Re: [time-nuts] Question about precise frequency / phase measurement
On 04/20/2012 03:49 PM, ewkeh...@aol.com wrote: It is a circuit that they for instance use in the 2110 where they take the reference input in case of 10 MHz divide by 2 and also divide the 5 MHz down to 500 Hz use an exor and out comes 5.000500 MHz filtered and divided by 5. A similar approach is being used in many rubidiums to generate the 5,3125 MHz signal, taking the 5 MHz, divide it by 16 and then XOR them together and then toss it through a LC tank to pick out the right frequency component. The rubidium is then tweaked using the C-field such that the locked 5 MHz lines up with SI second. That's just one aspect of why rubidiums have been relatively cheap from the start. The isotopic match of D lines allowing fairly easy filtering and selective pumping is another. The result is 1.000100 MHz which is mixed with the unknown divided to 1 MHz. The result is 100 Hz counted with a 100 MHz period counter and you have 1 E 12 in a second. My counter which is part of the system and thanks to Richard MCC is a PIC, has 0.1, 1, 10 and 100 seconds gate time. The 100 or 200 MHz are generated from the reference channel. All logic is in a MAX3000A G/A. The output is RS 232 and can also be stored on a USB memory stick, no PC needed. Austron uses a Xtal as a filter and I use 2 because I do not have access to their Xtal but it works. A nicer solution would be to use an AD 9833 DDS but it would require an additional PIC to do the math since the DDS can not produce an exact 1.000100 MHz. If some one is willing to do that chip please contact me off list. If you do quadrature signal multiplication, you can avoid the mirror frequency without high-Q filters. Look up the Tayloe detector for some inspiration. In this case you can generate an I and Q signal by adding a DFF. By producing a 2 kHz and 500 Hz, you let the 500 Hz be the I signal and then let the additional DFF have that as D input and clocked by the 2 KHz it will produce the 90 degree shifted Q signal on the Q output. By quadrature separation of the 5 MHz you can then use the 5 MHz I and Q, mix and then analogue sum prior some mild filtering such as a LC-tank. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Racal-Dana tactile switches
Gentlemen, I know I am not the only one in this group to have difficulties with weak tactile switches on Racal-Dana's 1991/2/6 range of counters. The other day I talked to the chief technician at Rosenkranz-Elektronik which is one of the biggest surplus suppliers in Germany. He knew the problem very well and his claim was that an exact replacement for the original Toko switches is no more produced anywhere in the world. Which may be an explanation why none of us managed to find an exact repelacement. His second claim was that the switches can be repared: After removing the cap gently grip the moving part with a pair of pliers and twist it a little bit while pulling it out a bit at the same time. In this way the moving part can be removed without destruction of the switch. Then you find the source of the problem inside: The weak and mostly destroyed rubber part inside. Replace it with the rubber part of a switch which has NEARLY the same dimensions. He told me that he had done such a repair for a number of times. Unfortunately he had no reference for the switches that he had used as the source for the replacement rubber. I am aware that this is only half of the solution of the problem but I checked his suggestion with a original switch that I had laying around as a replacement and found that his description worked for me. I made a photgraph of the switch to be found here: http://www.ulrich-bangert.de/Racal.JPG and perhaps anyone of you has an idea where to get a similar one from. The problem to find a similar switch is perhaps easier to solve than to locate a direct replacement. Note that the scale in the photo is in cm with subdivisions in mm. Best regards Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Racal-Dana tactile switches
Just a thought: On some equipment, the push-buttons are formed by a rubber mat which is shaped into domes with or without plastic buttons above. If you sacrificed an old calculator it might be possible to cut the rubber mat into individual buttons of a size suitable for refurbishing the Tokos Chris Stake -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Ulrich Bangert Sent: 21 April 2012 11:18 To: Time nuts Subject: [time-nuts] Racal-Dana tactile switches Gentlemen, I know I am not the only one in this group to have difficulties with weak tactile switches on Racal-Dana's 1991/2/6 range of counters. The other day I talked to the chief technician at Rosenkranz-Elektronik which is one of the biggest surplus suppliers in Germany. He knew the problem very well and his claim was that an exact replacement for the original Toko switches is no more produced anywhere in the world. Which may be an explanation why none of us managed to find an exact repelacement. His second claim was that the switches can be repared: After removing the cap gently grip the moving part with a pair of pliers and twist it a little bit while pulling it out a bit at the same time. In this way the moving part can be removed without destruction of the switch. Then you find the source of the problem inside: The weak and mostly destroyed rubber part inside. Replace it with the rubber part of a switch which has NEARLY the same dimensions. He told me that he had done such a repair for a number of times. Unfortunately he had no reference for the switches that he had used as the source for the replacement rubber. I am aware that this is only half of the solution of the problem but I checked his suggestion with a original switch that I had laying around as a replacement and found that his description worked for me. I made a photgraph of the switch to be found here: http://www.ulrich-bangert.de/Racal.JPG and perhaps anyone of you has an idea where to get a similar one from. The problem to find a similar switch is perhaps easier to solve than to locate a direct replacement. Note that the scale in the photo is in cm with subdivisions in mm. Best regards Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time- nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Racal-Dana tactile switches
I know its a hack but I used a small pcb switch and use a sawn off knitting needle when I wish to press one of those buttons. It's a design fault and eventually all of them will fail. Stewart On 21/04/2012 11:58, Chris Stake wrote: Just a thought: On some equipment, the push-buttons are formed by a rubber mat which is shaped into domes with or without plastic buttons above. If you sacrificed an old calculator it might be possible to cut the rubber mat into individual buttons of a size suitable for refurbishing the Tokos Chris Stake -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Ulrich Bangert Sent: 21 April 2012 11:18 To: Time nuts Subject: [time-nuts] Racal-Dana tactile switches Gentlemen, I know I am not the only one in this group to have difficulties with weak tactile switches on Racal-Dana's 1991/2/6 range of counters. The other day I talked to the chief technician at Rosenkranz-Elektronik which is one of the biggest surplus suppliers in Germany. He knew the problem very well and his claim was that an exact replacement for the original Toko switches is no more produced anywhere in the world. Which may be an explanation why none of us managed to find an exact repelacement. His second claim was that the switches can be repared: After removing the cap gently grip the moving part with a pair of pliers and twist it a little bit while pulling it out a bit at the same time. In this way the moving part can be removed without destruction of the switch. Then you find the source of the problem inside: The weak and mostly destroyed rubber part inside. Replace it with the rubber part of a switch which has NEARLY the same dimensions. He told me that he had done such a repair for a number of times. Unfortunately he had no reference for the switches that he had used as the source for the replacement rubber. I am aware that this is only half of the solution of the problem but I checked his suggestion with a original switch that I had laying around as a replacement and found that his description worked for me. I made a photgraph of the switch to be found here: http://www.ulrich-bangert.de/Racal.JPG and perhaps anyone of you has an idea where to get a similar one from. The problem to find a similar switch is perhaps easier to solve than to locate a direct replacement. Note that the scale in the photo is in cm with subdivisions in mm. Best regards Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time- nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Stanford Research PRS-10
Fellow time-nuts, On monday I picked up my PRS-10 and on friday I picked up the break-out board, PSU and manual. So, today I got around to put the pieces together, with no luck, as it did not lock. After locating a serial cable and hooking up, I was able to start query the PRS-10, and got some hints to the fact that the RF oscillator was sitting in the extreme low of it's control voltage. Check around, I then looked at the SP? command to get the non-standard 65535,2190,23 reading, which when cross-checking with the Appendix A should read 3158,2190,23. A little moment after entering it, the rubidium locked up, jumped in frequency and felt happy. I then stored the new SP setting into the EEPROM using SP! and where able to verify that with the SP!?. I wonder if this was an EEPROM error or someone fooling around error. It ended up not delaying me all that much, but it could have confused me for much longer if I would have been less lucky. Anyway, I wanted to share my experience. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Stanford Research PRS-10
I'm glad you got it going, but wasn't the consensus of the list that SRS had terrible support on their old gear? I like their arbitrary wabeform generators, but made a mental note to avoid SRS based on a post. I suppose I could have read it elsewhere. -Original Message- From: Magnus Danielson mag...@rubidium.dyndns.org Sender: time-nuts-boun...@febo.com Date: Sun, 22 Apr 2012 02:09:22 To: Time-Nutstime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] Stanford Research PRS-10 Fellow time-nuts, On monday I picked up my PRS-10 and on friday I picked up the break-out board, PSU and manual. So, today I got around to put the pieces together, with no luck, as it did not lock. After locating a serial cable and hooking up, I was able to start query the PRS-10, and got some hints to the fact that the RF oscillator was sitting in the extreme low of it's control voltage. Check around, I then looked at the SP? command to get the non-standard 65535,2190,23 reading, which when cross-checking with the Appendix A should read 3158,2190,23. A little moment after entering it, the rubidium locked up, jumped in frequency and felt happy. I then stored the new SP setting into the EEPROM using SP! and where able to verify that with the SP!?. I wonder if this was an EEPROM error or someone fooling around error. It ended up not delaying me all that much, but it could have confused me for much longer if I would have been less lucky. Anyway, I wanted to share my experience. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Stanford Research PRS-10
On 04/22/2012 02:31 AM, li...@lazygranch.com wrote: I'm glad you got it going, but wasn't the consensus of the list that SRS had terrible support on their old gear? I ordered break-out board, PSU and manual online, they shipped it and got it to me within days. It's not terrible. Pricey, yes, but not terrible. I have not tried to use their service department. BTW the PRS-10 is very much a current product, just as the SR620 (that was introduced in 1987). It was well packed. Manual was wrapped in plastic, put in a SRS binder which was also packed in a plastic bag. Inside there the PSU and break-out board was also in their own plast packages. Neat and well noted what it contained. I like their arbitrary wabeform generators, but made a mental note to avoid SRS based on a post. I suppose I could have read it elsewhere. Maybe it was not the complete story. Anyway, I have heard about a PRS-10 related issue, in which a PRS-10 had been slaved to a PPS and then jumped about 800 ns and then again about 400 ns. It sounds like uncalibrated input and output interpolators. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Racal-Dana tactile switches
Stewart wrote: It's a design fault and eventually all of them will fail. I'm not convinced of that. There has been substantial discussion of Racal switches on the list in the past, and I suggested at one point that the failure mechanism (dry, cracked rubber) could be related to the counter manufacturing process -- in particular, soldering and/or cleaning of the front panel PCBs. In my experience with 1992s (quite extensive), I have found that (i) in some counters the switches never seem to fail, while (ii) if one switch fails in a counter, all of the others are not long for the world. There does not (IME) appear to be any correlation with the color of the switch body or the markings on the switches. Then again, I suppose making switches that won't survive every possible abuse during whatever soldering and cleaning processes a customer might use could be considered a design fault Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
