I remembered a circuit cellar article on CSVD a few years ago (1993). http://www.dtweed.com/circuitcellar/caj00033.htm#473 I'll look at my past issues and if it's of interest to you I can scan & send you a copy. -Dal ----- Original Message ----- From: Bob Ammerman To: Sent: Tuesday, December 11, 2001 4:24 PM Subject: Re: [PIC]: CSVD or other on PIC (compress audio) > If anyone knows of _ANY_ software implementation of CVSD (for any machine) > for which source is available I would be EXTREMELY appreciative. > > Bob Ammerman > RAm Systems > > ----- Original Message ----- > From: "Richard Sloan" > To: > Sent: Tuesday, December 11, 2001 11:44 AM > Subject: Re: [PIC]: CSVD or other on PIC (compress audio) > > > We are a design house and have much experience in this field? > > Can we be of assistance? > > Richard Sloan > > >> I am mostly a software guy, and I've done a lot of reading about PICs > >> but am just now getting my hands dirty. > > >> I may end up using ISD's but I keep thinking there must be a better > >> way. I need to build about 100 identical circuit boards, so every $ > >> will add up. > > >> I've thought about using a dedicated PIC which would just read sound > >> data from memory and send it out via PCM or a D2A chip...but most of > >> the memory chips for use with a PIC seem quite small. > > >> One think I don't like the ISD's is the busy work it will take to > >> program 100 of them. Storing sound data in 100 flash memory chips > >> seems a bit more elegant. > > >> But how much memory can you really interface to a PIC? And how much > >> will it cost? > > >> Maybe the ISD turns out to be the crude but effective solution to the > >> problem? > > >> Phil > > > >> > > What DSP are you using and what is the part price? > >> > > >> >Both are now obsolete, and the price when they were alive was > >> >around NZ$7. I considered getting in touch with Rochester (???), a > >> >US company that takes the original manufacturer's masks and > >> >makes new chips for you, but the time I think would be better > >> >spent on developing a s/w alternative on a fast micro like PIC > >> >or AVR. As the original parts were designed for DRAM (in those > >> >days when power consuption was not the issue it is now and > >> >micros were a glint in an engineer's eye) an obvious enhancement > >> >is to design for the modern micro-power mega-SRAMs. Although > >> >the circuit I use currently is a DSP/PIC hybrid and works very well, > it > >> >would be fairly easy to dispense with the DSP in a new design. > >> >Having PCBs and DSPs to hand makes that unnecessary right now > >> > > >> >> Did you have to > >> >> write the DSP code, or is this a hardwired function of the chip? > Do > >> >> you know of any contemporary chips that might be similar? > >> > > >> >There is no coding, apart from a a couple of lines to send commands. > >> >The DSP handles the rest. I would luuurve to find a replacement but > >> >AFAICT there is nothing available in a single chip. Everything I've > >> >looked at so far is at the "scruffy" end of the market (eg ISD) and is > >> >good only for speech frequency bandwidth. For anything else the > >> >sound is so treble-less I can't use them > >> > > >> >-- > >> >http://www.piclist.com#nomail Going offline? Don't AutoReply us! > >> >email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > >> -- > >> http://www.piclist.com#nomail Going offline? Don't AutoReply us! > >> email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > > > > > > > > __________________________________________________________ > The Mind Factory INC > Richard Sloan > (613) 825-4758 phone > (613) 825-7758 fax > rsloan@themindfactory.com > > * Custom MP3 Development > * Custom Smart Cards > * Electronic Manufacturing > * Hardware / Firmware / Software Design > * Schematic and PCB layout > * 8051, 68HC11, PIC, AVR > * MP3, FAT16/32, IR, IRDA, USB, X10, VIDEO, TCP/IP, LCD > > * ALL PRICES QUOTED IN US$ UNLESS OTHERWISE NOTED > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body