let s build software cryptophones for over the internet well after a lot of trawling through archives i found the post i reproduce in full below is it time to get together to develop a tcp ip standard for crypto voice that we could then layer on point to point slip as the free standard for crypto voice like pgp is for mail ps note the date of this post appropriate huh from jpcampb afterlife ncsc mil thu jul from jpcampb afterlife ncsc mil joe campbell newsgroups comp compression research subject re sound compression algorithms date jul gmt organization the great beyond in article jun sequent com lff sequent com lou fernandez writes the techniques for production systems revolve around code excited linear prediction celp algorithms which capture ms or so of speech and attempt to match the speech with a combination of signals from a codebook choosing the combination which minimizes the error in case you d like to experiment with celp you can obtain a software implementation of the bps fed std celp coder for free the u s dod s federal standard based bps code excited linear prediction voice coder version celp fortran and c simulation source codes are now available for worldwide distribution at no charge on dos diskettes but configured to compile on sun sparc stations from bob fenichel national communications system washington d c fax in addition to the source codes example input and processed speech files are included along with a technical information bulletin to assist in implementation of fs celp an anonymous ftp site is being considered for future releases copies of the actual standard federal standard telecommunications analog to digital conversion of radio voice by bit second code excited linear prediction celp are available for each from gsa rm th d st sw washington d c the following articles describe the federal standard kbps celp coder it s unnecessary to read more than one campbell joseph p jr thomas e tremain and vanoy c welch the federal standard bps celp voice coder digital signal processing academic press vol no p campbell joseph p jr thomas e tremain and vanoy c welch the dod kbps standard proposed federal standard in advances in speech coding ed atal cuperman and gersho kluwer academic publishers chapter p campbell joseph p jr thomas e tremain and vanoy c welch the proposed federal standard bps voice coder celp speech technology magazine april may p for u s fed std bps celp realtime dsp code and information about products using this code contact john dellamorte dsp software engineering middlesex tpk suite bedford ma fax dspse bedford channel com dsp software engineering s code can run on a dsp research s tiger board a pc board with a tms c x and analog interface suited to development work or on intellibit s ae tms c based by card dsp research intellibit e duane ave p o box sunnyvale ca mclean va fax fax joe campbell n jbc jpcampb afterlife ncsc mil compuserve com my opinions are mine happiness reality expectations click clack
