{"id":354631,"date":"2024-02-29T17:10:39","date_gmt":"2024-02-29T17:10:39","guid":{"rendered":"\/forum\/?post_type=topic&p=354631"},"modified":"2024-02-29T17:12:32","modified_gmt":"2024-02-29T17:12:32","slug":"incorrect-group-delay-seen-in-post-s-parameter-element","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/incorrect-group-delay-seen-in-post-s-parameter-element\/","title":{"rendered":"Incorrect group delay seen in n-port s-parameter element in INTERCONNECT"},"content":{"rendered":"

Hello!<\/p>\n

I have the s-parameters of a 1×8 MMI in SiN that has a group delay of 2.4e-12, also made available in the Lumerical s-parameter export file with the “calcualte group delay” option.<\/p>\n

When I use a ONA to analyse the element in Interconnect after importing the data, I can see that the group delay is is correctly displayed in the results. However, when send a SECH pulse in the input and compare it with the output with OOSCs, the group delay varies a lot. I have take into consideration aliasing and selected an appropriate sampling rate. I have even carried out a parameter sweep of the sapmling rates and looked at the respective group delays obtained. The result does not show a group delay that saturates towards the calculated group delay at high sampling rates. Rather, it has a saw-tooth like behavior and drops by an order of magnitude below the expected value.<\/p>\n

I have attached a few slides to demosnstrate the problem. I would appreciate some insights into what might be causing this issue.<\/p>\n

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<\/a><\/p>\n","protected":false},"template":"","class_list":["post-354631","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t