There is an 8038 function generator chip (now obsolete and hard to get) available on Ebay, for anyone intrested.
http://cgi.ebay.co.uk/8038-Function...oryZ4663QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.co.uk/8038-Function...oryZ4663QQssPageNameZWDVWQQrdZ1QQcmdZViewItem