New product: tinyGTC, GNSS disciplined oscillator and universal 2 input Timer an

[techneut]

I had the same problem, It is a known problem. Use a simple USB 1.1 or 2.0 hub to make it work.

[Kurt_!]

I had the same problem, It is a known problem. Use a simple USB 1.1 or 2.0 hub to make it work.

I've already tried it. Unfortunately, the same thing happens.
Should I try it on a different PC and USB 2.0?

[erikka]

None are available in dial-up mode, except for the AT32....

This is normal behavior
In DFU mode the device runs a completely different FW showing only the DFU port.

[Kurt_!]

None are available in dial-up mode, except for the AT32....

This is normal behavior
In DFU mode the device runs a completely different FW showing only the DFU port.

The program ( STM32C...)isn't working on TinyGTC!?
It can't find any connections...
No problem with the TinySA Ultra

[erikka]

Follow guidelines published here: https://www.tinydevices.org/wiki/pmwiki.php?n=TinyGTC.FirmwareUpdate

[Kurt_!]

Follow guidelines published here: https://www.tinydevices.org/wiki/pmwiki.php?n=TinyGTC.FirmwareUpdate

So, it worked!
With Buddy 0.2...
Seek and ye shall find.

I thought it was another Python...

[cncjerry]

Hi,
My GTC arrived, impressive device, will be testing it this week now that my Cs beam and phase noise analyzer are back online and running great thanks to 5065Guru.

I had a hard time updating the firmware using DFUbuddy.  By the way, you need to read the readme at the start of the github to find the windows and linux releases.  Anyway, my computer, a dual CPU behemoth with a ton of memory, LTO5 tape, SAS drives etc, would not power the device fully during the DFUBuddy update. I needed to connect a powered USB hub to get it to erase the unit, the first step of programming the firmware. Success followed.

Thanks for another cool device.

Jerry

[KedasProbe]

Yes it would be better to add the actual download link instead of the project page
https://github.com/sourcebox/dfu-buddy/releases/

I see you are still updating the firmware regularly, any plans to add change notes? (even if they don't give much details)

[cncjerry]

what is the best mode for the input on the GTC and the best way to measure it before applying it to the device?

I haven't fully explored all the options, but what is the default input impedance?  And in that mode, what is the highest voltage level, 3.5V as below?  I have power meters including HP sensors, but they are all 50ohm, I believe.  I would like to check the voltage input because for instance, my 5061b cesium PPS is 10V, if I remember correctly.  So if the GTC can be run in 50ohm, is that the preferred safest mode and if so, then the numbers below for 50ohm would be applied.  Or would it be better to measure it with a scope in high impedance mode?  I can't remember how the HP power meters read PPS, if it is accurate or not.  I know some of the sensors measure heating but probably not those I have.

Absolute maximum short term DC input level: between -10 and +10 Volt
Recommended maximum DC input level: between -3.5 and +3.5 Volt
Absolute maximum short term AC input level: 10 Vpp
Recommended maximum AC input level: 3.5 Vpp  <--- this one and the one above seem to contradict each other.
Absolute maximum short term power into 50 ohm: +20 dBm
Recommended maximum power into 50 ohm: +10 dBm
Trigger level,: between 0 and 3.5 Volt
Input frequency A input: between 0.1 Hz and 7 GHz (for ZC407) or 12 GHz (for ZC412)
Input frequency B input: between 0.1 Hz and 350 MHz (max 50 MHz without prescaler)
Input trigger maximum time interval: No limit when measuring timestamp.
Input impedance: 1 MOhm/2 pF or 50 ohm (above 100 kHz)
Input hysteresis: 5 mV
Minimum input level in 50 Ohm: -20 dBm
Power meter range in 50 ohm input mode: -20 dBm to +20 dBm between 100 kHz and 1 GHz (see frequency dependent power level deviation chart below)

Thanks,

Jerry

[erikka]

With high frequencies like 10 MHz its best to use 50 ohm to avoid reflection that could become unstable and depending on cable flexing.
Keep the input level between 0 and +10 dBm

[cncjerry]

Hi,
 i'm having a problem measuring the delta between two 1PPS signals. I carefully measured the 1PPS coming out of my cesium beam that started at ten volts peak until it was down below 2V peak.  I have the tinygtc in 50ohm mode on that one port.  The tiny gtc, though, reports it as -27dBm and it should be closer to +7dbm. The other port I can't put it in 50ohm mode because the signal isn't that strong.  I don't know if this low -27dbm signal is my problem or not but i'm getting glitches that weren't there when I was using my HP 5370b.  I had a hard time trying to figure out how to get the tinygtc to output the delta between the two signals, but I think I have that correct now. It tracks well for the first several hundred or so points but then it starts glitching, -10e3 or -10e4 additive glitches.  I'll get a bunch of glitches and then it'll clear up and then I'll get a bunch more. It's not a phase transition. I'm using the tinygtc's internal GPS as a reference. I'm going to try using the cesium as a reference and 1PPS tomorrow.

The primary issue is with setting levels. It would be great If you made an external box that made setting levels easy.  For 1PPS signals, i've used a variable resistive divider in the past but I only have one.

Thanks

Jerry

[erikka]

As specified in the wiki the power meter does not function at 1 Hz.
One extra complication is that for 1 Hz you also cannot use show levels .

You do not mention setting the trigger level.
Keep in mind the tinyGTC inputs are DC coupled and require the correct setting of the trigger level.
With a 2 V PPS  between 0 and 2 V, suggest to set the trigger level at 0.5 V and no need  to enable 50 ohm
To reduce large input signal you can use a 50 ohm attenuator that can handle the power

[cncjerry]

I had set the trigger level to .6v as that was the same level used on my 5370b.  I am using attenuators, screw-on sma type, tested with high impedance inputs on my scope. I'd have to measure the high input impedance of the GTC, and the attenuators weren't as effective (mathematically) as they should have been due to the impedance mismatch.  What do you mean by show levels?  I don't remember seeing that in the menus. I'll have to measure the other channel, the one that is coming from Leo Bodnar's new GPSDO into the high impedance channel A. I'll have time for more testing tomorrow.

[erikka]

When using a 20 dB attenuator your get a factor 10 reduction in voltage. Your 20 Vpp source will become 2 Vpp after the 20 dB attenuator,
The tinyGTC input impedance in High-Z mode is 1 MOhm/2 pF, but with 20 dB attenuation the input impedance of the tinyGTC can be ignored.
COUNTER/SHOW LEVELS will only work for input frequencies above 10 kHz.

[erikka]

Have a look at this video:

[cncjerry]

Thanks Erikka, i  found the problem and it now is plotting the ADEV right on top of the 5370b plot.  Issue was the timestamp.  I  turned  off that option on the time difference and it corrected the problem. Maybe Timelab was picking up the timestamp sometimes that leads the channel B digits sent to Timelab.

[erikka]

This video shows the tinyGTC doing measurements over its entire frequency range starting at 0.1 Hz and going up to above the specified maximum 12 GHz input frequency. Your tinyGTC is not guaranteed to reach the same maximum frequency but for sure is will surpass 12 GHz.

[erikka]

A short video showing how to measure a mechanical device without an electrical connection

[Kurt_!]

A short video showing how to measure a mechanical device without an electrical connection

May I ask where you got the stand (3 legs) from?

[Name00]

Erikka: I received my TinyGTC recently.  I seem to be having trouble using or recognizing a square wave from my of my rubidium oscillators.  I've attached an image with it's corresponding sine wave.    Wondering if you can advise me on what I did wrong or need to set up?

I also Blender modified a stand from one for the NanoVNA-H4 (aka TinyPFA) that I found on Printables from Rik HORKM (NanoVNA-H4 Stand).   Since I can't seem to attach it I may have to find a different way to include or place it somewhere if someone is interested in it.

I've attached it as a Zip..  Print 2 of them and slip it over the lip on the bottom it won't slip seems okay for me for now..

[erikka]

The square wave seems symmetrical around zero volt so a zero volt trigger level should work
What settings did you use?

[erikka]

Don't know about the stand, it was a gift

[Name00]

The square wave seems symmetrical around zero volt so a zero volt trigger level should work
What settings did you use?

Source A/B (doesn't amtter), Gate 100ms, Presc: Off, 50 Ohm: checked, edge: Up, Trig Lv: 0, Show: levels, debounce: Off

[erikka]

Is there no triggering?
Does the self test succeed?
Can the tinyGTC mease its own OUT at 10 MHz?

[Name00]

Is there no triggering?
Does the self test succeed?
Can the tinyGTC mease its own OUT at 10 MHz?

Shows TOUT
Selftest: Pass:
Output: Square Wave - 10M shows it is counting it.  Also attached the output from the GTC on the scope below.
Using your latest Jan 22 firmware  - 1.0.63
Also cleared the config, and self tested again.