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[time-freq] Reflock II observations - SUCCESS!!

Steven Bible n7hpr at tapr.org
Tue Nov 22 03:38:03 UTC 2005


Hi Peter,

Glad to hear you are up and running.

I am a little perplexed that you had to change R22.  The op amp circuit is
to be a non-inverting amplifier with an adjustable offset.  Since the op amp
is power to +12 volts, you should be able to adjust the trimmer R24 for the
necessary frequency control voltage of your OCXO.  Was the range insufficent
for you?

73,

- Steve, N7HPR
 (n7hpr at tapr.org)


> -----Original Message-----
> From: time-freq-bounces at lists.tapr.org
> [mailto:time-freq-bounces at lists.tapr.org]On Behalf Of Peter
> Horbaczewskyj
> Sent: Monday, November 21, 2005 1:34 PM
> To: TAPR time and frequency projects
> Subject: Re: [time-freq] Reflock II observations - SUCCESS!!
>
>
> Hi everyone,
>
> I've just got my board working using a 1pps reference signal and my 10MHz
> oscillator..
>
> Changing the feedback resistor R22 from 10K to 68K has given me
> sufficient
> output voltage from the op amp.
>
> The pulse out from the XOR output was not 100ns as stated earlier
> but 100us
> (slip of the keyboard).
>
> 73, Peter GZXO
>
> ----- Original Message -----
> From: "Peter Horbaczewskyj" <peter at microwaves.f9.co.uk>
> To: "TAPR time and frequency projects" <time-freq at lists.tapr.org>
> Sent: Monday, November 21, 2005 2:05 PM
> Subject: Re: [time-freq] Reflock II observations - PROGRESS!!
>
>
> > Hi Steve,
> >
> > As the subject says, I'm making some progress with my setup.
> > I've taken Bobby's advice and started to use wire links as
> shorts on the
> > board.
> > Looking at the signals a lot closer with a scope, there actually is a
> > signal coming out of the XOR output.
> > Not a very big one I have to say though. approx 100ns every so
> often, very
> > difficult to see.
> > Doesn't seem to produce any reaction from the op amp circuitry.
> >
> > Then I decided to have a go and use the  PD2 UP signal. Finally
> there is
> > some movement
> > on the frequency meter. Problem now is that there is not enough
> range on
> > the output of the
> > op amp to reach the magical lock point of 10.0000MHz. Need to
> change the
> > gain so
> > that I can get 5-6V out as there is no other method of adjustment on my
> > oscillator.
> >
> > Perhaps someone can suggest the best way of achieving this. I
> assume that
> > the
> > "Offset Voltage Adjustment" pot will limit the range of the op
> amp output.
> >
> > 73, Peter G4ZXO
> >
> >
> > ----- Original Message -----
> > From: "Peter Horbaczewskyj" <peter at microwaves.f9.co.uk>
> > To: "TAPR time and frequency projects" <time-freq at lists.tapr.org>
> > Sent: Monday, November 21, 2005 11:20 AM
> > Subject: Re: [time-freq] Reflock II observations
> >
> >
> >> Hi Steve,
> >>
> >> The oscillator I am using is something that I had in my junk box.
> >> Basically it is an OCXO
> >> that is controlled by the voltage input from a pot circuit.
> The frequency
> >> range is about
> >> +/- 50Hz either side of 10MHz for a voltage range of 0 to 7.5V. I am
> >> currently using the
> >> 1pps signal as a reference source and I have tried both the
> 1pps config
> >> files supplied by
> >> Louis. Neither of them  it would seem appear to give an output
> on the XOR
> >> pin on the
> >> CPLD. Both the PD2 UP and PD2 DOWN signals are OK. The issue
> stems from
> >> the lack of
> >> signal to the TLC271CD op amp. Next thing to try is the PD2 UP signal.
> >> I'l keep you informed
> >> of any progress.
> >>
> >> The board as it stands is very neatly designed and laid out, but it
> >> doesn't lend itself very easily to
> >> development work or "suck and see" endeavours. Once it works I'm sure
> >> that it will be boxed up
> >> and quietly forgotten about.
> >>
> >> 73, Peter G4ZXO
> >>
> >> ----- Original Message -----
> >> From: "Steven Bible" <n7hpr at tapr.org>
> >> To: "TAPR time and frequency projects" <time-freq at lists.tapr.org>
> >> Sent: Monday, November 21, 2005 3:27 AM
> >> Subject: RE: [time-freq] Reflock II observations
> >>
> >>
> >>> Hi Peter,
> >>>
> >>> You mention 10 Mhz, what is your oscillator and what is your
> reference?
> >>>
> >>> 73,
> >>>
> >>> - Steve, N7HPR
> >>> (n7hpr at tapr.org)
> >>>
> >>>
> >>>
> >>> -----Original Message-----
> >>> From: time-freq-bounces at lists.tapr.org
> >>> [mailto:time-freq-bounces at lists.tapr.org]On Behalf Of Peter
> >>> Horbaczewskyj
> >>> Sent: Sunday, November 20, 2005 4:01 PM
> >>> To: TAPR time and frequency projects
> >>> Subject: Re: [time-freq] Reflock II observations
> >>>
> >>>
> >>> Hi Bobby,
> >>>
> >>> I totally agree with you, I've been trying to get my board working
> >>> tonight
> >>> with not much success at all.
> >>> You really need to go through all the files with a fine toothcomb and
> >>> drag
> >>> out the information, and hope
> >>> you've understood it correctly. Currently I am playing with a 10MHz
> >>> oscillator but don't seem to be getting
> >>> any signals out on the XOR output of the CPLD, using either
> of the "pps"
> >>> files. The other two outputs PD2 UP
> >>> and PD2 DN appear to be behaving as you would expect. However, moving
> >>> the
> >>> little 0 ohm links to select a
> >>> different output is not the easiest thing to do!! Time to get
> the scope
> >>> out
> >>> and have a proper look.
> >>>
> >>> By the way, I wonder if you realise that Altera provide a standalone
> >>> piece
> >>> of software for programming
> >>> their chips called "Quartus II Programmer" currently at Ver 5.0. This
> >>> certainly has the ByteBlaster MV as
> >>> an option and is pretty simple to use.
> >>>
> >>> The circuit that Steve has just published is essentially that one I
> >>> built
> >>> for my programmer, using a 74HC244
> >>> as the interface. This chip will certainly work down to around 2.0V as
> >>> opposed to the LS types which generally
> >>> need 5V.
> >>>
> >>> Time to go away and ponder what might have gone wrong.
> >>>
> >>>
> >>> Regards and 73, Peter G4ZXO
> >>
> >> _______________________________________________
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> >> time-freq at lists.tapr.org
> >> https://lists.tapr.org/cgi-bin/mailman/listinfo/time-freq
> >
> >
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>
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