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sinara-hw / mirny

4-channel Microwave synthesiser
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Phase noise measurements #41

Open maria-nowicka opened 1 month ago

maria-nowicka commented 1 month ago

The phase noise of the microwave synthesizer was measured using the internal oscillator in Mirny, and then compared when the module was clocked by the Kasli controller.

You can find the phase noise measurement for different frequencies in this table:

Summarizin_PN_comparision_Mirny_internal_vs_Kasli_CLK

For the same configurations as above, the table below shows: peak to peak, mean, and standard deviation.

Summarizin_PN_parameters_Mirny_internal_vs_Kasli_CLK

The graphs below are an extension of the tables. PN_comparision_Mirny_CLK_internal_vr_CLK_Kasli_1GHz

PN_comparision_Mirny_CLK_internal_vr_CLK_Kasli_5GHz

PN_comparision_Mirny_CLK_internal_vr_CLK_Kasli_6 8GHz

PN_Mirny_and_Mirny_with_Almazny_CLK_internal

PN_Mirny_and_Mirny_with_Almazny_CLK_Kasli

Here is the setup used for the measurements: Mirny+Almazny Phase noise (1)

gkasprow commented 1 month ago

It looks like we have at least 3 issues here: DC/DC converter noise on Mirny, DC/DC converter noise on Almazny and Kasli DC/DC converter noise. I can see the first and the third harmonics.

gkasprow commented 1 month ago

I verified Mirny in the same setup (same controller, same power unit, same cables) but with E5052B SSA and in my home lab (no RF sources nearby) And it looks completely different. mirny 1G

gkasprow commented 1 month ago

Mirny driven from Kasli Mirny_1G_Kasli

gkasprow commented 1 month ago

I managed to recreate same plots. One needs to switch units of spurious from Normalised to Power Mirny_1G_Kasli

gkasprow commented 4 weeks ago

I was playing with LC filters after the 5V5 converter and it looks like the 1.3MHz noise comes through the ground loops. We have two more DC/DC covnerters but they are within the ADI module and we can't see them in the phase noise spectrum The 3kHz noise is also caused by the 1.3Mhz converter - it produces ripples of such frequency. I'll dig deeper into it because we have such supply in many other designs.