Mathias Hilaire

Hello Afonso,
I am performing automatic jitter measurements on a scope to characterize a DUT under different conditions: temperature, power supply, datarate and so on.
The whole bench with different lab equipments is driven by Python scripts.
So I need to set my scope automatically.
I measure rise time, then I derive bandwidth, sample rate, and then record length given the digital signal on scope.
I need to take account clock recovery method, and also if BUJ is enabled or not.
As already written, I have formulas to calculate minimal record length when BUJ is disabled. When BUJ is enabled, I am not able to compute minimal record length. This is why I need a formula. But sadly you say this is not publicly available.
Do you have any idea to fix my issue?
Regards

Thank you Afonso for your reply.
In fact I would like to compute a priori required record length.
For instance, without using BUJ, it is possible to compute minimum record length without getting any warning from DPOJET using the following relationship: RLmin=100*Nbits/DR*SR, with:
RLmin: minimum record length
Nbits: number of bits in the pattern, ie. 127 for a PRBS7 signal
DR: datarate
SR: sample rate
For example, on a PRBS7 signal at 5Gbits/s and with a sample rate of 50Gsamples/s, we will get:
RLmin=100*127/5e9*50e9=127ksamples
If I set record length in the scope to 127ksamples, then I will not get any warning/error saying for example that the minimum number of patterns has not been reached.
It is working well.
If a 2nd order PLL is used instead of constant clock as clock recovery for the same signal, then computation will be :
RLmin=100*Nbits/DR*SR+4/JTFbw*SR, with:
JTFbw=Jitter Transfer Function bandwidth

Now, using BUJ, I would like to compute a priori minimum record length. Is there any way to calculate such minimum record length?

Thank you and kind regards

I am currently using a Tek DPO73304DX scope. When using BUJ as jitter separation model within DPOJET module, I would like to compute required number of samples (called Record Length).
For instance, on a 5Gbits/s digital signal, with sample rate=50Gsamples/s, I can observe that 20.99Msamples are required to make algorithm converge and estimate total jitter. How is it possible to compute this value of 20.99Msamples? What is the the calculation knowing bitrate and sample rate, and that constant clock mean is used for the clock recovery?
Thanks a lot and regards,
Mathias