Path: utzoo!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!uunet!rocket!pitaro From: pitaro@rocket.uucp (Michael Pitaro) Newsgroups: comp.dsp Subject: Re: US Gov. sends real-time audio at 2400 baud! Message-ID: Date: 11 Nov 90 18:17:26 GMT References: <1990Nov8.210640.2893@ux1.cso.uiuc.edu> <39484@ucbvax.BERKELEY.EDU> Sender: news@rocket.UUCP Organization: Lockheed Sanders Inc. Lines: 59 In-reply-to: jbuck@galileo.berkeley.edu's message of 9 Nov 90 18:31:59 GMT In article <39484@ucbvax.BERKELEY.EDU> jbuck@galileo.berkeley.edu (Joe Buck) writes: > Correct except that your rates are off by a factor of two. The LPC10-E > algorithm is 2400 bps; the federal standard CELP algorithm is 4800bps. > > -- > Joe Buck > jbuck@galileo.berkeley.edu {uunet,ucbvax}!galileo.berkeley.edu!jbuck You are, of course, correct on the vocoder bps rates. We recently completed the implementation of a 4800 bps Multi-Band Excitation (MBE) vocoder here so I should have caught that error. For anyone who's interested I've listed a few references for vocoders. It's not meant to represent anything but some papers I had in a vocoder folder sitting on my desk. ------------------------------ Linear Predictive Coding (LPC) ------------------------------ Thomas E. Tremain, "The Government Standard Linear Predictive Coding Algorithm: LPC-10", Speech Technology, April 1982, pp. 40-49. "Telecommunications: Analog to Digital Conversion of Voice by 2,400 Bit/Second Linear Predictive Coding", FED-STD-1015 November 28, 1984 George S. Kang and Stephanie S. Everett, "Improvement of the Excitation Source in the Narrow-Band Linear Prediction Vocoder", IEEE Trans on ASSP, Vol. ASSP-33, No. 2, April 1985, pp. 377-386. J.R. Blakley, et. al., "An Efficient Implementation of the LPC-10e Speech Coding Algorithm", MILCOM-87, pp. 24.6.1-24.6.5 John C. Nagengast, "The STU-III, Narrowband Speech Comes of Age", Military Speech Tech-87, pp. 44-47. --------------------------- Multi-Band Excitation (MBE) --------------------------- Daniel W. Griffin, "Multi-Band Excitation Vocoder," PhD Thesis, EECS Department, MIT, 1987. John C. Hardwick and Jae S. Lim, "A 4.8 kps Multi-Band Excitation Speech Coder", ICASSP-88 (??), pp. 374-377. ------------------------------------- Code Excited Linear Prediction (CELP) ------------------------------------- David P. Kemp, "Department of Defense Requirements for a 4800 bps Voice Coder", Military Speech Tech-87, pp. 48-50. Daniel Lin, "High-Quality 4800 bps Speech Coding for Real-Time Applications", Military Speech Tech-87, pp. 51-53. -- Michael Pitaro pitaro@rocket.sanders.com