engineers and decent machine tools. The prototype might not be cheap, b ut the unit price would depend on production volume, and cars are made in h igh volume.
-- Bill Sloman, Sydney
othly varied over 3.9mm with a resolution of better than 10 microns could g et one made if they had access to sufficiently skillful and ingenious mecha nical engineers and decent machine tools. The prototype might not be cheap, but the unit price would depend on production volume, and cars are made in high volume.
I don't think you'd need Arthur Clarke for that... Just (very precisely) control the temperature. Problem solved. :)
I mean, once you got it close.
I beg to differ on two counts.
Nobody wants that. They want the transmission lines to be phase matched as close as possible to each other. That doesn't mean just cut to identical lengths but also to compensate for variations in coax dielectric constant. I once helped design the AN/SRD-21 homing direction finder where two lengths of 150ft of RG-58c/u had to be phase matched to less than 1 degree at VHF frequencies (121.5 and 156-163MHz). I made the capital mistake of assuming the consistency of the coax cable over such long lengths. I eventually got it right, but it wasn't easy. That was at 150 MHz and I don't want to even think about what it would take to match coax cables at 77 GHz.
The prototype is never cheap. Yes, high volume would reduce cost. However, it's cheaper to just etch the interconnecting antenna cables onto a PCB and find tune it with phase shifters on the RADAR chip. For example, how does $0.10 per PCB in volume quantities sound? Nice of JYCPCB to post their customers products for public inspection and dissection. Can you beat $0.10 per PCB with coax cables in any volume level? I don't think so.
Incidentally, the antennas in the above photo are arranged as 4 transmit and 3 receive channels. The upper antennas are receive, while the lower are transmit. The reflected receive signal is weaker than the transmit signal and therefore requires a larger antenna with more gain. When installed in the automobile, the PCB is mounted vertically, with the "tips" of the antennas pointed upward. There is probably a ground plane reflector buried in the PCB or mounted behind the PCB to give additional gain and isolation. Here's one such antenna for 2.4GHz:
More 77 GHz antennas: I don't see any coaxial cables.
So, where's the magic? In my limited experience, it's in the final tweaking of the antenna design and layout after the computer simulations have done their best at getting it close. However, close is not good enough and tweaking is usually required. When the prototypes arrive, more tweaking. When the boards hit production, even more tweaking. The magic is knowing what to and where to tweak.
It's not enough to rub the magic lantern and wait for the genie to provide the answers. You sometimes have to sniff the lantern fumes and provide the answers yourself.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Mix it down very close (1-10 cm) to the probe tip with a 75 GHz local oscillator (LO) so you can use coaxial cables to carry a few GHz signal to the actual instrument.
Use multiple mixer with a common local oscillator and use multiple coaxial cables. If the LO path length to individual mixers are made slightly variable, it can be used to compensate for the variations in the signal path.
moothly varied over 3.9mm with a resolution of better than 10 microns could get one made if they had access to sufficiently skillful and ingenious mec hanical engineers and decent machine tools. The prototype might not be chea p, but the unit price would depend on production volume, and cars are made in high volume.
IIRR the HP laser interferometer used that technique to keep the length of it's laser tube exactly right - the wavelength of the laser light was some
632.8 nm (and I used to know it to ten digits) and if it moved much the las er would be resonant at a slightly different wavelength.-- Bill Sloman, Sydney
Very good info. Thanks.
My interest is in test fixtures where I definitely need coax. 50 GHz is just a stepping stone.
I'm interested in broadband DC to 80 GHz. I think I've come across some VNA's and spectrum analyzers that can do that (except for DC).
to 110 GHz:
It just takes money. So do corporate jets.
I found a new source for 50 GHz cables. Thor Labs:
TMM4 Microwave Cable, 4" (102 mm) $100.79
TMM8 Microwave Cable, 8" (203 mm) $111.39
TMM12 Microwave Cable, 12" (305 mm) $122.00
TMM24 Microwave Cable, 24" (610 mm) $153.83
TMM36 Microwave Cable, 36" (914 mm) $185.66
Datasheet
With prices like these, it doesn't make sense to buy used cables on eBay. You have no idea if the cable has been damaged, or the connectors have been abused.
Another problem is overtorquing the connectors. Brass needs 6 inch-oz, and stainless needs 8 inch-oz. The torque wrenches run $218.59 at Thor Labs:
If you need both, you are in for $437.18. That's expensive.
I found a supplier for a torque wrench for 2.4mm coax that is adjustable and can do both for US $19.71. Search eBay for item number 123971832152.
Calibrating a torque gauge is trivial. There are many methods. See
The big market for 100 GHz scopes is probably telecom, so the input would be optical fiber. Bang it with a femtosecond optical pulse, get the impulse response, and synthesize a digital filter to clean up the step response.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
All it takes is money.
They do have a 1mm 100 Ghz coax input. see page 21
The people designing internet backbone gear, or cell towers for 5G, can afford megabuck scopes.
Rigol is up to 2 GHz now. I remember when a 30 MHz scope cost as much as a new Ford, and a sampling head cost a new Jaguar.
Funny: I googled Rigol oscilloscope and the first thing I saw was an ad by Tek.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
You are right. The Tektronix 547 50 MHz scope cost $2,500 in 1968:
The average price of a new car was $2,822:
I was at MIT playing with Tek 453 scopes:
Pretty obvious, really: don't exceed 30Mhz. :)
-- No deal? No problem! :-D
fredag den 24. januar 2020 kl. 20.50.05 UTC+1 skrev John Larkin:
That's what mathematicians call a trivial solution.
-- Bill Sloman, Sydney
More like a stumbling block. You're likely to have a difficult time keeping up as the FCC moves from auctioning off everything in sight to auctioning off bands that are well out of sight. Are you ready for
3THz? Don't worry, because nobody else is either: 300GHz to 3THz signals are at or under 1 millimeter in wavelength, and for that reason called "submillimeter waves." I guess the article author, the FCC, or both don't know about micrometer and nanometer wavelengths.
Only $17,885 to start.
Notice that both RF heads in the cover photo have a length of waveguide exposed. I couldn't find a block diagram of the R&S ZVA 110 VNA, so I don't really know what the waveguide is doing. My wild guess(tm) is that they are down-converters similar to: Click on the "models" tab. 50-75GHz and 75-110GHz which might explain why the photo shows to RF heads.
Looks like the ZVA 110 also comes in various frequency ranges: R&S ZVA 8: 300 kHz to 8 GHz R&S ZVA 24: 10 MHz to 24 GHz R&S ZVA 40: 10 MHz to 40 GHz R&S ZVA 50: 10 MHz to 50 GHz R&S ZVA 67: 10 MHz to 67 GHz R&S ZVA 110: 10 MHz to 110 GHz Looks like "DC" is 10 MHz for this product and that you're not going to see DC to light in one giant sweep via one 1mm coax cable. I'm not sure, but I think you'll need to change RF heads (down-converters). Looking at the different models, my guess(tm) is that the basic VNA has 8 GHz bandwidth, and everything else is downconvereted in 8 GHz blocks. Just a guess(tm).
Agreed. I worked for a few companies in the past, who failed to appreciate the value of decent test equipment. I had a difficult time getting a management to sign off on purchasing a spectrum analyzer. Borrowing one from production was becoming rather awkward. So, I built a life size cardboard model of the spectrum analyzer that I wanted and covered the front and sides of the box with enlarged color photos of the real unit. With probes, power cords, and a few flashing LED's, I conspicuously planted it on my lab workbench and waited for management to notice.
Nothing happened for about a week when the "suits" suddenly arrived. There was some discussion for about 15 minutes, after which everyone simply left. I thought I had failed, when the VP of engineering arrived with a blank purchase order request form and demanded that I drop everything and fill it out before he changes his mind. The spectrum analyzer arrived about 3 weeks later.
Money is nice, especially when supported by self-promotion, corporate politics, and of course, magic.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
My only experience in the > 1GHz range involved waveguide.. mostly Ku band (13 GHz) a little Ka...the Ka stuff was smaller and cuter. I don't see much waveguide these days...
George H.
Mindreader! I have been looking for that exact video, but I would never have found it. I was looking in the eevblog forum instead of TSP. Many thanks.
Related:
Infiniium UXR-Series Datasheet:
TSP #45 - Experiments & Teardown of the Teledyne-LeCroy LabMaster 10-100zi
100GHz Oscilloscope, $1 Million, Feb 9, 2015:Labmaster 10-100zi Datasheet:
Anritsu Introduces 145 and 170 GHz Spectrum Master Ultraportable Spectrum Analyzers to Address Emerging Millimeter-wave Applications:
Bandwidths are rising. We need scopes that can keep up.
LOL! Thanks.
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