Inteo助听器是首次运用整合信号处理（integrated signal processing，ISP）技术平台达到稳定可听度和自然音质的助听器。Inteo采用的一个独特技术是可听度扩展，即运用线性移频算法将可听度扩展到高频区，这恰恰是传统助听设备无能为...Inteo助听器是首次运用整合信号处理（integrated signal processing，ISP）技术平台达到稳定可听度和自然音质的助听器。Inteo采用的一个独特技术是可听度扩展，即运用线性移频算法将可听度扩展到高频区，这恰恰是传统助听设备无能为力之处。自从该款助听器发布后．我们已进行了数次研究．争取让该技术的使用优化。虽然我们的研究仍在进行之中，对该项技术的理解也需要进一步加深．不过，至少我们已经知道如何利用这种技术．让患者获得最大受益，因此，我们将在这篇文章中和读者分享其中的体会。展开更多
As one of the most important components of the wideband wireless access technique, orthogonal frequency division multiplexing （OFDM） has a high usage rate of spectrum and combats inter-symbol interference （ISI） in...As one of the most important components of the wideband wireless access technique, orthogonal frequency division multiplexing （OFDM） has a high usage rate of spectrum and combats inter-symbol interference （ISI） in multi-path fading channel. However, when there are frequency offsets during the signal transmission, the inter-carrier interference （ICI） is introduced, which significantly degrades the performance. The existing ICI self-cancellation schemes such as PCC-OFDM are not optimum to minimize the interference considering both noise and ICI. In this paper, a new metric named S1NR （signal-to-interference- and-noise ratio） is proposed. We discuss the optimization issue when a constant frequency offset exists and in time-varying channels. The optimum weighting-coefficient-pair （OWCP） is obtained, which maximizes SINR theoretically through the alternant iteration algorithm. Simulations show that the performance of OWCP-OFDM is better than that of PCC-OFDM, especially when the frequency offset is large. Although the ICI self-cancellation scheme suffers bandwidth inefficiency, from the simulation results we can also see that the performance of OWCP-OFDM is much better than that of the standard OFDM systems with the same bandwidth efficiency when a frequency offset exists. Moreover, since the redundant modulation provides the capability to suppress ICI as well as a receiving SNR gain, it can be considered as exchanging the bandwidth for SNR.展开更多
Intensity flicker is a common form of degradation in archived film. Most algorithms on this distortion are complicated and uncontrolled. This paper presented a discrete mathematical model of flicker, designed a block-...Intensity flicker is a common form of degradation in archived film. Most algorithms on this distortion are complicated and uncontrolled. This paper presented a discrete mathematical model of flicker, designed a block-based estimation method of the model＇s parameters according to their features of intensity variation in large area. With this estimation result it constructed a compensation model to repair the current frame. This restoration approach is full automatic and the repair process of current frame does not need the information of frames behind it. The algorithm was realized to establish a simple and adjustable repair system. The experimental results show that the proposed algorithm can remove most intensity flicker and preserve tho wanted effects.展开更多
In this paper, a concept of image grading transmission is put forward to enhance data rate and to improve the usage of subcarriers in orthogonal frequency division multiplexing (OFDM). The idea originates from the wav...In this paper, a concept of image grading transmission is put forward to enhance data rate and to improve the usage of subcarriers in orthogonal frequency division multiplexing (OFDM). The idea originates from the wavelet packets representative of an image in which information is graded in terms of different priorities. The graded image facilitates more efficient use of adaptive subcarriers and bits allocation. The results of simulation in typical mobile environment prove that the output signal noise ratio (SNR) of the graded image excels that of the ungraded image by 1—2 dB under the same channel condition.展开更多
文摘Inteo助听器是首次运用整合信号处理（integrated signal processing，ISP）技术平台达到稳定可听度和自然音质的助听器。Inteo采用的一个独特技术是可听度扩展，即运用线性移频算法将可听度扩展到高频区，这恰恰是传统助听设备无能为力之处。自从该款助听器发布后．我们已进行了数次研究．争取让该技术的使用优化。虽然我们的研究仍在进行之中，对该项技术的理解也需要进一步加深．不过，至少我们已经知道如何利用这种技术．让患者获得最大受益，因此，我们将在这篇文章中和读者分享其中的体会。
基金Project (No. 2006AA01Z273) supported by the Hi-Tech ResearchDevelopment Program (863) of China
文摘As one of the most important components of the wideband wireless access technique, orthogonal frequency division multiplexing （OFDM） has a high usage rate of spectrum and combats inter-symbol interference （ISI） in multi-path fading channel. However, when there are frequency offsets during the signal transmission, the inter-carrier interference （ICI） is introduced, which significantly degrades the performance. The existing ICI self-cancellation schemes such as PCC-OFDM are not optimum to minimize the interference considering both noise and ICI. In this paper, a new metric named S1NR （signal-to-interference- and-noise ratio） is proposed. We discuss the optimization issue when a constant frequency offset exists and in time-varying channels. The optimum weighting-coefficient-pair （OWCP） is obtained, which maximizes SINR theoretically through the alternant iteration algorithm. Simulations show that the performance of OWCP-OFDM is better than that of PCC-OFDM, especially when the frequency offset is large. Although the ICI self-cancellation scheme suffers bandwidth inefficiency, from the simulation results we can also see that the performance of OWCP-OFDM is much better than that of the standard OFDM systems with the same bandwidth efficiency when a frequency offset exists. Moreover, since the redundant modulation provides the capability to suppress ICI as well as a receiving SNR gain, it can be considered as exchanging the bandwidth for SNR.
基金National Natural Science Foundation ofChina(No.69905003)
文摘Intensity flicker is a common form of degradation in archived film. Most algorithms on this distortion are complicated and uncontrolled. This paper presented a discrete mathematical model of flicker, designed a block-based estimation method of the model＇s parameters according to their features of intensity variation in large area. With this estimation result it constructed a compensation model to repair the current frame. This restoration approach is full automatic and the repair process of current frame does not need the information of frames behind it. The algorithm was realized to establish a simple and adjustable repair system. The experimental results show that the proposed algorithm can remove most intensity flicker and preserve tho wanted effects.
文摘In this paper, a concept of image grading transmission is put forward to enhance data rate and to improve the usage of subcarriers in orthogonal frequency division multiplexing (OFDM). The idea originates from the wavelet packets representative of an image in which information is graded in terms of different priorities. The graded image facilitates more efficient use of adaptive subcarriers and bits allocation. The results of simulation in typical mobile environment prove that the output signal noise ratio (SNR) of the graded image excels that of the ungraded image by 1—2 dB under the same channel condition.
