Re: [time-nuts] 10MHz Rubidium reference source for frequencycounter

Tom wrote: As I understand it, his project is to use the high frequency output of a ublox NEO-7M to discipline a MV89 with a James Miller-style analog PLL. * * * (perhaps someone can post an English translation for us) Tom, I have a machine-translated PDF (~2.5MB), but nowhere to put

Re: [time-nuts] HP 5061A manual

Wayne wrote: So, I ordered the manual from Artek [tale of woe] So, can anyone point me to another source for this manual. If you search on the KO4BB manu

Re: [time-nuts] Divide by five

Joe wrote: Looks like I can get the 74AC161 in DIP from Mouser. Thanks to everyone for the suggestions. I still like DIP for prototyping on breadboards. If by "breadboards" you mean plug-in breadboards, AC logic often does not play well with them. It wants a real ground plane and very short

Re: [time-nuts] 10 MHz OCXO recommendations

Mark wrote: I find the concept of occasionally adjusting a good OCXO which in turn is used as a reference works well for me.I have some that haven't needed adjustment for over 2 years (they are still well within one part per billion of being on frequency.) A few of us have advocated thi

Re: [time-nuts] My NTGS50AA failed

Ignacio wrote: I'm not very sure that the DAC is working, I suppose that the unit doesn't measure the DAC output, it reports the DAC commands. My voltage figures is what LH reports (so the NTGS50AA reports, probably what it is trying to do), but the frequency control pin of the oscillator is

Re: [time-nuts] My NTGS50AA failed

Ignacio wrote: I'm not very sure that the DAC is working, I suppose that the unit doesn't measure the DAC output, it reports the DAC commands. My voltage figures is what LH reports (so the NTGS50AA reports, probably what it is trying to do), but the frequency control pin of the oscillator is

Re: [time-nuts] Quad Driven Mixer 5 to 10 MHz Doubler Article

John wrote: It is a cute technique, not originated by me, but useful. Indeed it is. I designed a similar one using a quadrature hybrid splitter and level 7 mixer, and it's almost scary how well it works. It's as cute as a regenerative divide by two using a DBM. Best regards, Charles

Re: [time-nuts] Quad Driven Mixer 5 to 10 MHz Doubler Article

Brian wrote: Personally, I'm lazy and like the Wenzel "full wave rectifier" design with a nice BPF on the output to obtain a clean 10MHz. The advantage of the multiplier circuit is that the signal straight out of the mixer has excellent harmonic and 5MHz suppression. In my circuit with the

Re: [time-nuts] Lucent GPSDO comments

Paul wrote: Lots of noise on the ti/pps and you can see EFC is rising all the time. I will say in the past it had been a steady rise now there is a wave that might mean its slowing down a bit. But this all looks rattier then I would believe. According to the plot, the oscillator is still a

Re: [time-nuts] Quad Driven Mixer 5 to 10 MHz Doubler

For those who may be curious, I dug out the schematic for my version of the quadrature-driven DBM frequency doubler and posted it to ko4bb.com. It uses a quadrature hybrid coupler to generate +45 and -45 degree signals at 5MHz, buffers them with emitter followers, and applies them to the RF an

Re: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812...

Bob wrote: The 58503 is a Z3801 with a pretty instrument style package put around it - right? If so, it might / should have a 10811 in it rather than an MTI OCXO. I think there may be other minor differences between the 58503 and the Z3801, including a newer GPS engine, but I'm not positiv

Re: [time-nuts] 10811's

Bob wrote: As best anybody can tell, the improved phase noise and ADEV 10811's came out of a screening / select process. There is a finite chance that a "normal part number" 10811 could be as good as or better than a part from one of the "better part number" versions. That is particularly tr

[time-nuts] GPS in the news

Dark matter the source of GPS irregularities? Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cg

Re: [time-nuts] Practical considerations making a lab standard with an LTE lite

Dave wrote But given the TCXO"s sensitivity to temperature changes, I don't know whether it might be preferable to mount the LTE lite in its own box without any power supplies in it - perhaps with some thermally insulting material around the LTE lite so the crystal doesn't experience any fast te

Re: [time-nuts] Practical considerations making a lab standard with an LTE lite

Dave wrote: It would be great if there was a circuit published which can give 50 Ohn output impedance from a 12-15 power supply, which a) Doesn't load the TCXO b) Doesn't degrade the phase noise. WRT loading the TCXO, someone should establish quantitatively how high the load impedance must

Re: [time-nuts] Practical considerations making a lab standard with an LTE lite

Poul-Henning wrote: Charles' design works great from the outside, but doesn't do anything with respect to the thermal energy expended by the encapsulated device themselves, which will cause convection in the inner box. I have been using the technique for 30+ years, including with many OCXOs (

Re: [time-nuts] Practical considerations making a lab standard with an LTE lite

Said wrote: The 10MHz units have a different RF output than the 20MHz units. The 20MHz units have a 50 Ohms series-terminated and buffered RF output, while the 10MHz units have the TCXO output drive the MMCX connector directly without series impedance matching. Both drive the line with 3.0V CM

Re: [time-nuts] Practical considerations making a lab standard with an LTE lite

Hal wrote: > So driving 50 Ohms inputs is not optimal here, 1M inputs are much better for > this purpose. That only works if you have a (very) short connection to the next stage. Things get interesting if you have, say, 10 feet of unterminated coax. Thinking that the output was a sine wave,

Re: [time-nuts] Practical considerations making a lab standard with an LTE lite

Said wrote: The increased current for the driver will cause heating near the crystal in both the CMOS driver and the 3.0V LDO as the LDO has to convert the excess voltage into heat. This may or may not affect the crystal. There would be next to no additional heating in the CMOS driver, becau

Re: [time-nuts] NIST isolation amplifiers

Bruce wrote: Another issue is that if even one output needs high reverse isolation and low crosstalk, then even those outputs that arent so critical will also need high reverse isolation and low crosstalk to avoid degrading the crosstalk to the critical output. This brings up the distinction b

Re: [time-nuts] NIST isolation amplifiers

Bruce wrote: A single 2N or equivalent transistor in a suitable circuit dissipating about 200mW or so can achieve a reverse isolation of 35dB with distortion of around -40dBc (output +13dBm) with a gain of unity, and an output impedance of 50 ohms with a PN floor of around -180dBc/Hz or s

Re: [time-nuts] NIST isolation amplifiers

Bruce wrote: Almost. 1:1:2 (turns ratio) transformers used in each stage and 1:1 transformer on input. This allows a lower power supply voltage to be used. I spent a little time (emphasis on "little") fiddling with the simulation, and I did not immediately find any solution with 1:1:2 and 1

Re: [time-nuts] NIST isolation amplifiers

Dave wrote: The magnetic field in the core due to the current in the windings is proportional to current times number of turns. If there are more than one winding, add the currents. Yes, 2 x 20mA certainly exceeds 30mA. The core will be driven closer or into saturation and the inductance

Re: [time-nuts] Does adjusting ocxo's degrade adev / madev ?

Mark wrote: I've long had a nagging suspicion that OCXO's that are not adjusted will in practice have lower ADEV than ones that are tweaked regularly. Several days ago I noticed that one of my 10811's was performing quite well (I believe this is the first time any of 10811's have delivered

Re: [time-nuts] 10 MHz Filters

John wrote: For the most part, you don't want transformer isolation unless you plan on using balanced lines. There are worse things than ground loops out there, and lifting a coax shield away from ground is a great way to find all of them. You certainly need the shield grounded at RF, but y

Re: [time-nuts] Minicircuits specs

Bob wrote: My past experience with Minicircuits is that they will not give you any data the "extends" the spec on a part. Simply put - if you are after 1 MHz data on a part that stops at 10, they are not likely to supply it. I've had better luck getting data from them that is just not stated

Re: [time-nuts] KS-24361 Output spectrum to 100 MHz

Götz wrote: the 10 MHz may not be dirty. The spectrum you show is that of a 10 MHz rectangular wave and that's what on the output from the 10 MHz connector, just a (may be clean) TTL-level signal, nothing fancy. The odd harmonics of 10MHz do indicate a square-ish wave. But there is also qu

Re: [time-nuts] Lucent KS-24361 10 Mhz out success.

Alex wrote: "The OCXO in the TBolt beats the Morion parts by a wide margin. Bob " in what way dies it? phase noise ? harmonics? standalone frequency stability? Yes, all of those (specifically referring to the Trimble p/n 37265 OCXO used in the later Tbolts that we usually see as surplus).

Re: [time-nuts] PRS-45 Cs Standard

Do open up and take a look. Do take photos. Do share. :) Bet the bottom plate is a good start. Cheers, Magnus Perhaps you can also post the manual to Didier's site (ko4bb.com) so we can all follow along? Best regards, Charles ___ time-nuts ma

Re: [time-nuts] Documents relevant to SR620

Jeaen-Luis wrote: The size of the file is around 5.5 MB. Let me know if you are interested, and how I can send it to you. You can post it to k04bb.com: Best regards, Charles

Re: [time-nuts] KS problem

Bob wrote: This plot is the phase difference between the 10MHz from the KS vs the 10MHz from the PRS45A. Assuming the hiccoughs were the KS and not the PRS, it looks to me like you recorded two periods where the KS lost tracking. Did you have a good, outdoor antenna with clear view of the w

Re: [time-nuts] KS problem

Bob wrote: My homegrown unit uses the same antenna via a GPS Source MS-14 splitter, but the LEA-6T in my homegrown is probably a better receiver than the UT+. I'll have to pull the splitter out of the circuit to see if the KS doesn't like it. Maybe I'll just try a different port first, as t

Re: [time-nuts] KS problem

Bob wrote: No, I do not have a 360 degree view of the sky * * * I have the southerly 180 degrees from about 20 degrees elevation and up. I bought this KS as an example reference for my homegrown. It may be that it's just not up to the job under my conditions. This will affect the ult

Re: [time-nuts] KS problem

Bob wrote: The issue for me is that if it couldn't get a good timing solution, why did if fail quietly? I would expect it to at least go into holdover and turn on an alarm or something. It was giving me fits at least 4 times a day, so I should have some idea whether using a different port o

Re: [time-nuts] Linear voltage regulator hints... --> WHY?

Bob wrote: Separate from the analysis of the voltage on the OCXO, there is another part to this: Ok, so why am I harping on the "need" for all this from a system standpoint ? We've been around this track a time or two before, me frustrated with your "make it just good enough" philosophy and

Re: [time-nuts] Wanted: Expert opinion of HP 58503A GPS time and frequency receiver.

Dave wrote: As you will have gathered from my posts on this mailing list, I bought something from eBay that was supposed to be an HP 58503A: But I have every reason to believe has a new case and serial number label fitted to the old chassis. The serial number just fell off in fact, but I manage

Re: [time-nuts] Linear voltage regulator hints...

In response to Dan, Azelio wrote: What have you observed, out of the GPS, with the temperature variations? Also, when you say "the GPS temperature," what, exactly, are you measuring/reporting? Is the GPS's own time base varying with temperature?** And how much thermal isolation is there be

Re: [time-nuts] Linear voltage regulator hints...

Dan wrote: It's interesting what can be learned from looking at a bunch of data... Sure enough, BUT: Never forget that this same methodology has suckered many "researchers" into claiming causal relationships between the birth rate in some small Peruvian village and the price of raw steel i

Re: [time-nuts] Linear voltage regulator hints...

tvb wrote: But, you're right, it *is* a really good idea, and of course we all know the Trimble Thunderbolt does it this way. One reason why it's always the #1 favorite GPSDO among time nuts. That and the fact that the PLL loop parameters can be fiddled over RS232. Certainly, I'm surprised

Re: [time-nuts] Linear voltage regulator hints...

Dan wrote: The test was simple. A couple of seconds of warm air from a hair dryer on low setting (the air coming out is 15C above ambient, so not very much heat at all) through a paper tube blowing on the GPS. That little change causes the phase to shift about 200nS in just a few seconds. Tha

Re: [time-nuts] Connections for FE-5680A rubidium sources

Dave wrote: > I suggest you go to http://www.febo.com/pipermail/time-nuts/ back a couple > of years and you will find every thing you ever want to know about the FE > 5680A. Similar to the recent Lucent activity I did do that, and found various comments about various options, and people note

Re: [time-nuts] Linear voltage regulator hints...

Dan wrote: My gut feeling is you are right about the GPS time base being sensitive. It would be fun to hack into this and try clocking it off the OCXO, but I'm not there yet! :) One interesting way would be to use the disciplined OCXO output to drive a DDS synthesizer set to the GPS unit's c

[time-nuts] Frequency doubler with quadrature hybrid

Some time ago, I said I'd post a description and schematic of an excellent frequency doubler using a quadrature hybrid directional coupler to drive a diode DBM. It is now available on ko4bb.com following Didier's recent work on the site (Thank you, Didier, for this wonderful resource):

[time-nuts] Simple AC mains zero-cross detector

Every so often, the subject of logging the zero-crossings of the AC mains comes up. There are any number of ways to couple the AC mains to logic circuitry (coupling with very high value resistors, capacitor coupling, and optical isolation have been mentioned). A simple AC mains ZCD that is tr

Re: [time-nuts] Choke Rings and Points North

Inquiring minds surely are in high gear!! And to think, all I wanted to know was how close I needed to to point to north!! The need to point north is a legitimate question. There is a chance that they designed some magic into it to deliberately shape the response. Having taken a few apart,

Re: [time-nuts] Simple AC mains zero-cross detector

Bob wrote: The Collins paper on hard limiters does indeed apply here. You *could* make a 60 Hz chain that got down into << 1 us sort of resolution. I don't know how "much less than" 1uS you mean by "<<", but I was seeing less than 1uS jitter with the circuit described. Best regards, Charle

Re: [time-nuts] Simple AC mains zero-cross detector

Dave wrote: I'm not trying to downplay the circuit in the link above, but I want to offer another possible solution to Zero-Crossing needs. Here's an Idea For Design from EDN magazine that I've used a couple times in non-time-nut circuits, and I must say that it works beautifully. I have no

Re: [time-nuts] Simple AC mains zero-cross detector

Hal wrote: What are you going to do with data from the line accurate to 1 microsecond? Me? Nothing. I don't find the meanderings of the mains frequency all that interesting, aside from observing them from time to time via the sweep second hand of a synchronous wall clock. But lots of othe

Re: [time-nuts] Simple AC mains zero-cross detector

Gary wrote: Zero crossing and frequency measurement are not the same thing. Generally you zero cross detect to switch a load with the minimum glitch. For frequency measurement, I'd filter the signal before counting it. Grid-nuts are interested in *both* the instantaneous frequency of the gri

Re: [time-nuts] Simple AC mains zero-cross detector

Gary wrote: Why not use a lower voltage transformer, preferably not at a lethal voltage. You only need a couple of volts to drive the rest of the circuit. As you can see from the schematic, the voltage is diode-clamped almost immediately to ~ +/- 1.5v. The reason for using a 120v winding i

Re: [time-nuts] Simple AC mains zero-cross detector

Gary wrote: Why not use a lower voltage transformer, preferably not at a lethal voltage. You only need a couple of volts to drive the rest of the circuit. As you can see from the schematic, the voltage is diode-clamped almost immediately to ~ +/- 1.5v. The reason for using a 120v winding i

Re: [time-nuts] Simple AC mains zero-cross detector

Hal wrote: What sort of interference do you see? There is a general "grass" on the entire waveform. At our location, the tops of the sine wave are clipped off (as the power is delivered). See attached image (the orange trace is the AC we receive from the grid; cyan is the distortion resid

Re: [time-nuts] Simple AC mains zero-cross detector

Gary wrote: I try to minimize dangerous voltages. Anyway, the filtering reduces the slew, so you can't have it both ways. Starting with 120v gives you 10x the slew rate that starting with 12v does, whatever filtering you use. If by post processing you are averaging, then you certainly hav

Re: [time-nuts] Looking for J1 pinout newly purchased 10811D

Ulli wrote: I would also be interested to learn for which devices these board were originally made - couldn't find anything. The board should have a part number etched in copper, of the form "0-y". "" should be the instrument model number. Best regards, Charles

Re: [time-nuts] Simple AC mains zero-cross detector

Magnus wrote: So, I do not completely agree that a through-zero measurement with a TIC has all the information No, a series of time-stamped zero crossings doesn't have all of the information in the original signal, and a small glitch that occurs during the middle of a cycle (far away from a

Re: [time-nuts] Simple AC mains zero-cross detector

Mike wrote: From a Time-Nut perspective, isn't phase/frequency of the (nominal) 60 Hz all we'd be interested in? Phase is best measured at a zero crossing as this is the (only) phase measurement point which is independent of amplitude. That is the primary interest (as I understand it -- I am

Re: [time-nuts] Simple AC mains zero-cross detector

Didier wrote: A commend regarding your ZCD. You propose to use a dual 120V primary transformer to generate the isolated 120V AC needed by your circuit. Unless specifically designed for that purpose, the isolation between the two 120V primaries of a common transformer is probably not as good as t

Re: [time-nuts] Simple AC mains zero-cross detector

Ed wrote: It seems to me that a low voltage secondary should be OK by using a fast comparator IC rather than a transistor to decide - the gain of the IC allows for much smaller detection levels, so the equivalent zero-crossing velocity could be the same. An IC tripping in a 10 mV band should

Re: [time-nuts] Simple AC mains zero-cross detector

Chuck wrote: Transformers, such as are in wall warts, etc..., are wound in a way that is pretty good for 50Hz/60Hz operation, but have had nothing intentionally done to normalize operation at any other frequency. Nor have they had anything done to improve the fidelity of the signal they pass.

Re: [time-nuts] schematics of frequency counter

Li Ang wrote: RF pnp transistor is harder to get. I would like the front end works at 300MHz. My questions: 1) why the difference of DC bias of the 2 NPN matters? I thought only the frequency part is useful to a counter, amplitude information is useless right? You want the circuit to switch

Re: [time-nuts] New GPSDO on EBAY From China

Dave wrote: I found this new inexpensive GPSDO on ebay listed from a seller from China: It looks interesting and tempting BUT the seller doesn't give any spec's on the unit or osc type. The seller has 10 negative and 18 neutral feedback's in the past 6 months out of a total of 2110 for a

Re: [time-nuts] KS24361 Ulrich Z83XX software mod works

Some time ago, there was a thread about whether Z38xx writes to the GPSDO's NV memory every second, raising the possibility that it could prematurely wear out the NV memory if it were used continuously to monitor a GPSDO. Here is what Ulrich said (23 April 2013): due to the discussion that e

Re: [time-nuts] New GPSDO on EBAY From China

Li Ang wrote: This unit is done by BG7TBL. In his store on taobao.com, there is a adev chart. Please refrer to this link That ADEV chart (see below) raises more questions than it answers. At least the time constant is not too short (a very common problem with DIY GPSDOs). But when the GPS

Re: [time-nuts] Are these PRS10's worth it ?

Bruce wrote: By the way, The TS-2500 is a GPS-referenced source; however, the unit seems to compare its internal crystal oscillator with GPS, the PRS-10, and other 10 MHz sources (that can be connected for monitoring) and keeps track of their behaviors with a microprocessor. It appears the P

Re: [time-nuts] Any reason not to use one power amplifier and splitter for distribution amplifier?

Dave wrote: I was looking to make a 10 MHz distribution amp to feed test equipment with the output of a GPSDO. * * * 16-way Minicircuits splitter on eBay which I got for $40. I guess the loss is around 12 dB. Is there any reason not to just drive that with 22 dBm or so of power to get

Re: [time-nuts] Any reason not to use one power amplifier and splitter for distribution amplifier?

Bruce wrote: A 10nF cap connected to the emitter winding [instead of the collector] avoids capacitively coupling collector power supply noise to the output (assuming that the collector supply isnt ground.). Good point. I take pains with power supply design and very rarely have problems with

Re: [time-nuts] schematics of frequency counter

Actually, I dont want to ask my colledge for help. Everytime ,for each guy I ask for help, I need expain the entire system and principle of a frequency counter to him. They just keep asking questions instead of answering mine. In defense of the hardware guys, there are a lot of questions that

Re: [time-nuts] Any reason not to use one power amplifier and splitter for distribution amplifier?

Dave wrote: At 50 MHz, the loss from the common port is 12.8 dB, and the isolation between two ports sets of ports is either 38 or 48 dB To get the worst-case output-to-output isolation, you need to test two output ports that are electrically adjacent (i.e., that share the same last 2:1 spli

Re: [time-nuts] VC-OCXO EFC stability.

Luis wrote: With a multiturn pot and a 78L05 I can get a 0 to 5V EFC to tune an OCXO on desired freq. But... maybe other voltage regulators or other scheme have better temp stability than the old 78L05. Before I crawl lost in new'ish fancy regulator land does anybody know the killer solution/IC

Re: [time-nuts] Any reason not to use one power amplifier and splitter for distribution amplifier?

Dave wrote: Yes, but I was aware of this, and that's why I got two different isolation figures. What I was pointing out is that there will be *4* different isolation figures from any one output port, not just two. The lowest will be to the one electrically adjacent output, next (a bit highe

Re: [time-nuts] question Alan deviation measured with Timelab and counters

Stephane wrote: I need to make a squarer. I was hesitating between several methods : using a CMOS gate, but this will increase the flicker noise from what I've read, using an amplifier and clamping diodes or a fast comparator which might create some noise around the trigger point... Any reco

Re: [time-nuts] question Alan deviation measured with Timelab and counters

Stephane wrote: I'm now trying to evaluate various architectures of 2-channels squarers and a DMDT. For that I'm designing a PCB with 4 squarers : simple 74ac04 gate biased at VCC/2, a LT1016 comparator, the transistor based differential amplifier from Winzel and the one from Charles. Note t

Re: [time-nuts] (no subject)

Typically a PLL loop uses a PI loop-filter, making it a PI-control system with a steered integrator in the form of the oscillator. Many other control systems prefer to use the PID controller I have seen no evidence that the Thunderbolt, in particular, uses a D term. Nor have I seen any evid

Re: [time-nuts] 5>10 doubler

Andrea wrote: Now I have some 5MHz DOCXO. I have started to experiment with them and I would like to build a frequency doubler. * * * By the way, I see that really many of the 10MHz reference out there, are in effect doubled 5MHz ones so build a doubler seems reasonable for me. One th

Re: [time-nuts] 5>10 doubler

Bruce wrote: Using the square law characteristic will inevitably increase the phase noise floor particularly in the flicker region with respect to just using the switching characteristic of a JFET, diode or BJT (non saturated). Even FETs with very large transconductance and low pinchoff vol

Re: [time-nuts] SR620 question

Gerhard wrote: 1. Is it a drawback wrt ADEV when a SR620 does not have have the opt. oven if I have an ultra clean external reference? Does it use the external ref directly or does it just pull the own reference to the external value in the long run, no matter if it's the good or the bad oscil

Re: [time-nuts] 5>10 doubler

Gerhard wrote: It is a different game when you want to notch away sub/harmonics. One problem with using crystals as traps (notch filters) is that the series resistance of a crystal is several orders of magnitude higher than that of a good series-resonant LC -- generally in the 50-100 ohm ra

Re: [time-nuts] 5>10 doubler

I wrote: Once upon a time, Motorola made monolithic quad BJTs -- but I'm not aware of any matched quads similar to 2Ns at this time. Gerhard replied: There still are MAT04 HFA3046-3096-3127-3128 if duals are enough: SSM2220 MAT12 also mat02, mat03, maybe SSM2110 [probably meant SSM2210?

Re: [time-nuts] 5>10 doubler

I had forgotten about one quite promising candidate -- the THAT300 matched monolithic quad. I have some of those, too. I'll put it on the to-do list. To the best of my knowledge, they do not have reverse protection diodes across the B-E junctions (I've never had any reason to check). Best

[time-nuts] ***SPAM*** Re: 5>10 doubler

Andrea wrote: the square-law characteristic of devices should be avoided, so the configuration of the doubler must be some sort of "ideal" full wave rectifier I disagree strongly with this, at least where push-push JFET doublers are concerned. If you look at the schematic Bruce posted on hi

Re: [time-nuts] 5>10 doubler

I wrote: In both cases, when the FETs are conducting they are operating as common-source linear amplifiers, NOT as switches. should be, "common gate linear amplifiers" Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To

Re: [time-nuts] 5>10 doubler

Andrea wrote: I see. This configuration is in effect a common gate B-class (or AB, or "barely A") amplifier and the rectification is a side effect. But, what is the advantage between it and a couple of diode-connected transistors with a full A-class (more linear, so less spurs) amplifier in fro

Re: [time-nuts] 5>10 doubler

Andrea wrote: But, what is the advantage between it and a couple of diode-connected transistors with a full A-class (more linear, so less spurs) amplifier in front of it? If it's so, why use a nonlinear (or barely linear) gain stage to rectify? Using just one stage means in general less ph

Re: [time-nuts] 5>10 doubler

Bruce wrote: Whilst the output signal of the barely class A JFET amplifier has a lower unwanted harmonic content and thus requires less filtering to achieve a given suppression of unwanted harmonics and/or subharmonics, the question of the flicker phase noise penalty incurred by the barely cl

Re: [time-nuts] 5>10 doubler

Bill wrote: Push-Push Jfet amplifier with parallel inputs and a Toroid output transformer, no secondary along with a simple filter using a 10 MHz series resonate crystal connected to one drain and an adjustable capacitor connected to the other would work fine. You connect the other ends of th

Re: [time-nuts] 5>10 doubler

Andrea wrote: Can you put in another graph the calculated difference to a pure sine wave? I'm not sure what you mean by "the calculated difference to a pure sine wave." I already reported the amplitudes of all of the visible spurs (that is, the ones above the simulation noise floor), which

Re: [time-nuts] 00105-6013 schematic wanted

Luciano wrote: I am looking for the internal schematic of the 00105-6013 OCXO mounted in the old series of the HP5065A. I have two of them not working and I would like to fix it. That is the oscillator assembly used in at least some HP-105A and 105B oscillators. HP service manual 02479-1 (p

Re: [time-nuts] Good references on holdover?

You may find the following Master's thesis useful: Best regards, Charles ___ time-nuts mailing list -- ti

Re: [time-nuts] TimeSource 2700

John wrote: I recently purchased a Symmetricom TimeSource 2700 from ebay, the unit seems to work but I cant find any way to log into it, I'v tried both the CRAFT and RS232 ports but can't seem to get them to work using a NullModem or standard cable, does anyone have any information or tips I

Re: [time-nuts] WWVB receivers obsolete!?

There is a Spectracom Technical Note discussing this [TN13-101(A), dated March 12, 2012]: or

Re: [time-nuts] XOR frequency doubler question 5/10 Mhz

Chuck wrote: To make decent use of this technique, I believe that you would have to install 20 to 30dB of 5MHz rejection, and a 10MHz low pass filter in the output circuitry * * * The 5MHz rejection filter is necessary to prevent phase anomalies from appearing due to the beating of t

Re: [time-nuts] OXCO insulation

Brian wrote: Thought of trying aerogel insulation? Dust free varieties avoid handling issues. Be careful not to over-insulate the oven -- it depends on a certain amount of heat flow to ambient to balance the heater. The stability of the heater control loop depends on having the correct amou

Re: [time-nuts] homebrew counter new board test result

Attila wrote: I think the proper solution here would be to use a high speed comparator instead (with hysteresis). See below for three possibilities, in addition to the Wenzel-style squarer I posted previously. Circuit A is the simplest of these (and, in my view, best, because it minimizes

Re: [time-nuts] homebrew counter new board test result

Li Ang wrote: I have some LT1016 in hand, I will evaluate with it. I know it is tempting to use what is in hand rather than source new parts, but for squaring 10MHz the LT1719 and LT1720 are much better suited than the LT1016. They have internal hysteresis, which makes them much easier to

Re: [time-nuts] homebrew counter new board test result

The Schmitt trigger mostly avoids glitches on the output. Does it do anything to reduce timing noise if the input signal is clean enough that it doesn't make any glitches? No, it just avoids flipping state at the transition point(s). Note also that the hysteresis of logic gates with Schmitt

Re: [time-nuts] homebrew counter new board test result

Magnus wrote: A bit of hysteresis can help to avoid flipping back, but considering the type of signal, it passes the mid-point (0 V) at highest slew-rate, so there is very little risk of flipping back and fourth in the first place, so hysteresis may not even be needed. A 1 Vrms, 10MHz sine wav

[time-nuts] Recording mains frequency/phase [WAS: No GPS satellites]

ben wrote: I'm going to have to build one of these. Assume you have some sort of circuit that converts low-voltage AC from a transformer secondary to a pulse train, start a timer, and count x amount of pulses? Here is a zero-cross detector designed for this purpose:

Re: [time-nuts] Recording mains frequency

Daniel wrote: I designed a board with an OCXO, pic microcontroller, power supply, mains interface with optocoupler, and SD card for data collection..* * * The boards also have a small Li-Ion battery and battery charger for short power outages. Boards are manufatured and the most expe

Re: [time-nuts] 50 ohm Driver

Is [one gate sourcing or sinking current into paralleled gates that don't switch at exactly the same time] a real problem? How far off can the prop delay be for 2 gates on the same chip? I seem to remember reading something saying it was OK to just wire them up in parallel. It could have be

Re: [time-nuts] 50 ohm driver

I got excited when I found the SN74AS1004AD which has the exact same function and pin out but delivers 48 mA per channel. While one output did give me 0-3.0 V into 50 ohm, combining them, as we do for the 74AC, actually produced worse results. Can you post a link to the datasheet for your p

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