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

Peter Horbaczewskyj peter at microwaves.f9.co.uk
Tue Nov 22 11:27:47 UTC 2005


Hi Steve,

I checked the output of the op amp and it only went as high as 2.3V. 
Twiddling the pot only seemed to reduce the upper end.
As I needed approx 4.80V for my oscillator to be around 10MHz I changed R22 
to 68K. This gave me sufficient range to lock.

I'll check the components aorund the op amp to make sure they are correct, 
but for the moment it is working.

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: Tuesday, November 22, 2005 3:38 AM
Subject: RE: [time-freq] Reflock II observations - SUCCESS!!


> 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
>> >>
>> >> _______________________________________________
>> >> time-freq mailing list
>> >> time-freq at lists.tapr.org
>> >> https://lists.tapr.org/cgi-bin/mailman/listinfo/time-freq
>> >
>> >
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