I referred your software Scilab Xcos, I checked toolboxes but i can't find the Operational Transconductance Amplifier (OTA) in it, OTA is newly commercialising component in VLSI domain. I'm currently doing my research in OTA, if you can share the block to me then it will be helpful for my research.
Scilab Toolbox Signal Processing Toolbox
Operational Transconductance Amplifier block might not be available in Xcos yet. However, check the following scilab textbook companion https://scilab.in/textbook_run/1217/31/5
You can download scilab-coded solved examples from this book. This book does talk about Operational Transconductance Amplifier. Also check other scilab textbook companions for a better help using the link https://scilab.in/Completed_Books