Omnitek's new white paper covers the use of the Advanced Physical Analysis features of the Omnitek Ultra 4K Tool Box to perform physical layer analysis of 12G-SDI signals which differs from the techniques already adopted by the industry to measure SD-SDI, HD-SDI and 3G-SDI signals.
The paper explains the differences between traditional physical layer analysis and those that now need to be adopted for 6G-SDI and 12G-SDI to ensure repeatable and comparable results to those typically only available on very high-end oscilloscopes such as the Teledyne LeCroy SDA 820Zi-A.
When performing physical layer analysis there are two distinct areas of interest. These are the signal quality, viewed and measured using the Eye Diagram display, and signal jitter viewed and measured using jitter meters and jitter spectrum analysis tools.
Traditionally users expect to see a recognizable Eye Diagram that can be used to provide a visual level of signal quality. Ideally to ensure that the displayed Eye Diagram is without jitter the most appropriate waveform sampling and capture method must be employed.
One of the significant challenges of 12G-SDI signal measurement is how to accurately and repeatedly measure waveform amplitude because without this measurement values of rise time and fall time cannot be made. Due to the high 3rd and 5th harmonic frequencies of the 6GHz fundamental frequency (relative to the bandwidth of the BNC and cable) the signal actually sent by currently available transmitters is effectively a distorted sine wave. Making accurate amplitude measurements of signals like this depends on the measurement technique used.
Jitter measurement has always been a significant part of physical layer analysis as it ultimately determines whether or not that there will be errors in the data. The first challenge is to ensure that the jitter produced by a piece of equipment is within SMPTE limits and the second is how to identify what is causing out of specification jitter, which can often be determined by the frequency band in which it occurs.
The generation of known levels of jitter can be used to measure the susceptibility of equipment under test to jitter. The Ultra 4K Tool Box allows jitter of a user-defined frequency and amplitude to be introduced into the generated SDI output signal.
This white paper discusses these aspects of physical layer analysis using the Omnitek Ultra 4K Tool Box in comparison to the Teledyne LeCroy SDA 820Zi-A high-end oscilloscope and shows that the results are comparable and well within acceptable tolerances.
To read the entire white paper, click here.
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