LMH0344: How to set the eyes clock recovery of LMH0344 output eye diagrams

user4332223

Part Number: LMH0344

Hello all,

I have a Infiniium S-Series Oscilloscopes. I want to test the LMH0344 output eye diagrams. But I don't konw which clock recovery i should use. Because the Oscilloscopes has many clock recovery way, like Constant Frequency, First Order PLL, 2nd Order PLL. So, Page 12 of the data sheet, how to set the eye clock recovery? The eyes diagram salso shown below.

Thank you for you help.

over 6 years ago

0 Nasser Mohammadi over 6 years ago

TI__Guru* 93670 points

Greetings,

Model S Series Infinium scopes are real time scope. Please first enable factory default settings - while you are monitoring LMH0344 100-ohm Ac coupled differential outputs. Then set auto scale so I can capture LMH0344 output waveform. My comments are based on reading about this scope models. If you still have questions, please discuss this with your Infinium or Keysight application support.

Regards,,nasser

0 user4332223 over 6 years ago in reply to Nasser Mohammadi

Prodigy 50 points

Hi nasser,

Thank you for your reply.

I can capture LMH0344 output waveform. In fact, I want to capture the eye diagrams. First, I have to choose the method of clock recovery. There are many different way of clock recovery, but I don't konw which to chooice. shown below.

I had asked Keysight for help，but they said the user should know the method of the clock recovery. They had suggested we ask for help from the chip manufacturer.

Thank you.

0 Nasser Mohammadi over 6 years ago in reply to user4332223

TI__Guru* 93670 points

Hi,

You can select 3MHz loop bandwidth and leave the other two parameters as default.

For data rate, you can click on Measure Data Rate and then select what it is reporting.

Regards,,nasser

0 user4332223 over 6 years ago in reply to Nasser Mohammadi

Prodigy 50 points

Hi nasser,

Why use 3Mhz loop bandwidth? Is it the of 3G-SDI Jitter recommendation? I used to read the recommendation, The link is www.itu.int/.../R-REC-BT.1363-0-199802-S!!PDF-E.pdf . In Page 13 FIGURE 9, is it mean that the Timing jitter use 10Hz loop bandwidth and the Alignment jitter use 100KHz ? How to set other two parameters?
Thank you.

0 Nasser Mohammadi over 6 years ago in reply to user4332223

TI__Guru* 93670 points

Greetings,
Yes this is because 3G SDI loop bandwidth is normally about 3MHz.
Regards,,nasser

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LMH0344: How to set the eyes clock recovery of LMH0344 output eye diagrams