FIPS 137
FIPS 137, originally issued as FED-STD-1015, is a secure telephony speech encoding standard for Linear Predictive Coding vocoder developed by the United States Department of Defense and finished on November 28, 1984.[1] It was based on the earlier STANAG 4198[2] promulgated by NATO on February 13, 1984.
FED-STD-1015 was re-designated as Federal Information Processing Standard (FIPS) Publication 137, (FIPS PUB 137) on October 20, 1988.[3]
It is also known as "LPC-10".
The codec uses a bit rate of 2.4 kbit/s, requiring 20 MIPS of processing power, 2 kilobytes of RAM and features a frame size of 22.5 ms. Additionally, the codec requires a large lookahead of 90 ms.
Recently an improved version[according to whom?] of the standard was introduced. With a longer super frame structure and better VQ quantizer, the bit rate is reduced to 800 bit/s.<ref>{{cite journal
| last = Xianglin | first = Wang | author2 = C.-C. Jay Kuo | date = May 1998 | title = An 800 bit/s VQ-based LPC voice coder | journal = The Journal of the Acoustical Society of America | volume = 103 | issue = 5 | pages = 2778 | doi = 10.1121/1.422247 | bibcode = 1998ASAJ..103.2778W | s2cid = 14294667 | url = http://link.aip.org/link/?JASMAN/103/2778/1 | accessdate = 2007-03-24 | archive-url = https://archive.today/20130223071802/http://link.aip.org/link/?JASMAN/103/2778/1 | archive-date = 2013-02-23 | url-status = dead
References
- ↑ "FIPS PUB 137, Analog to Digital Conversion of Voice by 2,400 Bit/Second Linear Predictive Coding.". National Institute of Standards and Technology. https://ptabdata.blob.core.windows.net/files/2017/IPR2017-01077/v23_Exhibit%201022%20-%20FS1015-LPC10.pdf.
- ↑ "PARAMETERS AND CODING CHARACTERISTICS THAT MUST BE COMMON TO ASSURE INTEROPERABILITY OF 2400 BPS LINEAR PREDICTIVE ENCODED DIGITAL SPEECH". North Atlantic Treaty Organization. http://nso.nato.int/nso/.
- ↑ 53 FR 41221
External links
- CELP-3.2a and LPC-10
- Various Speech Coding Links
- LPC10 presentation, Soo Hyun Bae, ECE 8873 Data Compression & Modeling, Georgia Institute of Technology, 2004
Original source: https://en.wikipedia.org/wiki/FIPS 137.
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