I have been experimenting with three mixing devices: an RF
double-balanced mixer (MCL SRA-1B), a DFF (74AHCT74), and an EXOR
(74ACT86). The mixer and EXOR give similar results - the sum and
difference frequencies, and a slew of various other products that
need to be filtered out. What was
What did they leave out of the hardware? Hard to tell what to look for
when it's not there.
Thanks for sharing your experience.
--
eric
On Mon, Jul 1, 2013 at 10:43 PM, NeonJohn j...@neon-john.com wrote:
Before anyone wastes his money on a BeagleBone, I suggest you join the
mailing list and
On 02/07/13 06:43, NeonJohn wrote:
Before anyone wastes his money on a BeagleBone, I suggest you join the
mailing list and read the hundreds of messages each day that pass
through, most of them citing problems, mostly with the Linux implementation.
Basically, the ancient implementation of
On 07/02/2013 02:11 AM, Eric Williams wrote:
What did they leave out of the hardware? Hard to tell what to look for
when it's not there.
Thanks for sharing your experience.
I'm not sure what all is gone other than the USB port since I haven't
bought one. There is a list of omissions in
Hello,
Why do people go out of their way to avoid writing ebay on this list?
The statements are purposely written so that it is obvious that the
insert mystical phrase is ebay and not a generic auction site. What
history am I not aware of?
___
On 07/02/2013 02:14 AM, Iain Young wrote:
On 02/07/13 06:43, NeonJohn wrote:
Basically, the ancient implementation of Angstrom Linux is a POS. Just
barely enough code to be able to say, for example, that SPI works. It
does - sorta - but not well enough for any application where clock
Le 2 juil. 2013 à 02:52, Bob Camp a écrit :
Hi
snip
The reference I was making was to a pie in the sky 1.8 GHz clocked timer
integrated into a CPU chip. That would let you come up with ~ 600 ps timing
directly. Since it would be both unusual and very fast, a driver (potentially
I always thought it was a bit strange. As we say over here: call a spade a
spade
Sent from Samsung Mobile
Original message
From: Doug Calvert dfc-l...@douglasfcalvert.net
Date:
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Subject:
http://www.bbc.co.uk/news/science-environment-23140665
Rob
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To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
mc235...@gmail.com said:
Is that what you really want? In most modern x86 CPU's you have a TSC which
is a 64bit counter incremented at the cpu clock cycle speed . You can
capture that with a single instruction. NTP uses that if it is available.
So to get an accurate TI you just take 2 samples
On 7/1/2013 11:59 PM, Doug Calvert wrote:
Hello,
Why do people go out of their way to avoid writing ebay on this list?
The statements are purposely written so that it is obvious that the
insert mystical phrase is ebay and not a generic auction site. What
history am I not aware of?
I dunno
Not just engineering-friendly sites / lists.
The trend I have noticed is that any group which any one or more members
which for one reason or another has had a bad or unpleasant experience
with eBay AND spare no effort in complaining about or deriding others
and the mere mention of eBay sends
In message 51d29660.50...@sonic.net, Rex writes:
Like it or not, eBay is the main game now. and I see no reason to encode
mentions of EBAY. Who here hasn't made a purchase or sale that way?
In the early days it used to be that mentioning it by name on public
email lists would subject to massive
Hi
The issue there is the clock on the external inputs. The interupts can't
directly hit the TSC. They only get into the device after being clocked by a
much slower clock.
Bob
On Jul 2, 2013, at 3:32 AM, mike cook mc235...@gmail.com wrote:
Le 2 juil. 2013 à 02:52, Bob Camp a écrit :
Hi
The thing that finally canned the BB for me was the short SD card life.
Even though the implementation uses a virtualized root file system, it
still writes to the SD card about once a second. The result is that
even industrial grade SD cards rarely live over a year. With the Black
they
List,
In sorting through my mountain of old papers preparing for our moving, I cam
across an article that I had saved from Electronics magazines Engineer's
notebook in 1975.
The article was titled Dual-bandwidth loop speeds phase lock
I OCR'd it and re-drew the illustrations and schematic.
A few years back, some Group Owners, especially of ham lists, outlawed the
mention of eBay, because the concept of selling something to the highest
bidder somehow offended 'the ham ethic' that stuff should go to the 'most
needy or deserving' as measured by some underermined scale.
Pseudonames
On 7/2/13 7:41 AM, J. Forster wrote:
A few years back, some Group Owners, especially of ham lists, outlawed the
mention of eBay, because the concept of selling something to the highest
bidder somehow offended 'the ham ethic' that stuff should go to the 'most
needy or deserving' as measured by
Hi
The dual speed loop stuff generally was focused on cell phone synthesizers.
It's generally a little more complex for a gizmo where you want both settings
to be pretty slow / very accurate.
Bob
On Jul 2, 2013, at 10:27 AM, Perry Sandeen sandee...@yahoo.com wrote:
List,
In sorting
Note to self, Not getting on any Russian made rockets any time soon.
At least the rockets were unmanned, and hopefully no one on the ground
was hurt!
Sounds like this isn't the first time this happened, and it isn't the
first time they lost three Glonass birds. Wonder how much money was lost
in
$200 million for these three.
http://uk.reuters.com/article/2013/07/02/uk-russia-space-rocket-idUKBRE96103Y20130702?feedType=RSSfeedName=worldNews
Brian
On 7/2/2013 16:03, Dan Kemppainen wrote:
Note to self, Not getting on any Russian made rockets any time soon.
At least the rockets were
Hi
The choice with the mainstream chip sets these days seems to be GPS only or
everything. For timing, running everything is a bit interesting.
Bob
On Jul 2, 2013, at 12:03 PM, Dan Kemppainen d...@irtelemetrics.com wrote:
Note to self, Not getting on any Russian made rockets any time soon.
Are there any tricks to getting a HP 117A to lock to the current WWVB
transmissions.
I have read the thread for the Spectracom receivers.
Will this work with the 117A?
Thanks
73
Glenn
WB4UIV
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To
No kidding. Talk about embarrassing. I guess in the good old days, that
project manager would be packing his teacup to go spilt rocks in siberia
for the rest of his life, if he got off that lucky.
Brent
On Tue, Jul 2, 2013 at 12:03 PM, Dan Kemppainen d...@irtelemetrics.comwrote:
Note to
When WWVB changed to BPSK, the phase-tracking receivers were rendered
inoperative.
Paul Swed has a tested design for a Costas Loop receiver front end and
demod that properly tracks the BPSK carrier phase and routes it to a 117A
or similar receiver.
There are also some hacks that, knowing the
Crazy as this is I suspect I have the same article and though it may be
very useful on the costas loop I did not want to get tangled in a second
loop if I could avoid it.
Like you Perry the math gets touchy. But the circuit actually really get
tricky.
Regards
Paul.
On Tue, Jul 2, 2013 at 12:10
Johns
Right the costas loop is specifically for phase tracking rcvrs like the
117. Its a general purpose solution that keeps you out of the insides. But
that said you can take just the costas loop and integrate it into a 117. I
strongly belive that statement doesn't really address how things may
The way to run an embedded Linux system is NOT to run off the SD card.
Set up a small RAM disk and write to the disk image.
I think you could get this to work but you have to know a little about
unix-like OSes so you can make changes.
That is one reason I suggested the Item Atom. It is a
On Tue, Jul 2, 2013 at 12:32 AM, mike cook mc235...@gmail.com wrote:
... In most modern x86 CPU's you have a TSC which is a 64bit counter
incremented at the cpu clock cycle speed . You can capture that with a
single instruction. NTP uses that if it is available. So to get an
accurate TI you
Actually it's a US-Russian private enterprise (ILS) which is driving the
modernization (read cost-cuttings) of the Proton-M... as they have the
exclusive commercial launch rights. Failures started to add up since 2007.
Guantanamo would be more fitting today.
On 7/2/2013 7:26 PM, brent evers
Here we go again - the first send didn't seem to get through. This is
the second attempt.
This talk of Costas loops reminded me of something I wanted to
investigate some day. I read somewhere a while back about
carrier-phase measurements, and various methods for recovering the
GPS carrier
My lazy answer is GPSDOs work fine. This being time-nuts though and you did
use the word perfect means this is the start of a long thread.
Me I am staying with the Tbolt and 3801. Good enough.
Regards
Paul.
On Tue, Jul 2, 2013 at 2:21 PM, ed breya e...@telight.com wrote:
Here we go again - the
li...@rtty.us said:
The choice with the mainstream chip sets these days seems to be GPS only
or everything. For timing, running everything is a bit interesting.
Is anybody monitoring things to see how closely various systems track?
--
These are my opinions. I hate spam.
Hi Ed,
Are you talking about using GPS satellites, which means you have to have an
extremely accurate clock to know where they are to correct for doppler, or are
you talking about WWV, which means you have to deal with multi-path,
atmospheric doppler, fading, and propagation?
Bob - AE6RV
There is a Wiki article on Costas Loops that includes block diagrams.
There are books about the loop filter design.
Signal squaring is simply the Trig identity:
Sin(A)**2 = 1/2*[1 - cos(2*A)]
which has a DC term and a double frequency term. Sine is symmetriv about
the 0 axis.
In practice, with
More on your question:
I'm prettyt sure that just sticking up an antenna and hooking up a simple,
phase tracking receiver for GPS will yeild nothing useful, because there
are always several birds in view, so you will get a superposition of their
signals in the bandpass and each signal will be
John,
The SD Card issue is serious but not unique go the BBB. I believe there are
ways to configure any Linux distro to make the SD card read only, at the cost
of losing logging and data every time you power off. Alternately, one could
partition the SD card with a second partition just for
On Tue, 02 Jul 2013 11:21:24 -0700
ed breya e...@telight.com wrote:
For my needs, I'm more of a frequency-nut - I usually don't care
about getting time info, but I'd like perfect 10 MHz for reference.
Can using only the carriers lead to simple ways to get the same (or
better) frequency
Hi
Ok, cook book style:
Take the carrier, amplify it up, drive an agc to keep it up.
Drive the carrier into a full wave bridge rectifier made with low barrier diodes
Take the rectified output and feed it into a bandpass filter at 2X the carrier
The output is the squared carrier
There are at
This talk of Costas loops reminded me of something I wanted to
investigate some day. I read somewhere a while back about
carrier-phase measurements, and various methods for recovering the
GPS carrier frequencies, including the Costas loop, and something
with carrier-squaring. Nothing I found
Valid concerns all. What I am building is a squaring circuit for recovering the
carrier from a WAAS GPS satellite. Granted there is still some Doppler and
other issues, but the accuracy would not be bad and it just looks like a fun
thing to do. Plus, I can use my four foot diameter dish antenna
Ed nothing attached
On Tue, Jul 2, 2013 at 2:05 PM, ed breya e...@telight.com wrote:
This talk of Costas loops reminded me of something I wanted to investigate
some day. I read somewhere a while back about carrier-phase measurements,
and various methods for recovering the GPS carrier
I built an additional receiver assembly using a CMAX CME6005. This chip is
available from a fellow time-nut Brent for a reasonable cost. I will leave
those details to him. But in many respects the circuit looks like the
MAS6180. Same front end rf transformer mouser 42f101 yellow slug and 7500
pf
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