The most likely spv to pdf conversion is a situation when users want to print the output files from SPSS statistics software as PDF documents.
IBM SPSS statistics software supports the export of output/report files in PDF format. You can access this function via File ► Export function, where under the "Objects to Export" you select "All visible" option and PDF format as output.
Without access to SPSS, it will be very hard to export .spv files to .pdf or pretty much anything else.