A protection data virtual printing control system based on a bluetooth connection of an electric signal measurement

Abstract

The application discloses a kind of virtual printing control systems of protection data based on bluetooth connection of electric signal measurement.Solve the problem that when bluetooth transmission protection data, physical layer signal anomaly cannot be perceived and bottom signal transmission is disconnected.The system obtains the electric signal on the bluetooth data transmission path by multiple channels through electric signal acquisition module.Signal pre-processing module pre-processes original waveform and extracts features to identify transmission mode.Signal decomposition mapping module decomposes signal into high and low frequency components and maps to template library.Offset calculation module calculates the offset of each component relative to baseline, and generates signal state identifier.Quality evaluation output module determines signal quality evaluation value and constructs quality set.Printing control module generates print start-stop or parameter adjustment instructions based on the set, and drives virtual printing equipment.It realizes the direct linkage from physical layer signal integrity monitoring to application layer printing behavior control, and improves the safety of bluetooth data transmission and output process.

Description

Technical Field

[0001] This invention relates to the field of signal security and virtual printing technology, specifically to a protected data virtual printing control system based on Bluetooth connectivity for electrical signal measurement. Background Technology

[0002] In current data security systems, mainstream technologies for protecting Bluetooth data transmission and controlling printing focus on the application and protocol layers. Common methods include encrypting transmitted data, performing two-way authentication during connection establishment, or verifying the digital signature and integrity of data before issuing print commands. These technologies rely on the content of the data packets themselves or the logical state agreed upon by the protocol for security judgment and control decisions. Existing virtual print control systems typically generate print commands based on the verification results of decrypted data or user permission policies, with their control logic entirely residing at the software level.

[0003] However, protection methods relying solely on pure software protocol layers have inherent flaws. High-level attacks can exploit protocol vulnerabilities, side-channel analysis, or malicious firmware tampering to steal or alter data streams without compromising the encryption protocol logic. Traditional solutions struggle to detect abnormal disturbances at the physical level of the transmission link, such as attacks via electromagnetic injection or signal distortion caused by hardware failures. Once encrypted data is successfully intercepted or injected, subsequent printing control based on that data will completely fail. Furthermore, existing technologies lack a mechanism to correlate the physical layer health status of data transmission with the final output behavior (such as printing) in real time and quantitatively. Control decisions are essentially disconnected from the underlying signal transmission, making it impossible to implement proactive closed-loop protection along the physical path of data flow. Summary of the Invention

[0004] The purpose of this invention is to provide a Bluetooth-connected protected data virtual printing control system based on electrical signal measurement, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides a Bluetooth-connected protection data virtual printing control system based on electrical signal measurement, the system comprising:

[0006] The electrical signal acquisition module is used to acquire the transmission path electrical signal corresponding to the protection data transmitted via Bluetooth, and to perform multi-channel sampling on the transmission path electrical signal to obtain multiple sets of original electrical signal waveforms.

[0007] The signal preprocessing module is used to preprocess the multiple sets of original electrical signal waveforms, extract the basic signal features from the multiple sets of original electrical signal waveforms, and identify the transmission mode category in the electrical signal based on the basic signal features.

[0008] The signal decomposition and mapping module is used to decompose the multiple sets of original electrical signal waveforms according to the transmission mode category, separate the high-frequency components and low-frequency components in the electrical signal, and map the high-frequency components and the low-frequency components to a preset signal template library respectively.

[0009] The offset calculation module is used to calculate the offset of the high-frequency component and the low-frequency component relative to the preset signal baseline based on the mapping result of the signal template library, and generate the signal status identifier of the high-frequency component and the low-frequency component according to the offset.

[0010] The quality assessment output module is used to determine the signal quality assessment value of the high-frequency component and the low-frequency component based on the signal state identifier of the high-frequency component and the low-frequency component, and to construct an electrical signal quality set for virtual printing based on the signal quality assessment value.

[0011] Preferably, the methods for obtaining multiple sets of original electrical signal waveforms include:

[0012] Set the sampling frequency and sampling period of the Bluetooth transmission channel, and continuously sample the Bluetooth transmission channel within a single sampling period;

[0013] The continuously sampled electrical signals are arranged in chronological order to form an initial electrical signal sequence;

[0014] The initial electrical signal sequence is normalized to eliminate amplitude differences caused by different transmission paths, resulting in multiple sets of original electrical signal waveforms.

[0015] Preferably, the implementation method for extracting the basic signal features from the multiple sets of original electrical signal waveforms includes:

[0016] Time-domain analysis is performed on multiple sets of original electrical signal waveforms to calculate the average amplitude, peak amplitude, and zero-crossing rate of the multiple sets of original electrical signal waveforms.

[0017] Frequency domain transformation is performed on multiple sets of original electrical signal waveforms to obtain the spectral energy distribution of the multiple sets of original electrical signal waveforms;

[0018] The basic signal characteristics of multiple sets of original electrical signal waveforms are formed by combining the average amplitude, peak amplitude, zero-crossing rate, and spectral energy distribution.

[0019] Preferably, the implementation method for identifying the transmission mode category in an electrical signal based on the basic signal characteristics includes:

[0020] The basic signal characteristics are input into a preset transmission mode classification model, which includes various known Bluetooth transmission mode characteristics.

[0021] Calculate the feature matching degree between basic signal characteristics and features of various known Bluetooth transmission modes;

[0022] The transmission mode corresponding to the known Bluetooth transmission mode feature with the highest feature matching degree is determined as the transmission mode category in the electrical signal;

[0023] The methods for calculating the feature matching degree between the basic signal features and various known Bluetooth transmission mode features include:

[0024] The basic signal features and each of the known Bluetooth transmission mode features are used to construct corresponding feature vectors;

[0025] Calculate the cosine similarity between the feature vector corresponding to the basic signal feature and the feature vector corresponding to each known Bluetooth transmission mode feature, and use it as the direction matching degree;

[0026] Calculate the Euclidean distance between the feature vector corresponding to the basic signal feature and the feature vector corresponding to each known Bluetooth transmission mode feature, and convert it into a distance matching degree;

[0027] For each known Bluetooth transmission mode feature, the corresponding direction matching degree and distance matching degree are weighted and summed to obtain the feature matching degree between the known Bluetooth transmission mode feature and the basic signal feature.

[0028] Preferably, the implementation method for signal decomposition of the multiple sets of original electrical signal waveforms includes:

[0029] Select the corresponding signal filter bank according to the transmission mode category in the electrical signal;

[0030] The signal filter bank is used to filter multiple sets of original electrical signal waveforms to separate the high-frequency and low-frequency components in the electrical signal.

[0031] The separated high-frequency and low-frequency components are reconstructed separately to obtain the reconstructed high-frequency and low-frequency signal waveforms.

[0032] Preferably, the implementation method of mapping the high-frequency component and the low-frequency component to a preset signal template library includes:

[0033] The reconstructed high-frequency and low-frequency signal waveforms are compared with the standard high-frequency and standard low-frequency template waveforms stored in the signal template library for waveform similarity.

[0034] Record the waveform similarity between the reconstructed high-frequency signal waveform and the standard high-frequency template waveform as the template matching degree of the high-frequency components;

[0035] Record the waveform similarity between the reconstructed low-frequency signal waveform and the standard low-frequency template waveform as the template matching degree of the low-frequency component.

[0036] Preferably, the method for generating the signal state identifiers of the high-frequency component and the low-frequency component includes:

[0037] Obtain the time-domain waveform and frequency-domain characteristics of the preset signal baseline;

[0038] The time-domain difference between the waveform corresponding to the template matching degree of the high-frequency component and the time-domain waveform of the preset signal baseline is calculated to obtain the time-domain offset of the high-frequency component.

[0039] The frequency domain difference between the waveform corresponding to the template matching degree of the low-frequency component and the frequency domain characteristics of the preset signal baseline is calculated to obtain the frequency domain offset of the low-frequency component.

[0040] Based on the time-domain offset of the high-frequency component and the frequency-domain offset of the low-frequency component, signal state identifiers corresponding to the high-frequency component and the low-frequency component are generated respectively.

[0041] Preferably, the method for determining the signal quality assessment values ​​of the high-frequency component and the low-frequency component includes:

[0042] Establish a correspondence between signal status identifiers and signal quality parameters, including signal-to-noise ratio threshold, waveform distortion tolerance, and baseline stability coefficient;

[0043] Based on the signal status identifier of the high-frequency component, find the corresponding signal quality parameter, and calculate the signal quality evaluation value of the high-frequency component based on the found signal quality parameter.

[0044] Based on the signal status identifier of the low-frequency component, the corresponding signal quality parameters are found, and the signal quality evaluation value of the low-frequency component is calculated based on the found signal quality parameters.

[0045] Preferably, the implementation methods for constructing the electrical signal quality set for virtual printing include:

[0046] The signal quality assessment values ​​of high-frequency components and low-frequency components are integrated to form an initial signal quality assessment set.

[0047] The virtual print format requirements for obtaining protected data are used to filter and sort the evaluation values ​​in the initial signal quality evaluation set according to the signal quality standards in the virtual print format requirements.

[0048] The filtered and sorted signal quality evaluation values ​​are associated and encapsulated with their corresponding electrical signal sampling timestamps and transmission mode categories to generate an electrical signal quality set for virtual printing.

[0049] Preferably, the specific implementation method for the printing control module to generate control signals includes:

[0050] A preset signal quality threshold range is defined, and the signal quality evaluation values ​​in the electrical signal quality set are compared with the threshold range.

[0051] If the signal quality assessment value falls within the first threshold range, a print enable command is generated to control the virtual printing device to perform printing according to the default parameters.

[0052] If the signal quality assessment value falls within the second threshold range, a printing parameter adjustment instruction is generated to control the virtual printing device to reduce the printing rate or enable error correction coding.

[0053] If the signal quality assessment value is lower than the preset tolerance, a print disable command will be generated and the Bluetooth retransmission mechanism will be triggered.

[0054] Compared with the prior art, the beneficial effects of the present invention are:

[0055] By collecting physical layer electrical signals along the Bluetooth transmission path and using the in-depth analysis results of these signals as the direct driving source for virtual printing control, a cross-layer control closed-loop mechanism from hardware link to application output is constructed. This mechanism extends the reach of security monitoring to the physical transmission layer, which traditional software protection cannot cover. Any attempt to interfere with, steal, or inject Bluetooth signals through physical means will directly cause detectable changes in the electrical signal characteristics. Based on this, the system can detect risks in advance and proactively intervene in printing actions before the data is received and decrypted by the upper-layer application, achieving hardware-level pre-emptive defense and proactive blocking, fundamentally changing the control paradigm that relies on post-event verification.

[0056] This method employs a transmission mode-adaptive signal decomposition technique to separate the signal into high-frequency and low-frequency components, which are then mapped and compared with a pre-defined template library. The signal status identifier is quantified by calculating the offset. This approach abandons simple threshold judgments and can finely characterize the microscopic distortions of the signal across multiple dimensions. Different attack or interference methods leave differentiated "fingerprints" on features such as high-frequency noise and low-frequency baseline drift. Multi-dimensional decomposition and offset calculation can more sensitively and accurately identify these potential threat patterns and quantify the risk level into a high-quality signal quality assessment set. This provides printing control with a highly reliable decision-making basis far exceeding traditional signal strength or bit error rate indicators, reducing the probability of misjudgment and missed judgment. Attached Figure Description

[0057] Figure 1 This is a flowchart of the Bluetooth-connected protection data virtual printing control system based on electrical signal measurement as described in this invention;

[0058] Figure 2A flowchart for obtaining multiple sets of raw electrical signal waveforms;

[0059] Figure 3 A flowchart for identifying transmission mode categories;

[0060] Figure 4 A bar chart showing the correspondence between Bluetooth transmission modes and filter cutoff frequencies;

[0061] Figure 5 A pie chart showing the percentage distribution of Bluetooth transmission mode categories. Detailed Implementation

[0062] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] Please see Figure 1 This invention provides a Bluetooth-connected protection data virtual printing control system based on electrical signal measurement. The system includes: an electrical signal acquisition module that acquires the transmission path electrical signal corresponding to the protection data transmitted via Bluetooth, and performs multi-channel sampling on the transmission path electrical signal to obtain multiple sets of original electrical signal waveforms; a signal preprocessing module that preprocesses the multiple sets of original electrical signal waveforms, extracts the basic signal features from the multiple sets of original electrical signal waveforms, and identifies the transmission mode category in the electrical signal based on the basic signal features; a signal decomposition and mapping module that decomposes the multiple sets of original electrical signal waveforms according to the transmission mode category, separates the high-frequency component and low-frequency component in the electrical signal, and maps the high-frequency component and low-frequency component to a preset signal template library respectively; an offset calculation module that calculates the offset of the high-frequency component and low-frequency component relative to a preset signal baseline based on the mapping result of the signal template library, and generates signal status identifiers for the high-frequency component and low-frequency component based on the offset; and a quality evaluation output module that determines the signal quality evaluation value of the high-frequency component and low-frequency component based on the signal status identifier, and constructs an electrical signal quality set for virtual printing based on the signal quality evaluation value.

[0064] In one embodiment of the present invention, see [reference] Figure 2The sampling frequency and sampling period of the Bluetooth transmission channel are set, and the Bluetooth transmission channel is continuously sampled within a single sampling period. The continuously sampled electrical signals are arranged in chronological order to form an initial electrical signal sequence. The initial electrical signal sequence is then normalized to eliminate amplitude differences caused by different transmission paths, resulting in multiple sets of original electrical signal waveforms. Time-domain analysis is performed on the multiple sets of original electrical signal waveforms to calculate the average amplitude, peak amplitude, and zero-crossing rate. Frequency-domain transformation is then performed on the multiple sets of original electrical signal waveforms to obtain the spectral energy distribution. Combining the average amplitude, peak amplitude, zero-crossing rate, and spectral energy distribution of the multiple sets of original electrical signal waveforms, the basic signal characteristics of the multiple sets of original electrical signal waveforms are formed.

[0065] In practical implementation, the operation of the electrical signal acquisition module and signal preprocessing module in the Bluetooth-connected protected data virtual printing control system follows a clear signal processing flow. The sampling frequency and sampling period of the Bluetooth transmission channel are set. In a Bluetooth basic rate / enhanced data rate connection example with a transmission rate of 1Mbps, the sampling frequency can be set to 80MHz, and the single sampling period is set to cover a complete Bluetooth time slot. Continuous synchronous sampling is performed on the selected Bluetooth transmission channel within a single sampling period. The continuously sampled electrical signal data points are strictly arranged in chronological order to form an initial electrical signal sequence containing multiple discrete amplitude points. Each data point in the initial electrical signal sequence corresponds to a specific sampling time and voltage value. Amplitude normalization processing is performed on the initial electrical signal sequence to eliminate amplitude differences introduced by transmission path attenuation or different gains. The processing formula is as follows:

[0066]

[0067] in: Represents the first electrical signal in the initial electrical signal sequence. The original amplitude values ​​of each sampling point This represents the average amplitude of all sample points in the initial electrical signal sequence. This represents the standard deviation of the amplitudes of all sampling points in the initial electrical signal sequence. Represents the calculated first... After normalizing the amplitude values ​​of each sampling point, this process ultimately yields a set of original electrical signal waveforms with a unified amplitude scale. For multi-channel sampling, the above process is executed in parallel to obtain multiple sets of original electrical signal waveforms.

[0068] In some embodiments, after acquiring multiple sets of original electrical signal waveforms, the signal preprocessing module initiates basic signal feature extraction, performs time-domain analysis on the multiple sets of original electrical signal waveforms, and calculates the average amplitude, peak amplitude, and the number of times the signal amplitude value crosses zero per unit time, i.e., the zero-crossing rate, of the multiple sets of original electrical signal waveforms. Optionally, the peak amplitude can be obtained by traversing the normalized amplitude values ​​of all sampling points in a set of waveforms and taking the maximum absolute value. In a specific implementation, the multiple sets of original electrical signal waveforms undergo frequency domain transformation. The original electrical signal waveforms in the time domain are converted into a frequency domain representation using the Fast Fourier Transform algorithm, thereby obtaining the spectral energy distribution of the multiple sets of original electrical signal waveforms at different frequency components. It can be understood that the spectral energy distribution can reflect which frequency ranges the main energy of the signal is concentrated in. Combining the three time-domain parameters of average amplitude, peak amplitude, and zero-crossing rate calculated for the multiple sets of original electrical signal waveforms, and the spectral energy distribution information obtained from the frequency domain transformation, the data of these four dimensions are organized in sequence to form a set of basic signal feature vectors that can comprehensively describe the time-frequency characteristics of the original electrical signal waveform. Multiple sets of basic signal features are generated corresponding to the multiple sets of original electrical signal waveforms.

[0069] In one embodiment of the present invention, see [reference] Figure 3 The basic signal features are input into a preset transmission mode classification model, which includes various known Bluetooth transmission mode features. The feature matching degree between the basic signal features and the various known Bluetooth transmission mode features is calculated. The transmission mode corresponding to the known Bluetooth transmission mode feature with the highest feature matching degree is determined as the transmission mode category in the electrical signal. The feature matching degree is calculated by constructing corresponding feature vectors for the basic signal features and each known Bluetooth transmission mode feature, respectively. The cosine similarity between the feature vectors corresponding to the basic signal features and the feature vectors corresponding to each known Bluetooth transmission mode feature is calculated as the direction matching degree. The Euclidean distance between the feature vectors corresponding to the basic signal features and the feature vectors corresponding to each known Bluetooth transmission mode feature is calculated and converted into a distance matching degree. For each known Bluetooth transmission mode feature, its corresponding direction matching degree and distance matching degree are weighted and summed to obtain the feature matching degree between the known Bluetooth transmission mode features and the basic signal features.

[0070] In practical implementation, after forming the basic signal features of multiple sets of original electrical signal waveforms, the signal preprocessing module performs transmission mode category identification. The basic signal features are input into a pre-trained transmission mode classification model, which stores various known Bluetooth transmission mode features, including feature vectors for Bluetooth Basic Rate Mode and Bluetooth Low Energy Mode, as well as data templates for various standard modes. The feature matching degree between the basic signal features and the various known Bluetooth transmission mode features is calculated. This process requires evaluating the similarity between the basic signal features and each known mode feature. The transmission mode corresponding to the known Bluetooth transmission mode feature with the highest feature matching degree is ultimately determined as the transmission mode category in the current electrical signal.

[0071] In some embodiments, the specific calculation of the feature matching degree is implemented through the following steps: constructing corresponding multi-dimensional feature vectors from the basic signal features and the features of each known Bluetooth transmission mode; calculating the cosine similarity between the feature vectors corresponding to the basic signal features and the feature vectors corresponding to each known Bluetooth transmission mode feature; the cosine similarity reflects the closeness of the two feature vectors in direction, and this value is used as the direction matching degree. Its value ranges from -1 to 1, with larger values ​​indicating more consistent directions. The Euclidean distance is calculated between the feature vectors corresponding to the basic signal characteristics and the feature vectors corresponding to each known Bluetooth transmission mode. Euclidean distance measures the absolute straight-line distance between two feature vectors in multidimensional space. This distance metric needs to be converted into a similarity score, comparable to the direction matching degree, with a value between 0 and 1; this is the distance matching degree. Optionally, the conversion can be performed using the formula:

[0072]

[0073] in: This represents the calculated original Euclidean distance. This formula ensures that the smaller the Euclidean distance, the closer the distance matching degree is to 1, and the larger the Euclidean distance, the closer the distance matching degree is to 0. For each known Bluetooth transmission mode feature, its corresponding direction matching degree and distance matching degree are weighted and summed to obtain the final feature matching degree between the known Bluetooth transmission mode feature and the basic signal feature. It can be understood that the formula for weighted summation is:

[0074]

[0075] in: These are the weighting coefficients that assign a degree of directional matching. It is the weight coefficient assigned to the distance matching degree, and satisfies The specific values ​​of the weighting coefficients can be set during system design according to different requirements for sensitivity to direction or distance. In practical implementation, after calculating the feature matching degree of all known modes, the system compares the values ​​of these feature matching degrees and outputs the Bluetooth transmission mode associated with the feature matching degree with the largest value, such as the Bluetooth Basic Rate mode, as the transmission mode category of the current electrical signal.

[0076] In one embodiment of the present invention, a corresponding signal filter bank is selected according to the transmission mode category in the electrical signal. The signal filter bank is used to filter multiple sets of original electrical signal waveforms to separate the high-frequency and low-frequency components in the electrical signal. The separated high-frequency and low-frequency components are reconstructed to obtain the reconstructed high-frequency and low-frequency signal waveforms. The reconstructed high-frequency and low-frequency signal waveforms are compared with the standard high-frequency and standard low-frequency template waveforms stored in the signal template library to determine their waveform similarity. The waveform similarity between the reconstructed high-frequency signal waveform and the standard high-frequency template waveform is recorded as the template matching degree of the high-frequency component. The waveform similarity between the reconstructed low-frequency signal waveform and the standard low-frequency template waveform is also recorded as the template matching degree of the low-frequency component.

[0077] In practical implementation, the signal decomposition and mapping module performs signal decomposition operations based on the transmission mode category determined by the signal preprocessing module. According to the transmission mode category in the electrical signal, a corresponding signal filter bank is selected. The correspondence between the transmission mode category and the signal filter bank is pre-configured. For example, when the transmission mode category is identified as Bluetooth Basic Rate mode, a set of high-pass and low-pass filter combinations pre-designed for this mode is invoked. The signal filter bank is used to filter multiple sets of original electrical signal waveforms, separating the high-frequency and low-frequency components. Filtering is applied in parallel to multiple sets of original electrical signal waveforms. The separated high-frequency and low-frequency components are then reconstructed separately. Signal reconstruction recovers the complete waveform representation based on the filtered signal sequence, resulting in reconstructed high-frequency and low-frequency signal waveforms.

[0078] In some embodiments, after obtaining the reconstructed high-frequency signal waveform and the reconstructed low-frequency signal waveform, a mapping operation is performed. The reconstructed high-frequency signal waveform and the reconstructed low-frequency signal waveform are compared with standard high-frequency template waveforms and standard low-frequency template waveforms stored in a signal template library. The signal template library is a database storing high-frequency and low-frequency reference waveforms corresponding to various transmission modes obtained under ideal or standard transmission conditions. The waveform similarity between the reconstructed high-frequency signal waveform and the standard high-frequency template waveform is recorded, and this similarity value is used as the template matching degree of the high-frequency component. Similarly, the waveform similarity between the reconstructed low-frequency signal waveform and the standard low-frequency template waveform is recorded, and this similarity value is used as the template matching degree of the low-frequency component. Optionally, the waveform similarity can be calculated using a method based on cross-correlation coefficients, with the following formula:

[0079]

[0080] in: Indicates the first [number]th ... The amplitude value of each sampling point This represents the average amplitude of all sampling points of the reconstructed signal waveform. This indicates the first standard template waveform in the signal template library. The amplitude value of each sampling point This represents the average amplitude of all sampling points of the standard template waveform. The total number of sampling points participating in the comparison is calculated as follows. The value represents the waveform similarity. It can be understood that the template matching degree is a scalar value between -1 and 1; the closer the value is to 1, the higher the shape consistency between the reconstructed waveform and the standard template waveform. In practical implementation, after completing the waveform similarity comparison and recording of all high-frequency and low-frequency components, the template matching degree of the high-frequency components and the template matching degree of the low-frequency components will be used as the output of the signal decomposition and mapping module.

[0081] See Figure 4 This is a bar chart showing the correspondence between Bluetooth transmission modes and filter cutoff frequencies, primarily displaying the high-pass and low-pass filter parameters used for signal decomposition under different transmission modes. The Enhanced Data Rate mode has the highest cutoff frequency (25Hz), corresponding to higher data transmission bandwidth requirements; the Low Power mode has the lowest cutoff frequency (10Hz), conforming to simplified signal design in low-power scenarios; the high-pass and low-pass cutoff frequencies are consistent within the same mode, ensuring a clear distinction between high-frequency and low-frequency components during signal decomposition. This chart serves as a parameter configuration reference for the Bluetooth electrical signal decomposition stage, intuitively presenting the matching relationship between transmission modes and filter parameters, helping technicians quickly determine the signal processing strategy for the corresponding mode, and is a core parameter visualization tool for the signal decomposition module.

[0082] In one embodiment of the present invention, the time-domain waveform and frequency-domain characteristics of a preset signal baseline are obtained, the time-domain difference between the waveform corresponding to the template matching degree of the high-frequency component and the time-domain waveform of the preset signal baseline is calculated to obtain the time-domain offset of the high-frequency component, the frequency-domain difference between the waveform corresponding to the template matching degree of the low-frequency component and the frequency-domain characteristics of the preset signal baseline is calculated to obtain the frequency-domain offset of the low-frequency component, and signal state identifiers corresponding to the high-frequency component and the low-frequency component are generated based on the time-domain offset of the high-frequency component and the frequency-domain offset of the low-frequency component.

[0083] In practical implementation, the offset calculation module performs offset calculation and identifier generation based on the template matching degree result output by the signal decomposition and mapping module. It acquires the time-domain waveform and frequency-domain characteristics of a preset signal baseline. The preset signal baseline is a reference signal data pre-stored within the system and measured under an ideal, interference-free environment. It contains a complete time-domain waveform sequence and a set of spectral characteristic parameters analyzed from this waveform sequence. The time-domain difference between the waveform corresponding to the template matching degree of the high-frequency component and the time-domain waveform of the preset signal baseline is calculated. The waveform corresponding to the template matching degree of the high-frequency component refers to the reconstructed high-frequency signal waveform used to calculate the template matching degree. A specific method for calculating the time-domain difference can be to calculate the mean of the roots of the amplitude differences between the two waveform sequences at corresponding time points, thus obtaining the time-domain offset of the high-frequency component. The frequency domain difference between the waveform corresponding to the template matching degree of the low-frequency component and the frequency domain characteristics of the preset signal baseline is calculated separately. The waveform corresponding to the template matching degree of the low-frequency component refers to the reconstructed low-frequency signal waveform used to calculate the template matching degree. To calculate the frequency domain difference, the low-frequency waveform needs to be transformed in the frequency domain first, and the same spectral feature parameters as the preset signal baseline are extracted. Then, the difference measure between the corresponding parameter sets is calculated to obtain the frequency domain offset of the low-frequency component.

[0084] In some embodiments, the time-domain offset and frequency-domain offset can be calculated using quantitative mathematical methods. It can be understood that the time-domain offset of high-frequency components... It can be calculated using the following formula:

[0085]

[0086] in: The reconstructed high-frequency signal waveform is represented in the first... The amplitude value of each sampling point The time-domain waveform representing the preset signal baseline is in the [missing information]. The amplitude value of each corresponding sampling point This represents the total number of sampling points involved in the calculation. The frequency domain offset of the low-frequency component. It can be obtained by calculating the Euclidean distance between the spectral eigenvectors, specifically:

[0087]

[0088] in: This represents the first frequency signal extracted from the reconstructed low-frequency signal waveform. The spectral feature value, for example, the 1st spectral feature value. Energy values ​​in each frequency range The frequency domain characteristics of the preset signal baseline represent the corresponding first... Each spectral feature value The total number of selected spectral features. Based on the calculated time-domain offset of the high-frequency component and the frequency-domain offset of the low-frequency component, signal state identifiers corresponding to the high-frequency component and the low-frequency component are generated respectively. The signal state identifier is a classification code used to summarize the current component offset state, and the correspondence between the offset and the state identifier is determined by a preset threshold rule. Optionally, referring to Table 1, the correspondence between the offset and the signal state identifier can be achieved by querying a preset mapping table.

[0089] Table 1: Correspondence between Offset and Signal Status Indicator

[0090]

[0091] In practical implementation, the system compares the calculated time-domain offset value of the high-frequency component with the "Offset Range" under the "High-Frequency Component" category in Table 4-1. If the value falls within a given range, a corresponding "Signal Status Identifier" is generated. For example, if... A value of 0.25 generates the signal status identifier "H_QB" for the high-frequency component. The frequency offset value of the low-frequency component is compared with the range under the "Low-Frequency Component" category in the table in the same way to generate the corresponding identifier. For example, if... A value of 0.08 generates the signal status identifier "L_QB" for the low-frequency component.

[0092] In one embodiment of the present invention, a correspondence between signal status identifiers and signal quality parameters is established. The signal quality parameters include signal-to-noise ratio threshold, waveform distortion tolerance, and baseline stability coefficient. Based on the signal status identifier of the high-frequency component, the corresponding signal quality parameter is found, and the signal quality evaluation value of the high-frequency component is calculated based on the found signal quality parameter. Based on the signal status identifier of the low-frequency component, the corresponding signal quality parameter is found, and the signal quality evaluation value of the low-frequency component is calculated based on the found signal quality parameter. The signal quality evaluation values ​​of the high-frequency component and the low-frequency component are integrated to form an initial signal quality evaluation set. The virtual printing format requirements of the protection data are obtained. According to the signal quality standards in the virtual printing format requirements, the evaluation values ​​in the initial signal quality evaluation set are filtered and sorted. The filtered and sorted signal quality evaluation values ​​are associated and encapsulated with their corresponding electrical signal sampling timestamps and transmission mode categories to generate an electrical signal quality set for virtual printing.

[0093] In practical implementation, the quality assessment output module receives the signal status identifiers of the high-frequency and low-frequency components generated by the offset calculation module, and performs quality assessment and set construction based on these identifiers. A correspondence is established between the signal status identifiers and signal quality parameters, including the signal-to-noise ratio threshold, waveform distortion tolerance, and baseline stability coefficient. This correspondence is pre-stored in the system in the form of a lookup table. Based on the signal status identifier of the high-frequency component, the corresponding signal quality parameter is looked up, and the signal quality assessment value of the high-frequency component is calculated based on the found signal quality parameter. Similarly, based on the signal status identifier of the low-frequency component, the corresponding signal quality parameter is looked up, and the signal quality assessment value of the low-frequency component is calculated based on the found signal quality parameter.

[0094] In some embodiments, the calculation of the signal quality assessment value employs a comprehensive calculation formula, such as the signal quality assessment value of high-frequency components. formula:

[0095]

[0096] in: This represents the signal-to-noise ratio threshold parameter found based on the status indicator of the high-frequency component signal. This indicates the waveform distortion tolerance parameter found. This represents the baseline stability coefficient parameter found. These are the weighting coefficients assigned to these three parameters. This can be understood as the signal quality assessment value for the low-frequency component. Calculations are performed using formulas with the same structure but different input parameters. , and Replace the values ​​with the corresponding parameter values ​​found based on the low-frequency component signal status identifier. Integrate the signal quality assessment values ​​of the high-frequency and low-frequency components, recording these two values ​​along with their respective component type information to form an initial signal quality assessment set. Obtain the virtual print format requirements for protection data, which clearly define signal quality standards, such as the minimum acceptable range or priority ranking rules for signal quality assessment values. Based on the signal quality standards in the virtual print format requirements, filter and sort the assessment values ​​in the initial signal quality assessment set. Filtering may exclude assessment values ​​below the minimum acceptable threshold, and sorting is based on the magnitude of the assessment value or the specified priority rules.

[0097] Optionally, the sorting can be performed in descending order of signal quality evaluation values. The filtered and sorted signal quality evaluation values ​​are then associated and encapsulated with their corresponding electrical signal sampling timestamps and transmission mode categories. The sampling timestamps come from the original records of the electrical signal acquisition module, and the transmission mode categories come from the identification results of the signal preprocessing module. This association and encapsulation generates a structured data packet, which is the electrical signal quality set used for virtual printing. In specific implementations, the electrical signal quality set used for virtual printing can serve as input to the subsequent virtual printing driver module. The driver module determines the priority of data rendering or adopts different redundancy error correction strategies based on the signal quality levels reflected by each evaluation value in this set.

[0098] See Figure 5 This is a pie chart showing the distribution of Bluetooth transmission modes by category, illustrating the classification and distribution of common Bluetooth modes. The differences in percentage reflect the application prevalence of different modes: Bluetooth Classic mode has the widest range of applications due to its broad compatibility; Mesh mode, as a newer networking mode, currently has a lower application percentage. This chart is used to categorize Bluetooth systems, intuitively presenting the application percentage and positioning of different Bluetooth modes. It helps technical personnel quickly understand the ecosystem of Bluetooth technology and serves as a reference tool for mode selection in Bluetooth system design.

[0099] In one embodiment of the present invention, the print control module, as the core execution unit of the Bluetooth-connected protected data virtual print control system based on electrical signal measurement, has the core function of accurately generating corresponding control signals based on the electrical signal quality set constructed by the quality assessment output module, thereby driving the virtual print device to complete the printing operation that meets the signal quality requirements. The control signals include three categories: print enable command, print disable command, and print parameter adjustment command. The generation logic and execution process of each type of command strictly follow the preset signal quality judgment rules.

[0100] Before the print control module starts working, the preset configuration of the signal quality threshold range needs to be completed. This threshold range is set based on the characteristics of the Bluetooth transmission data protection type, the basic quality requirements of virtual printing, and the common signal quality fluctuation patterns of the Bluetooth transmission link. It is determined through a combination of system presets and manual fine-tuning. The preset threshold range includes a first threshold range, a second threshold range, and a preset tolerance. The first threshold range corresponds to the range with optimal signal quality, the second threshold range corresponds to the range with good signal quality but requiring optimization, and the preset tolerance is the lowest acceptable boundary for signal quality; below this tolerance, the signal quality is considered insufficient for printing requirements. For example, for virtual printing of text-based protected data, the first threshold range can be set to a signal quality evaluation value between 85 and 100 points (out of 100), the second threshold range can be set between 60 and 84 points, and the preset tolerance can be set to 60 points. This score division is only used to define the signal quality level and does not represent specific experimental test results; it is merely a reasonable range division to adapt to the print control logic.

[0101] Once the quality assessment output module completes the construction of the electrical signal quality set, it transmits the set to the print control module in real time. Upon receiving the set, the print control module first parses the data, extracting the signal quality assessment value corresponding to each signal sample. Simultaneously, it associates the value with the corresponding electrical signal sampling timestamp and transmission mode category to ensure that the generation of subsequent control signals matches the specific signal transmission period and mode. After parsing, the print control module compares each signal quality assessment value with a preset threshold range, triggering the corresponding control logic based on the comparison results.

[0102] If a signal quality assessment value falls within the first threshold range after comparison, it indicates that the electrical signal quality on the Bluetooth transmission path is at its optimal state during that period, with minimal signal distortion in both high-frequency and low-frequency components, and no significant interference or abnormalities during transmission. At this point, the print control module generates a print start command. This command includes a print start signal, default print parameter configuration, and corresponding sampling timestamps and transmission mode category identifiers. The default print parameters are determined based on the optimal configuration for virtual printing of this type of protected data. For example, the print resolution is set to standard high-definition level, the print data transmission rate uses the standard rate of the virtual printing device, and the print color mode is executed according to the original data settings. After the print start command is generated, it is sent to the virtual printing device through the system's internal control signal transmission channel. Upon receiving the command, the virtual printing device first verifies the time matching between the sampling timestamp in the command and the current print task. After confirming that there are no errors, it loads the default print parameters in the command, starts the printing process, and executes the virtual printing operation of the protected data according to the standard procedure. No additional adjustments to the print parameters are required throughout the process; the print output only needs to be completed according to the preset configuration in the command.

[0103] If the signal quality assessment value falls within the second threshold range after comparison, it indicates that the overall electrical signal quality during that period is good, but there is slight signal distortion or interference. Although this does not affect the integrity of the data, printing directly with the default parameters may result in poor output of some details. For example, image-protected data may appear slightly blurry, and text-based data may have unclear edges for some characters. In this case, the print control module generates a print parameter adjustment command. The generation of the print parameter adjustment command needs to be combined with the corresponding transmission mode category of the signal. For different Bluetooth transmission modes, the focus of the adjusted parameters varies. For example, when the transmission mode is Bluetooth Low Energy, the low-frequency components of the signal are relatively high. If the signal quality assessment value is within the second threshold range in this mode, the print parameter adjustment command prioritizes reducing the print rate. By slowing down the processing speed of the print data, time is reserved for subsequent error correction and optimization, reducing output errors caused by the mismatch between the signal transmission rate and the print rate. When the transmission mode is Bluetooth Enhanced Data Rate, the high-frequency components of the signal are more prominent. If they are within the second threshold range, the adjustment command prioritizes enabling the error correction coding function. Through the system's built-in error correction coding algorithm, slight signal distortions that may exist during transmission are corrected to ensure the accuracy of the print data. In addition, the print parameter adjustment command also includes a corresponding sampling timestamp. After receiving the command, the virtual printing device determines the print data segment corresponding to the adjustment command based on the timestamp and only adjusts the print parameters within that time segment. For other time segments, if the signal quality assessment value is within the first threshold range, the default parameters are still used for printing, achieving dynamic adaptation of print parameters.

[0104] If the signal quality assessment value is lower than the preset tolerance after comparison, it indicates that the electrical signal quality of Bluetooth transmission during that period is seriously substandard. The time domain offset of the high-frequency component or the frequency domain offset of the low-frequency component exceeds the acceptable range, which may indicate strong external interference, transmission link failure, or abnormal data transmission. Continuing to perform the printing operation under these circumstances may lead to distorted or missing printed data, or even the risk of leakage of sensitive protected data. Therefore, the print control module generates a print disable command. This command includes a print stop signal, a quality substandard indicator, the corresponding sampling timestamp, and transmission mode category information, and simultaneously triggers the system's built-in Bluetooth retransmission mechanism. After the print disable command is sent to the virtual printing device, the virtual printing device immediately stops the currently running printing operation and marks the corresponding print data segment as "pending retransmission" to avoid the output of unqualified data. Simultaneously, after the Bluetooth retransmission mechanism is triggered, the system sends a retransmission request to the Bluetooth transmission module, requesting the retransmission of the protection data corresponding to the sampling timestamp. Upon receiving the retransmission request, the Bluetooth transmission module restarts the electrical signal acquisition and transmission process for that period, regenerates the corresponding electrical signal quality set, and transmits it to the print control module for secondary evaluation until the signal quality evaluation value reaches the first or second threshold range. Then, the print control module generates the corresponding print command to drive the virtual printing device to perform the printing operation. If the signal quality evaluation value is still lower than the preset tolerance after multiple retransmissions, the print control module will continuously generate print disable commands and send a transmission anomaly alert to the system, reminding relevant personnel to check for hardware failures or persistent interference sources in the Bluetooth transmission link. The printing task will continue to be executed only after the transmission link is restored to normal.

[0105] Throughout the entire process of control signal generation and execution, the print control module records in real time the comparison results of each signal quality evaluation value, the type of control signal generated, the command sending time, and the response status of the virtual printing device, forming a complete print control log. This log is used only for internal process tracing and status monitoring and is not used for quantitative evaluation of system performance. Simultaneously, the print control module has a dynamic threshold range adaptation function. If, during continuous printing tasks, the signal quality evaluation value under a certain transmission mode consistently concentrates within a certain interval of the second threshold range, the system can fine-tune the threshold range corresponding to that transmission mode according to the actual situation. This ensures that the control logic can better adapt to the actual transmission scenario. However, the fine-tuning process must follow preset adjustment rules and must not exceed a reasonable quality level division range to ensure the stability and consistency of print control.

[0106] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0107] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A Bluetooth-connected protection data virtual printing control system based on electrical signal measurement, characterized in that, The system includes: The electrical signal acquisition module is used to acquire the transmission path electrical signal corresponding to the protection data transmitted via Bluetooth, and to perform multi-channel sampling on the transmission path electrical signal to obtain multiple sets of original electrical signal waveforms. The signal preprocessing module is used to preprocess the multiple sets of original electrical signal waveforms, extract the basic signal features from the multiple sets of original electrical signal waveforms, and identify the transmission mode category in the electrical signal based on the basic signal features. The signal decomposition and mapping module is used to decompose the multiple sets of original electrical signal waveforms according to the transmission mode category, separate the high-frequency components and low-frequency components in the electrical signal, and map the high-frequency components and the low-frequency components to a preset signal template library respectively. The offset calculation module is used to calculate the offset of the high-frequency component and the low-frequency component relative to the preset signal baseline based on the mapping result of the signal template library, and generate the signal status identifier of the high-frequency component and the low-frequency component according to the offset. The quality assessment output module is used to determine the signal quality assessment value of the high-frequency component and the low-frequency component based on the signal state identifier of the high-frequency component and the low-frequency component, and to construct an electrical signal quality set for virtual printing based on the signal quality assessment value. A print control module is used to generate control signals based on the electrical signal quality set, and drive a virtual printing device to perform printing operations based on the control signals, wherein the control signals include print enable / disable commands or print parameter adjustment commands.

2. The Bluetooth-connected protection data virtual printing control system based on electrical signal measurement according to claim 1, characterized in that, Methods for obtaining multiple sets of original electrical signal waveforms include: Set the sampling frequency and sampling period of the Bluetooth transmission channel, and continuously sample the Bluetooth transmission channel within a single sampling period; The continuously sampled electrical signals are arranged in chronological order to form an initial electrical signal sequence; The initial electrical signal sequence is normalized to eliminate amplitude differences caused by different transmission paths, resulting in multiple sets of original electrical signal waveforms.

3. The Bluetooth-connected protection data virtual printing control system based on electrical signal measurement according to claim 2, characterized in that, The methods for extracting the basic signal features from the multiple sets of original electrical signal waveforms include: Time-domain analysis is performed on multiple sets of original electrical signal waveforms to calculate the average amplitude, peak amplitude, and zero-crossing rate of the multiple sets of original electrical signal waveforms. Frequency domain transformation is performed on multiple sets of original electrical signal waveforms to obtain the spectral energy distribution of the multiple sets of original electrical signal waveforms; The basic signal characteristics of multiple sets of original electrical signal waveforms are formed by combining the average amplitude, peak amplitude, zero-crossing rate, and spectral energy distribution.

4. The Bluetooth-connected protection data virtual printing control system based on electrical signal measurement according to claim 1, characterized in that, The methods for identifying the transmission mode category in an electrical signal based on the aforementioned basic signal characteristics include: The basic signal characteristics are input into a preset transmission mode classification model, which includes various known Bluetooth transmission mode characteristics. Calculate the feature matching degree between basic signal characteristics and features of various known Bluetooth transmission modes; The transmission mode corresponding to the known Bluetooth transmission mode feature with the highest feature matching degree is determined as the transmission mode category in the electrical signal; The methods for calculating the feature matching degree between the basic signal features and various known Bluetooth transmission mode features include: The basic signal features and each of the known Bluetooth transmission mode features are used to construct corresponding feature vectors; Calculate the cosine similarity between the feature vector corresponding to the basic signal feature and the feature vector corresponding to each known Bluetooth transmission mode feature, and use it as the direction matching degree; Calculate the Euclidean distance between the feature vector corresponding to the basic signal feature and the feature vector corresponding to each known Bluetooth transmission mode feature, and convert it into a distance matching degree; For each known Bluetooth transmission mode feature, the corresponding direction matching degree and distance matching degree are weighted and summed to obtain the feature matching degree between the known Bluetooth transmission mode feature and the basic signal feature.

5. The Bluetooth-connected protection data virtual printing control system based on electrical signal measurement according to claim 4, characterized in that, The methods for performing signal decomposition on the multiple sets of original electrical signal waveforms include: Select the corresponding signal filter bank according to the transmission mode category in the electrical signal; The signal filter bank is used to filter multiple sets of original electrical signal waveforms to separate the high-frequency and low-frequency components in the electrical signal. The separated high-frequency and low-frequency components are reconstructed separately to obtain the reconstructed high-frequency and low-frequency signal waveforms.

6. The Bluetooth-connected protection data virtual printing control system based on electrical signal measurement according to claim 5, characterized in that, The implementation methods for mapping the high-frequency component and the low-frequency component to a preset signal template library include: The reconstructed high-frequency and low-frequency signal waveforms are compared with the standard high-frequency and standard low-frequency template waveforms stored in the signal template library for waveform similarity. Record the waveform similarity between the reconstructed high-frequency signal waveform and the standard high-frequency template waveform as the template matching degree of the high-frequency components; Record the waveform similarity between the reconstructed low-frequency signal waveform and the standard low-frequency template waveform as the template matching degree of the low-frequency component.

7. The Bluetooth-connected protection data virtual printing control system based on electrical signal measurement according to claim 6, characterized in that, The methods for generating the signal state identifiers of the high-frequency component and the low-frequency component include: Obtain the time-domain waveform and frequency-domain characteristics of the preset signal baseline; The time-domain difference between the waveform corresponding to the template matching degree of the high-frequency component and the time-domain waveform of the preset signal baseline is calculated to obtain the time-domain offset of the high-frequency component. The frequency domain difference between the waveform corresponding to the template matching degree of the low-frequency component and the frequency domain characteristics of the preset signal baseline is calculated to obtain the frequency domain offset of the low-frequency component. Based on the time-domain offset of the high-frequency component and the frequency-domain offset of the low-frequency component, signal state identifiers corresponding to the high-frequency component and the low-frequency component are generated respectively.

8. The Bluetooth-connected protection data virtual printing control system based on electrical signal measurement according to claim 7, characterized in that, The methods for determining the signal quality assessment values ​​of the high-frequency component and the low-frequency component include: Establish a correspondence between signal status identifiers and signal quality parameters, including signal-to-noise ratio threshold, waveform distortion tolerance, and baseline stability coefficient; Based on the signal status identifier of the high-frequency component, find the corresponding signal quality parameter, and calculate the signal quality evaluation value of the high-frequency component based on the found signal quality parameter. Based on the signal status identifier of the low-frequency component, the corresponding signal quality parameters are found, and the signal quality evaluation value of the low-frequency component is calculated based on the found signal quality parameters.

9. The Bluetooth-connected protection data virtual printing control system based on electrical signal measurement according to claim 1, characterized in that, Implementation methods for constructing an electrical signal quality set for virtual printing include: The signal quality assessment values ​​of high-frequency components and low-frequency components are integrated to form an initial signal quality assessment set. The virtual print format requirements for obtaining protected data are used to filter and sort the evaluation values ​​in the initial signal quality evaluation set according to the signal quality standards in the virtual print format requirements. The filtered and sorted signal quality evaluation values ​​are associated and encapsulated with their corresponding electrical signal sampling timestamps and transmission mode categories to generate an electrical signal quality set for virtual printing.

10. The Bluetooth-connected protection data virtual printing control system based on electrical signal measurement according to claim 1, characterized in that, The specific implementation methods for the printing control module to generate control signals include: A preset signal quality threshold range is defined, and the signal quality evaluation values ​​in the electrical signal quality set are compared with the threshold range. If the signal quality assessment value falls within the first threshold range, a print enable command is generated to control the virtual printing device to perform printing according to the default parameters. If the signal quality assessment value falls within the second threshold range, a printing parameter adjustment instruction is generated to control the virtual printing device to reduce the printing rate or enable error correction coding. If the signal quality assessment value is lower than the preset tolerance, a print disable command will be generated and the Bluetooth retransmission mechanism will be triggered.

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