调制与解调用于随机共振的微弱周期信号检测

提出了调制随机共振方法，实现了在大参数条件下从强噪声中检测微弱周期信号.将混于噪声中的较高频率的弱信号经调制变为一差频的低频信号作用于随机共振体系，该低频信号满足绝热近似理论，因而能产生随机共振；再经解调可获得埋于噪声中的原较高频率的弱信号.对埋于噪声中的未知频率，可采用连续改变调制振荡器的频率，以获得一个适当的差频信号输入到随机共振体系，根据输出信号共振谱峰的变化经解调而得待检弱信号的未知频率.该方法应具有较高的应用前景. 关键词： 调制与解调 非线性双稳系统 随机共振 微弱信号检测

Modulation and demodulation for detecting weak periodic signal of stochastic resonance

Modulated stochastic resonance method which can detect weak periodic signals under strong noise in wide parameter conditions is proposed in this paper. The high frequency weak signal mixed with noise is modulated to a low frequency difference signal. The signal conforms to the adiabatic elimination theory. So when it acts on stochastic resonance system, the stochastic resonance can arise. If the low frequency signal is demodulated, the original high frequency weak signal mixed with noise can be relrieved. To deal with the unknown frequency mixed with noise, the frequency of modulate oscillator is changed continuously to achieve a suitable difference frequency signal for inputting to stochastic resonance system. According to the change of resonance spectral peak value, the unknown frequency can be found from the demodulated signal. The method is effective for future application.