Those LH0033s are Calogic parts. Everything Calogic is very expensive because they only have their own very small fab on campus at their California headquarters.
I've seen the LH00033's in other circuitry and decided I'd like a few. After some looking around it turns out that they are obsolete. Don't know what would be a suitable equivalent.
Nice find Kerry. Fortunately I got my two FE-5630's when they were still around $130 (got there a little too late). In the winter time I let my GPSDO run so the heat adds to the radio shack to keep it warm; in the summer I turn it off and use the Rb standard only when I turn on the test gear to reduce the AC requirement a bit. I thought you were going to pipe the reference signal throughout the lab to all the boxes but guess you're satisfied with the accuracy of the OCXO's in the gear. It's interesting to watch both standards on the scope in a Lissajous pattern as you'd think they were very close (and they really are) but they're not exactly on the same frequency. Thanks for the video!
I had thought about using the frequency standard as the main reference clock but not sure how much life is left in the Rubidium frequency standard (the lamp voltage measures around 5.7V, OK but not great). For now, I am going to use it mainly to calibrate my lab gear clock sources.
Very cool. I got both of my Rubidium standards from a seller on eBay in California for $125 each.It was just the standard with a 0,5"" pitch Samtec muliti pin connector. I ended up making a double sided PCB with 5V and 15V switching regulators and surface mount TTL chips to get the signal off the board. and had to purchase connectors that would fit the standard on Digikey. The unit gets quite hot at operating temperature so I fashioned a box to house the thing and its PCB plus cooling and built another double sided SMD board that has TTL drivers that drive 8 BNC connectors at 10mhz and 1 other at 1pps. If I want a 10MHz sine wave I put one of the square wave outputs through a 10MHz low pass filter which does a great job. I use the 8 outputs to drive my signal generators and signal counters in the lab. Sometimes I wish I'd gone for 16 outputs rather than 8. Nevertheless for $125 they're great pieces of equipment to have around the lab. Oh, and I popped the cover off one of them and turned it on. The eerie purple glow coming from the rubidium physics packages is kinda soothing. -Vince
Yep, the 1pps signal is hard to capture if you assume (like i did) that it's a a square wave 50%high/50%low. I think my 1pps output is 100us wide.... havent looked at it in a while. I also was able to hook up the rs232 interface and talk to the unit from a serial terminal.
Yeah, the physical package does run hot. I suppose you could just get a used distribution amplifier and using the outputs from the amplifier to feed your equipment.
If you don't want to kludge together your own 10MHz distribution system you might consider one that is available from the ham radio organization called "TAPR"; you can go to their dot org site and search for the TADD-1; they also have a 1PPS distribution system, the TADD-2.
No problem Vince...I have three of them feeding all the boxes around the shop and even a receiver at my radio bench. BTW, you will have to provide a enclosure but they have one for sale that is made for that series of distribution amps.
Of course you can measure the 1pps pulselengh with your analog scope. You have to set the trigger correctly only. Most 30 year old scopes can do this, eg my Tek 465B or much older Hameg 604
It can, but given the 20us pulse width and a 1s cycle, the pulse would be very hard to see as you can only see small dots. Due to the fast rise time, the rising and falling edge would be impossible to see unless you go to a much narrower horizontal sweep.
Nice video. The 1PPS output of my Symmetricom GPSDO is similarly around the 20us you see. I built a pulse stretcher using a CD4047BM and in reterospec think this was probably a poor choice of component. Looking forward to seeing your design, perhaps you could recommend a faster component.
Love the video! Hard to watch on my TV because the audio level is so low. Consider running an AGC filter on your video prior to uploading (avidemux is open source and cross platform I think)
Any idea what the jumpers on the right board are for? Could the second connector at the top of the board be an undivided out rather than a second input? There doesn't seem enough components on that board to do much with a second input.
I was wondering the same thing. If I switch the jumper, the output disappears. Since there are empty footprints on the board, this jumper could be for some other purposes as well. No, the second connector is an input as I could use either one of the upper two inputs to drive the 1PPS output.
I don't know anything about frequency standards, but... Both being useable as an input would make sense if that board isn't designed to terminate the cable, but simply to be able to take a reference tap as the signal passes through, I.E. one connector literally wired through the board to the other with a feed to the decade counters in the middle. You could then choose to pass the reference signal through by putting it in line, or bypass it leaving a spare coax in the loom.
Those LH0033s are Calogic parts. Everything Calogic is very expensive because they only have their own very small fab on campus at their California headquarters.
This buffer chip is largely obsolete, I believe?
I've seen the LH00033's in other circuitry and decided I'd like a few. After some looking around it turns out that they are obsolete. Don't know what would be a suitable equivalent.
Nice find Kerry. Fortunately I got my two FE-5630's when they were still around $130 (got there a little too late). In the winter time I let my GPSDO run so the heat adds to the radio shack to keep it warm; in the summer I turn it off and use the Rb standard only when I turn on the test gear to reduce the AC requirement a bit. I thought you were going to pipe the reference signal throughout the lab to all the boxes but guess you're satisfied with the accuracy of the OCXO's in the gear. It's interesting to watch both standards on the scope in a Lissajous pattern as you'd think they were very close (and they really are) but they're not exactly on the same frequency. Thanks for the video!
I had thought about using the frequency standard as the main reference clock but not sure how much life is left in the Rubidium frequency standard (the lamp voltage measures around 5.7V, OK but not great). For now, I am going to use it mainly to calibrate my lab gear clock sources.
Very cool. I got both of my Rubidium standards from a seller on eBay in California for $125 each.It was just the standard with a 0,5"" pitch Samtec muliti pin connector. I ended up making a double sided PCB with 5V and 15V switching regulators and surface mount TTL chips to get the signal off the board. and had to purchase connectors that would fit the standard on Digikey. The unit gets quite hot at operating temperature so I fashioned a box to house the thing and its PCB plus cooling and built another double sided SMD board that has TTL drivers that drive 8 BNC connectors at 10mhz and 1 other at 1pps. If I want a 10MHz sine wave I put one of the square wave outputs through a 10MHz low pass filter which does a great job. I use the 8 outputs to drive my signal generators and signal counters in the lab. Sometimes I wish I'd gone for 16 outputs rather than 8. Nevertheless for $125 they're great pieces of equipment to have around the lab.
Oh, and I popped the cover off one of them and turned it on. The eerie purple glow coming from the rubidium physics packages is kinda soothing.
-Vince
Yep, the 1pps signal is hard to capture if you assume (like i did) that it's a a square wave 50%high/50%low. I think my 1pps output is 100us wide.... havent looked at it in a while. I also was able to hook up the rs232 interface and talk to the unit from a serial terminal.
Yeah, the physical package does run hot. I suppose you could just get a used distribution amplifier and using the outputs from the amplifier to feed your equipment.
If you don't want to kludge together your own 10MHz distribution system you might consider one that is available from the ham radio organization called "TAPR"; you can go to their dot org site and search for the TADD-1; they also have a 1PPS distribution system, the TADD-2.
Dino, Thank you so much. I'll definitely be purchasing both of these devices. -Vince
No problem Vince...I have three of them feeding all the boxes around the shop and even a receiver at my radio bench. BTW, you will have to provide a enclosure but they have one for sale that is made for that series of distribution amps.
Interesting logo on the high speed buffers. Seems to be the old Calogic logo. Never seen that before.
Yep these are indeed the expsensive Calogic parts.
Great video, Kerry. Thanks for sharing. 👍😊
Certainly a handy item to have, I use mine to tune my bits of gear from time to time, the ocxo's usually are pretty good though.
Of course you can measure the 1pps pulselengh with your analog scope. You have to set the trigger correctly only. Most 30 year old scopes can do this, eg my Tek 465B or much older Hameg 604
Yeah, it can be done. But it's arguably much easier to "zoom" in onto the signal using a DSO.
I'm sure you could have triggered the analog scope to show the pulse, it looks like it was set to automatic because the pulse was all over the place.
It can, but given the 20us pulse width and a 1s cycle, the pulse would be very hard to see as you can only see small dots. Due to the fast rise time, the rising and falling edge would be impossible to see unless you go to a much narrower horizontal sweep.
Nice video. The 1PPS output of my Symmetricom GPSDO is similarly around the 20us you see. I built a pulse stretcher using a CD4047BM and in reterospec think this was probably a poor choice of component. Looking forward to seeing your design, perhaps you could recommend a faster component.
Love the video! Hard to watch on my TV because the audio level is so low. Consider running an AGC filter on your video prior to uploading (avidemux is open source and cross platform I think)
Embarrassing! My chromecast volume was on 25%. Disregard the comment ^_^;; keep doing awesome stuff! Love your videos
No worries :-) Glad to see someone familiar with open source software!
I think you've answered the ultimate question asked to Dan Rather ¨Kenith whats the frequency?"
LOL :)
Any idea what the jumpers on the right board are for?
Could the second connector at the top of the board be an undivided out rather than a second input? There doesn't seem enough components on that board to do much with a second input.
I was wondering the same thing. If I switch the jumper, the output disappears. Since there are empty footprints on the board, this jumper could be for some other purposes as well.
No, the second connector is an input as I could use either one of the upper two inputs to drive the 1PPS output.
I don't know anything about frequency standards, but...
Both being useable as an input would make sense if that board isn't designed to terminate the cable, but simply to be able to take a reference tap as the signal passes through, I.E. one connector literally wired through the board to the other with a feed to the decade counters in the middle. You could then choose to pass the reference signal through by putting it in line, or bypass it leaving a spare coax in the loom.