针对信道环境恶劣条件下的大频率数字信号相干接收问题,提出了一种基于调参随机共振系统降低数字信号相干接收误码率(BER)的方法。从时域、频域及误码率三个方面对大频率二进制相移键控(BPSK)信号的随机共振相干接收方法进行了研究。首...针对信道环境恶劣条件下的大频率数字信号相干接收问题,提出了一种基于调参随机共振系统降低数字信号相干接收误码率(BER)的方法。从时域、频域及误码率三个方面对大频率二进制相移键控(BPSK)信号的随机共振相干接收方法进行了研究。首先,通过调整系数R改变非线性随机共振系统的参数a、b,将其共振频率提高R倍,从而实现大频率信号的随机共振,提高信号的信噪比(SNR);然后,对通过随机共振系统后的信号进行相干解调,并计算误码率。试验结果表明,与传统解调方法相比,该方法的误码率在低信噪比情况下有明显降低,当SNR=-14 d B时,较传统解调系统误码率可降低25.28%。随机共振系统提高了信号相干接收性能。随机共振理论在信号接收解调及信号处理等方面存在优势。展开更多
Electroceuticals are medical devices that employ electric signals to alter the activity of specific nerve fibers to achieve therapeutic effects. The rapid growth of RF microelectronics has resulted in the development ...Electroceuticals are medical devices that employ electric signals to alter the activity of specific nerve fibers to achieve therapeutic effects. The rapid growth of RF microelectronics has resulted in the development of very small, portable, and inexpensive shortwave and microwave radio frequency (RF) amplifiers, raising the possibility of utilizing these new RF technologies to develop non-contact electroceutical devices. However, the bio-electromagnetics literature suggests that beyond 10 MHz, RF fields cannot influence biological tissue, beyond simple heating, because effective demodulation mechanisms at these frequencies do not exist in the body. However, RF amplifiers operating at or near saturation have non-linear interactions with complex loads, and if body tissue creates a complex loading condition, the opportunity exists for the coupled system to produce non-linear effects, that is, the equivalent of demodulation may occur. Correspondingly, exposure of tissue to pulsed RF energy could result in the creation of low frequency demodulation components capable of influencing tissue activity. Here, we develop a one-dimen- sional, numerical simulation to investigate the complex loading conditions under which such demodulation could arise. Applying these results in a physical prototype device, we show that up to7.5% demodulation can be obtained for a 40 MHz RF field pulsed at 1 KHz. Implications for this research include the possibility of developing wearable, electromagnetic electroceutical de- vices.展开更多
文摘针对信道环境恶劣条件下的大频率数字信号相干接收问题,提出了一种基于调参随机共振系统降低数字信号相干接收误码率(BER)的方法。从时域、频域及误码率三个方面对大频率二进制相移键控(BPSK)信号的随机共振相干接收方法进行了研究。首先,通过调整系数R改变非线性随机共振系统的参数a、b,将其共振频率提高R倍,从而实现大频率信号的随机共振,提高信号的信噪比(SNR);然后,对通过随机共振系统后的信号进行相干解调,并计算误码率。试验结果表明,与传统解调方法相比,该方法的误码率在低信噪比情况下有明显降低,当SNR=-14 d B时,较传统解调系统误码率可降低25.28%。随机共振系统提高了信号相干接收性能。随机共振理论在信号接收解调及信号处理等方面存在优势。
文摘Electroceuticals are medical devices that employ electric signals to alter the activity of specific nerve fibers to achieve therapeutic effects. The rapid growth of RF microelectronics has resulted in the development of very small, portable, and inexpensive shortwave and microwave radio frequency (RF) amplifiers, raising the possibility of utilizing these new RF technologies to develop non-contact electroceutical devices. However, the bio-electromagnetics literature suggests that beyond 10 MHz, RF fields cannot influence biological tissue, beyond simple heating, because effective demodulation mechanisms at these frequencies do not exist in the body. However, RF amplifiers operating at or near saturation have non-linear interactions with complex loads, and if body tissue creates a complex loading condition, the opportunity exists for the coupled system to produce non-linear effects, that is, the equivalent of demodulation may occur. Correspondingly, exposure of tissue to pulsed RF energy could result in the creation of low frequency demodulation components capable of influencing tissue activity. Here, we develop a one-dimen- sional, numerical simulation to investigate the complex loading conditions under which such demodulation could arise. Applying these results in a physical prototype device, we show that up to7.5% demodulation can be obtained for a 40 MHz RF field pulsed at 1 KHz. Implications for this research include the possibility of developing wearable, electromagnetic electroceutical de- vices.
