Re: 577 Curve tracer ringing CRT and noisy step generator
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Re: M48Z35-70PC1 NVRAM for CSA803 & 11801 E5622 error
On Thu, Mar 14, 2019 at 09:28 PM, Maurice Smulders wrote: There might be a more elegant solution possible. The problem of battery ram
was discussed at length in the pinball forums, and people made other
solutions for it. Permanent ones. No battery to replace EVER.
For example:
Now, I couldn't find a 32Kx8 variant, but the RAMTRON chip you'd likely
need is the FM1808. Mouser seems to have it in stock, but at a pretty hefty
price, and you'd have to make the breakout board still (JLPCB maybe?)
There seems to be stock on eBay for lower prices from US sellers... I've done exactly this to my 2430A. I've replaced both of the dead Dallas NVRAM chips with Cirrus FM18W08 FRAMs in off-the-shelf SOIC to DIP converters (Aries LCQT-SOIC28), all bought from Farnell in the UK. The conversion works perfectly as far as I can tell, and the scope will never have dead batteries again. One day I might try the same trick on my CSA803A. Chris
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Re: 2247A PSU Troubleshooting
On Thu, Mar 14, 2019 at 03:57 PM, tom jobe wrote: There are about 17 one amp ultra fast diodes that are used to rectify
the low voltages on the secondary side of the transformer. About a dozen
of them are in a row next to the transformer in the middle of the A18
board and they are known to fail especially if they are marked "ZS" or
one other marking which I can't remember. If they are marked ZM or ZS they are well known to get leaky. Replace these diodes with MUR160 600V 1Amp from Mouser/DK.
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Re: Test input for an SD-32 sampling head
Hi, Reg.
Regarding fast pulses and such, there is a wealth of information at Jim
Andrews' page here: He founded
Picosecond Pulse Labs in 1980 and sold it to Tektronix in 2014. I used
PPL products with a CSA803 back in the mid 1990's at Lockheed. I think
the sampling head I used was an SD-24, but since it was about 25 years
ago, my memory is a bit fuzzy.
These days I have a 7904, a 7603, a 7S12, a 7S11, two S-4 sampling
heads, S-53 and S-51 triggering heads, etc in my garage lab. Oh, and a
couple of 10:1 probes I made out of board-edge SMA connectors, 450 ohm
(470 paralleled with 1.8k ohm) 0402 resistors, and 3-pin right-angle 0.1
inch spacing headers. I've not completely characterized the probes, but
at least they pass up to about 12-13 GHz without much attenuation above
the expected 20 dB. Planning to use them to probe some digital RF
boards I'm going to build for work (Raytheon). Too much trouble to try
to get a fast enough sampling scope at work :(
Enjoy the PPL app notes! I've referred to AN-2a through -2e often.
Thanks for the literature references. I'll have to check them out
(someday).
Jim Ford
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------ Original Message ------ From: "Reginald Beardsley via Groups.Io" <pulaskite@...> To: [email protected]Sent: 3/14/2019 6:03:56 PM Subject: Re: [TekScopes] Test input for an SD-32 sampling head I have one of Leo's 100 pS impulse units as a source for initial experiments. If I can narrow that to 10 -20 pS with discrete SMD parts I may be able to get the idea to work. There's a close connection to the Hilbert operator hiding in there somewhere.
I've been reading an excellent book on FPGA implementation of DSP by Roger Woods et al most of the afternoon. So I've not started on the dissertation yet. I can't really say much else until I understand the mathematics and physics of using the reverse biased diodes as capacitors. That should keep me entertained for a few weeks at least.
In any case, failure doesn't matter. It's a hobby project, not a client deliverable. I've been fascinated by the problem of getting a fast rise time edge for a long time. It's a bit of circular logic. My excuse for doing it is I bought an 11801 and my excuse for buying the 11801 is so I could try to do it. If I can narrow the 100 pS pulse by 5x I'll have an excuse to buy an SD-32.
I spent 3 years studying sparse L1 pursuits using "A Mathematical Introduction to Compressive Sensing" by Foucart and Rauhut as a text followed by reading the original papers by Donoho, Candes et al. Beats the hell out of watching television. I just wish I could find someone else who was interested in the subject to discuss it with. It's quite amazing what you can do with sparse L1 pursuits and really easy to do in practice. Understanding the math is not easy, but most people use FFTs without really understanding them.
Have Fun!
Reg
--- This email has been checked for viruses by AVG.
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Re: Test input for an SD-32 sampling head
Picosecond pulse labs used to sell NLTL's for pulse sharpening amonst other applications.
NLTLs are still commercially available.
Bruce
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On 15 March 2019 at 14:03 "Reginald Beardsley via Groups.Io" <pulaskite@...> wrote:
I have one of Leo's 100 pS impulse units as a source for initial experiments. If I can narrow that to 10 -20 pS with discrete SMD parts I may be able to get the idea to work. There's a close connection to the Hilbert operator hiding in there somewhere.
I've been reading an excellent book on FPGA implementation of DSP by Roger Woods et al most of the afternoon. So I've not started on the dissertation yet. I can't really say much else until I understand the mathematics and physics of using the reverse biased diodes as capacitors. That should keep me entertained for a few weeks at least.
In any case, failure doesn't matter. It's a hobby project, not a client deliverable. I've been fascinated by the problem of getting a fast rise time edge for a long time. It's a bit of circular logic. My excuse for doing it is I bought an 11801 and my excuse for buying the 11801 is so I could try to do it. If I can narrow the 100 pS pulse by 5x I'll have an excuse to buy an SD-32.
I spent 3 years studying sparse L1 pursuits using "A Mathematical Introduction to Compressive Sensing" by Foucart and Rauhut as a text followed by reading the original papers by Donoho, Candes et al. Beats the hell out of watching television. I just wish I could find someone else who was interested in the subject to discuss it with. It's quite amazing what you can do with sparse L1 pursuits and really easy to do in practice. Understanding the math is not easy, but most people use FFTs without really understanding them.
Have Fun!
Reg
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Re: M48Z35-70PC1 NVRAM for CSA803 & 11801 E5622 error
Reg,
There might be a more elegant solution possible. The problem of battery ram
was discussed at length in the pinball forums, and people made other
solutions for it. Permanent ones. No battery to replace EVER.
For example:
Now, I couldn't find a 32Kx8 variant, but the RAMTRON chip you'd likely
need is the FM1808. Mouser seems to have it in stock, but at a pretty hefty
price, and you'd have to make the breakout board still (JLPCB maybe?)
There seems to be stock on eBay for lower prices from US sellers...
Just a thought, make a breakout, put a SMD variant of the FM1808 plus
possibly some circuitry on it, and be done with it. No battery to deplete
anymore... You might even be able to find a DIP variant of it, and it looks
to be pin compatible...
There are some differences though, CE needs to be strobed. The datasheet
will tell the details...
Maurice
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On Mon, Mar 11, 2019 at 8:33 AM Adrian <Adrian@...> wrote: I'm happy to get a couple and mail them to you if that helps?
Adrian
On 3/11/2019 2:17 PM, Reginald Beardsley via Groups.Io wrote:
RS wouldn't allow me to enter any country except the UK when I tried to buy a couple.
Digikey says they'll have them in late May. I'm sure ST only makes a
small run, probably just once a year, because of the shelf life issue.
I asked a NA eBay seller about the origin and date code of their stock.
Came from a defunct distributor, but have a 2002 date code.
Unfortunately, with Farnell and their many names and websites, there is
no telling where their stock is. If shipment is by sea from the UK it
might still take until June :-(
so it looks as if I'm just going to have to wait.
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Re: 2247A PSU Troubleshooting
To prevent that ground ring short, always practice safe probing; use a probe condom.? One of those plastic SMA connector caps works well, or just tape in a pinch.Jim Ford?Sent from my Verizon, Samsung Galaxy smartphone
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-------- Original message --------From: nielsentelecom@... Date: 3/14/19 7:16 PM (GMT-08:00) To: [email protected] Subject: Re: [TekScopes] 2247A PSU Troubleshooting Nick,I have a 2246A that I had to get the ripple on the various DC busses knocked down. Replacing the ZS diodes was done, most of the secondary DC busses caps, a number of those were bad, I could not get all the voltages into spec with the single voltage adjuster. And I replaced those hot resistors near the HV section that scorch the board, they sit right in front of the air intake, and I replaced them with a higher wattage R and elevated them above the board. they were OK, but its a pain getting that power supply out! There is a HV cap in that section that will need constant discharging after powering up. It holds a lot of juice! I also blew the regulator chip in mine when I was probing around that tall heat sink, I forget which semi conductor, I had hit it with the ground ring on my scope probe on it. Pop, it went. I believe it has 150VDC on it. From your symptoms, it's similar to mine with the popped chip. Read about the delayed start feature, make sure it's doing what it's supposed to. There is also a crowbar circuit. I sourced that chip at DigiKey. I also created a resistive load to test the power supply voltages outside of the scope. I have lineman's gloves, and I put that HV CRT cable inside of that glove. I also elevated the board above a cardboard box with a box fan inside to cool those load resistors. It was a pain, but it worked very well. I have those resistor values if you need them. And I know all, doing it this way was not very safe! And I did use an isolation xformer.Nielsen TelecomTom Jobe helped me a few years ago get thru the repair. He has good advice. Search my handle and you will see what I did.
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Re: 2247A PSU Troubleshooting
Nick,
I have a 2246A that I had to get the ripple on the various DC busses knocked down. Replacing the ZS diodes was done, most of the secondary DC busses caps, a number of those were bad, I could not get all the voltages into spec with the single voltage adjuster. And I replaced those hot resistors near the HV section that scorch the board, they sit right in front of the air intake, and I replaced them with a higher wattage R and elevated them above the board. they were OK, but its a pain getting that power supply out! There is a HV cap in that section that will need constant discharging after powering up. It holds a lot of juice! I also blew the regulator chip in mine when I was probing around that tall heat sink, I forget which semi conductor, I had hit it with the ground ring on my scope probe on it. Pop, it went. I believe it has 150VDC on it. From your symptoms, it's similar to mine with the popped chip. Read about the delayed start feature, make sure it's doing what it's supposed to. There is also a crowbar circuit. I sourced that chip at DigiKey. I also created a resistive load to test the power supply voltages outside of the scope. I have lineman's gloves, and I put that HV CRT cable inside of that glove. I also elevated the board above a cardboard box with a box fan inside to cool those load resistors. It was a pain, but it worked very well. I have those resistor values if you need them. And I know all, doing it this way was not very safe! And I did use an isolation xformer.
Nielsen Telecom
Tom Jobe helped me a few years ago get thru the repair. He has good advice. Search my handle and you will see what I did.
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Re: Test input for an SD-32 sampling head
I have one of Leo's 100 pS impulse units as a source for initial experiments. If I can narrow that to 10 -20 pS with discrete SMD parts I may be able to get the idea to work. There's a close connection to the Hilbert operator hiding in there somewhere.
I've been reading an excellent book on FPGA implementation of DSP by Roger Woods et al most of the afternoon. So I've not started on the dissertation yet. I can't really say much else until I understand the mathematics and physics of using the reverse biased diodes as capacitors. That should keep me entertained for a few weeks at least.
In any case, failure doesn't matter. It's a hobby project, not a client deliverable. I've been fascinated by the problem of getting a fast rise time edge for a long time. It's a bit of circular logic. My excuse for doing it is I bought an 11801 and my excuse for buying the 11801 is so I could try to do it. If I can narrow the 100 pS pulse by 5x I'll have an excuse to buy an SD-32.
I spent 3 years studying sparse L1 pursuits using "A Mathematical Introduction to Compressive Sensing" by Foucart and Rauhut as a text followed by reading the original papers by Donoho, Candes et al. Beats the hell out of watching television. I just wish I could find someone else who was interested in the subject to discuss it with. It's quite amazing what you can do with sparse L1 pursuits and really easy to do in practice. Understanding the math is not easy, but most people use FFTs without really understanding them.
Have Fun!
Reg
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Re: 2247A PSU Troubleshooting
On Thu, Mar 14, 2019 at 08:29 PM, Nicholas Keller wrote:
But you are correct that this is starting
to feel overwhelming and I am losing confidence :(
Nick, That is the way some of these threads go. You don't need a variac at this stage. A while ago you mentioned you had an isolation transformer, as I recommended and you asked whether to connect the safety ground through to the 'scope. I recommended to do that and Brian S. made some good remarks, which didn't contradict my advice. In your current situation they are not relevant. What *is* relevant is that you isolate the mains-connected part i.e. up to the primary side of T2204 from the mains, nothing more, which is exactly what you did with the isolation transformer. I am not confusing you with another user, no variac or even autotransformer in your situation. OTOH, I'm not sure at the moment what the symptoms with your 'scope were and I'll have to look that up again. Unfortunately, I'll be quite busy over the next few days (promised to repair a few scopes). As long as you realise all the time that *inside* the now isolated (primary) part of your 'scope there are still places carrying a dangerously high potential between them, no longer against your 'scope's case, ground, the floor underneath your feet nor safety earth after you installed the isolation transformer to feed the primary side of the 2247A and you're sure it is in good shape i.e. *if it is safe*, you may take measurements. If you want, let me know what you know about the status and symptoms and I'll be able to look into it within a few days. Three things: 1. Make sure you understand where the dangerous voltages are and between which points, now that you have an isolation transformer installed, and have utter respect for those 2. Make sure you act accordingly 3. Don't despair! Raymond
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Re: TCP202 replacement body parts?
On Thu, Feb 28, 2019 at 4:57 PM Siggi via Groups.Io <siggi= [email protected]> wrote: I tried emailing buy@..., which acknowledged that the parts are
available, but instructed me to call 1-800-833-9200 ext 1 for sales. I
called this number, whereupon a very nice lady acknowledged the
availability and pricing, then proceeded to explain to me how she's unable
to process Canadian credit cards.
She then told me I could send a PO to the email above, and Tek would send
me an invoice, which I could pay by US check. She sincerely wished for me
to have a FedEx account or the like to arrange the shipping, as that's
going to be a problem otherwise also.
She could find no Tek representative in this here cold tundra that could
mediate this business either.
I'm happy to report that a kind gentleman member of this list had some parts he shared with me. I've transplanted the probe to a new housing and the patient looks to have survived. The little ball between the slide and the outer housing is feral, though. I don't know how many times it leaped for freedom, and I was sure I'd lost it several times. He also informed me that these probes are quite delicate and can fail in strange modes. In addition to the performance check in the service manual, he advised running my PG506 through the frequencies available for fast rise or high ampl, looking for "droop" on the measured waveform. Mine was pretty much ruler flat across all settings. In my performance testing this probe well exceeded spec. The rise seems to be on the order of 4.5ns and the 3dB bandwidth is closer to 100MHz than 50. DC accuracy was well inside 1% as received, and although the DC balance was totally out the window, it adjusted fine with the course balance trimmer on the probe.
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Re: 2247A PSU Troubleshooting
In my experience, the main transformer either works, or it doesn't... and yours works. Having an internal short to ground is what killed the few T2204's I know about.
There are about 17 one amp ultra fast diodes that are used to rectify the low voltages on the secondary side of the transformer. About a dozen of them are in a row next to the transformer in the middle of the A18 board and they are known to fail especially if they are marked "ZS" or one other marking which I can't remember. Regardless of markings, follow theT2204 secondaries and see what you get for voltage and ripple as it all gets rectified and filtered.
The Tekscopes message archive will remember the details of this and lots of other problems the 224x family had over the years, and it's all in there for you to read when you search on 2246, etc.
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On 3/14/2019 3:20 PM, Nicholas Keller wrote: It was suggested earlier this this thread that I should find 160-170VDC
across C2202. I tested across R2256 as they appear to share the same
connections, and got 156VDC. Next I checked for ripple using my DMM set to
VAC and got about 2.5V.
I also tested across C2203 by using the same ¡°negative¡± joint of
C2202/R2256 for the black probe and pin 10 of T2204 for the red probe:
result = 40.5VDC
I also got 40.5V at T2204 pins 8 and 9 which should give +7.5V and -7.5V
.... and 38.4V at all DC power pins at J1204
Does this point to a bad T2204? Is C2202 allowing too much ripple?
Thanks for everyone¡¯s support!
Nick
On Thu, Mar 14, 2019 at 3:29 PM Nicholas Keller via Groups.Io <Nirokeforums=
[email protected]> wrote:
OP here. Variacs weren¡¯t mentioned until today so perhaps you are
confusing me with another user. But you are correct that this is starting
to feel overwhelming and I am losing confidence :(
This is the first HV device I have worked on so I am not familiar with all
the components in the 2247A PSU. Most of my experience has been with
analog synthesizers, drum machines, and effects, though often the problem
has been PSU related.
Nick
On Thu, Mar 14, 2019 at 12:56 PM Raymond Domp Frank <hewpatek@...>
wrote:
On Thu, Mar 14, 2019 at 05:03 PM, Brian Symons wrote:
I was only answering to the comment about isolation transformers.
Hi Brian,
I found your post very informative but wanted to keep things as simple and
clear as possible for the OP. I had recommended a Variac and he wasn't sure
what to do. In his case he can either connect safety earth or not.
Raymond
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Re: 2247A PSU Troubleshooting
It was suggested earlier this this thread that I should find 160-170VDC across C2202. I tested across R2256 as they appear to share the same connections, and got 156VDC. Next I checked for ripple using my DMM set to VAC and got about 2.5V. I also tested across C2203 by using the same ¡°negative¡± joint of C2202/R2256 for the black probe and pin 10 of T2204 for the red probe: result = 40.5VDC I also got 40.5V at T2204 pins 8 and 9 which should give +7.5V and -7.5V .... and 38.4V at all DC power pins at J1204 Does this point to a bad T2204? Is C2202 allowing too much ripple? Thanks for everyone¡¯s support! Nick On Thu, Mar 14, 2019 at 3:29 PM Nicholas Keller via Groups.Io <Nirokeforums= [email protected]> wrote: OP here. Variacs weren¡¯t mentioned until today so perhaps you are
confusing me with another user. But you are correct that this is starting
to feel overwhelming and I am losing confidence :(
This is the first HV device I have worked on so I am not familiar with all
the components in the 2247A PSU. Most of my experience has been with
analog synthesizers, drum machines, and effects, though often the problem
has been PSU related.
Nick
On Thu, Mar 14, 2019 at 12:56 PM Raymond Domp Frank <hewpatek@...>
wrote:
On Thu, Mar 14, 2019 at 05:03 PM, Brian Symons wrote:
I was only answering to the comment about isolation transformers.
Hi Brian,
I found your post very informative but wanted to keep things as simple and
clear as possible for the OP. I had recommended a Variac and he wasn't sure
what to do. In his case he can either connect safety earth or not.
Raymond
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Re: Test input for an SD-32 sampling head
Chris, I think you refer here to the so-called "nose-to-nose" method of characterizing sampling scopes (Rush e.a.).
Albert
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On Thu, Mar 14, 2019 at 11:37 AM, cmjones01 wrote:
With difficulty. I believe there's a method involving three sampling heads
looking at each other's kickout pulses and some maths which can be used to
evaluate their performance.
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Re: Test input for an SD-32 sampling head
Reginald,
To obtain significant NLT compression, you need lots of stages, and a fast and big enough signal to start with - not easily done with conventional electronic and transmission line components. This sort of thing is easier to implement inside an IC made with GaAs or SiGe or such, where you can build many of the same thing, on a tiny scale. I think you'll find that most modern treatises on the subject (at least for very high speeds) are about using them within ICs - the physics is the same, but it does not readily translate to putting up a simple lumped element and transmission line system copy.
With the scale of parts and assemblies we can typically handle and see (with magnification) and build and work with, it may be OK to go from a one nanosecond range, compressing to tens of picoseconds, if you have enough stages - maybe 20-100.
Now, if you happen to have access to microwave/RF IC processes, then that's a different story.
Ed
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Re: 2247A PSU Troubleshooting
OP here. Variacs weren¡¯t mentioned until today so perhaps you are confusing me with another user. But you are correct that this is starting to feel overwhelming and I am losing confidence :( This is the first HV device I have worked on so I am not familiar with all the components in the 2247A PSU. Most of my experience has been with analog synthesizers, drum machines, and effects, though often the problem has been PSU related. Nick On Thu, Mar 14, 2019 at 12:56 PM Raymond Domp Frank <hewpatek@...> wrote: On Thu, Mar 14, 2019 at 05:03 PM, Brian Symons wrote:
I was only answering to the comment about isolation transformers.
Hi Brian,
I found your post very informative but wanted to keep things as simple and
clear as possible for the OP. I had recommended a Variac and he wasn't sure
what to do. In his case he can either connect safety earth or not.
Raymond
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Free for shipping: Tekelec V.35 interface module
Got it from the Telogy auctions years ago and have no use for it.? No part number, but comes with v.35 cable and internal ribbon cable.? Can provide photos to interested parties (please contact me directly).? Ships from 94085
-Dave
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Re: WTB 012-0648-00 6 pin LEMO M-M 30" cable for Tracking Generator
Hi Is 1s, 12mm, not 2s, 14,8mm Regards Miguel -----Mensaje original----- De: [email protected] [mailto: [email protected]] En nombre de Miguel Work Enviado el: jueves, 14 de marzo de 2019 19:52 Para: [email protected]Asunto: Re: [TekScopes] WTB 012-0648-00 6 pin LEMO M-M 30" cable for Tracking Generator is this? -----Mensaje original----- De: [email protected] [mailto: [email protected]] En nombre de Dennis Tillman W7PF Enviado el: jueves, 14 de marzo de 2019 2:24 Para: [email protected]Asunto: [TekScopes] WTB 012-0648-00 6 pin LEMO M-M 30" cable for Tracking Generator I got my TR502 Tracking Generator, DC508 Option 7, and TM503 Option 7 all set up and I then discovered I need the 6 pin LEMO cable (3 male pins and 3 female pins) that goes from the Spectrum Analyzer to the TR502 Tracking Generator Logic . The part number is 012-0648-00. If anyone has one for sale please contact me OFF LIST at dennis at ridesoft dot com. Thank you, Dennis Tillman W7PF
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Re: WTB 012-0648-00 6 pin LEMO M-M 30" cable for Tracking Generator
is this? -----Mensaje original----- De: [email protected] [mailto: [email protected]] En nombre de Dennis Tillman W7PF Enviado el: jueves, 14 de marzo de 2019 2:24 Para: [email protected]Asunto: [TekScopes] WTB 012-0648-00 6 pin LEMO M-M 30" cable for Tracking Generator I got my TR502 Tracking Generator, DC508 Option 7, and TM503 Option 7 all set up and I then discovered I need the 6 pin LEMO cable (3 male pins and 3 female pins) that goes from the Spectrum Analyzer to the TR502 Tracking Generator Logic . The part number is 012-0648-00. If anyone has one for sale please contact me OFF LIST at dennis at ridesoft dot com. Thank you, Dennis Tillman W7PF
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Re: Test input for an SD-32 sampling head
LOL With *great* difficulty. That's a large part of the appeal of the project. It's not very expensive and if I succeed serious bragging rights. It would be great fun to take to a Keysight trade show booth and put on their new 110 GHz DSO to check it.
I'll have to give an algebraic solution some thought. That had not occurred to me. I can't justify buying 3 fast heads. Just one is a real stretch to justify. But there may be a useful mathematical subterfuge.
Courtesy of a member of the EEVblog forum who was kind enough to give me the magic phrase, I found Michael Case's 1993 doctoral dissertation at UC Santa Barbara on "non-linear transmission line pulse generators". Very interesting approach. It uses the dispersion produced by reverse biased diodes at appropriate intervals to steepen the leading edge. I've only given it a quick glance. For reading I'll want a paper copy. But starting with a 21 pS edge from the laser diode driver Leo Bodnar is using i might not be too difficult. I'll have to work on the math a bit.
Have Fun!
Reg
I'm hoping that someone involved with the SD-30/32 heads will wander along and tell us how they did it at the factory.
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Maurice Smulders
Raymond Domp Frank