Conventional parameter estimation methods for pseudo-random binary code-linear frequency modulation(PRBC-LFM)signals require prior knowledge,are computationally complex,and exhibit poor performance at low signal-to-no...Conventional parameter estimation methods for pseudo-random binary code-linear frequency modulation(PRBC-LFM)signals require prior knowledge,are computationally complex,and exhibit poor performance at low signal-to-noise ratios(SNRs).To overcome these problems,a blind parameter estimation method based on a Duffing oscillator array is proposed.A new relationship formula among the state of the Duffing oscillator,the pseudo-random sequence of the PRBC-LFM signal,and the frequency difference between the PRBC-LFM signal and the periodic driving force signal of the Duffing oscillator is derived,providing the theoretical basis for blind parameter estimation.Methods based on amplitude method,short-time Fourier transform method,and power spectrum entropy method are used to binarize the output of the Duffing oscillator array,and their performance is compared.The pseudo-random sequence is estimated using Duffing oscillator array synchronization,and the carrier frequency parameters are obtained by the relational expressions and characteristics of the difference frequency.Simulation results show that this blind estimation method overcomes limitations in prior knowledge and maintains good parameter estimation performance up to an SNR of-35 dB.展开更多
针对中波广播窄带信道条件下传输效率受限的问题,从参数编码与混合编码的机理差异出发,建立基于码激励线性预测(Code Excited Linear Prediction,CELP)的低速率声编码模型,并给出编码速率与信道带宽的匹配方法。以某地市级中波发射台为...针对中波广播窄带信道条件下传输效率受限的问题,从参数编码与混合编码的机理差异出发,建立基于码激励线性预测(Code Excited Linear Prediction,CELP)的低速率声编码模型,并给出编码速率与信道带宽的匹配方法。以某地市级中波发射台为验证平台,在多类典型传输场景下对声编码方案应用前后的信号指标与音频质量进行对比测试。实测数据表明,该方案对中波广播频谱利用率与语音传输质量均有不同程度的改善。展开更多
基金the National Natural Science Foundation of China(Grant Nos.61973037 and 61673066).
摘要Conventional parameter estimation methods for pseudo-random binary code-linear frequency modulation(PRBC-LFM)signals require prior knowledge,are computationally complex,and exhibit poor performance at low signal-to-noise ratios(SNRs).To overcome these problems,a blind parameter estimation method based on a Duffing oscillator array is proposed.A new relationship formula among the state of the Duffing oscillator,the pseudo-random sequence of the PRBC-LFM signal,and the frequency difference between the PRBC-LFM signal and the periodic driving force signal of the Duffing oscillator is derived,providing the theoretical basis for blind parameter estimation.Methods based on amplitude method,short-time Fourier transform method,and power spectrum entropy method are used to binarize the output of the Duffing oscillator array,and their performance is compared.The pseudo-random sequence is estimated using Duffing oscillator array synchronization,and the carrier frequency parameters are obtained by the relational expressions and characteristics of the difference frequency.Simulation results show that this blind estimation method overcomes limitations in prior knowledge and maintains good parameter estimation performance up to an SNR of-35 dB.
摘要针对中波广播窄带信道条件下传输效率受限的问题,从参数编码与混合编码的机理差异出发,建立基于码激励线性预测(Code Excited Linear Prediction,CELP)的低速率声编码模型,并给出编码速率与信道带宽的匹配方法。以某地市级中波发射台为验证平台,在多类典型传输场景下对声编码方案应用前后的信号指标与音频质量进行对比测试。实测数据表明,该方案对中波广播频谱利用率与语音传输质量均有不同程度的改善。