hybridfree/eevblog-posts huggingface dataset:
UBLOX MAX-M8W-0-10 - making changes persistent - Page 1
Forum section: electronics / general

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: November 10, 2019, 11:51:36 am
content: I have a MAX-M8W-0-10 module running on a small adapter PCB I designed and built. When I connect to it using U-center, it's initially at 9,600 Baud. I can use U-center to send a message changing the Baud rate to 115,200 and then I have to change the Baud rate setting in U-center before the MAX-M8W-0-10 is 'seen' again by U-center.What I want to do is save the Baud rate (and maybe other) settings in non-volatile flash so that the module starts up with the changed Baud rate etc. So far I've failed to do this.In U-center, if I have the module running at 115,200 and I then go to serial settings and change to 115,200 (yes, the same Baud rate) and hit send then it is still connected and gives me a prompt to save the settings which I accept but they don't persist through a full power cycle.Any suggestions or ideas why it isn't saving?

author: Psi
author_rank: Super Contributor
timestamp: November 10, 2019, 12:11:27 pm
content: It's been a long time since i used U-centerbut i also remember having this issue.From memory there is a special place in the software where you set it to store the data to permanent NVM
fluke 83v input inpeadance - Page 1
Forum section: electronics / general

author: m3vuv
author_rank: Super Contributor
timestamp: October 30, 2019, 10:30:10 pm
content: hi all ive a fluke 83v,would anyone know the input inpeadance on the 6v range?,also is there a way to turn the auto ranging off?,ive looked in the manaul but cant find the info i want,cheers Paul.m3vuv.

author: retiredcaps
author_rank: Super Contributor
timestamp: October 31, 2019, 02:49:39 am
content: Press the range button to switch meter into manual range mode.In the 6V range, my Fluke 87V shows 11.11Mohm. Your 83V is likely the same.
What fun can be had with a symetricom S300 - Page 1
Forum section: electronics / general

author: Marck
author_rank: Regular Contributor
timestamp: October 30, 2019, 08:40:32 am
content: I have the opportunity to get a hold of a Symetricom S300. Part number 1520R-S300-RB. It has the Rubidium oscillator. I was wondering if I was to get a hold of it what fun things could I do with it ? Apart from having a stratum 1 clock in the house.I think it only has a few years let until the gps epoch will cause it issues with reported time.Any ideas or advice for fun things to do with it would be appreciated.ThanksM
Siglent probe compensation signal amplitude? - Page 1
Forum section: electronics / general

author: fabrizio_fabrice
author_rank: Unknown
timestamp: October 30, 2019, 05:46:15 pm
content: As a newbie to Siglent's unique jargon, could someone provide the output amplitude spec of what they call the "Compensation Signal", for the SDS1201X-E (and probably most others)?The term "calibrator" appears nowhere in their documentation.Thank you!!Fabricerepeats to self: compensation signalcompensation signalcompensation signal....

author: tggzzz
author_rank: Super Contributor
timestamp: October 30, 2019, 06:46:57 pm
content: I doubt you could rely on the amplitude.The only important characteristic of the cal signal is that it has moderately sharp edges and a flat top. That's all that is necessary to enable a *10 probe's LF to be adjusted.

author: fabrizio_fabrice
author_rank: Unknown
timestamp: October 30, 2019, 10:31:51 pm
content: QuoteAgreed; I asked only to be sure I set the "probe scale" correctly. My problem was adjusting to this scope, which does things that no self-respecting analog scope would ever do: change its vertical scale factor when other settings are changed.It amazes me that Siglent sees no need to spec it, even to the point of inventing a unique term for it that no search will find. No wonder I can read the manual and still have little idea what it means.Still, I'd like to know what it is, nominally. Anyone know??

author: tggzzz
author_rank: Super Contributor
timestamp: October 31, 2019, 12:00:30 am
content: Quote from: fabrizio_fabrice on October 30, 2019, 10:31:51 pmSnort!Tautech is a silent distributor; he might know.
where to sell FLUKE calibration equipment? - Page 1
Forum section: electronics / general

author: Mato
author_rank: Contributor
timestamp: October 21, 2019, 10:12:41 am
content: Hi folks,I hope this is not the wrong place to ask a question like this. Over the years, I bought some FLUKE and BEAMEX calibration devices. I worked in a cal LAB for 12 years now, and it was always my dream to have a little calibration labour of my one. The problem is that the thinks that I bought early on are not the thinks I work with.I bought a FLUKE 743b... and realised I need the Hart protocol. So I purchased a fluke 744, and that solved my problem for a while. Then I bought a Beamex device and realised I like it more, so I stick to it. And now the 743b and 744 are collecting dust.The same happened with my pressure calibrator stuff. I bought a fluke 700 PTP1 + fluke 700g27 and used it 10x, and that is it... I also have some extraordinary stuff and simply don't know what to do with it.And this are the devices I think I can sell. Some other exotic staff where I put 5000eur+ only in software options are the hard ones. Any ideas?Is E-bay the answer?

author: coromonadalix
author_rank: Super Contributor
timestamp: October 21, 2019, 10:32:46 am
content: Try here in the EEVblog buy sell thread, you wont loose the fees on Ebay ... but after a while if it not sell push them on Ebay ??
GPSDO w/o oven? - Page 1
Forum section: electronics / general

author: thinkfat
author_rank: Unknown
timestamp: October 15, 2019, 05:41:19 pm
content: Found this listing on ebay, claims to be the most energy efficient GPS reference standard. Apparently, no oven used for stabilizing the XO. Good idea or bad? Crystal oscillators tend to be quite susceptible to temperature change and it seems this device uses a 1PPS signal from a GPS receiver, which means its regulation is going to be very slow.eBay auction: #133190999917

author: Gyro
author_rank: Super Contributor
timestamp: October 15, 2019, 07:42:20 pm
content: I can understand their goal of saving power but that shouldn't exclude a TCXO.Quote
MOVED: Beginner DMM in $50 for guitar related diy - Page 1
Forum section: electronics / general

author: beachbuminthesun
author_rank: Newbie
timestamp: October 11, 2019, 02:25:18 pm
content: This topic has been moved toBeginners.https://www.eevblog.com/forum/index.php?topic=213862.0
Voltage calibrator question  - Page 1
Forum section: electronics / general

author: nnills
author_rank: Contributor
timestamp: October 08, 2019, 06:07:19 pm
content: Hi,I read a document by fluke about artifact calibration and thought about how I would do something like this(for voltage only). The document mentions PWM DAC's. Now the question is: if the 10V reference is for example 9.9999000V how does one make a 10V output? I thought of a boost converter of which the output is compared to the reference with a sensitive voltmeter. That would require using In-Amps and such. Is this a reasonable approach? And what do the real pro's use?small sub-question:would the following be a good calibration procedure?1. measure with a short2. measure 10V@10V range3. measure transfer ratio(divider): 1V@10V range compared to 10V input divided by transfer divider4. measure 1V@1V range with 10V input divided by transfer divider5. measure 100mV@100mV range with 1V@1V range divided by transfer divider

author: Echo88
author_rank: Frequent Contributor
timestamp: October 08, 2019, 08:49:53 pm
content: I cant follow the idea, normally its done like this:Calibrators like the Fluke 5440 or 57XX-series use a PWM-DAC and two zener-refs in series (2x ~7V =14V), which gives them the ability to go from 0 to +-11V.Using a trimmed 10V-reference for the DAC isnt necessary, since all calibration constants are used in software and the needed internal zener -> 10V-converter would worsen the overall specs since it contributes additional long-term-drift, TC, noise.Your calibration procedure looks very similar to the Fluke 752A which is usually used for this type of calibration (when left-side voltage reference + DAC is seen as a calibrator).

author: nnills
author_rank: Contributor
timestamp: October 09, 2019, 08:49:59 am
content: And would the 1V and 100mV be divided before or after the DAC? And the 100V range be amplified x10 or is 110V regulated down, divided by 10 and compared to the 10V dac output? Or can I look this up in some kind of service manual?In any case, thank you for the first response.Edit: I initially thought that de divider and the null meter would be in the instrument.

author: Kleinstein
author_rank: Super Contributor
timestamp: October 09, 2019, 04:14:23 pm
content: Some calibrators include a null-meter or even a good resolution low level meter used as a null meter.The DAC usually only works with a fixed input voltage. So the higher ranges are amplified from the DAC output in some way.Amplification could be checked against an external Hamon type divider or internally against the PWM DAC.For 1 V they may just use the PWM DAC. For even lower voltages a divider (can be inside the instrument) may be used after the DAC.There are a few manuals around on how the calibrators work.
hich  - Page 1
Forum section: electronics / general

author: smidmr
author_rank: Newbie
timestamp: October 08, 2019, 11:20:26 am
content: Hello Everyone;I would like to learn parallelism between two planes that i measured. How can i do it in Verisurf? Which command do i need to use?Thank you in advance...

author: MiDi
author_rank: Frequent Contributor
timestamp: October 08, 2019, 11:56:31 am
content: Hello smidmr,you should give your topics explanatory title, my translator and search did not know the word "hich".Maybe here is the wrong audience present for you, this Forum is electronics related.Metrology section is meant as electrical metrology.
Please help me understand 2 types of GPSDO and Rb modules - Page 1
Forum section: electronics / general

author: tkamiya
author_rank: Super Contributor
timestamp: September 24, 2019, 01:04:13 am
content: I am hoping someone can help me understand this. I've seen similar discussions take place both for GPSDO with Crystal Oscillators and Rubidium modules. It appears there are two types of each.I've read frequency agile Rb modules (ones you can change output frequency) is one kind of Rb (sa.22c and fe5650, etc), and there is another one that you cannot change frequency. (ie. T-bolt, PRS10, etc). Words like phase noise and PLL are thrown out often in discussions. I vaguely remember frequency agile types are less suitable if ultimate in stability is needed such as multiplying the output into GHz range.I've also read similar discussions with Crystal GPSDO. Smaller units are often said to be PLL type and are less costly than other type. (but frequency agile?)I'm sorry this is SO vague but that's the reason for this post. I need to understand this. There was a wiki page on this, but it doesn't go into this discussion deep enough.Would someone help me fully understand this?

author: dietert1
author_rank: Super Contributor
timestamp: September 24, 2019, 08:50:21 pm
content: When you use a local oscillator to build a tracking filter, the filter bandwidth depends on oscillator frequency/phase noise. The more stable the local oscillator is, the longer you can let it run free and the smaller will be the filter bandwidth. If the local oscillator is unstable/noisy, you need a tight feedback loop to keep it locked to the filter input. Filter bandwidth will then be higher.If the local oscillator has analog tuning, the analog interface requires a lot of care. When talking about filter bandwidths of less than 1 Hz it is easier to use a digital interface, where you send tuning commands that get executed with a precision of 24 or 32 bits. I remember doing a project comparing a FE5680A rubidium clock to a long wave standard frequency emission (DCF77). I used a VXI module HP E1430A to do the phase comparison. That is a digital receiver, so i did not have any analog tuning - very nice to work with.Can't you write a sentence of what you want to do? Want to buy something?Regards, Dieter

author: tkamiya
author_rank: Super Contributor
timestamp: September 24, 2019, 10:24:35 pm
content: Huh??Yes, I ate a really good hot dog for lunch.

author: martinr33
author_rank: Frequent Contributor
timestamp: October 01, 2019, 04:05:19 am
content: Ok...With the 5650/5680 devices, there are two basic versions.Earlier versions have a programmable divider that you can set to a wide range of frequencies with a serial port. These units are a bit less stable than the newer units.Newer units have a hardware set divider, adjustable by jumpers. These units have a tighter control loop, so less jitter than the earlier units.Both are very stable over long periods. You need a 12digit counter and great reference to see timing noise. They will clearly expose short-term GPS drift.

author: tkamiya
author_rank: Super Contributor
timestamp: October 04, 2019, 10:27:40 pm
content: Thanks!
UBLOX MAX-M8 series Driver Availability - Page 1
Forum section: electronics / general

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: October 01, 2019, 01:00:42 pm
content: I need to choose an updated GPS module for a design that currently uses an old Navsync CW25 GPS module. The data needed is position, altitude, date, time, and 1PPS. I prefer the GNSS (multi-system) modules that are now available and I'm looking for advice on what the new module should be; requirements are for:1. Ease of use (for me) which means drivers available that I can drop into a C code IDE2. Runs off 3.3 volts3. Supports an active (powered) antenna systemMy existing system runs on the M0+ core of a PSoC 6 which communicates with the old module via UART and, initially, I'd like to drop in a replacement that uses the same (or close) UART Comms (so I can get it running quickly) but, in the medium term, the desire is to change over to I2C or SPI to talk to the new module, which I assume will have to involve some kind of proprietary Comms system (I'm not familiar with any of them).I've been looking at theUBLOX MAX-M8 Seriesand there are drivers available for it on githubherebut they seem only to be for the serial Comms. What would you guys reccomend (or not) as a module that meets my needs and are there any easy-to-use code downloads for the non-UART Comms?Thanks in advance.

author: mycroft
author_rank: Regular Contributor
timestamp: October 01, 2019, 02:28:08 pm
content: Not sure if it satisfies all your requirements but this is a nice and small GPS receiver:http://navspark.mybigcommerce.com/navspark-mini-6pcs-pack/.

author: awallin
author_rank: Frequent Contributor
timestamp: October 02, 2019, 04:55:46 am
content: the new modules from ublox seem to be quite popular, F9P and F9T (timing).Not sure if they also managed to lower current consumption with the new generation of chips?an active antenna might want +5V, not just 3V3.most (all?) settings available through their u-center program are also adjustable on a low level through the UART.
Manual for FEI FE-5440A or TD-1251/U - Page 1
Forum section: electronics / general

author: volvo_nut_v70
author_rank: Regular Contributor
timestamp: September 30, 2019, 01:10:24 am
content: Just wondering if anyone has any of the manuals for this beast, the US Air Force manual numbers are T.O. 49B3-36-1 (OP manual) and T.O. 49B3-36-2 (Service manual).I tried FEI, they won't sell you a manual unless you can provide them with a copy of the PO purchasing the unit......Anyone have any experience with it?Thanks!

author: picburner
author_rank: Frequent Contributor
timestamp: September 30, 2019, 04:44:58 pm
content: It is for sale on eBay but the seller requires a very, very large amount.

author: volvo_nut_v70
author_rank: Regular Contributor
timestamp: September 30, 2019, 06:43:19 pm
content: Thanks for the reply! Yes I just saw that, that is a very silly price!
Analog meters tutorial - Page 1
Forum section: electronics / general

author: 001
author_rank: Super Contributor
timestamp: September 26, 2019, 08:00:41 pm
content: HiCan anybody told me what is main rules for analog meters? Any links?I hear about 1/3 scale trick but didnt understand it

author: ArthurDent
author_rank: Super Contributor
timestamp: September 28, 2019, 03:42:22 am
content: For best accuracy use a range that gives above 1/3 of full scale deflection. Below 1/3 F.S., accuracy can get much worse.

author: 001
author_rank: Super Contributor
timestamp: September 30, 2019, 06:09:25 pm
content: Quote from: ArthurDent on September 28, 2019, 03:42:22 amLeft or right side?Thanx

author: Grandchuck
author_rank: Super Contributor
timestamp: September 30, 2019, 06:30:41 pm
content: As close to full-scale deflection as possible, without over ranging of course.Another item for best accuracy is to use a mirrored scale to avoid parallax error. Look straight in; not an an angle. Your line of sight should be perpendicular to the meter face. True whether or not a mirror arc is present. With a mirror, one will see two pointers when not observing straight on.
low frequency high precision LCR fixtures - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: September 24, 2019, 10:26:20 pm
content: Has anyone built fixture like this for use with low frequencies (hint 1 KHz) but high resolution (5 digits+)?like the science of blade contacts. What material is suitable for this? I was imagining telfon milled with springs in it to move some kind of plated bits that have wires brazed onto them. But what should they be plated with?DO you think a thick silver electroplating that is lapped to be flat would work? (say for jamming coils into them)I don't see why a kelvin one can't be made for even small components like 1206Or maybe even.. just cutting a silver ingot apart and using solid silver contacts (its a one off)? is there a reason to bother with plating (the plating process is more expensive then the little bits of solid silver for a home gamer)

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: September 24, 2019, 11:59:17 pm
content: Do a Google image search on the HP 16047E fixture used on their LCR meters. Pretty good example of the right way to do it. Remember that lead loop area will get you on 5-digit measurements. They have a different one for SMT parts.

author: coppercone2
author_rank: Super Contributor
timestamp: September 25, 2019, 12:09:28 am
content: does not seem hard to fabricate from a 30$ silver ingot. They don't even use springs, just screws.

author: coppercone2
author_rank: Super Contributor
timestamp: September 25, 2019, 12:12:12 am
content: how do you think a good one for SMT parts would look like? I am kind of thinking that you can dip a specific SMT package in vaseline, carefully dip it into epoxy , let it cure good then carefully mill surface layers off to make the part half submerged in its mold when its inserted then make slide plates that come in from the sidesfun project for micro millI don't want to deal with pogo pins they are annoyinghttps://testequipment.center/LCR-Impedance/LCR-Impedance-Test-Fixtures

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: September 25, 2019, 12:02:41 pm
content: You don't need the silver ingot when making a 4-terminal measurement. I think the HP fixture is just gold plated brass or similar. Pure copper would be too soft. We have one at work. I should take the bottom off and see how they connected the bars.

author: coppercone2
author_rank: Super Contributor
timestamp: September 25, 2019, 10:09:18 pm
content: it seems easier and more sturdy just to buy the silver and cut slivers out of it with a jewelers saw to make it. I don't see why you would plate something given the cost of all the work.. even building around digikey/mcmaster parts is more annoying.. I think I can make a bit that slides into the channel the size of the endmill I use and sand it to perfection.. easier so long you can take the 30$ initial hitI think messing with plating's besides for annodization and large bits only makes sense for large volumes? I think most people would tend to use pogo pins anyway.. no one would be messing around with gold plating custom hardware
Anyone built a current coil like a Fluke550/coil - Page 1
Forum section: electronics / general

author: volvo_nut_v70
author_rank: Regular Contributor
timestamp: September 14, 2019, 02:48:13 pm
content: Has anyone built a current calibration coil like the Fluke 5500/coil?

author: mimmus78
author_rank: Unknown
timestamp: September 14, 2019, 04:34:25 pm
content: Yes I built one. Wrap solid annealed copper wire around a big jar, than zip a cable tie (not too strong) to create the center of the coil and open it as flower ... zip stronger to fix the position and done. Than if you like you can create the enclosure ... but I never did it, I really used it only few times. It worked as it should.

author: boggis the cat
author_rank: Regular Contributor
timestamp: September 19, 2019, 01:01:03 am
content: Quote from: volvo_nut_v70 on September 14, 2019, 02:48:13 pmWe have built several coils for use in the lab – 10, 20, 50, and 100 turn. Also a 'butterfly' coil for tong-type current detectors.The tricky part is getting the turns reasonably even – you don't want the magnetic field to betoohinky. To maintain the shape, you can place the completed coil on a piece of MDF or similar and cable-tie it down through holes. Fluke pot their coils which makes the assembly rigid but would take a lot more effort.(We have the 52120A/3KA and /6KA coils. These are part of our accredited capability, while the 'roll your own' aren't.)

author: volvo_nut_v70
author_rank: Regular Contributor
timestamp: September 24, 2019, 09:18:19 pm
content: Any particular coil diameters used?
Wavetek 9100 Scope Opt Failure Questions - Page 1
Forum section: electronics / general

author: Testtech
author_rank: Regular Contributor
timestamp: September 26, 2019, 05:59:32 pm
content: I have a Wavetek 9100 with the Opt 250 scope cal board.This unit has self test failures in the scope board as shown in the pictures. This has been an intermittent problem, when working, it works correctly. But this is difficult to duplicate.The basic calibrator functions work correctly at all times, the problem seems to be confined to the scope board.If the self test is run repeatedly, the "Measured" values will be different.Anyone have experience with this instrument?
Noise amp front end - sample & hold to replace front-end coupling capacitor? - Page 1
Forum section: electronics / general

author: alanambrose
author_rank: Frequent Contributor
timestamp: September 16, 2019, 10:25:23 am
content: Hi,You might remember this thread a while back:https://www.eevblog.com/forum/metrology/characterising-low-frequency-noise/msg855778/?topicseen#msg855778I've been mulling over for a while whether it might be possible to avoid all the hassle of the tricky input capacitor (e.g. ~1,000 uF tantalum) with some kind of sample-and-hold to provide DC bias to a DC-coupled front end?Of course, the problem would be to make this low noise itself to avoid influencing the readings much.Presumably (without doing any calcs) an adc/dac pair wouldn't cut it, and most analogue sample-and-hold designs will introduce too much noise themselves. So how about e.g. a manually operated 'sample' reed relay / simple low pass filter / low leakage hold capacitor into a high impedance / low noise follower applying DC bias to the DC-coupled front end?Alan

author: Kleinstein
author_rank: Super Contributor
timestamp: September 16, 2019, 03:11:11 pm
content: The sample and hold part is kind of modified filter, so not that different to the RC used in input coupling. The main change is having a switch and much lower resistor instead of a fixed larger resistor. The extra S&H may add an extra high impedance (e.g. AZ OP) buffer with extra noise.AC input coupling with a switchable resistor to ground would act very much like a S&H stage. This kind of sets the low frequency limit rather low, but still the same DA, leakage and similar effects as with a coupling capacitor.
noise floor of hp4338 ohm meter? - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: September 23, 2019, 01:52:45 am
content: This is a commonly used device, and I got one, but it was a repair job and it seems a bit jumpy.You have some options to select current and range to increase your SNR with this gear (1kHz measurement).Does anyone have one and can tell me what I can expect in terms of noise and jumpyness for measurements? Like on a copper bus bar its dancing around in the micro ohms level. I don't know if its normal or how much a fixture/shield/guard can fix.The meter manual just has accuracy as 0.4% but does not cite noise and average requirements. I have no experience with such low level AC measurement, for reference I measured a DE-5000 to use ~4.5mA rms current source, wheras this can be configured between 1uA-10mA current source. 1uA AC @ 1KHz without a metal shield seems like a hard measurement, but I am wondering if I should try replacing more parts in analog signal chain or try to invest in fixturing.measurements:1 inch copper ~0.5mm thick with kelvin spread out across a 1 inch square @ 10mA @ 1 miliohm full scale:sample speed medium: 10-500uOhm (unsuable), heavy dancingSlow sample speed : +- 2uOhmThis is unshielded on a table with long wire (5 feet) alligator clips from the fixture attached by banana soldered to original HP cables.Is the slow sample speed 2uOhm dancing reasonable, or should it be stable to the 100 nanoOhm (LSB) level? I figure thats unreasonable.If it is unreasonable, what would a fixture look like to measure this with low noise? How much can you get out of this meter without using the very slow digital averaging?It's not impressive compared to a DC ohm meter, but its 1KHz AC so I am a bit lost.Does anyone have a graph that shows the regimes where different front panel sampling speed options are reasonable to use? I assume its a question of amplifier gain and amplifier noise and external noise.What would be a shield chamber used for external noise in this case? or is this all internal?
Voltage Transducer for Oscillography (DIN rail) - Page 1
Forum section: electronics / general

author: Moro
author_rank: Newbie
timestamp: September 06, 2019, 04:54:48 pm
content: Hello,My first post, but a long time reader of these EEVblog forums.I'm looking for ideas and suggestions for a problem I am having. In short, I need a transducer that will allow me to view mains voltage waveforms on a scope, but in a permanent installation. It would need to be UL (or equivalent) listed.The longer story is that I've developed a disturbance fault recorder using a microcontroller and a separate ADC chip. To date, it's been used in a few research labs using my own homebrew transducer board, but now I've an opportunity to install some of my recorders in the wild. A homebrew board connected to the mains isn't going to cut it with the end users involved. To keep life simple, I thought I would use an off the shelf voltage transducer, but now that I look they all seem to be calculating RMS voltage. Not what I need at all. Really I need something like an isolation transformer or a Hall effect transducer in a DIN rail box.The input side would be either 230 V or 120 V nominal, maybe three phase (but 3x single phase will do too), and the output would be a bipolar voltage of say +/- 5 V. It would be in a fixed installation, so DIN mounting would be preferred but not essential.I've wondered if there's something on the market that would do this? If there is I'm not using the correct terms to find it.Thanks in advance for any suggestions.

author: pigrew
author_rank: Frequent Contributor
timestamp: September 06, 2019, 05:11:25 pm
content: Can you use a plain old AC transformer,like this one, but lower voltage output? The disadvantage is that the bandwidth may be somewhat low.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 06, 2019, 05:28:59 pm
content: A transformer is probably the way to go. The bandwidth is limited, but not that bad, but one would have to check. However the very small ones would likely no work to well and may give extra waveform distortion (especially at 230 V). With some luck a good transformer for a door bell may work (if build for low no load loss) - some a available for the DIN rail.
Relationship SNR of notch signal and phase noise of atomic/molecular clocks - Page 1
Forum section: electronics / general

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: September 06, 2019, 09:13:41 am
content: Most clocks and oscillators work by having a resonator that has little loss (lower = better) and then building a negative resistor to compensate for the little loss that is there. (Incidentally, this results in the interesting contradiction that a lower phase noise LC or xtal oscillator will usually also use less power, since you need to add less energy to compensate for the losses of the resonator).Atomic clocks and their close family of molecular clocks don't use this principle: To my understanding, they instead use a material in very, very low concentrations (lower = better to get increased sharpness of the peak) in a vacuum. This atom or molecule will then have a set of resonances at which it will absorb the EM power very well, and has almost no absorption at any other frequencies. In other words it is kinda like the opposite of a resonator used in aforementioned oscillators. As the extent of this absorption is, to my knowledge, very low (as you want very few molecules to be resonating, to keep the energy levels nice and discrete). So you can, I think, kinda think of it as having a low SNR - you have only a small difference between the loss at the notch frequency vs the loss at other frequencies.Is there any good starting point to look at the relationship between this SNR and phase noise? I think most atomic clocks in-and-of-themselves have poor phasenoise, and get good phasenoise by using them to tune the frequency of a low-phase noise OCXO or such.
Datron 4200 1000V ac? - Page 1
Forum section: electronics / general

author: acts238willy
author_rank: Regular Contributor
timestamp: April 13, 2019, 07:21:22 pm
content: I can't find the 4200A Datron manual on line. Can either the 4200 or the 4200A provide 1000V ac?

author: Testtech
author_rank: Regular Contributor
timestamp: April 13, 2019, 09:38:32 pm
content: You bet! Limited upper frequency limit.

author: Echo88
author_rank: Frequent Contributor
timestamp: April 13, 2019, 10:46:04 pm
content: If someone has the manual please upload it to ko4bb/xdevs or another pdf-archive, since the only other manuals ive found were all behind stupid pdf-sites were you need to register to read it. Thanks.

author: acts238willy
author_rank: Regular Contributor
timestamp: April 13, 2019, 10:51:56 pm
content: 4200 or 4200A... or both?Any special option numbers only, or all units?Thanks!

author: LaserEng
author_rank: Regular Contributor
timestamp: September 06, 2019, 03:11:40 am
content: Does anyone know what the difference between 4200 and 4200A is? Iv'e been searching but haven't been able to find anything conclusiveThe 4200 manuals are available on K04BB's site but I cannot find the 4200A manuals anywhere.

author: branadic
author_rank: Super Contributor
timestamp: September 06, 2019, 05:48:37 am
content: The difference are thighter stability and accuracy specs for the A model. Same for all other Datron calibrators, e.g. Datron 4000/4000A.-branadic-

author: LaserEng
author_rank: Regular Contributor
timestamp: September 06, 2019, 07:28:03 am
content: Not sure if that is entirely accurate for the AC units, It's easy to come across data for the 4200 but quite hard for the 4200ASeems from what I have found so far is that the 4200 will go up to 1000V without any extra option fitted, the user manual on K04BB mentions only 2 options for the 4200 (ignoring options for things like rack mounting, mains voltage etc).Option 30 - AC Current to 2 AOption 41 - Rear OutputBut for the 4200A for 1000V it must have Option 10 or it is limited to 200VOption 10 - 1000V RangeOption 30 - AC Current to 2 AOption 42 - RearOutput
MHM 2020, nice clock from Microchip - Page 1
Forum section: electronics / general

author: FrankBuss
author_rank: Unknown
timestamp: August 30, 2019, 07:36:30 am
content: This looks like a nice device:but I couldn't find a price for it. I guess it costs more than the usual PIC microcontroller?

author: Andreas
author_rank: Super Contributor
timestamp: August 30, 2019, 08:55:21 am
content: From the data sheet: 216 kghttps://www.microsemi.com/document-portal/doc_download/1244235-microchip-mhm-2020-maser-data-sheetso with a rough estimation of $1000/kg for industrial electronics you get about the price tag of a JJA.with best regardsAndreas
Fluke Y5002 and Y5001 interface cable schematics and parts list needed - Page 1
Forum section: electronics / general

author: volvo_nut_v70
author_rank: Regular Contributor
timestamp: August 23, 2019, 02:38:28 pm
content: Hello;Does anyone have the manuals or schematics and parts list for the Y5002 and Y5001 interface cables? They connect the Fluke 5220A and 5205 to various Fluke calibrators like the 5100B, 5440 etc.Greatly appreciate any help!
Question for Agilent 34410A users - Page 1
Forum section: electronics / general

author: Hrvoje_CRO
author_rank: Regular Contributor
timestamp: August 22, 2019, 03:20:39 pm
content: Hello!I have purchased from eBay 34410A multimeter and i have some concerns.Why as i connect probe (as soon as i connect on red input probe) and instrument is on DCV range i hear relay inside clicking like crazy. Also in resistance mode relay clicks from time to time and than stops. The important thing to mention is that only happens when instrument is in AUTO Range mode. Othervise the instrument is working fine.Any 34410A users here? Please help me with advice.Thank you in advance!Regards,Hrvoje

author: PA0PBZ
author_rank: Super Contributor
timestamp: August 22, 2019, 03:59:03 pm
content: Please don't double post your questions!

author: Hrvoje_CRO
author_rank: Regular Contributor
timestamp: August 22, 2019, 04:43:15 pm
content: Quote from: PA0PBZ on August 22, 2019, 03:59:03 pmI tried to delete my post but i receive this message: You cannot delete your own topics in this board. Check to make sure this topic wasn't just moved to another board.I apologize for that.

author: tomato
author_rank: Regular Contributor
timestamp: August 22, 2019, 07:11:16 pm
content: Quote from: Hrvoje_CRO on August 22, 2019, 03:20:39 pm
Datron 4200 options? - Page 1
Forum section: electronics / general

author: Scopetechniques
author_rank: Contributor
timestamp: August 14, 2019, 08:37:44 pm
content: Hello,I have a Datron 4200 AC Calibrator with options 30, 42, 80, 90.It is on the original label from Datron attached to the back of the unit "30 42 80 90".I am having a problem identifying option 42.30 - AC Current calibrator41 - Rear output (I thought the 42 was a typo on my unit, but it does not have rear output and never did).42 - ?80 - 115VAC 60Hz81 - 115VAC 50Hz82 - 115VAC 400Hz90 - Rack mount kit installed.Thanks,Victor
"Rubidium atomic clock" on eBay - Page 1
Forum section: electronics / general

author: Bud
author_rank: Super Contributor
timestamp: August 04, 2019, 02:22:25 am
content: How do you use this "clock" if it has no contacts? Is it supposed to be part of a machine with some sort of exciter and detector?https://www.ebay.ca/itm/Rb-High-Precision-Low-Phase-Noise-Rubidium-Atomic-Clock-Soviet-Ussr-DIY/123737315177?hash=item1ccf519769:g:~K0AAOSw0VBctceWEdit: added a copy of eBay picture for this topic archive purpose.

author: ArthurDent
author_rank: Super Contributor
timestamp: August 04, 2019, 02:37:16 am
content: It looks like a Rb gas filled cell removed from a Rb frequency standard. Interesting thingy to put on your shelf but of no practical use.

author: tkamiya
author_rank: Super Contributor
timestamp: August 05, 2019, 02:02:55 am
content: You mean they don't roll around at exact revolution?

author: Bud
author_rank: Super Contributor
timestamp: August 05, 2019, 02:59:43 am
content: It probably won't if your shelf is leveled

author: testpoint1
author_rank: Frequent Contributor
timestamp: August 14, 2019, 02:18:08 am
content: it is Rubidium Cell, outside is SRD diode, 6.8GHz frequecny
Simple GPSPO (GPS Programmable Oscillator) - Page 1
Forum section: electronics / general

author: Datman
author_rank: Regular Contributor
timestamp: August 08, 2019, 12:19:39 pm
content: Hi all!For periodic frequency counter tests I started experimenting with a u-blox NEO-7N GPS receiver bought from chipworld on ebay for only 9.98$ (but at his moment he sells only NEO-7M receivers for a little higher price). I don't know if it is a good one (the chip under the shield is a ublox G7020-KT, then it seems to be good...), but it works. I have written a program for Arduino (ATmega328P) to adjust the pulse out signal frequency from 1Hz to 15MHz in 1Hz steps.Output frequency is very accurate when GPS signal is received. There could be more or less jitter, because frequencies come from an internal 48MHz, then integer sub multiples should have less jitter than others, i.e. 12MHz have a low jitter; 10MHz have more jitter; nevertheless, in some cases it is not very clear... If I'm right, 8MHz or 6MHz is not as good as 12MHz, but it's only an example, because I'm not sure and I can't verify at this moment. In the PCB is also mounted a little battery. According to a schematic diagram I found, it should be a MS621FE-FL11E rechargeable Li-MnO2 3V 5.5mAh (five mAh!): at full charge, it should last for about 6 days. During this time, the internal TCXO maintains the adjustment and produce the same exact frequency also in absence of a GPS signal.Before discovering the TCXO adjust memory, I added to the software a correction menu: I can set correction in 20th of a ppm (-5.00, -4.95, -4.90, ... , -0.05, 0, +0.05, ..., +4.95, +5.00 ppm). It is recalled at each startup, applied to the current frequency and sent to the GPS module as no-lock frequency (GPS module can switch between two frequencies depending on the GPS-lock status), but it should not be applied if the error correction is already stored in the module!Then the question is:That's OK I can install a higher capacity battery, but how can I manage all this?If battery goes low after a long time or it is the first time I use that module and GPS signal is not locked, how can the program know that settings (with the frequency correction) are lost or never stored, then it has to apply an external correction?I would not make something very complex, because it is not a commercial project, but a simple solution would be useful for me and for each one would be interested in this very simple project.If someone has already addressed this topic, he could share his solution.Thank you allGianluca from Roma, ItalyP.s.: I've added a En version, with instructions and other in English.

author: ogden
author_rank: Super Contributor
timestamp: August 09, 2019, 07:48:42 am
content: I am afraid that your subject is misleading. What GPS signals actually are:https://en.wikipedia.org/wiki/GPS_signals
Hymeg HMC resistor Temp. coeff? - Page 1
Forum section: electronics / general

author: GEOelectronics
author_rank: Regular Contributor
timestamp: July 21, 2019, 07:23:52 pm
content: Anyone have an old HMC catalog showing temperature coefficient for HV reistors?This appears to be identical to the Hymeg HA series.George Dowell

author: GEOelectronics
author_rank: Regular Contributor
timestamp: July 22, 2019, 12:37:21 am
content: Project goal- build an industrial grade accuracy 1G Ohm shop standard resistor to help compare/sort stock 1G resistors for other projects (Ohmite 1G 1% Slim-Mox 1 and 2 watt versions).The standard resistor is built with 10 ea. 99M Ohm 0.1% HV resistors in series contained in a temperature lag filled with Dow dielectric compound. Trimmed with an auxiliary 10M series resistor to 1G Ohm for when used in it's primary function.A convenient daily secondary function is to use it at 990M, as a HV divider for a 10M input digital panel meter set up to monitor a regulated 1kV bench power supply.Here is a picture of the 990M module in the silicone bath for further testing.Nothing fancy, but this will bring my workbench up a notch in the high-impedance HV and High MegOhm measuring accuracy department.
National Instruments NI 4070 - Page 1
Forum section: electronics / general

author: IRFP
author_rank: Contributor
timestamp: July 14, 2019, 05:01:48 pm
content: Hello,Request for advice.What do you think about NI PCI 4070 multimeter cards?View the photo.Thank you for your return

author: dacman
author_rank: Frequent Contributor
timestamp: July 16, 2019, 12:14:06 am
content: My experience is with the PXI 4070 and it is a very good DMM card. Its max rated input is 300 Vrms.

author: Henrik_V
author_rank: Regular Contributor
timestamp: July 22, 2019, 12:02:25 pm
content: Depends on the price you have to pay and the things you really need (or want) to do with it.I like the PXI(e?) version, ... with the PCI(e?) I would be afraid to have a PC with that type of slot in 5 or 10 years.The full power of these devices is in sync'ed combination with other hardware.
Battery EMI - Noise producing or suppressing? - Page 1
Forum section: electronics / general

author: IanJ
author_rank: Unknown
timestamp: July 16, 2019, 04:24:25 pm
content: Hi all,I'm using a couple of Lithium-Ion batteries (PP3 type) mounted just about 5mm off a pcb with somewhat sensitive electronics (Vref op-amps etc stability in the uV's) on it.Now given a battery has electrons flying all over the place internally, but are also encased in an aluminium jacket (shield!) I just wondered what the effect of such a mounting would have on the electronics (EMI).......I don't mean via the electrical connections but issues radiated as EMI etc from the body of the battery.So far I have noticed absolutely no negative effects at all......no extra noise or drift etc.Ian.

author: Grandchuck
author_rank: Super Contributor
timestamp: July 16, 2019, 04:33:03 pm
content: This article discusses some ideas:https://www.sciencedirect.com/science/article/pii/S1110016817301710

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 16, 2019, 10:15:36 pm
content: A battery is a large, nonlinear, electrochemical capacitor.They are, in general,extremelyquiet, in and of themselves, with noise being dominated by fluctuations in ambient temperature, and the noise equivalent to the ionic motion inside (i.e., Johnson noise of the internal resistance, which is very low, fractional ohms).This is down in the nanovolts (batteries are often used to power extremely sensitive amplifiers and instruments, for this very reason), anything detectable is entirely due to your circuit or its surroundings.Tim
New Atomic Clock - Page 1
Forum section: electronics / general

author: mindcrime
author_rank: Unknown
timestamp: July 21, 2019, 05:53:38 pm
content: Thought the time-nuts here might find this interesting...https://www.vice.com/en_us/article/bj9qzv/the-most-precise-atomic-clock-ever-could-change-our-understanding-of-physics

author: Stray Electron
author_rank: Super Contributor
timestamp: July 21, 2019, 06:06:51 pm
content: 9.4 x 10 -19 seconds!WOW!I remember when HP conducted the Hafele and Keating Experiment by flying several HP 5016 Cesium Beam Atomic Clocks around the world in opposite directions finally proving the relativistic predictions on time.
Metrology of Electron Volt measurements- Which forum would be the proper home? - Page 1
Forum section: electronics / general

author: GEOelectronics
author_rank: Regular Contributor
timestamp: July 15, 2019, 04:07:36 pm
content: My main hobby is measuring electromagnetic energy in terms of electron-volts, at the high end of the electromagnetic spectrum, photons that are referred to as X-Rays or Gamma Rays. The science is called "Gamma Spectrometry".This is a rather specific, precise hobby, requires known reference sources, measurement of voltages, HV, etc. and much calibration is involved (eV, keV, MeV). Everything is related back to NIST (NBS) and government labs standards.A large part of this is squeezing out as much information as is possible from available equipment.I feel that these projects need to be posted somewhere, would someone here recommend the proper forum or sub forum where such work might be of interest and appreciated?These measurements have a multitude of practical applications, including identification of both radioactive and stable elements (of the periodic table).George Dowell

author: Dr. Frank
author_rank: Super Contributor
timestamp: July 15, 2019, 05:47:56 pm
content: Sounds like physics.. very interesting!That clearly belongs to the Metrology section.Have you got any references/links?Frank

author: GEOelectronics
author_rank: Regular Contributor
timestamp: July 15, 2019, 11:35:58 pm
content: Yes Frank, here is a link:https://www.qsl.net/k/k0ff/Identifying_stable_elements_via_XRF_with_Amateur_Apparatus/Pub2PDF.pdfGeorge Dowell
LED astray (volt meters) - Page 1
Forum section: electronics / general

author: PerranOak
author_rank: Frequent Contributor
timestamp: July 12, 2019, 04:27:23 pm
content: I fancy breaking from my trusty DMMs and getting a few of those little LED voltage "meters" or should I say "display units".I realise that they will be of low accuracy but they could be useful while in the initial stages of experimenting/adjusting/messing.Can anyone recommend a make/model?Cheers.

author: schmitt trigger
author_rank: Super Contributor
timestamp: July 12, 2019, 04:44:30 pm
content: Those are very useful to simultaneously measure current and voltage of multi-output supplies and see the effects of -for instance- cross regulation.Purchase any E-bay special which has a trimmer adjustment.
Newbie question about TICC and TIMELAB - Page 1
Forum section: electronics / general

author: tkamiya
author_rank: Super Contributor
timestamp: July 11, 2019, 03:16:41 pm
content: I am working with newly acquired TAPR TICC and TIMELAB.On graph, there are two lines. TICC has two input ports, ChA and ChB. TIMELAB has two lines. Statistic below has two lines. So far, it makes sense. TIMELAB uses blue and magenta. But what I cannot tell is, which color represents which port. I read the TIMELAB manual 3 times. Looked for info on web few times. I cannot find the answer.I thought I could find it from result (comparing Cs and GPSDO) but they are basically tracking each other. So that was no help. Tried disconnecting one, the whole count stopped.I know this is probably a dumbest question ever on EEVBLOG but can someone please help me out?

author: tkamiya
author_rank: Super Contributor
timestamp: July 11, 2019, 08:32:14 pm
content: I think I found it.Legend > Select > ChannelThe first channel (assuming it's ChA) will be Ch 0 and second one will be Ch 1.Color has dependency to where the source shows up in "spreadsheet" under the graph, and does not necessary reflect input. It gets really confusing as I can rearrange the order in which input appears.