TAPR offers a FatPPS kit to stretch the pulse out, and it looks like they're back in stock. I have one but haven't assembled it yet. https://tapr.org/product/fatpps-pulse-stretcher/
Larry On Tue, Apr 21, 2020 at 8:17 AM Dana Whitlow <[email protected]> wrote: > I've seen PPS ticks as short as 100 nsec from some equipment. Didn't think > to try the headphone > trick at the time, but am dubious about hearing pulses that short at > ordinary pulse amplitudes. > > Dana > > > On Tue, Apr 21, 2020 at 6:37 AM Bob kb8tq <[email protected]> wrote: > > > Hi > > > > One of the simplest justifications I can think of for a dirt cheap > > “Chinese” > > digital ’scope is to capture short burst stuff like narrow pps pulses. > > > > 10 us / non-adjustable is a *very* common spec for a 1 PPS. > > > > Bob > > > > > On Apr 21, 2020, at 4:56 AM, Chris Burford <[email protected]> > > wrote: > > > > > > I reached out to SRS several months ago to inquire if the pulse width > > could be configured from the default of 10 micro second. Their responses > > was no. > > > > > > Chris > > > > > > -----Original Message----- > > > From: time-nuts <[email protected]> On Behalf Of Taka > > Kamiya via time-nuts > > > Sent: Monday, April 20, 2020 22:35 > > > To: Discussion of precise time and frequency measurement < > > [email protected]> > > > Cc: Taka Kamiya <[email protected]> > > > Subject: Re: [time-nuts] Using speaker / earphone for PPS testing (not > a > > question) > > > > > > Out of all signal source, the shortest 1 pps is PRS-10 at 10 micro > > second. T-bolt is quite short as well but I don't have a definite data. > > > For those, speaker method worked just fine. I'm just sharing what I > > learned on happenstance. > > > > > > --------------------------------------- > > > (Mr.) Taka Kamiya > > > KB4EMF / ex JF2DKG > > > > > > > > > On Monday, April 20, 2020, 11:05:02 PM EDT, Bill Byrom < > > [email protected]> wrote: > > > > > > It's easy to trigger on short pulses on most oscilloscopes if you > follow > > these steps: > > > (1) Do NOT use Auto Trigger mode. Instead use Normal trigger mode. > > > (2) Set the vertical coupling mode to DC. > > > (3) Set the vertical gain (volts/div) and offset so that the baseline > > (OFF voltage between pulses) and pulse ON voltage should both be visible > on > > the vertical scale. > > > (4) Set the trigger coupling mode to DC and the trigger source to the > > proper channel. > > > (5) Set the trigger voltage to the midpoint between the pulse OFF and > ON > > voltage. > > > (6) Set the trigger slope appropriately, depending on the polarity of > > the 1 PPS pulse. > > > (7) Many oscilloscopes have a trigger indicator LED. It should flash > > visibly on each 1 PPS signal. > > > (8) If you are using an analog scope which does NOT have a microchannel > > plate (which was used on the Tektronix 2467 family and a few other > models), > > the pulse ON signal may be difficult to see at a fast time/div setting, > > even with a high scope intensity setting. But you can slow down the > > time/div of an analog scope to something easy to see, such as 10 ms/div. > > This will allow you to see a bright sweep each time the scope triggers, > > even if a short pulse can't be seen. > > > (9) When using a digital oscilloscope, turn on the peak detect display > > mode. This allows the oscilloscope to keep a high sampling rate even if > the > > time/div is set for a moderately slow sweep. > > > > > > If the 1 PPS signal is very short, you won't be able to hear it on a > > speaker with a direct connection as you describe. But you can use a pulse > > stretcher circuit (such as a 555 timer IC) to drive a LED or speaker > with a > > long output pulse (such as 10 ms). If you use two 555 IC's (or a 556 dual > > timer IC), you can even configure one section as a one-shot and the other > > as a tone generator so that a beep is produced for each pulse. The 555 > and > > 556 may be sold as LM555/LM556 or NE555/NE556. > > > -- > > > Bill Byrom N5BB > > > Retired Tektronix Application Engineer > > > > > > On Mon, Apr 20, 2020, at 9:25 PM, Taka Kamiya via time-nuts wrote: > > >> Maybe everyone but I knew, but I just did this and found it useful. > > >> 1 pps signal from some GPS are notoriously narrow and difficult to > sync > > >> on and see on scopes. LED will barely light if some kind of stretcher > > >> is not used. If your purpose is ONLY to see if it's there or not, > hook > > >> up a small speaker, earphone, amplified or not, and you can hear the > > >> tick-tick sound. > > >> > > >> I like DIYing and many times, I wonder if pps distribution circuit is > > >> working. I can tell a very short pulse that will barely register on > > >> LED is clearly audible. > > >> I thought I'd share. > > >> > > >> --------------------------------------- > > >> (Mr.) Taka Kamiya > > >> KB4EMF / ex JF2DKG > > >> _______________________________________________ > > >> time-nuts mailing list -- [email protected] > > >> To unsubscribe, go to > > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > >> and follow the instructions there. > > >> > > > > > > _______________________________________________ > > > time-nuts mailing list -- [email protected] > > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > > and follow the instructions there. > > > > > > _______________________________________________ > > > time-nuts mailing list -- [email protected] > > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > > and follow the instructions there. > > > <1PPS - 1MΩ.png>_______________________________________________ > > > time-nuts mailing list -- [email protected] > > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > > and follow the instructions there. > > > > > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
