Re: [time-nuts] I can't get a nice waveform from my rubidium !
Claude, your output is a square wave on 50 Ohm as write close the connector. Use this filter to have a clean sinewave output. http://www.timeok.it/files/5_and_10mhz_low_pass_notch_filter.pdf Luciano www.timeok.it On Thu 17/04/14 7:32 AM , Claude Fender wrote:Hello List, I've recently bought a Quartzlock 10A R (rubidium). Does anyone has experience with this unit? My unit has two outputs with no options. The problem is the shape of the waveform (see attachments), it's the same shape for the two outputs. When I connect an output directly to the oscilloscope, the shape is nearly squared and when I use a probe, the shape is nearly sine ! When I send a 10 MHz signal from a generator, the waveform is a clean sine with or whithout the probe. So what signal should I except from this rubidium ? Or most probably, what is wrong with my use of the oscilloscope ? (The frequency is ok by the way (+2E-10) and I didn't open the case yet) Thanks for any advice Claude ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts [1] and follow the instructions there. - Message sent via Atmail Open - http://atmail.org/ Links: -- [1] http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ 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] I can't get a nice waveform from my rubidium !
If your scope probe is 1:1 (or set to 1:1 if it has a switch), be aware that most 1:1 scope probes have high capacitance and not much bandwidth. I have as number of 100MHz Tektronix scope probes (in the 10:1 setting) that have a specified bandwidth of 6 MHz in the 1:1 setting. That would definitely make you square wave look like a sine wave. Didier KO4BB On April 20, 2014 2:59:44 AM CDT, tim...@timeok.it wrote: Claude, your output is a square wave on 50 Ohm as write close the connector. Use this filter to have a clean sinewave output. http://www.timeok.it/files/5_and_10mhz_low_pass_notch_filter.pdf Luciano www.timeok.it On Thu 17/04/14 7:32 AM , Claude Fender wrote:Hello List, I've recently bought a Quartzlock 10A R (rubidium). Does anyone has experience with this unit? My unit has two outputs with no options. The problem is the shape of the waveform (see attachments), it's the same shape for the two outputs. When I connect an output directly to the oscilloscope, the shape is nearly squared and when I use a probe, the shape is nearly sine ! When I send a 10 MHz signal from a generator, the waveform is a clean sine with or whithout the probe. So what signal should I except from this rubidium ? Or most probably, what is wrong with my use of the oscilloscope ? (The frequency is ok by the way (+2E-10) and I didn't open the case yet) Thanks for any advice Claude ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts [1] and follow the instructions there. - Message sent via Atmail Open - http://atmail.org/ Links: -- [1] http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ 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. -- Sent from my Nexus 7 tablet. ___ 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] I can't get a nice waveform from my rubidium !
Hi Claude I don't have any specific experience of this unit but suspect your problem may be down to impedance matching. The manual for the Quartzlock A10-M specifies the output impedance as being 50 ohms nominal and it would be reasonable to assume this is the same. Scope inputs and scope probes won't present such a low impedance so the use of a coaxial pass through 50 ohm termination would be my first suggestion, if you haven't got one to hand just try hanging a 50 ohm resistor, anywhere between 47 and 56 ohms say, across the output and ground and monitoring across that. This is quite a common problem, especially on supposedly square wave outputs, so chances are your unit is fine. Regards Nigel GM8PZR In a message dated 17/04/2014 08:17:12 GMT Daylight Time, lab...@yahoo.fr writes: Hello List, I've recently bought a Quartzlock 10A R (rubidium). Does anyone has experience with this unit? My unit has two outputs with no options. The problem is the shape of the waveform (see attachments), it's the same shape for the two outputs. When I connect an output directly to the oscilloscope, the shape is nearly squared and when I use a probe, the shape is nearly sine ! When I send a 10 MHz signal from a generator, the waveform is a clean sine with or whithout the probe. So what signal should I except from this rubidium ? Or most probably, what is wrong with my use of the oscilloscope ? (The frequency is ok by the way (+2E-10) and I didn't open the case yet) Thanks for any advice Claude ___ 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] I can't get a nice waveform from my rubidium !
Hi I believe that you have a problem with that probe. A broken ground is one possibility, a significant mismatch between the probe output and the scope input is another possibility. Bob On Apr 17, 2014, at 1:32 AM, Claude Fender lab...@yahoo.fr wrote: Hello List, I've recently bought a Quartzlock 10A R (rubidium). Does anyone has experience with this unit? My unit has two outputs with no options. The problem is the shape of the waveform (see attachments), it's the same shape for the two outputs. When I connect an output directly to the oscilloscope, the shape is nearly squared and when I use a probe, the shape is nearly sine ! When I send a 10 MHz signal from a generator, the waveform is a clean sine with or whithout the probe. So what signal should I except from this rubidium ? Or most probably, what is wrong with my use of the oscilloscope ? (The frequency is ok by the way (+2E-10) and I didn't open the case yet) Thanks for any advice Claude 10AR-sm.jpgnoprobe.gifwithprobe.gif___ 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] I can't get a nice waveform from my rubidium !
Hi Claude, Am 17.04.2014 07:32, schrieb Claude Fender: connect an output directly to the oscilloscope, the shape is nearly squared and when I use a probe, the shape is nearly sine ! When I send a 10 MHz signal from a generator, the waveform is a clean sine with or whithout the probe. I assume you use the same probe for the generator and the rubi. Was the probe calibrated for square wave? That's important - if you haven't calibrated it yet, you should do that at first. Are you using the 1:1 position? What, if you use a 1:10 probe/position? Is it the original Rigol probe? What is the output impedance of your generator, 50 ohms? What is the output impedance of your Rubidium? If you don't know, attache a trim-pot as load, in parallel to the scope (without probe). Adjust the pot until the output voltage has dropped to half of the unloaded voltage. Measure the value of your pot - that's the output resistance of your Rubidium. What I imagine: the probe isn't calibrated or has a problem, the Rubidium output is square wave, but the probe doesn't respond correctly (to low the upper cut-off frequency). The generator will always look ok (with or without a defective probe), since it outputs a sine wave anyway. Cheers Volker ___ 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] I can't get a nice waveform from my rubidium !
On Thu, 17 Apr 2014 06:32:52 +0100, Claude Fender wrote: My unit has two outputs with no options. The problem is the shape of the waveform (see attachments), it's the same shape for the two outputs. When I connect an output directly to the oscilloscope, the shape is nearly squared and when I use a probe, the shape is nearly sine ! According to the pict , the low output is supposed to be a CMOS square Is it called A10-R ? www.technical-sys.com/QL%20A10-R%20DS.pdf But termination would as other say be an issue. Dig into your drawer and pull out a BNC-T , and one of those 50ohm termination resistors you know you saved , when you were running old coax based ehternet on rg-58 cable. Have saved me a few times on my Rigol that hasn't got 50 termination built in. Else use your freq counter as termination , it ought to have 50ohm termination. BNC-T on scope , rubi on one end of tee , and counter on other end of tee (50 ohm terminated). CFO Denmark ___ 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] I can't get a nice waveform from my rubidium !
Thanks for your replies. With a 50 ohms resistor (about 49 ohms in fact), I've got something interesting but not perfect (I will try to find a 50 ohms terminaison). Unfortunately it didn't work with the counter as terminaison (see attachments). The two outputs have the same waveforms, I will open the case and try to understand how this is done. And yes it's a 10A-R (the new name is A10-M). Claude On Thursday, 17 April 2014, 21:43, cfo xne...@luna.dyndns.dk wrote: On Thu, 17 Apr 2014 06:32:52 +0100, Claude Fender wrote: My unit has two outputs with no options. The problem is the shape of the waveform (see attachments), it's the same shape for the two outputs. When I connect an output directly to the oscilloscope, the shape is nearly squared and when I use a probe, the shape is nearly sine ! According to the pict , the low output is supposed to be a CMOS square Is it called A10-R ? www.technical-sys.com/QL%20A10-R%20DS.pdf But termination would as other say be an issue. Dig into your drawer and pull out a BNC-T , and one of those 50ohm termination resistors you know you saved , when you were running old coax based ehternet on rg-58 cable. Have saved me a few times on my Rigol that hasn't got 50 termination built in. Else use your freq counter as termination , it ought to have 50ohm termination. BNC-T on scope , rubi on one end of tee , and counter on other end of tee (50 ohm terminated). CFO Denmark ___ 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.attachment: 50ohms_resistor.gifattachment: 1megaohm_counter.gifattachment: 50ohms_counter.gif___ 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.
