The DSP implement of speech compress in the word-data co-transmit terminal unit of the air-ground data link [compress read compression]

Air-ground data link is a kind of data communication technology, which is studied and developed by many people now. The information contents transmitted on the air-ground data link is very much, which includes the radar intelligence information, the sail intelligence, the weather intelligence, the conduct order, the request instructions report, the airplane parameters and surveillances report, etc. Therefore, it is very important to increase the capacity and improve the baud rate of air-ground data link. Under the research background of the next generation air-ground data link, this paper presents an implementation scheme of high quality speech compression in the word-data co-transmit unit in the air-ground data link system. The scheme is based on the improved CS-ACELP algorithm contributed by ITU-T G.729 recommendation. This scheme could economize the channel bandwidth for transmitting speech, increase the channel capacity of air-ground data link and improve the utilizing efficiency of that. Comparing with the ADPCM coding scheme used in some current data transmit transceivers, the compression efficiency of speech data is 4 times, and the quality of tone is as good as it. In this paper, the hardware implementation and software design is given. After measuring the experiment and analyzing its result, the conclusion is obtained, which is the scheme, is presented in this paper is appropriate for the speech transmitting in the new air-grounds data link system. In the scheme implementation, we utilize the end recursion method to do the searching computation for adaptive codebook. Thus, the run efficiency of algorithm is improved more. In addition, we consider the hardware characteristics of TMS320VC5416 DSP chip, and effectively assign and use these peripheral resources on the chip.