应用离散余弦变换的去谐波扫描技术

通常在处理环节消除可控震源产生的谐波干扰会对有效信号产生不良影响;而去谐波扫描技术将这一过程提前到激发阶段,即通过改造原设计信号,实现在激发过程中使输出的谐波噪声最小,从而提高输出信号的精度和信噪比.现有去谐波扫描技术中,硬件方面主要通过对重锤信号与平板信号非线性二次拟合求取改正量实时控制伺服阀,以提高响应精度减少畸变...

Anti-harmonics sweep based on discrete cosine transform (DCT)

Seismic signals are excited by a controlling vibration system for sweeping signals in vibroseis seismic exploration. It is very common that there exists distortion between swept signals and output signals. For the technology for vibrator distortion correction, the hardware solution is realized by real-time control of a servo valve to obtain the correction amount through nonlinear quadratic fitting of hammer signals and plate signals, so as to improve response accuracy and reduce distortion. The software solution is realized by using the difference fitting between plate signals and hammer signals. This paper introduces a method to calibrate swept signals with the difference between force signals and preset swept signals in harmonic domain. The difference function is directly obtained by analyzing the harmonic component of the force signals and the preset swept signals. The harmonic interference is harmonic, so the algorithm reflects the changes caused by harmonic distortions more directly. It is realized by software correction,and it is convenient and fast, and has a good initial application effect.