Tham khảo tài liệu 'adaptive filtering part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 350 Adaptive Filtering The filters are managed as circular buffers and inline functions are used whenever possible. The sampling rate is 8 kHz and the number of bits per sample is 16 the minimum allowed by the AIC23 codec suited for speech signals. This way we have 125 ụs between two consecutive samples and this is the maximum processing time to meet real-time requirements 28125 instructions under a 225 MHz clock . The time delay estimator has the largest amount of total processing time being not possible to completely update the time delay estimation within 125 ụs. Between two consecutive samples we update only a small portion of the filter coefficients. An optimal step approach The optimal step approach of Ozbay Kavsaoglu 2010 also uses the Texas Instruments TMS320C6713 with DSKC6713 because it is an up to date architecture. The authors established an experimental setup including the DSKC6713 board a laptop computer an amplifier a loudspeaker and two microphones. They have considered two scenarios of application in the first scenario two microphones were placed close to the loudspeaker in the second scenario one microphone was placed close to the loudspeaker and speech trial was implemented in the far-end microphone. The experimental results show the adequacy of the proposed solution. 6. Experimental results This section presents some experimental results obtained with the AEC systems described in Subsections and respectively. The short-length centered adaptive filter approach Using a single TM5320C50 DSP with no external memory the system detects and cancels an echo with a delay of more than 380 ms. Considering a configuration with 64 Kwords of data memory the maximum supported delay is larger than seconds. Table 3 shows the computational requirements for a TMS320C50 DSP. Considering an unidirectional configuration and an active region of 4 miliseconds the maximum supported echo delay is very significant greater than seconds . Module .
