Accurate acquisition device and method of power frequency in audio forensics

Abstract

The invention discloses an accurate acquisition device and method of power frequency in audio forensics, which belongs to the technical field of acquisition of the power frequency. The acquisition device comprises frequency acquisition points and an upper computer, wherein each frequency acquisition point comprises a precise voltage transformer depressurization module, a signal conditioning module, an anti-alias filter module, a singlechip and a wireless communication unit; and the upper computer is in wireless connection with the frequency acquisition point through the wireless communication unit. The acquisition method comprises the following steps of: (1) distributing the frequency acquisition points in each acquisition cell; (2) putting data obtained through sampling into a buffer memory for buffering; (3) transmitting to the upper computer through the wireless communication unit; (4) putting the received data into a DMA (Direct Memory Access) buffer area through the upper computer, and carrying out frequency calculation; (5) transmitting the data to a database server; and (6) storing the data to the database server. According to the acquisition device and method, power frequency signals can be accurately converted and stored, and a prefecture level power frequency database is quickly established.

Description

technical field The invention belongs to the technical field of power grid frequency collection, and more specifically relates to a device and method for accurately collecting power grid frequency in audio forensics. Background technique In voice forensics, from the perspective of power grid frequency characteristics, the recording signal is acquired, analyzed and evaluated for its authenticity, and the characteristic parameters related to the recording time and recording location are extracted to identify the recording location, which can be used as a court or other administrative authority. Evidence of departmental accreditation. The power grid frequency can reflect the voice recording time, recording location, and according to certain analysis, it has always been a matter of great concern to the public security and judicial departments. Due to the large frequency fluctuation of my country's power grid, coupled with the complex characteristics of my country's power grid...

AI Technical Summary

Problems solved by technology

In view of the fact that the existing technology cannot use the complex power grid characteristics of our country to verify the recording, and the judicial judgment needs to distinguish the authenticity of the recording evidence and the need to judge the accurate recording location, the present invention provides an accurate power grid frequency in audio forensics. Acquisition device and method, which can establish a regional power grid frequency database, and quickly determine the recording location and recording time by checking the recorded grid frequency with the grid frequency of each community

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