CN112287161A - Power grid frequency signal acquisition and storage method and system for digital evidence obtaining - Google Patents
Power grid frequency signal acquisition and storage method and system for digital evidence obtaining Download PDFInfo
- Publication number
- CN112287161A CN112287161A CN202011218842.6A CN202011218842A CN112287161A CN 112287161 A CN112287161 A CN 112287161A CN 202011218842 A CN202011218842 A CN 202011218842A CN 112287161 A CN112287161 A CN 112287161A
- Authority
- CN
- China
- Prior art keywords
- power grid
- grid frequency
- time
- audio
- storing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 27
- 238000011161 development Methods 0.000 claims abstract description 8
- 230000005540 biological transmission Effects 0.000 claims description 4
- 238000012545 processing Methods 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000007781 pre-processing Methods 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000011840 criminal investigation Methods 0.000 description 1
- 238000013480 data collection Methods 0.000 description 1
- 230000005674 electromagnetic induction Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 238000013139 quantization Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 230000005236 sound signal Effects 0.000 description 1
- 238000007619 statistical method Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F16/00—Information retrieval; Database structures therefor; File system structures therefor
- G06F16/60—Information retrieval; Database structures therefor; File system structures therefor of audio data
- G06F16/61—Indexing; Data structures therefor; Storage structures
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F16/00—Information retrieval; Database structures therefor; File system structures therefor
- G06F16/60—Information retrieval; Database structures therefor; File system structures therefor of audio data
- G06F16/68—Retrieval characterised by using metadata, e.g. metadata not derived from the content or metadata generated manually
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F9/00—Arrangements for program control, e.g. control units
- G06F9/06—Arrangements for program control, e.g. control units using stored programs, i.e. using an internal store of processing equipment to receive or retain programs
- G06F9/46—Multiprogramming arrangements
- G06F9/50—Allocation of resources, e.g. of the central processing unit [CPU]
- G06F9/5005—Allocation of resources, e.g. of the central processing unit [CPU] to service a request
- G06F9/5027—Allocation of resources, e.g. of the central processing unit [CPU] to service a request the resource being a machine, e.g. CPUs, Servers, Terminals
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
- G06Q50/00—Systems or methods specially adapted for specific business sectors, e.g. utilities or tourism
- G06Q50/06—Electricity, gas or water supply
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2209/00—Indexing scheme relating to G06F9/00
- G06F2209/50—Indexing scheme relating to G06F9/50
- G06F2209/5018—Thread allocation
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/10—Power transmission or distribution systems management focussing at grid-level, e.g. load flow analysis, node profile computation, meshed network optimisation, active network management or spinning reserve management
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D10/00—Energy efficient computing, e.g. low power processors, power management or thermal management
Landscapes
- Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- General Engineering & Computer Science (AREA)
- Business, Economics & Management (AREA)
- Software Systems (AREA)
- Health & Medical Sciences (AREA)
- Economics (AREA)
- Databases & Information Systems (AREA)
- Data Mining & Analysis (AREA)
- Multimedia (AREA)
- Water Supply & Treatment (AREA)
- Tourism & Hospitality (AREA)
- General Business, Economics & Management (AREA)
- Strategic Management (AREA)
- Primary Health Care (AREA)
- Marketing (AREA)
- Human Resources & Organizations (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Power Engineering (AREA)
- Library & Information Science (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
Abstract
The invention discloses a digital evidence-obtaining-oriented power grid frequency signal acquisition and storage method and system, wherein the method comprises the following steps: the step-down transformer is used for reducing the voltage of the power grid signal, and the reduced voltage of the power grid signal is transmitted to the sound card; reading an audio sample captured by a sound card by using a code compiled by an upper computer development tool; returning a time value when the audio sample starts to be captured by adopting a high-precision clock source to obtain time stamp information corresponding to the audio sample; storing the collected audio samples and the timestamp information together to form an audio database; and converting the acquired audio samples into power grid frequency reference signals of a time-frequency domain by a short-time Fourier transform and extremum adding method, and storing the power grid frequency reference signals and the timestamp information together to form a time-frequency domain database. The invention realizes the accurate and stable acquisition of the power grid frequency reference signal, ensures the establishment of the power grid frequency reference database, and provides data guarantee for the practical and effective multimedia digital evidence obtaining work based on the power grid frequency criterion.
Description
Technical Field
The invention belongs to the technical field of multimedia digital evidence obtaining, and particularly relates to a digital evidence obtaining-oriented power grid frequency signal acquisition and storage method and system.
Background
The rapid development of modern science and technology enables people to enter an information age and an intelligent age, and digital multimedia contents are easy to be tampered and attacked while being informationized, so that some error information is spread. If the multi-media file which is intentionally tampered or forged is applied to the fields of court evidence, media release, criminal investigation, security and the like, the social security and justice are badly affected. Thus, the need for multimedia digital forensics is increasing and plays a vital role in many industries. The multimedia digital evidence collection covers a series of identification targets of time stamp identification, generation place identification, generation equipment identification, tampering trace detection and the like of the multimedia file so as to ensure the integrity, the reality and the reliability of the file.
The network frequency (ENF) can provide partial solutions for audio and video forensics. The grid frequency is the power transmission frequency in the grid, which is nominally 50 or 60 Hz. However, in the power network, due to the complex factors of the non-ideality of the power generation system, the time variation of the overall load, the uncertainty of the external environment, etc., the grid frequency is not a fixed value, but slightly varies in a random manner around the center frequency. Therefore, the power grid frequency, which varies slightly around the nominal value, carries signals, and the signals of the power grid frequency are propagated in the air in the form of sound waves through the vibration of the electrical appliance, and multiple harmonics exist. Such signals are widely present in the environment and, although not audible to the human ear, are largely captured by recording equipment both indoors and outdoors. The fluctuation modes of the grid frequency are kept consistent in the same grid, namely, the grid frequency signals are the same in the same grid, and the grid frequency signals of different grids are different. Due to the randomness of the grid frequency and the consistency in the same grid, the grid frequency signal acts as a time stamp to the recording, becoming a "natural signature" of the audio signal, or can be regarded as a "digital watermark" with respect to time, which makes it possible to authenticate the digital recording based on the grid frequency as authentic. By accurately comparing the power grid frequency signals recorded in the audio file to be detected with the power grid frequency signals in the database, the creation time of the recording file can be identified, and even whether the file is artificially tampered, edited or damaged or not can be detected.
In the detection and analysis of the power grid frequency, the establishment of a power grid frequency reference database is crucial, if no power grid frequency reference signal exists, the power grid signals extracted from the audio file to be checked cannot be compared to determine the timestamp information of the audio file, and other evidence obtaining work around the power grid frequency is difficult to be carried out better. Therefore, the establishment and maintenance of the accurate and stable power grid frequency reference signal acquisition system is an important guarantee for the practical and effective multimedia digital evidence obtaining work based on the power grid frequency criterion. Furthermore, obtaining an accurate and sufficient grid frequency reference signal also facilitates statistical analysis of the grid frequency to determine its a priori statistical characteristics.
Disclosure of Invention
The invention aims to provide a digital evidence-obtaining-oriented power grid frequency signal acquisition and storage method and system, and solves the problems of acquisition and storage of power grid frequency signals and establishment of a power grid frequency reference database.
The invention provides a digital evidence-obtaining-oriented power grid frequency signal acquisition and storage method, which comprises the following steps of:
the step-down transformer is used for reducing the voltage of the power grid signal, and the reduced voltage of the power grid signal is transmitted to the sound card;
and collecting power grid frequency signals from the sound card by using codes compiled by an upper computer development tool, and storing a data file containing time information to form a database.
Furthermore, the uninterrupted power supply provides power-off protection for power grid frequency signal acquisition and storage.
Furthermore, collecting the power grid frequency signal from the sound card, storing the data file containing the time information, and forming the database specifically comprises the following steps:
reading an audio sample captured by a sound card;
returning a time value when the audio sample starts to be captured by adopting a high-precision clock source to obtain time stamp information corresponding to the audio sample;
storing the collected audio samples and the timestamp information together to form an audio database;
and converting the acquired audio samples into power grid frequency reference signals of a time-frequency domain by a short-time Fourier transform and extremum adding method, and storing the power grid frequency reference signals and the timestamp information together to form a time-frequency domain database.
Further, collecting the power grid frequency signal from the sound card, and storing the data file containing the time information specifically comprises the following steps:
the sound card starts to collect power grid frequency signals and starts to time;
judging whether the acquisition time reaches a preset threshold value or not; if not, continuing to collect; and if so, storing the power grid frequency signals collected in the duration.
The invention also provides a digital evidence-obtaining-oriented power grid frequency signal acquisition and storage system, which comprises:
the step-down transmission module is used for reducing the voltage of the power grid signal by using the step-down transformer and transmitting the reduced voltage of the power grid signal to the sound card;
and the acquisition and storage module is used for acquiring the power grid frequency signals from the sound card by using the codes compiled by the upper computer development tool and storing the data files containing the time information to form a database.
Further, the acquisition and storage module comprises:
the acquisition submodule is used for reading an audio sample captured by the sound card;
the time submodule is used for returning a time value when the audio sample starts to be captured by adopting a high-precision clock source to obtain time stamp information corresponding to the audio sample;
the audio submodule is used for storing the acquired audio samples and the timestamp information together to form an audio database;
and the time-frequency sub-module is used for converting the acquired audio samples into power grid frequency reference signals of a time-frequency domain through a short-time Fourier transform and extremum adding method, and storing the power grid frequency reference signals and the timestamp information together to form a time-frequency domain database.
The invention has the beneficial effects that: the digital evidence obtaining-oriented power grid frequency signal acquisition and storage method and system realize accurate and stable acquisition of the power grid frequency reference signal, ensure the establishment of the power grid frequency reference database and provide data guarantee for the practical and effective multimedia digital evidence obtaining work based on the power grid frequency criterion.
Furthermore, the invention adopts a double-storage program, firstly, a high-precision clock source is adopted to return to the starting time value, and the audio samples read from the sound card are stored to form an audio database so as to carry out high-precision slow-speed processing on the power grid frequency signals; and secondly, storing the acquired audio samples as the power grid frequency signals of a time-frequency domain by adopting a short-time Fourier transform (STFT) plus extremum method, and directly calling data for matching so as to be convenient for quick processing.
Further, the present invention proposes a new program structure: and three-thread program, wherein one main thread is responsible for recording (reading data), one auxiliary thread is responsible for storing data, and the other auxiliary thread is responsible for judging time. And the program continuously collects and times the data, and when the collection time reaches a preset threshold value, the read recording file is directly written into the package by using the storage thread, so that the requirement on the instantaneity of the program is reduced. Each thread of the three-thread program is responsible for one function, better division of labor is achieved, compared with the existing program which achieves collection and storage by reading and writing data at the same time, the three-thread program can reduce the burden of data reading operation in the main program and improve collection precision.
Drawings
FIG. 1 is a schematic diagram of a hardware configuration of a grid frequency reference signal acquisition system according to the present invention;
FIG. 2 is a flow chart of the core function software algorithm of the power grid signal acquisition system of the present invention;
fig. 3 is a schematic diagram of a digital evidence-oriented power grid frequency signal acquisition and storage system of the invention.
Detailed Description
The invention will be further described with reference to the accompanying drawings in which:
the invention provides a digital evidence-obtaining-oriented power grid frequency signal acquisition and storage method and system, firstly, a 220V power grid signal of a power supply network is reduced to a 0.1V power grid signal through a step-down transformer, then the power grid signal is transmitted to an upper computer through a sound card interface, and then a double storage program is adopted, wherein firstly, after a high-precision clock source is adopted to return a time value when the acquisition is started, an audio sample read from a sound card device is stored, and time stamp information of audio is reserved so as to carry out high-precision slow-speed processing on the power grid frequency signal; and secondly, storing the acquired audio file as a time-frequency domain power grid frequency signal by adopting a short-time Fourier transform (STFT) plus extreme value method, and directly calling data for matching so as to be convenient for quick processing.
The invention provides a digital evidence-obtaining-oriented power grid frequency signal acquisition and storage method, which comprises the following steps of:
s1, directly connecting the power supply network with a high-precision sound card of a computer through a step-down transformer;
and S2, automatically acquiring a power grid frequency signal from the sound card by using the codes compiled by the computer development tool, and storing a data file containing time information to form a database. Meanwhile, an uninterrupted power supply is arranged outside to protect the whole system, so that data loss under the emergency power-off condition is prevented.
In step S1, the key point is to connect the power supply network directly to the high-precision sound card of the computer through a step-down transformer, and to transmit the fluctuation of the power network to the computer, and the specific hardware configuration is as shown in fig. 1. The step-down transformer is a specific transformer, which can convert the high voltage at the input end into the ideal voltage at the output end, which is relatively low, so as to achieve the purpose of step-down. The working principle of the step-down transformer is an electromagnetic induction principle and consists of a coil and an iron core closed magnetic circuit. The coil is sleeved on the iron core column and cut by the same alternating magnetic flux, each coil generates the same induced potential, the number of turns of the coil is in direct proportion to the voltage of the coil, and therefore the voltage can be reduced by controlling the turn ratio of the coil.
The single-phase step-down control transformer that this patent adopted is the electric wire netting signal input sound card for 0.1V with the 220V electric wire netting signal step-down of power socket department. Because the maximum input voltage allowed by the sound card is 5V, the power grid signal after voltage reduction can be clearly recorded by the sound card, thereby providing a hardware basis for storing the data file containing the time information.
In step S2, the key is to build a complete grid frequency reference signal database. In order to successfully perform power grid frequency signal evidence obtaining, digital evidence obtaining based on power grid frequency, especially in a timestamp verification process, power grid frequency to be verified needs to be compared with a power grid frequency reference signal. Therefore, the reference signal acquisition system needs to meet certain requirements of accuracy and stability. The software part of the acquisition system provided by the special patent is mainly divided into five modules, namely acquisition, timing, storage, preprocessing and power-off protection.
The basic functions are as follows:
an acquisition module: after the voltage of a power grid frequency signal at the power supply is reduced by the voltage reducer, the power grid frequency signal enters a computer through the sound card equipment, a captured audio sample in the sound card equipment is read, and data are temporarily stored in a register to be stored conveniently.
A timing module: and a high-precision clock source is adopted to return the time value for starting to collect, so that the time stamp information of the audio frequency can be conveniently reserved.
A storage module: and storing the acquired audio sample and the timestamp information in a file together to form an audio database.
A preprocessing module: and converting the collected audio samples into power grid frequency reference signals of a time-frequency domain by a short-time Fourier transform (STFT) and extremum adding method, and storing the power grid frequency reference signals and the time stamp information in a file to form a time-frequency domain database.
A power-off protection module: and starting a standby power supply under the condition of emergency power failure, saving current data by an application program, and closing the system.
In the existing programs, the data is read while being written. The data is written immediately after being read in and the data of one hour is saved through program circulation, and the data acquisition is possibly influenced by the speed of reading and writing, so the thread is called to store after the data of one hour is considered to be read, and the time is judged by using the secondary thread, so that the burden of data reading operation in the main program is reduced. In order to improve the acquisition precision, a new program structure is proposed in the experiment: in a three-thread program, one main thread is responsible for recording (reading data), one auxiliary thread is responsible for storing data, and the other auxiliary thread is responsible for judging time, and fig. 2 is a flow chart for realizing power grid frequency reference signal audio acquisition software. Judging whether the acquisition time reaches a preset threshold value or not; if not, continuing to collect; and if so, storing the power grid frequency signals collected in the duration. The initial time and the time length of the acquisition can be set at will, for example, the acquisition is started at the time of the integral point, and the time length is set to be one hour, namely, whether the current time of the acquisition is the time integral point is judged; if not, continuing to collect; and if so, storing the power grid frequency signal acquired in the duration. It can be seen from the figure that the program continuously collects data, and when the time reaches the end point, the storage thread is adopted to directly write and encapsulate the recording file for one hour, so that the requirement on the instantaneity of the program is reduced. Each thread of the three-thread program is responsible for one function, so that better division of labor is realized. And finally, returning a current time value through a high-precision clock source, taking the current time as the file name of the acquired audio file, and storing the audio sample and the timestamp information in the file together to form an audio database.
The audio file storage parameters are as follows:
sampling rate: 400/800Hz
And (3) quantization precision: 16bit
Sound channel: single sound channel (Mono)
And (4) storage format: PCM/WAV
Naming mode: week _ month _ day _ hour _ minute _ second _ year wav (e.g., Fri _ Sep _25_11_00_00_2020.wav)
After the audio file is stored, the audio file needs to be preprocessed, and the time-domain power grid frequency signal is converted into a time-domain power grid frequency signal for direct matching. The time domain signal is converted into a time-frequency domain signal by an STFT plus extremum method. The short-time fourier transform can be calculated by dividing a long time signal into equal length shorter time signals, then calculating the fourier transform of each shorter signal, and plotting the transformed spectrum as a function of time. And the maximum value of the frequency spectrum energy in each section of signal is regarded as the instantaneous value of the power grid frequency at the moment, so that the power grid frequency signal of the time-frequency domain is obtained.
The power failure condition also needs to be considered when acquiring the power grid frequency signal. When adopting uninterrupted power source to supply power, if the outage condition appears in the procedure operation, other power supplies power when using, because acquisition system does not judge the acquisition signal, can not know after the procedure storage that this section data acquisition is invalid data, can cause the problem that is difficult to match to the matching work afterwards. If other power supplies are not used for supplying power, the data acquisition in the time period adopts a three-thread program, real-time storage is not performed, data is read for one hour and stored once, and the acquired data in the time span of the hour is lost. Meanwhile, if the backup power is accessed after the power is off, data collection of the backup power is meaningless. Therefore, the power supply source can be identified to realize acquisition when the power grid frequency signal exists, and temporary data is stored and the machine is automatically shut down under the condition of sudden power failure.
The invention also provides a digital evidence-oriented power grid frequency signal acquisition and storage system, as shown in fig. 3, the system comprises:
the step-down transmission module 1 is used for reducing the voltage of the power grid signal by using a step-down transformer and transmitting the reduced voltage of the power grid signal to the sound card;
and the acquisition and storage module 2 is used for acquiring the power grid frequency signals from the sound card by using the codes compiled by the upper computer development tool, and storing the data files containing the time information to form a database.
Further, the acquisition and storage module 2 includes:
the acquisition submodule 21 is used for reading an audio sample captured by the sound card;
the time submodule 22 is configured to return a time value when the audio sample starts to be captured by using a high-precision clock source, so as to obtain timestamp information corresponding to the audio sample;
the audio submodule 23 is configured to store the acquired audio sample and the timestamp information together to form an audio database;
and the time-frequency sub-module 24 is used for converting the acquired audio samples into power grid frequency reference signals of a time-frequency domain through a short-time Fourier transform and extremum adding method, and storing the power grid frequency reference signals and the timestamp information together to form a time-frequency domain database.
It will be understood by those skilled in the art that the foregoing is merely a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included within the scope of the present invention.
Claims (6)
1. A digital evidence-obtaining-oriented power grid frequency signal acquisition and storage method is characterized by comprising the following steps:
the step-down transformer is used for reducing the voltage of the power grid signal, and the reduced voltage of the power grid signal is transmitted to the sound card;
and collecting power grid frequency signals from the sound card by using codes compiled by an upper computer development tool, and storing a data file containing time information to form a database.
2. The digital evidence oriented power grid frequency signal acquisition and storage method of claim 1, wherein the uninterruptible power supply provides power-off protection for the power grid frequency signal acquisition and storage.
3. The digital evidence obtaining oriented power grid frequency signal acquisition and storage method as claimed in claim 1, wherein the method comprises the following steps of acquiring power grid frequency signals from a sound card, storing data files containing time information, and forming a database:
reading an audio sample captured by a sound card;
returning a time value when the audio sample starts to be captured by adopting a high-precision clock source to obtain time stamp information corresponding to the audio sample;
storing the collected audio samples and the timestamp information together to form an audio database;
and converting the acquired audio samples into power grid frequency reference signals of a time-frequency domain by a short-time Fourier transform and extremum adding method, and storing the power grid frequency reference signals and the timestamp information together to form a time-frequency domain database.
4. The digital forensic-oriented electrical grid frequency signal as claimed in claim 1, comprising in particular the steps of:
the sound card starts to collect power grid frequency signals and starts to time;
judging whether the acquisition time reaches a preset threshold value or not; if not, continuing to collect; and if so, storing the power grid frequency signals collected in the duration.
5. A digital forensic-oriented grid frequency signal acquisition and storage system, the system comprising:
the step-down transmission module is used for reducing the voltage of the power grid signal by using the step-down transformer and transmitting the reduced voltage of the power grid signal to the sound card;
and the acquisition and storage module is used for acquiring the power grid frequency signals from the sound card by using the codes compiled by the upper computer development tool and storing the data files containing the time information to form a database.
6. The digital evidence oriented power grid frequency signal acquisition and storage system of claim 5, wherein the acquisition and storage module comprises:
the acquisition submodule is used for reading an audio sample captured by the sound card;
the time submodule is used for returning a time value when the audio sample starts to be captured by adopting a high-precision clock source to obtain time stamp information corresponding to the audio sample;
the audio submodule is used for storing the acquired audio samples and the timestamp information together to form an audio database;
and the time-frequency sub-module is used for converting the acquired audio samples into power grid frequency reference signals of a time-frequency domain through a short-time Fourier transform and extremum adding method, and storing the power grid frequency reference signals and the timestamp information together to form a time-frequency domain database.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011218842.6A CN112287161A (en) | 2020-11-04 | 2020-11-04 | Power grid frequency signal acquisition and storage method and system for digital evidence obtaining |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011218842.6A CN112287161A (en) | 2020-11-04 | 2020-11-04 | Power grid frequency signal acquisition and storage method and system for digital evidence obtaining |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112287161A true CN112287161A (en) | 2021-01-29 |
Family
ID=74351112
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011218842.6A Pending CN112287161A (en) | 2020-11-04 | 2020-11-04 | Power grid frequency signal acquisition and storage method and system for digital evidence obtaining |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112287161A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113839463A (en) * | 2021-08-27 | 2021-12-24 | 新天绿色能源股份有限公司 | Wind-solar hydrogen production control system and communication method thereof |
| CN115174762A (en) * | 2022-06-27 | 2022-10-11 | 武汉大学 | Evidence obtaining method of video time stamp |
| CN116155623A (en) * | 2023-04-17 | 2023-05-23 | 湖南大学 | Digital audio encryption method and system based on power grid frequency characteristic embedding |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102592588A (en) * | 2012-01-10 | 2012-07-18 | 清华大学 | Digital audio record integrity detection method |
| CN103048539A (en) * | 2012-12-28 | 2013-04-17 | 南京工程学院 | Accurate acquisition device and method of power frequency in audio forensics |
| CN203037739U (en) * | 2012-12-28 | 2013-07-03 | 南京工程学院 | Accurate acquisition device of power grid frequency in audio forensics |
| CN104156578A (en) * | 2014-07-31 | 2014-11-19 | 南京工程学院 | Recording time identification method |
| CN204086396U (en) * | 2014-08-20 | 2015-01-07 | 南京工程学院 | Power phase acquisition and storage device in a kind of fixed telephone network |
| US20150052073A1 (en) * | 2013-08-15 | 2015-02-19 | Lockheed Martin Corporation | Inference of timestamp, location, and signature information using statistical signal processing of powerline data |
| KR101795483B1 (en) * | 2016-07-19 | 2017-11-10 | 고려대학교 산학협력단 | Method and device for collecting electrical network frequency signal from online media |
| US20180088899A1 (en) * | 2016-09-23 | 2018-03-29 | Eventide Inc. | Tonal/transient structural separation for audio effects |
| CN211826236U (en) * | 2020-02-10 | 2020-10-30 | 南京工程学院 | Power grid frequency acquisition circuit in audio frequency |
-
2020
- 2020-11-04 CN CN202011218842.6A patent/CN112287161A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102592588A (en) * | 2012-01-10 | 2012-07-18 | 清华大学 | Digital audio record integrity detection method |
| CN103048539A (en) * | 2012-12-28 | 2013-04-17 | 南京工程学院 | Accurate acquisition device and method of power frequency in audio forensics |
| CN203037739U (en) * | 2012-12-28 | 2013-07-03 | 南京工程学院 | Accurate acquisition device of power grid frequency in audio forensics |
| US20150052073A1 (en) * | 2013-08-15 | 2015-02-19 | Lockheed Martin Corporation | Inference of timestamp, location, and signature information using statistical signal processing of powerline data |
| CN104156578A (en) * | 2014-07-31 | 2014-11-19 | 南京工程学院 | Recording time identification method |
| CN204086396U (en) * | 2014-08-20 | 2015-01-07 | 南京工程学院 | Power phase acquisition and storage device in a kind of fixed telephone network |
| KR101795483B1 (en) * | 2016-07-19 | 2017-11-10 | 고려대학교 산학협력단 | Method and device for collecting electrical network frequency signal from online media |
| US20180088899A1 (en) * | 2016-09-23 | 2018-03-29 | Eventide Inc. | Tonal/transient structural separation for audio effects |
| CN211826236U (en) * | 2020-02-10 | 2020-10-30 | 南京工程学院 | Power grid frequency acquisition circuit in audio frequency |
Non-Patent Citations (1)
| Title |
|---|
| 刘育明: "电力系统频率测量及其在数字语音真伪鉴别中的应用", 《中国优秀博士学位论文全文数据库 工程科技Ⅱ辑》, pages 1 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113839463A (en) * | 2021-08-27 | 2021-12-24 | 新天绿色能源股份有限公司 | Wind-solar hydrogen production control system and communication method thereof |
| CN115174762A (en) * | 2022-06-27 | 2022-10-11 | 武汉大学 | Evidence obtaining method of video time stamp |
| CN115174762B (en) * | 2022-06-27 | 2024-04-16 | 武汉大学 | Evidence obtaining method for video time stamp |
| CN116155623A (en) * | 2023-04-17 | 2023-05-23 | 湖南大学 | Digital audio encryption method and system based on power grid frequency characteristic embedding |
| CN116155623B (en) * | 2023-04-17 | 2023-08-15 | 湖南大学 | Digital audio encryption method and system based on power grid frequency characteristic embedding |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112287161A (en) | Power grid frequency signal acquisition and storage method and system for digital evidence obtaining | |
| CN204882843U (en) | Transformer remanence detects and demagnetization device | |
| RU2008146082A (en) | CHECK THE CONFIGURATION OF THE INTELLIGENT ELECTRONIC DEVICE | |
| CN105093140A (en) | Transformer remanence detection and demagnetization method and device | |
| CN104732974A (en) | Intelligent recording and recognizing system | |
| CN111210129B (en) | Power distribution network planning service management information system based on meshing | |
| CN112394224B (en) | Audio file generation time tracing dynamic matching method and system | |
| Grigoras et al. | Advances in ENF database configuration for forensic authentication of digital media | |
| WO2022127574A1 (en) | Method and apparatus for simulating past and future data, and terminal device | |
| CN111751645A (en) | Transformer direct-current magnetic bias monitoring method, device, equipment and system | |
| Grigoras et al. | Analytical framework for digital audio authentication | |
| CN116896064B (en) | Power utilization characteristic analysis system and method for power utilization load | |
| CN106557550A (en) | A kind of implementation method and device of the quick storage, retrieval and completion of distribution terminal self-described fixed point record | |
| CN117076888A (en) | Preprocessing storage method for switch cabinet acquired data | |
| CN112486009B (en) | Time service signal abnormal waveform recording analyzer and method | |
| CN115825602A (en) | Load identification method and system for comprehensive multivariate information similarity analysis | |
| Xu et al. | Design and implementation of vibration on-line monitoring system of power transformer | |
| CN111190073B (en) | Power grid wide area measurement interaction and search service system | |
| CN206906470U (en) | A kind of wind power generating set lightning recorder | |
| CN209460343U (en) | A kind of portable intelligent recording monitoring device | |
| CN109557392A (en) | A kind of newspaper collecting literary grace integrates, the portable recording detection system of analysis | |
| Jones et al. | An Electric Network Frequency Analysis Technology Demonstrator for Educational Purposes | |
| Cao et al. | Real-time monitoring of unmanned substation based on audio recognition | |
| CN208156088U (en) | A kind of warning device based on power quality index monitoring | |
| CN110058191A (en) | A kind of long-range verification system of intelligent electric energy meter |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |