On Fri, 07 Dec 2012 17:50:55 -0500, "Charles P. Steinmetz"
wrote:
>John wrote:
>
>>What's *really* interesting, though, is the idea that collectively
>>we might develop some standard measurement protocols that would be
>>reproducible in a number of (amateur) labs.
>
>I agree, but I didn't dare
Hello Bert,
The boards look nice but tell me nothing of the circuitry. How about sending
the schematics ?? That way I
can appreciate what it is that you have.
BillWB6BNQ
p.s. By the way, what ever happen with that DMTD you were going to produce
about three years ago ?
ewkeh...@aol.com
John wrote:
What's *really* interesting, though, is the idea that collectively
we might develop some standard measurement protocols that would be
reproducible in a number of (amateur) labs.
I agree, but I didn't dare to dream so large when I wrote:
From my perspective, the most interesting
-nuts-boun...@febo.com] On
Behalf Of paul swed
Sent: Friday, December 07, 2012 1:38 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPSDO Alternatives
Bob
Yes would agree these are the attributes of a solution thats interesting.
Numbers of folks have created
source where we can buy both the OCXO and GPS used for less than $100.
>
> If you want to factor in lower performance, I'll grant a waver for the fact
> that you can average multiple gizmos and the result will get better by the
> square root of the number of gizmos. If it'
m
>>> [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp
>>> Sent: Thursday, December 06, 2012 18:23
>>> To: Discussion of precise time and frequency measurement
>>> Subject: Re: [time-nuts] GPSDO Alternatives
>>>
>>> Hi
>>>
>>>
And then it becomes popular and guess what happens to the price?
Tom
- Original Message -
From: "Bob Camp"
To: "'Discussion of precise time and frequency measurement'"
Sent: Friday, December 07, 2012 12:15 PM
Subject: Re: [time-nuts] GPSDO Alternativ
1/4 the price.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Jim Lux
Sent: Friday, December 07, 2012 10:13 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] GPSDO Alternatives (GLUE)
On 12/6/12 5:01 PM, Bob Camp wrote:
> Hi
&g
Jim right on target for my 2 cents,
Simple is often hard.
Regards
Paul
WB8TSL
On Fri, Dec 7, 2012 at 10:12 AM, Jim Lux wrote:
> On 12/6/12 5:01 PM, Bob Camp wrote:
>
>> Hi
>>
>> The solution to the problem is well known in several forms. Cost is below
>> $5 for pretty much all of them. No need t
On 12/6/12 11:20 PM, Don Latham wrote:
Good thought, Bob. AD9548 $27, eval board a whopping $250, get a
thunderbolt :-). The eval board has a lot of SMA's on it...
This is a general problem with eval boards these days.. They provide a
lot of functionality on the board to make it easy to evalu
On 12/6/12 5:01 PM, Bob Camp wrote:
Hi
The solution to the problem is well known in several forms. Cost is below $5
for pretty much all of them. No need to re-invent the wheel. The gotcha is that
you can't do it 100% with internal CPU peripherals. You will need *some* glue.
I think that's th
On 12/6/12 11:12 PM, Hal Murray wrote:
Suppose you just implement a simple bang-bang control.
Suppose the EFC is 1 volt and the frequency is correct but the GPSDO
phase is a bit early relative to the GPS PPS. So the FF says early
and the software says go-faster. That keeps happening for a
On 12/6/12 1:56 PM, Bob Camp wrote:
Hi
The single best thing about a TBolt is Lady Heather.
Consider how many years it's taken to get it to where it is today. Consider
how many people have worked extensively on it. It's a wonderful thing to
have available.
Could you make a homebrew gizmo look
ebo.com
>> [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp
>> Sent: Thursday, December 06, 2012 18:23
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] GPSDO Alternatives
>>
>> Hi
>>
>> Here's
Hi
In this case it's very much a "you get what you pay for" sort of thing. You are
indeed comparing an hourglass to a cesium standard.
Bob
On Dec 7, 2012, at 2:20 AM, "Don Latham" wrote:
> Good thought, Bob. AD9548 $27, eval board a whopping $250, get a
> thunderbolt :-). The eval board has a
Hi
You are driving an integrator (the OCXO). You want a very stable voltage on the
EFC to get the loop to close. A PWM is as simple a model for a 1 bit D/A as
any. One bit A/D's are a feedback on a 1 bit D/A. You do some stuff to move the
noise around and to get it all to work.
Bob
On Dec 7
Hi
To make things play nice, you would like to have the timer counters reset at a
specified point. That way the math all works out nicely.
Bob
On Dec 7, 2012, at 12:18 AM, Hal Murray wrote:
>
> li...@rtty.us said:
>> That would be an input capture rather than an interrupt.
>
> Thanks. Yes,
Good thought, Bob. AD9548 $27, eval board a whopping $250, get a
thunderbolt :-). The eval board has a lot of SMA's on it...
Don L
Bob Camp
> Hi
>
> If all you want is a "something" locked to a GPS:
>
> Take the pps from the GPS and hook it to an AD9548. You probably will
> need a 50 cent CPU to se
Hello,
metastability is not an issue in this type of application, nor can it be
avoided since we have two different clock domains.
It would only shift the capture point by one counter clock cycle back or
forth if the edge happens right on the transition point. At that point we
have 50% un
> The output from a OCXO is divided down and then the phase of the divided
> down 10MHz RF is compared to the PPS and you don't need to even know the how
> far apart they are. All you need to know is "led or lag" just a one bit
> answer. An XOR gate or a flip flop can tell you that.
Does a 1
li...@rtty.us said:
> That would be an input capture rather than an interrupt.
Thanks. Yes, that's the term I was trying to remember.
li...@rtty.us said:
> To be useful, you need an input capture that:
> 1) Runs at a fast enough clock (1 GHz would be nice)
> 2) Has enough bits to get to 1 pps
saidj...@aol.com said:
> Then setting up a test system we noted that the timer can capture with
> 32MHz resolution which is good enough for a low-cost GPSDO implementation,
> but that they gated the input pin through a flip-flop running at CPU core
> speed, which was around 6MHz if I remember corr
s-boun...@febo.com
> [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp
> Sent: Thursday, December 06, 2012 18:23
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] GPSDO Alternatives
>
> Hi
>
> Here's another way to look at t
over.
Don
--
From: "Chris Albertson"
Sent: Thursday, December 06, 2012 6:30 PM
To: "Discussion of precise time and frequency measurement"
Subject: Re: [time-nuts] GPSDO Alternatives
> On Thu, Dec 6, 2012 at 4:09 PM, dlewis6767 wrote:
>
>> could you not
The other timer on the ATmega328 lacks an input capture pin and
register. I did not check all of the different AVR microcontrollers
used in Arduinos.
On Fri, 7 Dec 2012 02:03:39 +, Mark Sims
wrote:
>I think only TIMER2 on the AVR has the clk/4 limitation. The other timers
>can count at f
Hi
Here's another way to look at this:
An hourglass full of sand (with some attention) and a cesium standard are both
ways to answer the question "what time is it?". Let's say you need a new
$40,000 tube replacement in your 5371 and management asks "what else can we
do?". An hour glass is in
Hi
If all you want is a "something" locked to a GPS:
Take the pps from the GPS and hook it to an AD9548. You probably will need a 50
cent CPU to set up the registers. No muss, no fuss, nothing to invent or
design.
Weather it does what you need to do is an entirely different question. Without
Hi
PSoC's are another attractive possibility that suffers from the same basic
"re-clock everything" flaw. Lots of time down the drain there….
Bob
On Dec 6, 2012, at 8:22 PM, saidj...@aol.com wrote:
> David,
>
> The NXP LPC932 processor series are very cheap and small, and we got very
> exci
Hi
Unless you really want to go crazy with measuring very long delays, you do
indeed want to align the pps from your OCXO with the pps from your GPS.
Bob
On Dec 6, 2012, at 8:48 PM, "Don Latham" wrote:
> Chris: yes, dividing would have to be done. Doesn't TVB have a simple
> divider block?
>
Hi
The Shera counter is not running in the same fashion you would be running an
input capture pin.
Bob
On Dec 6, 2012, at 8:45 PM, David wrote:
> Sorry. The Shera counter is 16 bits and not 12 bits but that does not
> change what I posted.
>
> On Thu, 06 Dec 2012 19:17:48 -0600, David
> w
Chris: yes, dividing would have to be done. Doesn't TVB have a simple
divider block?
You don't really have to "close" the difference, just maintain it?
Don L
Chris Albertson
> You'd have to seriously divide down the output from the 10MHz OCXO if
> you
> were going to use it as an interrupt. Maybe
Sorry. The Shera counter is 16 bits and not 12 bits but that does not
change what I posted.
On Thu, 06 Dec 2012 19:17:48 -0600, David
wrote:
>It is not a 16 bit capture and it does not run at 1/4 the clock rate.
>
>The Shera uses a 12 bit counter to capture the phase difference
>between the OCX
The ATmega328 apparently has something similar going on since the
datasheet says that the maximum external asynchronous clock frequency
is 1/4 of the CPU frequency. That is why I suggested synchronously
clocking the CPU directly from the OCXO. Atmel's datasheet is
annoyingly vague about some matt
There are lots of sampling ADCs which will support that type of
operation directly or you can easily design and build a sampling phase
detector but that all involves significant extra circuitry outside of
the microcontroller.
Take a look at the Racal Dana 1992 reference frequency multiplier
option
David,
The NXP LPC932 processor series are very cheap and small, and we got very
excited to see timers running at up to 32MHz internally if I remember
correctly.
Then setting up a test system we noted that the timer can capture with
32MHz resolution which is good enough for a low-cost GPS
It is not a 16 bit capture and it does not run at 1/4 the clock rate.
The Shera uses a 12 bit counter to capture the phase difference
between the OCXO frequency divided by 16 and GPS pulse per second
output to a resolution of about 42ns.
What I suggested effectively captures the same phase differ
Hi
The solution to the problem is well known in several forms. Cost is below $5
for pretty much all of them. No need to re-invent the wheel. The gotcha is that
you can't do it 100% with internal CPU peripherals. You will need *some* glue.
Bob
On Dec 6, 2012, at 7:43 PM, Chris Albertson wrote
What if the OCXO had a sine wave output and then you used the PPS leading
edge to gate the sine wave to a sample and hold. then the sample is
measured by the Arduino's ADC? I think(?) you get a 10-bit ADC or is it
8-bits. The problem is the required speed of the sample and hold, maybe
not easy t
Hi
The simplest phase detector does indeed work. It just does not work very well.
Not correcting the oscillator at all works, you will have time and frequency to
some level of accuracy. Not correcting it at all is a whole lot cheaper and
simpler.
Bob
On Dec 6, 2012, at 7:30 PM, Chris Albertso
Hi
Again, the math is pretty simple.
A 16 bit capture running at a 1/4 clock is not going to get you very near a
Shera. It's even further from the more modern "enhanced Shera" designs.
Bob
On Dec 6, 2012, at 6:59 PM, David wrote:
> You can use the ATmega328 16 bit timer/counter in input ca
On Thu, Dec 6, 2012 at 4:09 PM, dlewis6767 wrote:
> could you not add just a little 'glue' outside the uP to relieve it a tad.
>
> Let the GPS' 1pps gate some ttl counters and then read for overflow or
> underflow after xxx seconds. Have the uP determine dac correction setting
> back to the TXC
he TXCO.
-Don
--
From: "Bob Camp"
Sent: Thursday, December 06, 2012 5:55 PM
To: "Discussion of precise time and frequency measurement"
Subject: Re: [time-nuts] GPSDO Alternatives
Hi
To be useful, you need an input capture that:
1) Runs at a fast enough clock (1 GH
You can use the ATmega328 16 bit timer/counter in input capture mode
to count the number of 10 MHz OCXO cycles per pulse per second period
to a resolution of 100ns but there are some problems:
The ATmega328 16 bit timer/counter external clock is limited to 1/4 of
the CPU frequency with an asynchro
Hi
To be useful, you need an input capture that:
1) Runs at a fast enough clock (1 GHz would be nice)
2) Has enough bits to get to 1 pps (say 32 bits)
3) Has a built in period set, so the hardware works without a lot of silly stuff
Often you find parts that will do some of the above, but not all
Bob et al:
Have been following this thread with interest.
Re the input capture versus interrupt, I do believe (at least the 2560
does this) that you can do both. It's been a while since I looked. a
look at the hardware manual. Was interested in this feature to do
hardware timing.
Norm
On Thu, Dec
Hi
That would be an input capture rather than an interrupt.
Bob
On Dec 6, 2012, at 6:16 PM, Hal Murray wrote:
>
> albertson.ch...@gmail.com said:
>> You'd have to seriously divide down the output from the 10MHz OCXO if you
>> were going to use it as an interrupt. Maybe to divide by 10,000? a
albertson.ch...@gmail.com said:
> You'd have to seriously divide down the output from the 10MHz OCXO if you
> were going to use it as an interrupt. Maybe to divide by 10,000? and even
> at the higher clock rate you'd still have poor resolution.
> I image each interrupt handler would sample some
Hi
The math is pretty straightforward.
Let's say the clock is 10 MHz, that's 100 ns.
Say a handful is 5 +/- 3 (2 to 8)
Your measure will bounce up and down by 6x100 ns = 600 ns.
Over a 100 second period that's going to be 6.0 x10^-9 bounce in the data.
If you run a 100 second loop as well,
You'd have to seriously divide down the output from the 10MHz OCXO if you
were going to use it as an interrupt. Maybe to divide by 10,000? and even
at the higher clock rate you'd still have poor resolution.
I image each interrupt handler would sample some internal counter and the
background task
On 12/6/2012 4:35 PM, Charles P. Steinmetz wrote:
From my perspective, the most interesting development would be an offer
by someone with a very well equipped lab to test any DIY GPSDO with a
consistent protocol and publish the results. That way, we could all see
how the various approaches com
December 06, 2012 4:36 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPSDO Alternatives
Don wrote:
>you guys are reinforcing that just because its' cheap won't mean it
>won't work.
Of course it doesn't. But keep in mind that &q
Don wrote:
you guys are reinforcing that just because its' cheap won't mean it
won't work.
Of course it doesn't. But keep in mind that "working" spans several
orders of magnitude in this area, and what one needs to design and
build depends on what degree of "working" one needs to support th
ebo.com] On
Behalf Of Dale J. Robertson
Sent: Thursday, December 06, 2012 12:45 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] GPSDO Alternatives
Arduino is Dirt Cheap!
At it's cheapest it is just an atmel AVR, a crystal, 2 caps and a
resistor
with the arduino bootloader programmed into
o.com] On
> Behalf Of Dale J. Robertson
> Sent: Thursday, December 06, 2012 12:45 PM
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] GPSDO Alternatives
>
> Arduino is Dirt Cheap!
> At it's cheapest it is just an atmel AVR, a crystal, 2 caps and a
resistor
none of
them could be used for a "very nice GPSDO"?
Dale
Just fooling around, no offence intended.
-Original Message-
From: Bob Camp
Sent: Thursday, December 06, 2012 1:57 PM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] GPSD
ailto:time-nuts-boun...@febo.com] On
Behalf Of Dale J. Robertson
Sent: Thursday, December 06, 2012 2:09 PM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] GPSDO Alternatives
Bob,
Did Atmel (AVR) kill your dog or something?
They have some pretty power
mber 06, 2012 1:57 PM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] GPSDO Alternatives
Hi
That is where most of these tools were many years ago. Competition has
forced them to open things up quite a bit. You can code a very nice GPSDO
and no
lto:time-nuts-boun...@febo.com] On
> Behalf Of Dale J. Robertson
> Sent: Thursday, December 06, 2012 12:45 PM
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] GPSDO Alternatives
>
> Arduino is Dirt Cheap!
> At it's cheapest it is just an atmel AVR, a crystal, 2 caps an
ebo.com] On
> Behalf Of Dale J. Robertson
> Sent: Thursday, December 06, 2012 12:45 PM
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] GPSDO Alternatives
>
> Arduino is Dirt Cheap!
> At it's cheapest it is just an atmel AVR, a crystal, 2 caps and a resistor
> with th
On 12/6/12 9:45 AM, Dale J. Robertson wrote:
Arduino is Dirt Cheap!
And available over the counter retail at hundreds of Radio Shacks..
You get an idea during the day, and you can run out and buy one right
then.. (yes, you can mail order, but the fastest turnaround is a few
days, unless you p
cise time and frequency measurement
Subject: Re: [time-nuts] GPSDO Alternatives
Boy do I have to agree. uProcs by the dozens and with all kinds of counters
onboard.
I think it was Bob who said none of thats the challenge.
It is the phase comparison method and a stable D/A converter and reference.
up with some ginormous
> commercial arduino board.
> Dale
>
> -----Original Message-----
> From: Keenan Tims
> Sent: Thursday, December 06, 2012 10:38 AM
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] GPSDO Alternatives
>
> As a lurker, I just want to chime in an
l run fine with
none of the above on the internal clock.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Dale J. Robertson
Sent: Thursday, December 06, 2012 12:45 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] GPSDO Alterna
06, 2012 10:38 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] GPSDO Alternatives
As a lurker, I just want to chime in and say that I for one would love
to see an open-source GPSDO implementation. There are quite a few open
hardware designs out there, but as Bob suggests, all the interesting
bit
Once you have a willing group, let them work with what
ever they are comfortable with. The bigger decisions and issues are
elsewhere.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Keenan Tims
Sent: Thursday, December 06, 2012 10:
Interesting Arthur. I don't think I had a clue you were selling them and
would have paid the difference of what I actually picked one up for. Though
mine was clean and I have not a complaint in the world. Like you I watched
things go up and they were very controlled day by day. At the time it
seeme
As a lurker, I just want to chime in and say that I for one would love
to see an open-source GPSDO implementation. There are quite a few open
hardware designs out there, but as Bob suggests, all the interesting
bits are tied up in the closed-source software they run. And most of
them are no longer
On 12/6/12 1:06 AM, Chris Albertson wrote:
Yes. The idea was the simplest GPSDO that can be build with no PCB around
an Arduino. We already know how to build compllelx and expensive GPSDO.
That is "too easy".
I think you can use the PWM DAC on the Aruino to drive the OCXO. The
bandwidth of
Hi
There are many marvelous things you can do in software. In some cases you are
fundamentally limited by the hardware. Regardless of the hardware chosen, the
effort is 99.99% in other areas. Starting with a hardware platform that lets
you evolve (even if it's a few dollars more) is generally a
Hi
Simple answer - no, not in a precision part. They are neither high enough
resolution or deterministic enough to give you very high resolution.
More complex answer - you can do just about anything if you are willing to
limit the best possible outcome. With the normal integration times you pr
Chris:
> The question I have again is about a simple phase detector.
I did ask if the arduino interrupt ports could be used as a phase
detector; one on the GPS and one on the OXCO. Too much jitter? If the 12
MHz clock is too slow, would an 80 MHz clock ARM arduino style processor
work? I'm simply
On Wed, Dec 5, 2012 at 2:50 PM, wrote:
>
>
> If there is one thing I learned, it is that one is never finished improving
> the software. That is why we are time-nuts I guess.
>
This is the reason I suggested using the Arduino. It is so easy to program
that MANY people will be able to contribute
Chris,
If you want to understand how to approach the issue, you need to study the Shera
controller system. It does exactly what you and others are discussing doing.
It
is relatively simple, straight forward and the HEX file is available to program
the CPU with. The circuit board is all ready m
have the hardware.
>
> Bob
>
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of Jim Lux
> Sent: Wednesday, December 05, 2012 7:58 AM
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] GPSDO Alternatives
&
Yes. The idea was the simplest GPSDO that can be build with no PCB around
an Arduino. We already know how to build compllelx and expensive GPSDO.
That is "too easy".
I think you can use the PWM DAC on the Aruino to drive the OCXO. The
bandwidth of this signal is "way low" so you can filter th
Now you can see the problem with designs that require both a PCB and a
programmed uP. Most people can't do either of these and those who can
typically are good at only one. Then you find someone and after he looses
interest the project is dead and un-suportable.
So I was thinking of how to bui
plement something like this until I retire and I suspect I’d be lucky if I
> matched the performance of my best existing GPSDO. The other alternative
> that occurs to me is simply connecting a high end OCXO to a Thunderbolt
> board.
>
> Sorry if I come across as overly c
(:
> Message: 3
> Date: Wed, 05 Dec 2012 22:24:43 +0100
> From: Volker Esper
> To: Discussion of precise time and frequency measurement
>
> Subject: Re: [time-nuts] GPSDO Alternatives
> Message-ID: <50bfbb9b.7010...@t-online.de>
> Content-Type: text/plain; charset
Good list Bob,
many people underestimate what it takes to make a working, commercial
GPSDO, especially one that has to perform in volume and beyond a single well
taken care of unit in a Ham shack.
Once you have taken care of items 1) and 2), the real work begins. This is
where our custome
nuts-boun...@febo.com] On
Behalf Of Volker Esper
Sent: Wednesday, December 05, 2012 4:25 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPSDO Alternatives
Am 05.12.2012 18:31, schrieb Bob Camp:
> Hi
>
> If the intent is to come up with something in the sa
Don't forget that an OCXO needs faster than 10K seconds EFC updates, that's
why you need resolution first.
On Wed, Dec 5, 2012 at 10:24 PM, Volker Esper wrote:
>
> Am 05.12.2012 18:31, schrieb Bob Camp:
>
>> Hi
>>
>> If the intent is to come up with something in the same league as the TBolt
>> t
Am 05.12.2012 18:31, schrieb Bob Camp:
Hi
If the intent is to come up with something in the same league as the TBolt
there are a few other things you will need:
1) Something to compare the two pps signals to within 0.1 ns
Following Ulrich Bangerts suggestions, that a loop time constant s
I wonder if two hardware interrupts on the Arduino itself could not be
used for phase locking? There's also an ARM 80 MHz version of the
Arduino package that might be applied, admittedly at higher cost...
Don
Jim Lux
> On 12/5/12 12:06 AM, Bruce Griffiths wrote:
>> Hal Murray wrote:
>>> albertson.
Subject: Re: [time-nuts] GPSDO Alternatives
A low noise sample and hold is still required.
Bruce
Bob Camp wrote:
> Hi
>
> Does the synchronous filter on the PWM still have a sample and hold in
it, or has somebody come up with a different approach?
>
> Bob
>
> On Dec 5, 20
hardware.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Jim Lux
Sent: Wednesday, December 05, 2012 7:58 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] GPSDO Alternatives
On 12/5/12 12:06 AM, Bruce Griffiths wrote:
> Hal Murray wrot
A low noise sample and hold is still required.
Bruce
Bob Camp wrote:
Hi
Does the synchronous filter on the PWM still have a sample and hold in it, or
has somebody come up with a different approach?
Bob
On Dec 5, 2012, at 3:06 AM, Bruce Griffiths wrote:
Hal Murray wrote:
alber
On 12/5/12 12:06 AM, Bruce Griffiths wrote:
Hal Murray wrote:
albertson.ch...@gmail.com said:
What is the simplest phase detecter that could work? I think only
that, and
then a duouble oven crystal from eBay, a GPS and and Arduido.
You also need a good D2A to drive the EFC on the osc.
A sy
Hi
Does the synchronous filter on the PWM still have a sample and hold in it, or
has somebody come up with a different approach?
Bob
On Dec 5, 2012, at 3:06 AM, Bruce Griffiths wrote:
> Hal Murray wrote:
>> albertson.ch...@gmail.com said:
>>
>>> What is the simplest phase detecter that co
Chris
There is a low cost solution and I have the input circuit perfect for GPS
on a $1 gate array I have boards and am presently using Shera original
version. Would like to buy his version 402NE but have not been able to get a
response from him. Have repeatedly asked for help on this list fo
Hal Murray wrote:
albertson.ch...@gmail.com said:
What is the simplest phase detecter that could work? I think only that, and
then a duouble oven crystal from eBay, a GPS and and Arduido.
You also need a good D2A to drive the EFC on the osc.
A synchronous filter of a suitably l
albertson.ch...@gmail.com said:
> What is the simplest phase detecter that could work? I think only that, and
> then a duouble oven crystal from eBay, a GPS and and Arduido.
You also need a good D2A to drive the EFC on the osc.
> Yes the Aruino is expensive compared to a bare uP chip but usin
With the price of T-Bolts now higher, does it make sense to build your own
GPSDO?
What is the simplest phase detecter that could work? I think only that,
and then a duouble oven crystal from eBay, a GPS and and Arduido.
Yes the Aruino is expensive compared to a bare uP chip but using one, I
thin
Hi
I would guess that HP/Agilent/Symmetricom and Trimble made 100X more GPSDO's
than the next five people in the business combined over the 1995 to 2005 period.
Bob
On Dec 4, 2012, at 10:26 AM, paul swed wrote:
> Al
> I like the truetime products. In general easy to understand and last a long
Al
I like the truetime products. In general easy to understand and last a long
time.
But there never seemed to be that many. Sure they were used in broadcasting
and maybe power. But the others like the 3801 and tbolt were used in telco
and mobile apps so there were 10,000s turned out and thats why
Most of the choices I've seen here mention the Tbolts, 3801, 3805, etc,
but I have never seen anyone mention the TrueTime XL-AK. It advertises 40
nsec 1 pps. Frequency as 1 x 10-12 per day. I have one and it seems to work
well but have no way to test it against anything else yet. It has four
Indeed and it seems the 3801s have a premium above the Tbolts these days.
I have both.
I picked up the tbolt much later and I simply waited for a good deal to
show up. It took a year. I wasn't in a hurry.
But that said I am still interested in the newer versions if they are
reasonable in cost.
Rega
Hi
They certainly aren't flooding the market these days the way they were a few
years ago. I suspect you still can get them "cheap" if you are willing to wait
a while. Even the two hundred dollar price is pretty good compared to the price
of a newly manufactured OCXO based GPSDO.
Bob
On Dec 3
Yes sir $139. But boy I have not seen cheap tbolts in bit. As I recall
$260 these days?
On Mon, Dec 3, 2012 at 9:12 PM, Bob Camp wrote:
> Hi
>
> The gotcha is that you go from paying surplus prices to paying new prices.
> New price to new price, they certainly are cheaper. Not so easy to beat a
Hi
The gotcha is that you go from paying surplus prices to paying new prices. New
price to new price, they certainly are cheaper. Not so easy to beat a $100
TBolt on price (if you can find one).
Bob
On Dec 3, 2012, at 8:50 PM, Magnus Danielson wrote:
> On 12/04/2012 02:44 AM, paul swed wrote
On 12/04/2012 02:44 AM, paul swed wrote:
Hmmm new and better.
That means better stability, noise, lower power, lower heat, for less and
works with lady heather? :-)
I can hope.
Mostly cheaper actually. Better GPS to start with, probably. Lower
power, most probably.
We should discuss if we ca
1 - 100 of 102 matches
Mail list logo
