All, Just to convince myself that my setup is OK, I decided to check my 5370A counter by doing ADEV/MDEV on its own OCXO output, a self-check as recommended in the manual. 50 ohms input on START, HiZ input on STOP, thresholds in preset (~ 0 Volt), common input (internally bridged), rising edge on START, falling edge on STOP. The results are shown in purple. I also measured the HP 8644A OCXO output the same way and got the green plot. No surprise there, more noise because the counter is measuring an external source as opposed to its own timebase. Based on that, I know that the 5370A counter is not the one generating all that noise on the 5328A divider readings. The one thing I will do just for fun is to measure all the OCXOs I have in-house to see if results will vary a lot. I will try to keep the START-to-STOP interval small using an external delay line on the STOP input instead of bridging inside.
>From all that discussion, and after having tried various settings, I come up to the conclusion that the HP 5328A counter makes a good general purpose divider, for example, checking GPS PPS performance. But I need a much better performing divider for serious low jitter source measurements. One thing I notice on my 5370A, I don't get ~50 ns readings when the thresholds are set to PRESET (0.00 on the readout). I get ~45 ns. I can adjust the thresholds to get 50 ns, but I would have expected the readings to be much closer to 50ns, even with a sine wave. Amplitude is 400mV pk-pk. Is this typical of the 5370A, or it needs calibration? Bert. ps: I am thankful to Magnus, Bruce, John, Pete and a few others for the hints on ADEV and MDEV measurements. I also got a few emails of people who are, like me, learning a lot from this email exchange. ----- Original Message ---- From: "[email protected]" <[email protected]> To: [email protected] Sent: Wed, March 17, 2010 4:14:51 PM Subject: time-nuts Digest, Vol 68, Issue 95 Send time-nuts mailing list submissions to [email protected] To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to [email protected] You can reach the person managing the list at [email protected] When replying, please edit your Subject line so it is more specific than "Re: Contents of time-nuts digest..." Today's Topics: 1. Re: HP 5328A Divider / Timebase Output performance (SAL CORNACCHIA) 2. Frequency divider PCB: Current status on "pre-orders", and pointers to documentation. (David C. Partridge) 3. Re: Frequency divider PCB: Current status on "pre-orders", and pointers to documentation. ([email protected]) 4. Re: Frequency divider PCB: Current status on "pre-orders", and pointers to documentation. (Bill Mason) 5. Re: HP 5328A Divider / Timebase Output performance (Magnus Danielson) 6. Re: HP 5328A Divider / Timebase Output performance (Bruce Griffiths) ---------------------------------------------------------------------- Message: 1 Date: Wed, 17 Mar 2010 08:46:27 -0700 (PDT) From: SAL CORNACCHIA <[email protected]> Subject: Re: [time-nuts] HP 5328A Divider / Timebase Output performance To: Discussion of precise time and frequency measurement <[email protected]> Message-ID: <[email protected]> Content-Type: text/plain; charset=iso-8859-1 Hi Bert, Could You tell me?how to?produced the trace for two timebase oscillators. Thank You ?Best regards, Sal C. Cornacchia Electronic RF Microwave Engineer (Ret.) ________________________________ From: "Bert, VE2ZAZ" <[email protected]> To: [email protected] Sent: Wed, March 17, 2010 11:01:14 AM Subject: [time-nuts] HP 5328A Divider / Timebase Output performance OK, I am doing a 24-hour ADEV analysis of the HP 5328A Timebase Output when set to divide-by-10,000,000. I use the 10MHz output from an HP 8644A sig.gen. OCXO. I split that 10MHz signal into two; one end goes to the the input of the HP 5328A counter. The other 10MHz end goes to the Stop input of the 5370A. The Start input gets the 5328A Timebase Output PPS. The 5370A is free running. I have included the plot of what I get so far. I would tend to say that the divider is pretty lousy for short term, but it is all fine for longer runs, right? Is this what I should expect from a TTL/ECL divider chain designed in the '70s-'80s? How would this compare to a modern divider chain, like the PIC divider or David Partridge's divider board? Since I get a straight line pretty much up to 500s or so, do I conclude that the divider dominates the system noise up to there? Of course, the 5370A timebase drift has to be taken into account but is not subtracted on that plot. Thanks, Bert. ? ? ? __________________________________________________________________ Yahoo! Canada Toolbar: Search from anywhere on the web, and bookmark your favourite sites. Download it now http://ca.toolbar.yahoo.com. ------------------------------ Message: 2 Date: Wed, 17 Mar 2010 18:28:23 -0000 From: "David C. Partridge" <[email protected]> Subject: [time-nuts] Frequency divider PCB: Current status on "pre-orders", and pointers to documentation. To: <[email protected]>, <[email protected]>, <[email protected]>, <[email protected]>, "'Discussion of precise time and frequency measurement'" <[email protected]> Message-ID: <2eb42b61c3d34c6faa8edf823a998...@apollo> Content-Type: text/plain; charset="us-ascii" The current situation is that I have almost enough statements of intent to get to the magic 50 which will allow a price of GBP14.50 per board plus delivery. For the avoidance of doubt, this is the price for a bare PCB, not for a kit, and definitely not for a made up board. I intend to "keep the book open" until 18:00 Zulu (UTC or GMT) on Sunday 21st March, I will then count up what I have and order that many boards (and maybe a few over to get a nice round number). I've received numerous reqeusts for the design documentation, schematic, and a bill of materials They can all be downloaded from my website, but there's no way (yet) to navigate to them (a round tuit problem). Write up: <http://www.perdrix.co.uk/FrequencyDivider/Frequency%20Divider%202.pdf> Schematic: <http://www.perdrix.co.uk/FrequencyDivider/Frequency%20Divider%202%20Schemat ic.pdf> and BOM: <http://www.perdrix.co.uk/FrequencyDivider/Frequency%20Divider%202%20Bill%20 of%20Materials.pdf> The schematic and write up have both been updated today, and the BOM is new today. For those who worry about SMT soldering, you don't need a reflow oven, it can all be done with tweezers, a small tipped iron, fine solder wire, and liquid flux (or a flux pen). A good pair of strong reading glasses helps too! See: <http://www.curiousinventor.com/guides/Surface_Mount_Soldering/101> I've also had questions on part pricing: Back in 2008, the cost to populate one PCB using a MAX999, thick film resistors, and standard (X7R) chip capacitors was about GBP28 including Molex headers and SMB sockets. I don't expect it to be massively different now. I'm afraid I don't have full parts kits, and the necessary up front costs to do so is more than my finances allow at present. FWIW, the ADCMP600 is a bit pricier than the MAX999, and is supposed to be "better", though I'm not sure in what respects it is better. If you want the lowest possible level of phase noise, you would follow the bill of materials recommendations and use thin film resistors and C0G capacitors in the clock shaper part of the circuit at the very least, but this adds considerably to the cost (for example 100nF C0G 1206 capacitors are about 1 pound each, while an X7R part is only a few pence). Regards, David Partridge ------------------------------ Message: 3 Date: Wed, 17 Mar 2010 14:37:47 -0400 From: [email protected] Subject: Re: [time-nuts] Frequency divider PCB: Current status on "pre-orders", and pointers to documentation. To: [email protected], [email protected] Message-ID: <[email protected]> Content-Type: text/plain; charset="us-ascii" Hi David, please put me on the list, I need 1ea PCB board.. My call is HG5ED. Best regards, Ernie. Ps. hope Paypal is OK? -----Original Message----- From: David C. Partridge <[email protected]> To: [email protected]; [email protected]; [email protected]; [email protected]; 'Discussion of precise time and frequency measurement' <[email protected]> Sent: Wed, Mar 17, 2010 7:28 pm Subject: [time-nuts] Frequency divider PCB: Current status on "pre-orders", and pointers to documentation. The current situation is that I have almost enough statements of intent to et to the magic 50 which will allow a price of GBP14.50 per board plus elivery. For the avoidance of doubt, this is the price for a bare PCB, ot for a kit, and definitely not for a made up board. I intend to "keep the book open" until 18:00 Zulu (UTC or GMT) on Sunday 1st March, I will then count up what I have and order that many boards (and aybe a few over to get a nice round number). I've received numerous reqeusts for the design documentation, schematic, and bill of materials They can all be downloaded from my website, but there's no way (yet) to avigate to them (a round tuit problem). Write up: <http://www.perdrix.co.uk/FrequencyDivider/Frequency%20Divider%202.pdf> Schematic: <http://www.perdrix.co.uk/FrequencyDivider/Frequency%20Divider%202%20Schemat c.pdf> and BOM: <http://www.perdrix.co.uk/FrequencyDivider/Frequency%20Divider%202%20Bill%20 f%20Materials.pdf> The schematic and write up have both been updated today, and the BOM is new oday. For those who worry about SMT soldering, you don't need a reflow oven, it an all be done with tweezers, a small tipped iron, fine solder wire, and iquid flux (or a flux pen). A good pair of strong reading glasses helps oo! See: <http://www.curiousinventor.com/guides/Surface_Mount_Soldering/101> I've also had questions on part pricing: Back in 2008, the cost to populate ne PCB using a MAX999, thick film resistors, and standard (X7R) chip apacitors was about GBP28 including Molex headers and SMB sockets. I on't expect it to be massively different now. I'm afraid I don't have ull parts kits, and the necessary up front costs to do so is more than my inances allow at present. FWIW, the ADCMP600 is a bit pricier than the MAX999, and is supposed to be better", though I'm not sure in what respects it is better. If you want the lowest possible level of phase noise, you would follow the ill of materials recommendations and use thin film resistors and C0G apacitors in the clock shaper part of the circuit at the very least, but his adds considerably to the cost (for example 100nF C0G 1206 capacitors re about 1 pound each, while an X7R part is only a few pence). Regards, avid Partridge ______________________________________________ ime-nuts mailing list -- [email protected] o unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts nd follow the instructions there. ------------------------------ Message: 4 Date: Wed, 17 Mar 2010 14:41:32 -0500 From: "Bill Mason" <[email protected]> Subject: Re: [time-nuts] Frequency divider PCB: Current status on "pre-orders", and pointers to documentation. To: <[email protected]>, "'Discussion of precise time and frequency measurement'" <[email protected]> Message-ID: <73a1edf9e0364908b9e0f233e4b4e...@maryjo2> Content-Type: text/plain; charset="us-ascii" David: Please put me on the list for two each of the divider boards plus documentation, etc.... Thanks: Bill Mason W5STP [email protected] [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of David C. Partridge Sent: Wednesday, March 17, 2010 1:28 PM To: [email protected]; [email protected]; [email protected]; [email protected]; 'Discussion of precise time and frequency measurement' Subject: [time-nuts] Frequency divider PCB: Current status on "pre-orders",and pointers to documentation. The current situation is that I have almost enough statements of intent to get to the magic 50 which will allow a price of GBP14.50 per board plus delivery. For the avoidance of doubt, this is the price for a bare PCB, not for a kit, and definitely not for a made up board. I intend to "keep the book open" until 18:00 Zulu (UTC or GMT) on Sunday 21st March, I will then count up what I have and order that many boards (and maybe a few over to get a nice round number). I've received numerous reqeusts for the design documentation, schematic, and a bill of materials They can all be downloaded from my website, but there's no way (yet) to navigate to them (a round tuit problem). Write up: <http://www.perdrix.co.uk/FrequencyDivider/Frequency%20Divider%202.pdf> Schematic: <http://www.perdrix.co.uk/FrequencyDivider/Frequency%20Divider%202%20Schemat ic.pdf> and BOM: <http://www.perdrix.co.uk/FrequencyDivider/Frequency%20Divider%202%20Bill%20 of%20Materials.pdf> The schematic and write up have both been updated today, and the BOM is new today. For those who worry about SMT soldering, you don't need a reflow oven, it can all be done with tweezers, a small tipped iron, fine solder wire, and liquid flux (or a flux pen). A good pair of strong reading glasses helps too! See: <http://www.curiousinventor.com/guides/Surface_Mount_Soldering/101> I've also had questions on part pricing: Back in 2008, the cost to populate one PCB using a MAX999, thick film resistors, and standard (X7R) chip capacitors was about GBP28 including Molex headers and SMB sockets. I don't expect it to be massively different now. I'm afraid I don't have full parts kits, and the necessary up front costs to do so is more than my finances allow at present. FWIW, the ADCMP600 is a bit pricier than the MAX999, and is supposed to be "better", though I'm not sure in what respects it is better. If you want the lowest possible level of phase noise, you would follow the bill of materials recommendations and use thin film resistors and C0G capacitors in the clock shaper part of the circuit at the very least, but this adds considerably to the cost (for example 100nF C0G 1206 capacitors are about 1 pound each, while an X7R part is only a few pence). Regards, David Partridge _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ------------------------------ Message: 5 Date: Wed, 17 Mar 2010 20:53:09 +0100 From: Magnus Danielson <[email protected]> Subject: Re: [time-nuts] HP 5328A Divider / Timebase Output performance To: Discussion of precise time and frequency measurement <[email protected]> Message-ID: <[email protected]> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Bert, VE2ZAZ wrote: > OK, I am doing a 24-hour ADEV analysis of the HP 5328A Timebase Output when > set to divide-by-10,000,000. I use the 10MHz output from an HP 8644A sig.gen. > OCXO. I split that 10MHz signal into two; one end goes to the the input of > the HP 5328A counter. The other 10MHz end goes to the Stop input of the > 5370A. The Start input gets the 5328A Timebase Output PPS. The 5370A is free > running. I have included the plot of what I get so far. > > I would tend to say that the divider is pretty lousy for short term, but it > is all fine for longer runs, right? Do you have any cycle slips in the measurement series? You should remove those if they occur before ADEV processing. You could get better results than those presented from that technology, but maybe this mode isn't the best. If you send me the data offlist I could look at it if you want. Cheers, Magnus ------------------------------ Message: 6 Date: Thu, 18 Mar 2010 09:14:42 +1300 From: Bruce Griffiths <[email protected]> Subject: Re: [time-nuts] HP 5328A Divider / Timebase Output performance To: Discussion of precise time and frequency measurement <[email protected]> Message-ID: <[email protected]> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Bert, VE2ZAZ wrote: > OK, I am doing a 24-hour ADEV analysis of the HP 5328A Timebase Output when > set to divide-by-10,000,000. I use the 10MHz output from an HP 8644A sig.gen. > OCXO. I split that 10MHz signal into two; one end goes to the the input of > the HP 5328A counter. The other 10MHz end goes to the Stop input of the > 5370A. The Start input gets the 5328A Timebase Output PPS. The 5370A is free > running. I have included the plot of what I get so far. > > I would tend to say that the divider is pretty lousy for short term, but it > is all fine for longer runs, right? > > Is this what I should expect from a TTL/ECL divider chain designed in the > '70s-'80s? How would this compare to a modern divider chain, like the PIC > divider or David Partridge's divider board? > > Since I get a straight line pretty much up to 500s or so, do I conclude that > the divider dominates the system noise up to there? > > Of course, the 5370A timebase drift has to be taken into account but is not > subtracted on that plot. > > Thanks, > > Bert. > > Bert Trigger jitter in the 5328 input? Trigger jitter at the 5370A input? What are signal levels at the 5328 and 5370A inputs? What were the input attenuator settings on the 5370A and the 5328A? What were the input impedance settings for the 5328A and 5370A? A well designed divider with no input trigger jitter issues will have an output jitter well below the 5370A noise floor when dividing down a low noise source. Typical cycle to cycle jitter of ACMOs logic is ~1ps rms. Typical cycle to cycle jitter of HCMOs logic is ~4ps rms. Typical cycle to cycle jitter of ECL logic is <1ps rms. However using a clean well filtered power supply for the critical parts of the divider is advisable. Even the noise level exhibited by the 5328 divider is well below that of your GPS receiver. When comparing one low noise frequency standard against another you using the divider and the 5370A you can significantly reduce the effect of the divider noise by 1) Connect the divider output to the EXT arming input 2) Connect the divider input signal to the START input 3) Connect the frequency to be compared to the STOP input 4) Select EXT ARM operation. The divider output then merely selects the threshold crossing of its input signal to start the 5370A time interval measurement. As long as the jitter is small compared with the input signal period this should work well. Bruce ------------------------------ _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts End of time-nuts Digest, Vol 68, Issue 95 ***************************************** __________________________________________________________________ Connect with friends from any web browser - no download required. Try the new Yahoo! 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