In message 4f669a4d.3010...@lazygranch.com, gary writes:
DC in a transformer raises the low frequency corner a bit. Obviously not
a problem in your case.
I just double-checked, because that rang a bell. I did reinstate
the capacitors as 2.2uF films in the final article for exactly that
reason.
gary schrieb:
Just meditating out loud, if you were to go push pull with a ferrite
antenna AND you are winding it yourself, you could avoid the biasing
resistors by putting a center tap in the antenna itself, then tie that
center tap to an appropriate bias voltage. I haven't seen this done,
Poul-Henning Kamp schrieb:
In message 4f64f279.4040...@arcor.de, ehydra writes:
Marek Peca schrieb:
This was almost the only reason for ferrite rod -- simplicity and
attenuation of TVs, some LCDs, 50Hz etc.
If you make the antenna about 10x bigger you can omit the whole
ferrite.
I
In message 4f65d971.8070...@arcor.de, ehydra writes:
http://home.earthlink.net/~christrask/Complementary%20Push-Pull%20Amplifiers.pdf
In my implementation, it covered DC to 200MHz until I low-pass'ed it.
His designs are always a good source but this one is AC-coupled ;-)
Not in my
I wonder because ALL of the shown circuits in his pdf are AC-coupled.
It is maybe possible to servo-loop with OpAmps but surely not worth the
effort.
Useful too as a Scope FET-probe.
- Henry
Poul-Henning Kamp schrieb:
In message 4f65d971.8070...@arcor.de, ehydra writes:
On Sun, 18 Mar 2012 13:25:54 +
Poul-Henning Kamp p...@phk.freebsd.dk wrote:
In message 4f65d971.8070...@arcor.de, ehydra writes:
http://home.earthlink.net/~christrask/Complementary%20Push-Pull%20Amplifiers.pdf
In my implementation, it covered DC to 200MHz until I low-pass'ed it.
His
The circuit in question doesn't appear to be in the PDF. You need to use
a lot of caution with Lankford's theories. I don't want to get into a
pissing contest, so I will leave it at that.
Push pull with transformers goes back to the tube days. It is a
convenient scheme to kill 2nd harmonic
My choice would be a center tapped, shielded, air core loop, running into
a low noise instrumentation amp. Center tap of loop to twinax shield,
grounded at preamp.
The instrumentation amp has fixed gain, and very high CMRR and PSRR. It
also does the differential to single ended conversion
ehydra wrote:
I wonder because ALL of the shown circuits in his pdf are AC-coupled.
It is maybe possible to servo-loop with OpAmps but surely not worth
the effort.
Useful too as a Scope FET-probe.
Not really the gain inaccuracy is somewhat excessive.
One can do much better with the right
In message 20120318182440.7cb729c2b018b0b2ca5f9...@kinali.ch, Attila Kinali w
rites:
On Sun, 18 Mar 2012 13:25:54 +
Not in my implementation, I have eliminated the input capacitor because
the active element is 3cm from the PCB,
Could you explain how the distance of the antenna to the PCB
DC in a transformer raises the low frequency corner a bit. Obviously not
a problem in your case.
I should point out that every active device Lankford puts in the signal
chain adds noise since the amp is really just a buffer, not an
amplifier. You really want front end gain so that devices
In message Pine.LNX.4.64.1203170042050.2576@tesla, Marek Peca writes:
My only argument against your versatile and well-performing solution is
that it is a little bit overkill.
As if running a handfull precision oscillators just for fun isn't
overkill also ? :-)
In other words, it would be
Moin!
On Fri, 16 Mar 2012 13:45:04 +
Poul-Henning Kamp p...@phk.freebsd.dk wrote:
Hmm.. i someday have to look for a good introdcution into this stuff
that doesn't rely on a lot of math. All the books i have rely at least
on Laplace.. often on z-transformation as well. And that math isn't
On Fri, 16 Mar 2012 20:02:27 -0700
gary li...@lazygranch.com wrote:
I lost track of who wrote this, but why is it assume a ferrite rod has
non-linear phase. [Group delay error I presume). Now I assume this
presumes the rod is used in a LC circuit, but if the Q is not high, the
phase
In message 20120317104723.8c1832454f14a3f91a4fb...@kinali.ch, Attila Kinali w
rites:
That said, i think this can be ignored for all practical purposes
in an VLF receiver, as the enviromental changes in the atmospheric
signal path are much larger than the small error you get from the
filter. But
On Sat, 17 Mar 2012 10:01:13 +
Poul-Henning Kamp p...@phk.freebsd.dk wrote:
That said, i think this can be ignored for all practical purposes
in an VLF receiver, as the enviromental changes in the atmospheric
signal path are much larger than the small error you get from the
filter. But
In message 2012031719.9536107ebf82050fe14ee...@kinali.ch, Attila Kinali w
rites:
On Sat, 17 Mar 2012 10:01:13 +
Could you explain why? Yes, you need a higher BW for Loran-C,
but the phase(f) function will give you only a distortion of
the signal and a constant time delay in your signal
:47:23
To: Discussion of precise time and frequency measurementtime-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] WWVB BPSK Receiver Project? (fwd)
On Fri, 16 Mar 2012 20:02:27 -0700
gary li...@lazygranch.com wrote
On Sat, 17 Mar 2012 10:15:17 +
Poul-Henning Kamp p...@phk.freebsd.dk wrote:
In message 2012031719.9536107ebf82050fe14ee...@kinali.ch, Attila Kinali
w
rites:
On Sat, 17 Mar 2012 10:01:13 +
Could you explain why? Yes, you need a higher BW for Loran-C,
but the phase(f) function
On Sat, 17 Mar 2012 10:27:03 +
li...@lazygranch.com wrote:
What I don't have a lot of hands on experience is with open circuit
magnetics. (I do with closed circuit magnetics.) But I claim if the
ferrite rod antenna is not capacitively loaded to resonate at the
comm frequency, then there
On Sat, 17 Mar 2012 10:15:17 +
Poul-Henning Kamp p...@phk.freebsd.dk wrote:
Either you need to characterize the exact behaviour of your filter
and build the necessary compensation for its phase/frequency behaviour
into your receiver, or you need a very flat filter (both freq+phase)
in
Any filter's group delay can be equalized by all pass filters.
Delay builds up at the filter corner. Since everything in the real world
is causal, you add delay outside that corner frequency but in the
passband to equalize it. This is to say, you can't remove delay, but
just add it to flatten
Hello, gary,
I lost track of who wrote this, but why is it assume a ferrite rod has
non-linear phase. [Group delay error I presume). Now I assume this presumes
the rod is used in a LC circuit, but if the Q is not high, the phase
linearity won't necessarily be bad.
Basically I'd like to hear
On Sat, 17 Mar 2012 06:13:28 -0700
gary li...@lazygranch.com wrote:
On 3/17/2012 5:44 AM, Attila Kinali wrote:
On Sat, 17 Mar 2012 10:15:17 +
Poul-Henning Kampp...@phk.freebsd.dk wrote:
Either you need to characterize the exact behaviour of your filter
and build the necessary
Dear Poul-Henning,
My only argument against your versatile and well-performing solution is
that it is a little bit overkill.
As if running a handfull precision oscillators just for fun isn't
overkill also ? :-)
I don't know -- are there any limits for the fun in a time-nut sense? :-)
I hope
I've designed filters for datacom chips. I know filtering. My point is
the original author is making some assumptions in the design which are
not stated.
Yes, my fault, I didn't write it properly, so by a ferrite rod in
context of DCF/WWVB reception, I meand a ferrite antenna in an LC tuned
Any filter's group delay can be equalized by all pass filters.
Delay builds up at the filter corner. Since everything in the real world is
causal, you add delay outside that corner frequency but in the passband to
equalize it. This is to say, you can't remove delay, but just add it to
flatten
Which basically matched my assumption. If the inductor is loaded, you
have a narrowband filter. So again, this does not imply that a ferrite
rod antenna per se has phase distortion. It is the LC filter than
effects the group delay.
On 3/17/2012 6:19 AM, Marek Peca wrote:
Hello, gary,
I
Yes, in order to equalize group delay, you need to know what to
equalize. But with an educated guess as to the system response, he could
get close.
All this said, in 2012, I would rather the amplifier be simple gain, the
inductor not loaded with capacitance and the filtering done past the
Which basically matched my assumption. If the inductor is loaded, you have a
narrowband filter. So again, this does not imply that a ferrite rod antenna
per se has phase distortion. It is the LC filter than effects the group
delay.
Yes, exactly. Excuse my loose speech before not explicitly
Hi
The problem with delay compensation in a Time Nut environment is that to do it
you add delay. Your all pass network adds enough delay to the fast part of
the passband to make it come out the same as the slow part. In real circuits
you inevitably add some delay everywhere with the all pass,
Yes, in order to equalize group delay, you need to know what to equalize. But
with an educated guess as to the system response, he could get close.
All this said, in 2012, I would rather the amplifier be simple gain, the
inductor not loaded with capacitance and the filtering done past the
I think the tempco of the ferrite is more significant than drift in the
analog filter. Of course this again implies the better design is to not
load the inductor with a cap, i.e. stay broadband, and then just filter
post the preamp.
The open circuit voltage will be lower without the resonant
I think the tempco of the ferrite is more significant than drift in the
analog filter.
Perhaps I was unclear in this as well. I do not use nor plan to use any
other filter than the (ferrite-L)-C resonant circuit itself. So, yes, the
tempco of the ferrite makes its coefficients variation.
That would be 36ns group delay variation if I did the math correctly.
However, what material are you using for the ferrite? The material can
have a significant tempco.
On 3/17/2012 7:17 AM, Marek Peca wrote:
However, for f0=77.5kHz and B=1kHz, the LC circuit with Q=40 gives phase
error
That would be 36ns group delay variation if I did the math correctly.
OK
And in article P. Hetzel: Time dissemination via the LF transmitter DCF77
using a pseudo-random phase-shift keying of the carrier, 2nd EFTF
Neuchatel, 1988., they conclude with timing results of about 2..10e-6 s
RMS
http://www.fair-rite.com/newfair/materials61.htm
OK, assuming type 61, it is 0.1%/deg C. Let's go with +/- 5 degrees,
which would be for indoor use. I don't have the equation handy for a
damped LC. Certainly undamped would be worst case. f=1/(2*pi*sqrt(LC)).
When the dust settles, the
Hi Marek -
I don't know where you are in CZ. I'm on the boarder in DE near PL and
CZ. The distance to DCF77 is about 450km and if I check the amplitude
across 24h I see considerable very deep fading effects! I think it is
useless as a phase-coupled time receiver. At least in specific
Dear Henry,
I don't know where you are in CZ. I'm on the boarder in DE near PL and CZ.
my former measurement (the one at YouTube, fairly good reception, winter)
has been done under Erzgebirge, Teplice, CZ. Now I moved near Sumava
(Boehmischer Wald), so tests may follow, if I will return to
-boun...@febo.com
Date: Sat, 17 Mar 2012 16:10:48
To: Discussion of precise time and frequency measurementtime-nuts@febo.com
Reply-To: ehy...@arcor.de, Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] WWVB BPSK Receiver Project? (fwd)
Hi
gary wrote:
OK, assuming type 61, it is 0.1%/deg C.
IME, Type 78 is the usual choice for resonant antennas below 200 kHz
(tempco of initial permeability = 1.0%/deg C). I have seen Type 33
used for broadband LF/MF antennas (tempco of initial permeability =
0.1%/deg C). Type 61 is
Marek Peca schrieb:
This was almost the only reason for ferrite rod -- simplicity and
attenuation of TVs, some LCDs, 50Hz etc.
If you make the antenna about 10x bigger you can omit the whole ferrite.
The only benefit of a ferrite loaded coil is the size of it!
In ancient time radios had flat
To: Discussion of precise time and frequency measurementtime-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] WWVB BPSK Receiver Project? (fwd)
gary wrote:
OK, assuming type 61, it is 0.1%/deg C.
IME, Type 78 is the usual
To: Marek Pecama...@duch.cz; Discussion of precise time and frequency
measurementtime-nuts@febo.com
Reply-To: ehy...@arcor.de, Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] WWVB BPSK Receiver Project? (fwd)
Marek Peca schrieb:
This was almost
In the end every antenna receives the EM wave! The EM-wave is the far
field. The antenna works in the near field where a dominant component
can be the E or M. That depends on the antenna. Between the near and the
far field the field is converted and local Z0 highly complicated.
As far as I know
and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] WWVB BPSK Receiver Project? (fwd)
Marek Peca schrieb:
This was almost the only reason for ferrite rod -- simplicity and
attenuation of TVs, some LCDs, 50Hz etc.
If you make the antenna about 10x bigger you can omit the whole
No, there is a geometric saturation. You can't use the better
permeability in reality.
The optimum length to width relation is about 6 to 10 for ferrite rods.
Here is a diagram:
http://ehydra.dyndns.info/NG/time-nuts/Pettengill%20002.jpg
This is one of the classics in my link list:
In message 4f64f279.4040...@arcor.de, ehydra writes:
Marek Peca schrieb:
This was almost the only reason for ferrite rod -- simplicity and
attenuation of TVs, some LCDs, 50Hz etc.
If you make the antenna about 10x bigger you can omit the whole ferrite.
I have used two antennas, an unloade
In message 20120315234624.a2da94430a247d235ca68...@kinali.ch, Attila Kinali w
rites:
How good would that DAC need to be?
Depends on the level of ambition ?
1-4MB RAM
over a 256kB RAM it's get pretty thin if you want to stay in the uC
busines. Unless you want to use an ARM9 or better with
Moin!
On Fri, 16 Mar 2012 07:09:05 +
Poul-Henning Kamp p...@phk.freebsd.dk wrote:
In message 20120315234624.a2da94430a247d235ca68...@kinali.ch, Attila Kinali
writes:
On the other hand, if you dont have to support an OS and work on the
bare metal, you can get away with very little RAM.
In message 20120316085256.9e25deaeee4f7f8617989...@kinali.ch, Attila Kinali w
rites:
Hmm... do you mean you want to store all samples of an hour and then
avarage over it?
That would be the ideal way to do it, since it would make one heck of
a comb filter and eliminate pretty much anything else.
p...@phk.freebsd.dk said:
Hmm... do you mean you want to store all samples of an hour and then
avarage over it?
That would be the ideal way to do it, since it would make one heck of a comb
filter and eliminate pretty much anything else.
That only works if your reference clock is stable
-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Poul-Henning Kamp
Sent: Friday, March 16, 2012 4:23 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] WWVB BPSK Receiver Project? (fwd)
In message 20120316085256.9e25deaeee4f7f8617989
In message b8fa03dc1dd84a588a317b314a6fc...@vectron.com, Bob Camp writes:
Could you generate a lead and a lag estimate of the signal (in addition
to your center) and integrate against each of them on the fly? If so you
would need a *lot* less memory. I seem to recall you tried something like
this
On Fri, 16 Mar 2012 03:08:47 -0700
Hal Murray hmur...@megapathdsl.net wrote:
p...@phk.freebsd.dk said:
Hmm... do you mean you want to store all samples of an hour and then
avarage over it?
That would be the ideal way to do it, since it would make one heck of a comb
filter and
In message 20120316141539.d8305feaa33c99781667e...@kinali.ch, Attila Kinali w
rites:
Hmm.. i someday have to look for a good introdcution into this stuff
that doesn't rely on a lot of math. All the books i have rely at least
on Laplace.. often on z-transformation as well. And that math isn't
meaningful.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Poul-Henning Kamp
Sent: Friday, March 16, 2012 9:03 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] WWVB BPSK Receiver Project? (fwd
In message 34c510bb3c6449b89ac4f7fbc20f4...@vectron.com, Bob Camp writes:
One assumption is that you will indeed be capturing / averaging for several
days. I'd include some sort of model for sunrise / sunset shifts (might be
just ignore for the next hour).
Some of my best results had 8 buffers
into
the signal estimation side of the process.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Poul-Henning Kamp
Sent: Friday, March 16, 2012 12:27 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] WWVB
In message f8ac6c21eb1140b384332cb89b642...@vectron.com, Bob Camp writes:
My main concern on short averages is the relatively long path from WWVB to
most of the target audience. The day / night phase shift is fairly
significant over a long path.
So do I relative to DCF77 which I used for my
Bob,
To address that diurnal phase issue, for fun, we could set up a
cloud-based time-nuts WWVB common view network. With a
couple of sites in each state, imagine the wonderful daily or
hourly animated plots that would result.
/tvb
Hi
My main concern on short averages is the relatively long
Hello,
thank you for your oppinion.
On Thu, 15 Mar 2012, Poul-Henning Kamp wrote:
In message Pine.LNX.4.64.1203152001370.3542@tesla, Marek Peca writes:
Yes, it should work on any USB audio capable OS, ie. Linux, Windows,
MacOS etc.
I would like to recommend against this approach for a
I lost track of who wrote this, but why is it assume a ferrite rod has
non-linear phase. [Group delay error I presume). Now I assume this
presumes the rod is used in a LC circuit, but if the Q is not high, the
phase linearity won't necessarily be bad.
Basically I'd like to hear more from
Forgot to Cc: the maillist, sorry. So, FYI:
-- Forwarded message --
Date: Thu, 15 Mar 2012 16:31:14 +0100 (CET)
From: Marek Peca ma...@duch.cz
To: David J Taylor david-tay...@blueyonder.co.uk
Subject: Re: [time-nuts] WWVB BPSK Receiver Project?
Hello,
I would perhaps be
In message Pine.LNX.4.64.1203152001370.3542@tesla, Marek Peca writes:
Yes, it should work on any USB audio capable OS, ie. Linux, Windows, MacOS etc.
I would like to recommend against this approach for a number of reasons.
First, yes, while you can do undersampling and such, it puts very high
On Thu, 15 Mar 2012 22:27:53 +
Poul-Henning Kamp p...@phk.freebsd.dk wrote:
If I, based on my design, were to design a gadget for doing VLF
time-nuts stuff, it would be:
Floating Input trafo with center-tap for powering antenna
16 bit 1MSPS ADC
ARM chip
10MHz clock input
1PPS sync
On 3/15/12 3:27 PM, Poul-Henning Kamp wrote:
In messagePine.LNX.4.64.1203152001370.3542@tesla, Marek Peca writes:
Yes, it should work on any USB audio capable OS, ie. Linux, Windows, MacOS etc.
I would like to recommend against this approach for a number of reasons.
First, yes, while you
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