ch = makevalidfield(ch) fixes common invalid field names for structed arrays ARGUMENTS ch ... name of channel as string RETURNS ch ... new name of channel as string with invalid fieldnames removed Created by JJ Loh Updated by Phil Dixon Nov 2008 - This function now uses recursion to fix channel names with multiple problems Updated by Phil Dixon Nov 2011 - subcase ':' can handle invalid characters at the end of the field updated by Phil Dixon March 2013 - added new cases Updated by Philippe C. Dixon May 2014 - added new cases - use of 'strrep' to clean code Updated by Philippe C. Dixon Oct 2016 - Removed '_' as invalid field - Added '^,=' as invalid fields - Truncates any field that exceeds MATLAB's maximum name length - Converts numeric channel names x to nx Updated by Oussama Jlassi and Philippe C. Dixon Aug 2023 - Improved code execution speed -------------------------------------------