Evaluation of low rate speech coders for HF

• Published in: 1993 IEEE International Conference on Acoustics, Speech, and Signal Processing Vol. 2; pp. 163 - 166 vol.2
• Main Authors: Tremain, T.E., Kemp, D.P., Collura, J.S., Kohler, M.A.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 1993
• Subjects: Bit rate; Code standards; Communication standards; Electronic equipment; Hafnium; Narrowband; Speech analysis; Speech processing; Standards development; Testing
• ISBN: 0780309464; 0780374029; 9780780309463; 9780780374027
• ISSN: 1520-6149; 2379-190X
• DOI: 10.1109/ICASSP.1993.319259

In 1988, the NATO Tri-Service Group for Communications and Electronics Equipment (TSGCEE) Sub Group 11 (SG/11) established Working Group 2 (WG/2, Narrowband Speech) to develop a voice processor standard for a secure voice system for operation in the high frequency (HF) range. The voice processors evaluated had bit rates of 600, 800, 900, and 1200 bit/s. Forward error correction was added to bring the total bit rate up to 2400 bit/s. The authors compare the performance of the three candidate US low-rate speech coders to that of the standard 2400-bit/s linear predictive coder (LPC) under a number of different test conditions. Under the majority of the test conditions, the 800-bit/s speech coder is performing close to the present standard LPC-10 at 2400 bit/s. The one area where there is a loss of performance in the 800-bit/s speech coder relative to the LPC-10 is in the severe CVC (constant vowel consonant) intelligibility test conditions. All the tests were to be completed and a coder at 800 bit/s was to be selected at the WG/2 meeting in March 1993.< >