In message 531f7161.2080...@sasktel.net, Ed Palmer writes:
I just picked up an Isotemp OCXO107-10 Oscillator. I thought it looked
like it might be interesting, but it turns out that it's better than I
thought. It's got a Dewar flask! I found the specs, but it didn't
mention anything about
Thanks a lot for the input!
I will try to use the LMH6702 as buffer.
The correct way to measure the HCMOS oscillator would probably be to use a
high impedance buffer with very low noise, to simulate driving a 10pF load
or so. But I guess that is not easy to do. The LMH6702 voltage noise is
Why not AC couple the HCMOS output to the LMH6702 input?
Bruce
Anders Time wrote:
Thanks a lot for the input!
I will try to use the LMH6702 as buffer.
The correct way to measure the HCMOS oscillator would probably be to use a
high impedance buffer with very low noise, to simulate driving a
On 12/03/14 10:57, Anders Time wrote:
Thanks a lot for the input!
I will try to use the LMH6702 as buffer.
The correct way to measure the HCMOS oscillator would probably be to use a
high impedance buffer with very low noise, to simulate driving a 10pF load
or so. But I guess that is not easy to
The LMH6702 is a wicked fast op amp which will react accordingly it there are
parasitics in the feedback path. I have only used them with well laid out PWBs
and extremely short traces to surface mount resistors. Under those conditions,
they work beautifully as advertised. Not sure anyone other
Thanks guys
It is now reading UTC, but only after a power off routine. That confused me !
I can't afford the time to let it re-survey, and used the Query command with a
0 instead of a ?. Re-querying it with a question mark it replied that
there would be no survey on power up. The iPhone
Tom
I may have missed your comment do you have one of these? It appears there
is very little data on them. Must not have been popular.
So from the posts I can give you a good guess. It would be a TRF receiver
without a crystal filter. This can be as reasonable as 4 transistor stages
to get that
Are you putting the unknown signal to be measured on an interrupt pin?
that will work for low enough frequencies but most uPs have a built-in
counter. It is a hardware register on the uP chip that will increment for
each pulse on a pin. then you read that number and divide by the gate
time.
Sorry forgot to add this.
As for delayed turn on. That can work but why not simply have the software
go into a 5 or 10 second wait before it does anything else. Display
warming up or please wait on the LCD.
On Wed, Mar 12, 2014 at 7:18 AM, Chris Albertson
albertson.ch...@gmail.comwrote:
Hi Paul...
Thanks for that insight, There are 2 4046's on the board, but the guts of
the RX are hidden inside a can. It does have a time code output which could
be fun to play with. Am hoping to learn a bit more before I tear into it in
earnest.
Tom Holmes, N8ZM
-Original Message-
From:
Tom,
On 18/11/13 23:15, Tom Van Baak wrote:
Magnus,
I'm going to push back a bit on your mains sampling claim. Mostly, I'd like to
see the results of the professional I-Q demodulated gear that you mentioned.
Can you post raw data, or a sample plot?
I don't have much of that myself. I do
I am using old Wavetek 180 signal generator for the tests. I just hooked
its TTL output directly to the pin of MCU. The STM32F4xx has core clock
168 mHz and its inputs capable to handle pretty wide range of frequency.
I don't think 1-2 mHz connected to the pin should be a problem. At least
LCD connected to the same MCU. And it has relation to the core clock
too. So, nothing on LCD before I reset entire MCU. I think initial
incorrect core clock reading cause a lot of issues. Probably my only
option will be to implement some external relay and timer to turn on MCU
few seconds
On Wed, 12 Mar 2014 11:48:04 -0400, d0ct0r wrote:
LCD connected to the same MCU. And it has relation to the core clock
too. So, nothing on LCD before I reset entire MCU. I think initial
incorrect core clock reading cause a lot of issues. Probably my only
option will be to implement some
On Wed, Mar 12, 2014 at 10:48 AM, d0ct0r t...@patoka.org wrote:
LCD connected to the same MCU. And it has relation to the core clock too.
So, nothing on LCD before I reset entire MCU. I think initial incorrect
core clock reading cause a lot of issues. Probably my only option will be
to
On Wed, Mar 12, 2014 at 9:10 AM, cfo xne...@luna.dyndns.dk wrote:
On Wed, 12 Mar 2014 11:48:04 -0400, d0ct0r wrote:
If you have a conditioning circuit betewwn the OCXO and the STM , i'd
like to see it. As i have the need for one , trying to interface a 5v OCXO
to a NXP 1114 Arm , that wants
Many thanks, Poul.
This info is consistent with the wiring on my unit. By looking and
doing continuity tests, I've found ground on pins 2, 4, 6, and 7. The
wire on pin 3 is red so that's also likely a match to yours for the +5 lead.
Ed
On 3/12/2014 2:31 AM, Poul-Henning Kamp wrote:
In
So the question is, will this really stop the annoying survey every time ?
I'd browse the manual looking for fine print. The idea you are looking for
is that after a survey it will save the location. If it has a saved location
on power up it will use it rather than do a new survey.
The
So we know there are deviations in line freq. But it seems strange in this era
of very accurate and inexpensive freq references.
How much is related to the generation? It seems in this era of switching
supplies and other complex loads that even if the power were perfect at the
generator the
xne...@luna.dyndns.dk said:
If you have a conditioning circuit betewwn the OCXO and the STM , i'd like
to see it. As i have the need for one , trying to interface a 5v OCXO to a
NXP 1114 Arm , that wants max 1.8v in the clockinput.
What's wrong with a simple resistive divider?
--
These
Now that I've got the TIC going, I'm working on the PLL math for my GPSDO. My
question is about moving averages. I've put in a moving average for the TIC.
From that, I've calculated the slope, and have put a moving average on the
slope to settle it down. I think this boils down to a moving
Hi Tom,
On 12/03/14 18:15, Tom Knox wrote:
So we know there are deviations in line freq. But it seems strange in
this era of very accurate and inexpensive freq references.
May seem strange, yes.
How much is related to the generation? It seems in this era of
switching supplies and other
Bob,
On 12/03/14 18:24, Bob Stewart wrote:
Now that I've got the TIC going, I'm working on the PLL math
for my GPSDO. My question is about moving averages. I've
put in a moving average for the TIC. From that, I've
calculated the slope, and have put a moving average on the
slope to settle it
On Wed, 12 Mar 2014 09:42:05 -0700, Chris Albertson wrote:
There are logic level converter chip made for this purpose or you can
use a comparator and compare the 5V clock to ground. Or just a diode to
clip the sine wave. If you connect a code. Sometimes you can set buy
with a pair of
Sun of gun what a guess. If there are two 4046s then they may indeed be
running quadrature. Not bad at all. Who would have thunk it.
If you decide to tear into things, maybe some pictures would be helpful.
I have a fair eye for figuring things out. I do expect under the can to be
from 2-3
In message 53208ed8.4090...@sasktel.net, Ed Palmer writes:
Many thanks, Poul.
This info is consistent with the wiring on my unit. By looking and
doing continuity tests, I've found ground on pins 2, 4, 6, and 7. The
wire on pin 3 is red so that's also likely a match to yours for the +5 lead.
Try:
http://www.linear.com/product/LTC6957
Bruce
cfo wrote:
On Wed, 12 Mar 2014 09:42:05 -0700, Chris Albertson wrote:
There are logic level converter chip made for this purpose or you can
use a comparator and compare the 5V clock to ground. Or just a diode to
clip the sine
Hi Magnus,
Thanks very much for this response! It will be very easy to add the
exponential averager to my code and do a comparison to the moving average. I
have no experience with PI/PID. I'll have to look over the literature I have
on them and relate that to what I'm controlling.
It
Yes the shapes of the waveforms for voltage and current, especially
deviation from sinusoidal currents and phase shifts due to generation -
transmission system - loads, are of great interest to the utilities in load
planning. Of very great interest to the utility industry in the past
decade, are
Analog Devices, Linear Technology and Maxim have fast comparators
73
Alex
On 3/12/2014 11:02 AM, cfo wrote:
On Wed, 12 Mar 2014 09:42:05 -0700, Chris Albertson wrote:
There are logic level converter chip made for this purpose or you can
use a comparator and compare the 5V clock to ground.
mag...@rubidium.dyndns.org said:
Exponential averger takes much less memory. Consider this code:
x_avg = x_avg + (x - x_avg) * a_avg;
Where a_avg is the time-constant control parameter.
Also note that if a_avg is a power of 2, you can do it all with shifts rather
than multiplies.
Note that
So we know there are deviations in line freq. But it seems strange in this
era of very accurate and inexpensive freq references. How much is related to
the generation?
Controlling the line frequency is a giant PLL, with horrible complications.
The simple setup for a big generator is that if
Hi Hal,
In the moving averages I'm doing, I'm saving the last bit to be shifted out and
if it's a 1 (i.e. 0.5) I increase the result by 1.
Bob
From: Hal Murray hmur...@megapathdsl.net
To: Discussion of precise time and frequency measurement
Sounds kind of like this oscillator. I found it to be very low
power but it took about a week for it to really settle down and
until then I was continually adjusting the EFC.
http://i906.photobucket.com/albums/ac262/rjb1998/Oscillator_zps63a30a2f.jpg
-Arthur
In message 1394653389.44185.yahoomail...@web122901.mail.ne1.yahoo.com, Arthur
Dent writes:
Sounds kind of like this oscillator. I found it to be very low
power but it took about a week for it to really settle down and
until then I was continually adjusting the EFC.
The pinout looks the same.
HP 58503A
Hi Hal
Good point, I don't want the display lighting my office up at night, hence I
often turn it off.
What I really need is the circuit of the front panel, then I could dim the
display and leave in on 24/7
Thanks
Dave
___
time-nuts
Could be, but I didn't see a good picture of that oscillator. Here's the
one I bought:
http://www.ebay.com/itm/121264125456?orig_cvip=true
Ed
On 3/12/2014 1:43 PM, Arthur Dent wrote:
Sounds kind of like this oscillator. I found it to be very low
power but it took about a week for it to
In message 5320c644.4070...@sasktel.net, Ed Palmer writes:
Could be, but I didn't see a good picture of that oscillator. Here's the
one I bought:
http://www.ebay.com/itm/121264125456?orig_cvip=true
Looks exactly like mine.
Good Bargain btw, the list price was north of $1k originally.
--
x_avg = x_avg + (x - x_avg) * a_avg;
Hi again Magnus,
In fact, I just post-processed some data using that formula in perl. It looks
great, and will indeed save me code and memory space. And, it can be a user
variable, rather than hard-coded. Thanks for the heads up!
Bob
All:
Some crude approximations.
Generators that I know of do in fact have a negative slope of frequency
versus load. This is deliberate, to enable stable load sharing.On
small systems, you try to set the slopes proportional to load capacity
so that load sharing remains proportional in
The photo looks like one of the 2 units I have but the info on
one if my oscillators says:
CTS Knights
970-2074-0
5 Mhz
0410-2540
8947
I'm pretty sure the last numbers are the
date code. If more than one company made these units they
could have been in some piece of equipment made
b...@evoria.net said:
In the moving averages I'm doing, I'm saving the last bit to be shifted out
and if it's a 1 (i.e. 0.5) I increase the result by 1.
That's just rounding up at an important place. It's probably a good idea,
but doesn't cover the area I was trying to point out. Let me
It's hard to see in the picture, but my oscillator is labelled:
0410-2540
Model OCXO107-10
Freq 5.000 MHz
S/N6396-40
Notice the same '0410-2540' line. So you're probably right. I wouldn't
be surprised to find that Lucent had multiple sources for the oscillator
and their part
Hal says: For exponential smoothing, a_avg will be a fraction. Let's pick
a_avg to be 1/8. That's a right shift by 3 bits. I don't think there is
anything magic about shifting, but that makes a particular case easy to spot
and discuss.
Hi Hal,
Yeah, I've been sitting here manually running
This is a FIR x IIR question...
moving average = FIR filter with all N coeficients equalling 1/N
exponential average = using a simple rule to make an IIR filter
Daniel
Em 13/03/2014 00:55, Bob Stewart escreveu:
Hal says: For exponential smoothing, a_avg will be a fraction. Let's pick a_avg
Hi Daniel,
re: FIR vs IIR
I'm not a DSP professional, though I do have an old Smiths, and I've read some
of it. So, could you give me some idea what the FIR vs IIR question means on a
practical level for this application? I can see that the MA is effective and
easy to code, but takes up
On Wed, Mar 12, 2014 at 9:13 PM, Daniel Mendes dmend...@gmail.com wrote:
This is a FIR x IIR question...
moving average = FIR filter with all N coeficients equalling 1/N
exponential average = using a simple rule to make an IIR filter
Isn't his moving average just a convolution of the data
47 matches
Mail list logo
