[time-nuts] FE-5680A Loop Lock Indicator

Bob Stewart bob at evoria.net
Sun Sep 22 17:12:11 EDT 2013


I hadn't thought of using a pullup resistor.  I'd have to get out the calculator to see if it's worth it, though.  It's only taking a load for a minute or two till it locks, so I don't think it's a problem.

Bob





>________________________________
> From: Chris Stake <stake at btinternet.com>
>To: 'Discussion of precise time and frequency measurement' <time-nuts at febo.com>; 'Bob Stewart' <bob at evoria.net> 
>Sent: Sunday, September 22, 2013 2:06 PM
>Subject: RE: [time-nuts] FE-5680A Loop Lock Indicator
> 
>
>I have a circuit that seems to work well:
>The lock indicator is a weak source but a good sink so it interfaces more
>naturally with a pnp or p-channel device. Pull it up to 5V with 100K and
>connect this point to the gate of a P channel Mosfet whose source is also
>connected to 5V. Connect the drain of the mosfet to a LED anode and take the
>LED cathode via 220 R to 0V.
>This way, the sense of the indicator is correct (0n = lock) and the drive
>capability of the lock signal works in your favour.
>
>Chris Stake  
>
>
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
>> Behalf Of Bob Camp
>> Sent: 22 September 2013 18:53
>> To: Bob Stewart; Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator
>> 
>> Hi
>> 
>> If you want 10 ma through the LED (which should be plenty) then the
>> collector resistor would be right around 1.2K
>> 
>> Bob
>> 
>> On Sep 22, 2013, at 1:32 PM, Bob Stewart <bob at evoria.net> wrote:
>> 
>> > D'oh, that should say "I could increase the COLLECTOR resistor to 1500
>> ohms".
>> >
>> >
>> >
>> >
>> >> ________________________________
>> >> From: Bob Stewart <bob at evoria.net>
>> >> To: Discussion of precise time and frequency measurement
>> >> <time-nuts at febo.com>
>> >> Sent: Sunday, September 22, 2013 12:27 PM
>> >> Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator
>> >>
>> >>
>> >> Except that it doesn't work with even 1500 ohms in the base lead.  The
>> LED immediately comes on and stays on.  I could increase the emitter
>> resistor to 1500 ohms and get around 8.5-9ma through the LED, but I'm done
>> playing with it until I get a proper box to put it all in.  This is just a
>> random 3mm LED out of an HP 37203A, so maybe that has something to do with
>> it?  I haven't looked at the specs.
>> >>
>> >> Bob
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>> ________________________________
>> >>> From: Bob Camp <lists at rtty.us>
>> >>> To: Discussion of precise time and frequency measurement
>> >>> <time-nuts at febo.com>
>> >>> Sent: Sunday, September 22, 2013 12:12 PM
>> >>> Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator
>> >>>
>> >>>
>> >>> Hi
>> >>>
>> >>> Circuit should be:
>> >>>
>> >>> 2N2222 with emitter to ground, collector to LED, base to lock
>indicator
>> via the 4.7K resistor. The LED is hooked to +15 via another resistor.
>> >>>
>> >>> If you have ~ 10 ma in the LED then the base needs less than 0.1 ma to
>> do the job with a 2222. A 4.7K should be plenty.
>> >>>
>> >>> Alternate circuit:
>> >>>
>> >>> 2N2222 with base to lock indicator / no resistor at all, emitter to
>> ground via a 1K resistor, collector to LED. LED to +15 via a 1.5K
>resistor.
>> >>>
>> >>> Either one should work. Both turn on the LED when the output is high
>> and off when the output is low. In order to turn on when it's high you
>need
>> to get an inversion ahead of the 2N2222.
>> >>>
>> >>> Bob
>> >>>
>> >>>
>> >>> On Sep 22, 2013, at 12:17 PM, Bob Stewart <bob at evoria.net> wrote:
>> >>>
>> >>>> Hi Bob,
>> >>>>
>> >>>> I tried 4700 and even 1500, but they're too large.  I guess the
>little
>> flash of the LED at power-on is the hint that 1K is right at the ragged
>> edge.  It would probably make a big difference if there was a 100 or even
>> 47 ohm resistor between the emitter and the LED, but my little board is
>> starting to get burnt up, wires are starting to get frayed, and it does
>> work, so this cake is done.
>> >>>>
>> >>>> Bob
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>>> ________________________________
>> >>>>> From: Bob Camp <lists at rtty.us>
>> >>>>> To: Discussion of precise time and frequency measurement
>> >>>>> <time-nuts at febo.com>
>> >>>>> Sent: Sunday, September 22, 2013 6:31 AM
>> >>>>> Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator
>> >>>>>
>> >>>>>
>> >>>>> Hi
>> >>>>>
>> >>>>> If you trace out the chip that drives the lock indicator it's got
>> some sort of strange gating in it's supply pin. That gets you even less
>> output than you would expect from a CMOS gate. I would not count on it
>> putting out more than 1 ma at 5 volts. A 4.7K resistor to the 2N2222 base
>> should be about right.
>> >>>>>
>> >>>>> Bob
>> >>>>>
>> >>>>> On Sep 21, 2013, at 10:34 PM, Bob Stewart <bob at evoria.net> wrote:
>> >>>>>
>> >>>>>> Thanks for the heads-up, Bob.  I'll do it the next time the iron is
>> hot.  Fortunately, it's only on for about a minute or so, then there's no
>> drive from the FE-5680A.  Is 3ma really that big a deal?  I know squat
>> about CMOS gates.  I guess it is pulling the voltage down by 25%, though.
>> >>>>>>
>> >>>>>> Bob
>> >>>>>>
>> >>>>>>
>> >>>>>>
>> >>>>>>
>> >>>>>>
>> >>>>>>> ________________________________
>> >>>>>>> From: Robert LaJeunesse <rlajeunesse at sbcglobal.net>
>> >>>>>>> To: Bob Stewart <bob at evoria.net>; Discussion of precise time and
>> >>>>>>> frequency measurement <time-nuts at febo.com>
>> >>>>>>> Sent: Saturday, September 21, 2013 9:24 PM
>> >>>>>>> Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator
>> >>>>>>>
>> >>>>>>>
>> >>>>>>>
>> >>>>>>> Bob,
>> >>>>>>>
>> >>>>>>>
>> >>>>>>> I would bump that base resistor up a lot higher, to load the FE-
>> 5680 less. The PN2222 has enough gain it only needs about 0.3 mA base
>drive
>> to work as intended. You'd get that with a 10K base resistor.
>> >>>>>>>
>> >>>>>>>
>> >>>>>>> Bob LaJeunesse
>> >>>>>>>
>> >>>>>>>
>> >>>>>>>
>> >>>>>>>> ________________________________
>> >>>>>>>> From: Bob Stewart <bob at evoria.net>
>> >>>>>>>> To: Time Nuts <time-nuts at febo.com>
>> >>>>>>>> Sent: Saturday, September 21, 2013 10:02 PM
>> >>>>>>>> Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator
>> >>>>>>>>
>> >>>>>>>>
>> >>>>>>>> Hi John,
>> >>>>>>>>
>> >>>>>>>> Thanks for the response.  I managed to cobble something up with
>> >>>>>>>> LTSpiceIV, and get it to work.  And for me, that's saying
>> >>>>>> something!    Here's what I wound up with:
>> "http://www.evoria.net/AE6RV/GPSstd_PLL/LED-driver.png", where V2 is the
>> Loop Lock Indicator.  The PN2222 shorts out the LED until it goes into
>> lock, then the LED comes on.  It does give a short pulse when power is
>> first applied and things are equalizing.  Even with a 1K resistor, the
>4.2V
>> from Lock signal is pulled down to 3V.
>> >>>>>>>>
>> >>>>>>>> And here's a pic of my Rb standard on it's temporary home with
>the
>> LED on a scrap of breadboard:
>> >>>>>>>> "http://www.evoria.net/AE6RV/GPSstd_PLL/Rb.standard.png".
>> >>>>>>>>
>> >>>>>>>> Bob
>> >>>>>>>>
>> >>>>>>>>
>> >>>>>>>>
>> >>>>>>>>
>> >>>>>>>>
>> >>>>>>>>> ________________________________
>> >>>>>>>>> From: jmfranke <jmfranke at cox.net>
>> >>>>>>>>> To: Bob Stewart <bob at evoria.net>; Discussion of precise time
>> >>>>>>>>> and frequency measurement <time-nuts at febo.com>
>> >>>>>>>>> Sent: Saturday, September 21, 2013 6:58 PM
>> >>>>>>>>> Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator
>> >>>>>>>>>
>> >>>>>>>>>
>> >>>>>>>>> Yes, but put an isolation resistor between the output and the
>> >>>>>>>>> base of the transistor, something between 3K and 5K should
>> >>>>>>>>> work. The LED will light upon power on and extinguish when lock
>> is achieved.
>> >>>>>>>>>
>> >>>>>>>>> John  WA4WDL
>> >>>>>>>>>
>> >>>>>>>>>
>> >>>>>>>>> --------------------------------------------------
>> >>>>>>>>> From: "Bob Stewart" <bob at evoria.net>
>> >>>>>>>>> Sent: Saturday, September 21, 2013 6:10 PM
>> >>>>>>>>> To: "Discussion of precise time and frequency measurement"
>> >>>>>>>>> <time-nuts at febo.com>
>> >>>>>>>>> Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator
>> >>>>>>>>>
>> >>>>>>>>>> Hi Bob,
>> >>>>>>>>>>
>> >>>>>>>>>> I hooked the big voltmeter up to it, and it shows +4.2V out for
>> about a minute, and then goes to 0. Looking on the web, it seems like I
>can
>> use that to drive a 2N2222 and put the LED and dropping resistor in the
>> collector path with the emitter to ground? Does that sound right?
>> >>>>>>>>>>
>> >>>>>>>>>> Bob
>> >>>>>>>>>>
>> >>>>>>>>>>
>> >>>>>>>>>>
>> >>>>>>>>>>
>> >>>>>>>>>>
>> >>>>>>>>>>> ________________________________
>> >>>>>>>>>>> From: Bob Camp <lists at rtty.us>
>> >>>>>>>>>>> To: Discussion of precise time and frequency measurement
>> >>>>>>>>>>> <time-nuts at febo.com>
>> >>>>>>>>>>> Sent: Saturday, September
>> >>>>>> 21, 2013 4:12 PM
>> >>>>>>>>>>> Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator
>> >>>>>>>>>>>
>> >>>>>>>>>>>
>> >>>>>>>>>>> Hi
>> >>>>>>>>>>>
>> >>>>>>>>>>> Those readings sound a lot more like a CMOS gate output than
>> some sort of open drain / open collector discrete driver.
>> >>>>>>>>>>>
>> >>>>>>>>>>> Bob
>> >>>>>>>>>>>
>> >>>>>>>>>>>
>> >>>>>>>>>>> On Sep 21, 2013, at 4:43 PM, Bob Stewart <bob at evoria.net>
>> wrote:
>> >>>>>>>>>>>
>> >>>>>>>>>>>> Hi Bob,
>> >>>>>>>>>>>>
>> >>>>>>>>>>>> It's rather curious. Using my handheld DVM in the diode
>> >>>>>>>>>>>> scale, I get a reading of 448 in one direction and 458 in
>> >>>>>>>>>>>> the other with it off and cold. In the 2K ohms scale, I get
>> >>>>>>>>>>>> 561 and 562 ohms. Later on, I'll pop the top off again and
>> >>>>>>>>>>>> take a pic so I can expand it and look at it. For what it's
>> >>>>>>>>>>>> worth, my DDS board is 2 revisions earlier than the one
>> >>>>>>>>>>>> Matthias Bopp
>> >>>>>> modifies here
>>
>"http://www.dd1us.de/Downloads/precise%20reference%20frequency%20rev%201_0.
>> pdf"
>> >>>>>>>>>>>>
>> >>>>>>>>>>>> Bob
>> >>>>>>>>>>>>
>> >>>>>>>>>>>>
>> >>>>>>>>>>>>
>> >>>>>>>>>>>>
>> >>>>>>>>>>>>
>> >>>>>>>>>>>>> ________________________________
>> >>>>>>>>>>>>> From: Bob Camp <lists at rtty.us>
>> >>>>>>>>>>>>> To: Discussion of precise time and frequency measurement
>> >>>>>>>>>>>>> <time-nuts at febo.com>
>> >>>>>>>>>>>>> Sent: Saturday, September 21, 2013 3:00 PM
>> >>>>>>>>>>>>> Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator
>> >>>>>>>>>>>>>
>> >>>>>>>>>>>>>
>> >>>>>>>>>>>>> Hi
>> >>>>>>>>>>>>>
>> >>>>>>>>>>>>> As far as I know the lock output is a CMOS output that will
>> drive a couple of ma. There are so many variations that yours may indeed
>be
>> an open collector and good to +15 volts.
>> >>>>>>>>>>>>>
>> >>>>>>>>>>>>> Bob
>> >>>>>>>>>>>>>
>> >>>>>>>>>>>>> On Sep 21, 2013, at 10:55 AM, Bob Stewart <bob at evoria.net>
>> wrote:
>> >>>>>>>>>>>>>
>> >>>>>>>>>>>>>> The instructions I got with this Rb said that you could
>hook
>> an LED through a 5-10K resistor to the +15 supply and get a lock
>> indication. I'm using a 10K resistor and the LED lights as soon as it's
>> powered up from cold. Is the loop lock indicator circuit broken or is it
>> just another strange option for these things? I saw on one site that if
>you
>> do it this way it prevents lock, but mine seems to lock OK with or without
>> the voltage.
>> >>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>
>> >>>>>>>>>>>>>> Bob - AE6RV
>> >>>>>>>>>>>>>> _______________________________________________
>> >>>>>>>>>>>>>> time-nuts mailing list -- time-nuts at 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 at 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 at 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 at 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 at 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 at 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 at 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 at 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 at 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 at 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 at 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 at 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 at febo.com To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
>
>
>


More information about the time-nuts mailing list