Weak signal generation device

Abstract

The invention discloses a weak signal generation device. A control processing module is connected with two acquisition modules and connected with a computer, a DDS (direct digital synthesis) module, a measurement display module and a micro-current source module; the DDS module is connected with a filtering module; the filtering module is connected with the micro-current source module; the micro-current source module is connected with a signal conditioning module; the signal conditioning module is connected with a first acquisition module and a phase detection module respectively; and an output end of the phase detection module is connected with a second acquisition module. The weak signal generation device disclosed by the invention can communicate with the computer; a clock signal from a logging instrument is used as the clock signal of the DDS module, and a synchronous signal from the logging instrument is connected into the phase detection module of the device; and through the device, the frequency is adjustable, the amplitude is controllable, the output signal can be automatically synchronized with a logging transmission signal, and signal parameters can be calibrated and displayed.

Description

technical field [0001] The invention relates to the technical field of well logging weak signal processing, in particular to a weak signal generating device suitable for simulated well logging in a laboratory environment. Background technique [0002] In petroleum electrical logging technology, the magnitudes of direct detection signals are millivolt (mV), microvolt (μV) and nanovolt (nV), etc., which requires the data acquisition system in the logging instrument to have a certain resolution signal capability. In actual instrument design, production and debugging, in order to test and verify the performance of the weak signal acquisition system of the instrument, it is necessary to use the acquisition system to directly collect weak signals of corresponding magnitudes in the laboratory, but the generation of this weak signal is actually difficult. The minimum output signal amplitude of a conventional general-purpose signal generator is mV (for example, 10mV). When a signal ...

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Problems solved by technology

In actual instrument design, production and debugging, in order to test and verify the performance of the weak signal acquisition system of the instrument, it is necessary to use the acquisition system to directly collect weak signals of corresponding magnitudes in the laboratory, but there are actually difficulties in the generation of this weak signal

The minimum output signal amplitude of a conventional general-purpose signal generator is mV (for example, 10mV). When a signal with a smaller amplitude is required, it can be realized by dividing the voltage of the resistor, and the performance of the amplitude, frequency, phase, and noise of the weak signal output by the voltage division cannot be guaranteed; In addition, in the actual test process, it is required that the phase synchronization between the weak signal and the logging signal is required to more realistically simulate the actual logging signal, which is difficult for a general signal generator to satisfy.

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