[time-nuts] 1 PPS visual Test

[David McGaw]

Using "Normal" triggering, any digital scope will allow you to see 
the 1PPS edges clearly.  Most analog scopes should have enough 
brightness at reasonably high sweep rate to see the edges in a 
darkened room or using a hood.  Turn the brightness up to just below 
the point where a steady dot is seen on the screen with no trigger.

David

At 01:02 PM 6/25/2007, you wrote:
>Randy,
>and that's what I'm looking for, the actual measurement isn't that
>important, the fidelity of the pulse is. The concern is, that if I over
>drive the out put amplifiers of the distribution amps, I can make a VERY
>ugly picture, much like taking a five MHz sine wave, and turning it into a
>"dirty" semi square wave generator.
>
>Raimond
>
>-----Original Message-----
>From: Randy Warner [mailto:randy at geodetics.com]
>Sent: Monday, June 25, 2007 10:57
>To: Raimond.Melkers at L-3Com.com; 'Discussion of precise time and frequency
>measurement'
>Subject: RE: [time-nuts] 1 PPS visual Test
>
>Raimond,
>
>About the only thing you can do is put the scope in normal trigger mode,
>looking for a positive going transition. If you set the horizontal sweep at
>about 1mS/cm you should see the rising edge of the pulse once per second. If
>you have an old scope without any storage capability the image will
>naturally fade quickly. This may take some tweaking on the trigger settings
>for the scope, but you should be able to find a combination of trigger
>settings and horizontal division size that will work.
>
>If your scope's trigger circuitry is stable enough you should be able to
>decrease the horizontal division size so that you can get a general idea of
>what the leading edge of the 1PPS pulse looks like. Depending on the
>receiver it should have a very fast rise-time and be a smooth ramp.
>
>Naturally, you will not be able to make any measurements as to the accuracy
>of the pulse, but this will give you a quick health check.
>
>Best regards,
>
>Randy Warner
>Senior Applications Engineer
>Geodetics, Inc.
>858.729.0872
>
>-----Original Message-----
>From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
>Behalf Of Raimond Melkers
>Sent: Monday, June 25, 2007 8:43 AM
>To: 'Discussion of precise time and frequency measurement'
>Subject: [time-nuts] 1 PPS visual
>
>  Any suggestions on the simplest, semi inexpensive way, to be able to look
>at a one Pulse Per Second wave form? It's seems that most oscilloscopes will
>not let me look that low in frequency. Basically I want to know, and see if
>I have a pure, clean 1 PPS waveform.
>
>thanks,
>Raimond
>
>
>
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