There are two ways to measure the carrier frequency using a Spectrum analyzer.
1) have bandwidth sufficient to capture all the sidebands produced
by the FM signal.
2) Have your bandwidth set very narrow, 10Hz or so and tune it directly
on the carrier frequency. The carrier frequency should
At 03:56 PM 11/29/2012 +, you wrote:
By theory, yes... but we use a sound card with a lot of flicker noise
on the lower
end, also we have the 10...20Hz low freq. cutoff due the usage of a
servo / single
5V power. Also the raising noise below 100Hz (ADC serve noise on the
ADC power /
If you want a low noise mixer use a varicap mixer. A varicap has no
ohmic characteristics thus
no Johnson noise.
Secondly, You can create low noise harmonics using a vaicap multiplier
or a nonlinear transmission
line using inductors and nonlinear capacitors (varicaps). NIST has been
One way is to divide by 10 and then multiply by 16.
Divide by 10 and then follow by 4 tuned frequency doublers.
This should introduce little phase noise.
Another way to do it is to divide by 10, then pass the output thru a
narrow 16 MHz filter and amplify. Sounds difficult but the filter
At 12:58 AM 1/4/2013 +, time-nuts-requ...@febo.com wrote:
Where can one get some of these mythical 74HC90 's and 74AC90 's that
have been mentioned.
None of the usual places have them, ie ebay, digi-key, farnell, or
even the Chinese.
Also data-sheets are not to be found.
Thanks
This
If you divide by 5 the phase noise sideband amplitude (voltage) will be
divided by 5.
That is a reduction of 14db for all phase noise sideband frequencies . Then
when you multiply that by 8 you will add the phase noise
sidebands will be multiplied by 8 or 3x6db or 18 db. So the end result
At 07:51 PM 1/4/2013 +, you wrote:
My question is about the phase noise of the final 16MHz signal. Do
crystal filters clean up the signal. It seems that after several
16MHz crystals in series the output should look a lot like an XO.
For offsets out to 100 Hz or so, using a crystal
Discrete amplifiers are always less noisy than integrated amplifiers.
If you want really low noise design a one with JFETs and Bipolar transistors.
I am trying to understand the contribution to phase noise by the opamps.
Perhaps the threshold is shifting and amplifier is being driven to
At what frequency do you have 1 nv per square root Hz with opamp and
what opamp ?
The 1/f region is the killer and if it is a low frequency shift in the
input
effectively changing the threshold then you have to be concerned about the
1/f region.
Discrete embedded JFETs have the best 1/f
Low noise voltage at the cost of noise current which is around 1000 times that
of low noise JFETs.
The discussion suggest that opamps contribute to the sideband phase noise
of the signal. I am interested in the mechanism that adds this phase noise.
It would have to be a small shift in either
Yes---it's too bad that the proposed WWVB changes don't increase the
number of transitions at all. Could they not do the
low-modulation-index DCF77-like signal on top of the BPSK? That is,
put some small, fast phase wiggles on top of the slow 180-degree
transitions (or 120-degree transitions
Has anyone ever used an Lock-in Amplifier such as
a PAR HR-8 or later models as part of a receiving
system for WWVB? These are mostly used in detecting
weak signals in noise in scientific experiments. Some have used
the analog output to phase lock a voltage controlled
oscillator to the input
Wow, I have not checked this list for some time. But there is a lot said
about zero crossing detectors.
Lots and lots of replies, so many that I have not looked at all of them.
1. Do not use CMOS inverters. Even though so much has been published on
using these in linear mode by
adding a
Lets see. 10 mHz is .01Hz
Do any of you remember when this mHz thing started?
It happened about the same time DE9 connectors became DB9
and DA15 connectors became DB15 connectors.
Also, during that time the RS232 spec did not specify a connector.
Just signals, voltage levels and rise/fall times.
Does someone have a list of the options that are not listed in the
PTS catalog?
Bill wa4lav
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I am new to the list and would like to know if anyone has a list of the
suffixes (options) for PTS synthesizers. There seem to be a number of them
that are not in their catalog.
73
Bill wa4lav
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To
My experiments with CW laser diodes is that they don't take well to
being switched on and off with out a soft start.
They will only last a certain number of on off cycles before output begins
to drop and they quit working. Perhaps something
has changed in the last few years.
I need to
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