Re: Measure crystal motional parameters? Needs 1Hz frequency steps
There is one item that may have been overlooked. The frequency error of the reference source for the PLL is 0.5 ppm., as used in the VNA. At 70 MHz, that is a 35 Hz error. I did a 6 pole crystal filter design at that frequency but I did not use a VNA to capture the series resonate frequency and then find the motional L and C. I used a vector voltmeter and signal generator phase locked forcing the source to reach series resonance. It was precise because of the nature of the high gain of the PLL.
Anyway, the 1 Hz step is certainly a nice requirement met by dividing the sweeps into segments. However, the accuracy of those steps may compromise the quality of determining the series resonate point, particularly aggravating in a high unloaded Q crystal.
Alan
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Re: Measure crystal motional parameters? Needs 1Hz frequency steps
The software that comes with the AIM4170/4300 can automatically measure crystals.? I have designed about 20 different crystal filters? using this software and the results are virtually perfect with the constructed filter matching the synthesized one.? If interested I have a couple of videos describing how to synthesize crystal filters.
I use a program called SimSmith to analyze the filters and it can import NanoVNA data directly.
73,
Larry, W0QE
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Show quoted text
On 10/29/2019 3:30 PM, Alan G3XAQ wrote: There are programs for the N2PK type of instrument that use a fixture like this
to measure quartz crystal paramters Lm, Cm and ESR. Has anyone done this with their nanoVNA? I think it will need a firmware change to allow frequency steps on 1Hz instead of the usual 100Hz.
Thanks,
Alan G3XAQ
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Re: Measure crystal motional parameters? Needs 1Hz frequency steps
Hi Alan Oristo just told QRP has the solution Kind regards Kurt -----Oprindelig meddelelse----- Fra: [email protected] < [email protected]> P? vegne af Alan G3XAQ Sendt: 29. oktober 2019 23:59 Til: [email protected]Emne: Re: [nanovna-users] Measure crystal motional parameters? Needs 1Hz frequency steps Hello Kurt. Thanks very much for the feedback describing how things have moved on. You say NanoVNA-saver can increase the number of steps, but can it also reduce the step size? Even 101 points with 1Hz steps would be usable, but the default 100Hz steps make it unusable for this application. 1Hz steps really are a mandatory requirement when measuring crystals. Best wishes, Alan
On Tue, Oct 29, 2019 at 10:48 PM, Kurt Poulsen wrote:
Hi Alan
This an old design I did only to comport those believing a crystal
should be measured in a 12ohm environment. It has bearings on
mesurements with non VNA instruments I have totally dropped the
attenuators as introducing errors as I mentioned in the report as
figure of merit 100 times worse than without.
The one I use now is shown in attached images.
The NanoVNA-saver can increase the number of point to as many you like
so this way round it can surpasses the 101 point limitation Kind
regards Kurt
-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af
Alan G3XAQ
Sendt: 29. oktober 2019 22:31
Til: [email protected]
Emne: [nanovna-users] Measure crystal motional parameters? Needs 1Hz
frequency steps
There are programs for the N2PK type of instrument that use a fixture
like this
WA%20and%20N2PK%20VNA%20.pdf
to measure quartz crystal paramters Lm, Cm and ESR. Has anyone done
this with their nanoVNA? I think it will need a firmware change to
allow frequency steps on 1Hz instead of the usual 100Hz.
Thanks,
Alan G3XAQ
|
Re: Measure crystal motional parameters? Needs 1Hz frequency steps
Hi Alan Yes I missed that point and agree 1Hz step is a must. But I have seen mentioned in a posting frequency steps of 1Hz for a special firmware but when and from whom I do not recall Kind regards Kurt -----Oprindelig meddelelse----- Fra: [email protected] < [email protected]> P? vegne af Alan G3XAQ Sendt: 29. oktober 2019 23:59 Til: [email protected]Emne: Re: [nanovna-users] Measure crystal motional parameters? Needs 1Hz frequency steps Hello Kurt. Thanks very much for the feedback describing how things have moved on. You say NanoVNA-saver can increase the number of steps, but can it also reduce the step size? Even 101 points with 1Hz steps would be usable, but the default 100Hz steps make it unusable for this application. 1Hz steps really are a mandatory requirement when measuring crystals. Best wishes, Alan
On Tue, Oct 29, 2019 at 10:48 PM, Kurt Poulsen wrote:
Hi Alan
This an old design I did only to comport those believing a crystal
should be measured in a 12ohm environment. It has bearings on
mesurements with non VNA instruments I have totally dropped the
attenuators as introducing errors as I mentioned in the report as
figure of merit 100 times worse than without.
The one I use now is shown in attached images.
The NanoVNA-saver can increase the number of point to as many you like
so this way round it can surpasses the 101 point limitation Kind
regards Kurt
-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af
Alan G3XAQ
Sendt: 29. oktober 2019 22:31
Til: [email protected]
Emne: [nanovna-users] Measure crystal motional parameters? Needs 1Hz
frequency steps
There are programs for the N2PK type of instrument that use a fixture
like this
WA%20and%20N2PK%20VNA%20.pdf
to measure quartz crystal paramters Lm, Cm and ESR. Has anyone done
this with their nanoVNA? I think it will need a firmware change to
allow frequency steps on 1Hz instead of the usual 100Hz.
Thanks,
Alan G3XAQ
|
Re: Measure crystal motional parameters? Needs 1Hz frequency steps
you can find firmware here:
Just tested 0.4.2 supports 1 Hz steps.
Frequency steps smaller than 1 Hz is not supported, because frequency is represented with integer value in the code.
So, each frequency needs to be integer despite the fact that si5351 supports fractional frequencies.
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Re: Remove plastic screen protector?
All the NanoVNA devices use resistive touchscreen devices so it is irrelevant if you leave it on or take it off. However, replacing it with a real screen protector is always a good idea.? ... Larry On Tue, 29 Oct 2019 at 6:50 PM, gusagar54<gusagar@...> wrote: The protector is just that, a protector, and even more: it decreases de efficiency of the capacitive touch screen, so the idea is taking it out at once. Do you leave the protective film when you get a new phone, of course not! Do it and try to move the cursors and you will se what am I talking about. El mar., 29 oct. 2019 a las 14:23, Joe St. Clair AF5MH (< saintc@...>) escribi¨®: I don't think of this as a screen protector. It looks like the film
commonly seen on on much newly purchased electronics. I think its just to
keep smudges off during final assembly and shipping. The Nano is just
unusual (unique?) in that they screw the bezel on over the film. Perhaps
the display or electronics sub-assemblies arrived with the film in place
and final assembly just adds the battery, standoffs, back cover and bezel
without removing the film. I have a couple of these and on one I just
worked the film off from under the bezel. On another, I removed the bezel
screws - that was easier. If you are a screen protector kind of person, you
might do well to buy or salvage one and cut it to size. Real screen
protectors are tougher than this film.
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Re: edelay vs ELECTRICAL DELAY and other fun
#internals
On Tue, Oct 29, 2019 at 07:02 PM, Oristo wrote:
gnuplot> f(x) = a+(b*x)+(c*x*x)
This is really a 2nd order polynomial...it seems to be entirely adequate. Higher order (x^3...) polynomials can be made to fit almost anything in a strict range, but IMO much above 3rd is not /generally/ useful describing behaviour. In some cases, we can estimate what the behavior is, such as a trig function * an exponential, such a sin(x)*e^(-p). This looks like a very good fit, but of course, only the accompanying fit stats will tell the tale...it is often too easy to make a mistake in this area. OTOH, this is prolly not that critical at this point? -- On the banks of the Piscataqua Rich NE1EE
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Re: edelay vs ELECTRICAL DELAY and other fun
#internals
On Tue, Oct 29, 2019 at 10:34 PM, <erik@...> wrote:
From 1 to 10 reduces a factor 3. To 100 should reduce again with factor 3. But
it seems a bit less reduction.
More points means more long measurement and more high probability of some interference spike. I think may be there is need for a median filtering, but there is too small memory in order to do median filter for a large amount of points
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Re: Measure crystal motional parameters? Needs 1Hz frequency steps
On Wed, Oct 30, 2019 at 01:23 AM, Oristo wrote:
At least QRP's recent firmwares accept 1Hz steps, e.g.:
yes, it supports 1 Hz step, also there is fixed frequency rounding error and it measure exactly these frequencies which are requested. With old firmware versions you will get random frequency errors and minimum span 5-10 kHz. So, I recommend to update.
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Re: Measure crystal motional parameters? Needs 1Hz frequency steps
You say NanoVNA-saver can increase the number of steps, but can it also reduce
the step size? Even 101 points with 1Hz steps would be usable, but the default
100Hz steps make it unusable for this application. 1Hz steps really are a
mandatory requirement when measuring crystals. At least QRP's recent firmwares accept 1Hz steps, e.g.: scan usage: scan {start(Hz)} {stop(Hz)} [points] scan 10000 10100 100 frequencies 10000 10001 10002 10003 ... 10098 10100
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Re: Remove plastic screen protector?
On Tue, Oct 29, 2019 at 11:50 PM, gusagar54 wrote:
The protector is just that, a protector, and even more: it decreases de
efficiency of the capacitive touch screen, so the idea is taking it out at
once.
Different types of protectors exist for plastic screens: One is just meant to protect the plastic screen surface from scratches (and fingerprints) while being handled during manufacturing and transport, the other is meant to protect the screen from scratches during use. The first type of protector is usually peeled off by the user once he starts using the device, the second type is often applied immediately thereafter. This type of protector was common in the old days, when screen digitizers were resistive. The one in the NanoVNA is resistive, not capacitive. The resistive digitizer consists of two transparent and slightly conductive layers at close proximity but not touching. Pen pressure makes the two layers touch and the resulting resistance pattern across the layers along the X- and Y-axes is determined. The position of touch may be derived from the resistance pattern. Resistive panels need a flexible (plastic) top layer, which is scratch-sensitive. That's why many users of resistive film screens used to apply a replaceable scratch-protection film. A capacitive touch screen needs just one solid outside surface. It can be made from glass(like) material. The proximity of the finger or a special pen has a capacitive influence and the location is determined by the panel's electronics. The transparent covers that people put on their phone's screens are mostly for shock protection. All modern telephone and pad touch screens are capacitive. It's easy to see and feel: A resistive screen (like the NanoVNA's) is visibly deformed (dimpled) when the pen is put onto the surface, whereas with a capacitive screen, no movement is visible. Raymond
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Re: edelay vs ELECTRICAL DELAY and other fun
#internals
Averaging reduces noise with the square of the number of averages .. assuming independent random noise. I told gnuplot to fit a cubic: gnuplot> f(x) = a+(b*x)+(c*x*x) gnuplot> fit f(x) 'ch1_100.p' u 1:2 via a,b,c ... rms of residuals 6.24453e-006 (for 10 avg) 5.63911e-006 (for 100 avg) 1.15592e-005 (for 1 avg) From 1 to 10 reduces a factor 3. I got 1.85 To 100 should reduce again with factor 3. I got 1.1 I saw nothing problematic in main.c measure_gamma_avg(), but was a little surprised to see floats inside the loop. IMO, scanraw is probably obscure enough that supporting average only for powers of 2 would allow accumulating integer data by shifts, then converting accumulated to float gamma.
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Re: Measure crystal motional parameters? Needs 1Hz frequency steps
Hello Kurt. Thanks very much for the feedback describing how things have moved on. You say NanoVNA-saver can increase the number of steps, but can it also reduce the step size? Even 101 points with 1Hz steps would be usable, but the default 100Hz steps make it unusable for this application. 1Hz steps really are a mandatory requirement when measuring crystals.
Best wishes,
Alan
toggle quoted message
Show quoted text
On Tue, Oct 29, 2019 at 10:48 PM, Kurt Poulsen wrote:
Hi Alan
This an old design I did only to comport those believing a crystal should be
measured in a 12ohm environment. It has bearings on mesurements with non VNA
instruments
I have totally dropped the attenuators as introducing errors as I mentioned in
the report as figure of merit 100 times worse than without.
The one I use now is shown in attached images.
The NanoVNA-saver can increase the number of point to as many you like so this
way round it can surpasses the 101 point limitation
Kind regards
Kurt
-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af Alan G3XAQ
Sendt: 29. oktober 2019 22:31
Til: [email protected]
Emne: [nanovna-users] Measure crystal motional parameters? Needs 1Hz frequency
steps
There are programs for the N2PK type of instrument that use a fixture like
this
to measure quartz crystal paramters Lm, Cm and ESR. Has anyone done this with
their nanoVNA? I think it will need a firmware change to allow frequency steps
on 1Hz instead of the usual 100Hz.
Thanks,
Alan G3XAQ
|
Re: Remove plastic screen protector?
The protector is just that, a protector, and even more: it decreases de efficiency of the capacitive touch screen, so the idea is taking it out at once. Do you leave the protective film when you get a new phone, of course not! Do it and try to move the cursors and you will se what am I talking about. El mar., 29 oct. 2019 a las 14:23, Joe St. Clair AF5MH (< saintc@...>) escribi¨®: I don't think of this as a screen protector. It looks like the film
commonly seen on on much newly purchased electronics. I think its just to
keep smudges off during final assembly and shipping. The Nano is just
unusual (unique?) in that they screw the bezel on over the film. Perhaps
the display or electronics sub-assemblies arrived with the film in place
and final assembly just adds the battery, standoffs, back cover and bezel
without removing the film. I have a couple of these and on one I just
worked the film off from under the bezel. On another, I removed the bezel
screws - that was easier. If you are a screen protector kind of person, you
might do well to buy or salvage one and cut it to size. Real screen
protectors are tougher than this film.
|
Re: Measure crystal motional parameters? Needs 1Hz frequency steps
Hi Alan This an old design I did only to comport those believing a crystal should be measured in a 12ohm environment. It has bearings on mesurements with non VNA instruments I have totally dropped the attenuators as introducing errors as I mentioned in the report as figure of merit 100 times worse than without. The one I use now is shown in attached images. The NanoVNA-saver can increase the number of point to as many you like so this way round it can surpasses the 101 point limitation Kind regards Kurt -----Oprindelig meddelelse----- Fra: [email protected] < [email protected]> P? vegne af Alan G3XAQ Sendt: 29. oktober 2019 22:31 Til: [email protected]Emne: [nanovna-users] Measure crystal motional parameters? Needs 1Hz frequency steps There are programs for the N2PK type of instrument that use a fixture like this to measure quartz crystal paramters Lm, Cm and ESR. Has anyone done this with their nanoVNA? I think it will need a firmware change to allow frequency steps on 1Hz instead of the usual 100Hz. Thanks, Alan G3XAQ
|
Measure crystal motional parameters? Needs 1Hz frequency steps
There are programs for the N2PK type of instrument that use a fixture like this
to measure quartz crystal paramters Lm, Cm and ESR. Has anyone done this with their nanoVNA? I think it will need a firmware change to allow frequency steps on 1Hz instead of the usual 100Hz.
Thanks,
Alan G3XAQ
|
Re: usb controled rf generator.
On Tue, Oct 29, 2019 at 03:27 PM, <erik@...> wrote: Two adf4351 modules. One at two GHz into LO port of mixer and the other at 2
till 3 GHz through 3 GHz low pass filter This seems a relatively economical LPF into RF port of mixer.
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Re: Question: Is it possible to use calibration imperfections to detect the quality of calibration standards???
#calibration
Dr. David Kirkby from Kirkby Microwave Ltd
On Tue, 29 Oct 2019 at 20:11, <erik@...> wrote: The vertical scale is the abs of the measured s11. Zero to one. Red an
green lines
The pink line is S11 open phase minus S11 short phase minus pi.
What would the offset delay do to the rotation of S11 open and short.
Would it impact the phase or also the magnitude.
Would it be constant shift or frequency dependent?
Hi, I need to go out, so don't have time to re-arrange all these equations into the form you want, but hopefully it will get you started. A section of transmission line with a vacuum dielectric causes a phase shift phi of phi = 2*Pi*L/lambda where lambda is the wavelength (metres), and L the length (metres). The wavelength lambda = c/f where f is the frequency in Hz, and c the velocity of light in a vacuum. so phi = 2*Pi*L*f/c *So the phase shift is directly proportional to frequency, and directly proportional to the length of the line. * Some manufacturers of cal kits use a length (e.g. Rohde and Schwarz), and others a delay (e.g. Keysight). They are related by the velocity of light in *vacuum*, not air or the dielectric. That's the convention used - it is obviously not realistic in practice. The delay d (seconds) of that transmission line lf length L is L/c, where c is the velocity of light in vacuum. e.g. 30 ps is 8.9938 mm. So the phase shift phi is proportional to frequency, and proportional to the delay. Obviously you get phase wrapping too, but that's another issue. If those don't make any sense, I would have screwed up somewhere. -- Dr David Kirkby Ph.D C.Eng MIET Kirkby Microwave Ltd Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD, Essex, CM3 6DT, United Kingdom. Registered in England and Wales as company number 08914892 Tel 01621-680100 / +44 1621-680100
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Re: edelay vs ELECTRICAL DELAY and other fun
#internals
Averaging reduces noise with the square of the number of averages
From 1 to 10 reduces a factor 3. To 100 should reduce again with factor 3. But it seems a bit less reduction.
|
Re: edelay vs ELECTRICAL DELAY and other fun
#internals
|
Kurt Poulsen
Rich NE1EE
Oristo
gusagar54
