Jitter removing technology for digital communication of measuring line of wired telemetry digital seismograph

Abstract

The invention relates to a reliability technology of measuring line digital communication in a digital seismograph. Thousands of acquisition stations are connected in series in a seismic survey line of the digital seismograph. In order to ensure the sampling rate of AD conversion of each acquisition station to be consistent, the acquisition stations are not provided with local clocks, and only oneprecision crystal oscillator in the cross station is used as a clock source of the whole measuring line. The acquisition station extracts a clock from a cross station command to be used as a clock source of the station, but error codes occur when the number of acquisition stations connected in series exceeds a certain number, and complete crash of communication can be caused when the number of acquisition stations connected in series is larger. The reason of communication failure is caused by accumulation of signal jitter of digital transmission of a measuring line, and how to eliminate jitter in digital signal transmission is the biggest problem in development and research of a wired digital seismograph. The crystal filter scheme and the double-phase-locked-loop scheme provided by the invention are matched for use, so that accumulated jitter of digital signals in the measuring line can be effectively eliminated, and reliable digital communication among thousands of acquisition stations connected in series on the seismic measuring line is ensured.

Description

technical field [0001] The invention relates to a reliability technology of digital communication on the survey line of a wired telemetry seismograph. Background technique [0002] Field survey network of wired telemetry digital seismograph such as figure 1 As shown in Fig. 1, thousands of acquisition stations are connected in series on each horizontal seismic line with the intersection station as the center. The acquisition station does not have a clock, and only a precision quartz crystal oscillator in the cross station is used as the clock source of all acquisition stations and power stations on the entire survey line. Both the acquisition station and the power station use the clock recovered from the cross station command to forward commands and data. And it is used as the reference working clock of the AD converter of the collection station, thereby ensuring that the sampling interval of the AD converter of each collection station is exactly the same. [0003] In pra...

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