Bandwidth emphasis earthquake data acquisition device and manner

摘要

An improved geophysical data acquisition system is disclosed for enhancing effective system bandwidth of a seismic signal having an amplitude frequency spectrum characterized by high amplitude low frequencies and low amplitude high frequencies. A low-cut filter (35) is provided which has a frequency response with its low frequency end attenuation limited. The low-cut filter (35) has the effect of increasing effective channel bandwith while simultaneously allowing low frequency signals from deep within the earth to be included in the output signal. Effective channel bandwidth is increased because low frequency seismic signals are attenuated, automatically allowing channel gain to be increased by a gain ranging amplifier. Increased channel gain automatically amplifies the low-amplitude high-frequency end of the spectrum resulting in increased effective bandwidth. A high frequency boost filter (30) is provided whereby the high frequency signal components of the seismic signals may be further relatively amplified thereby enhancing the channel effective bandwidth. The boost filter (30) is provided in the system's input stage in order to keep its effect on system input noise to a minimum.