Terrestrial digital television high-definition transmission system adaptive to various signal sources

Abstract

The invention discloses a terrestrial digital television high-definition transmission system adaptive to various signal sources, and the system comprises a signal source receiving module which is used for receiving a high-definition optical fiber signal and a high-definition satellite signal; the encoder is connected with the signal source receiving module and is used for encoding the HD-SDI signal into a video signal in an AVS + format; the transcoder is connected with the signal source receiving module and is used for transcoding the Dolby AC-3 accompanying sound into a DRA format; the switcher is used for receiving the DTMB code stream signals output by the encoder and the transcoder and carrying out signal switching according to preset switching logic to ensure stable transmission of the signals; and the transmitter is used for transmitting the switched DTMB code stream signal so as to realize terrestrial digital television broadcasting of the high-definition signal. According to the terrestrial digital television high-definition transmission system adaptive to the multiple signal sources, signals are efficiently coded and transcoded through the advanced coder and the advanced transcoder, and the transmission efficiency is improved while the signal quality is ensured.

Description

Technical Field

[0001] The present invention specifically relates to a high-definition terrestrial digital television transmission system adapted to multiple signal sources. Background Art

[0002] With the continuous development of digital television technology, terrestrial digital television broadcasting, as an important television transmission method, has been widely used. However, there are still some deficiencies in the existing terrestrial digital television transmission systems in terms of signal source adaptation, signal processing, transmission stability, and system reliability. For example, format differences of different signal sources may increase the complexity of signal processing, unstable factors during signal transmission may affect the viewing experience of viewers, and the fault diagnosis and maintenance efficiency of the system need to be improved. Therefore, there is a need for a high-definition terrestrial digital television transmission system that can adapt to multiple signal sources, efficiently process signals, stably transmit, and have good reliability. Summary of the Invention

[0003] The present invention provides a high-definition terrestrial digital television transmission system adapted to multiple signal sources to solve the above-mentioned technical problems, and specifically adopts the following technical solutions:

[0004] A high-definition terrestrial digital television transmission system adapted to multiple signal sources, comprising:

[0005] A signal source receiving module, configured to receive a high-definition optical fiber signal and a high-definition satellite signal, where the high-definition optical fiber signal is an HD-SDI signal, and the video format of the high-definition satellite signal is AVS+, and the audio format is Dolby AC-3;

[0006] An encoder: connected to the signal source receiving module, configured to encode the HD-SDI signal into a video signal in AVS+ format. The encoder includes a first power module, a first heat dissipation module, a first monitoring and display module, a first communication module, and a first signal processing module. The first signal processing module includes an HD-SDI / ASI board. The encoder separates the video, audio, and metadata information in the signal through an internal de-embedding module, performs AVS+ encoding and compression on the video signal, performs DRA encoding and compression on the audio signal, and finally synchronously multiplexes the encoded video and audio signals to generate a standard DTMB bitstream signal;

[0007] The transcoder, connected to the signal source receiving module, is used to transcode Dolby AC-3 audio into DRA format. The transcoder includes a second power module, a second heat dissipation module, a second monitoring and display module, a second communication module, and a second signal processing module. The second signal processing module includes an AC-3 / PCM board and a PCM / DRA board. The transcoder decodes the AC-3 signal into a PCM digital baseband through the AC-3 / PCM board, and then encodes the PCM audio into DRA format through the PCM / DRA board, and multiplexes it synchronously with the video signal to generate a standard DTMB bitstream signal;

[0008] The switcher, connected to the encoder and the transcoder, is used to receive the DTMB bitstream signals output by the encoder and the transcoder, and perform signal switching according to the preset switching logic to ensure the stable transmission of the signals;

[0009] The transmitter, connected to the switcher, is used to transmit the switched DTMB bitstream signal to achieve terrestrial digital television broadcasting of high-definition signals.

[0010] Further, the AVS+ encoding and compression process of the encoder includes:

[0011] Allocating frame types, including I frames, P frames, and B frames;

[0012] Performing intra-frame prediction to generate residual data;

[0013] Performing inter-frame prediction to reduce temporal redundancy;

[0014] Performing integer discrete cosine transform on the residual data to separate low-frequency and high-frequency components;

[0015] Performing dynamic quantization to compress high-frequency video redundancy and control the bit rate;

[0016] Performing entropy encoding to further compress the bit rate.

[0017] Further, the DRA audio encoding and compression process of the encoder includes:

[0018] Preprocessing, including stereo channel mapping, dynamic range compression, and loudness normalization;

[0019] Converting the time-domain PCM signal to the frequency domain through an improved discrete cosine transform;

[0020] Performing dynamic bit allocation, preferentially retaining the mid-low frequency bands that are more sensitive to the human ear;

[0021] Performing non-uniform quantization of the frequency domain coefficients and compressing them with Huffman coding;

[0022] Encapsulating the DRA frame header.

[0023] Further, the AC-3 decoding PCM digital baseband process of the transcoder includes:

[0024] Find the starting position of the frame through the synchronization code 0x0B77 in its fixed 16-bit synchronization header;

[0025] Parse the static metadata to obtain the channel configuration and sampling rate of the audio;

[0026] Separate the frequency-domain coefficients and reconstruct the spectral envelope of the signal;

[0027] Dynamically allocate bits and decode the mantissa;

[0028] Convert the frequency-domain coefficients to time-domain PCM samples using the inverse modified discrete cosine transform;

[0029] Overlap and add an overlap window to eliminate block effects.

[0030] Further, the process of encoding the PCM audio of the transcoder into the DRA format includes:

[0031] Encode the PCM audio into the DRA format, and the specific process is the same as the audio DRA encoding process in the encoder;

[0032] The AVS+ video and metadata demultiplexed in the AC-3 / PCM board are sent to the PCM / DRA board for caching;

[0033] When constructing the DRA signal, restore the original timestamp to the DRA frame header;

[0034] According to the timestamp of the read video and the DRA audio frame header after encoding, merge the bitstreams with the corresponding timestamps to ensure audio-visual synchronization.

[0035] Further, the switch has an automatic switching function, which can automatically select the optimal link for signal transmission according to the signal quality of the main link and the backup link to ensure the stability and continuity of the signal.

[0036] Further, the automatic switching function of the switch is implemented based on a signal quality evaluation module. The signal quality evaluation module can monitor the signal strength, bit error rate, and delay of the main link and the backup link in real time, and automatically trigger a switching operation according to a preset threshold. The signal quality evaluation module includes:

[0037] A signal parameter acquisition unit for real-time acquisition of the signal strength, bit error rate, and delay of the main link and the backup link;

[0038] A signal quality scoring unit that calculates the signal quality scores of the main link and the backup link according to the collected parameters according to a preset weight;

[0039] The handover decision unit determines whether to trigger a handover operation based on the signal quality score and a preset handover threshold, and controls the switch to perform the corresponding handover action.

[0040] Furthermore, the system further includes an intelligent fault diagnosis module, which can monitor the operating status of each component of the system in real time, and automatically perform fault diagnosis and alarm when an abnormality is detected, so as to repair the fault in time and ensure the stable operation of the system.

[0041] Furthermore, the intelligent fault diagnosis module has a self-learning function, which can automatically optimize the fault diagnosis algorithm according to historical fault data, improve the accuracy and efficiency of fault diagnosis. The self-learning function includes:

[0042] The fault data collection unit is used to collect the fault data of each component of the system, including the fault type, occurrence time, and duration.

[0043] The fault mode analysis unit analyzes the collected fault data to identify common fault modes and associated factors.

[0044] The algorithm optimization unit automatically adjusts the parameters of the fault diagnosis algorithm according to the results of the fault mode analysis, optimizes the diagnostic logic, and improves the accuracy and response speed of fault diagnosis.

[0045] Furthermore, the intelligent fault diagnosis module can also communicate with an external maintenance system, transmit the fault information to the maintenance personnel in real time, and receive the remote instructions of the maintenance personnel to achieve remote fault handling and system maintenance. The communication function includes:

[0046] The communication interface unit provides a communication interface with the external maintenance system, supporting wired or wireless communication methods.

[0047] The fault information transmission unit transmits the fault diagnosis results and related data to the external maintenance system in real time, including the fault location, fault type, and recommended repair measures.

[0048] The remote instruction receiving unit receives the remote instructions sent by the maintenance personnel through the external maintenance system and executes the corresponding operations, such as restarting the component, adjusting the parameters, and running the diagnostic program.

[0049] For the terrestrial digital TV high-definition transmission system adapted to multiple signal sources of the present application, the beneficial effects of the present invention are as follows:

[0050] The present invention provides a terrestrial digital TV high-definition transmission system adapted to multiple signal sources. The system can receive and process high-definition optical fiber signals and high-definition satellite signals, has strong adaptability, and improves the flexibility and application range of the system.

[0051] The present invention provides a terrestrial digital TV high-definition transmission system adaptable to multiple signal sources. Through advanced encoders and transcoders, the signals are efficiently encoded and transcoded, ensuring signal quality while improving transmission efficiency.

[0052] The present invention provides a terrestrial digital TV high-definition transmission system adaptable to multiple signal sources. The switch has an automatic switching function and can automatically select the optimal link according to signal quality, ensuring signal stability and continuity. Brief Description of the Drawings

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0054] Figure 1 It is a schematic diagram of a terrestrial digital TV high-definition transmission system adaptable to multiple signal sources of the present invention;

[0055] Figure 2 It is a schematic diagram of the encoder of a terrestrial digital TV high-definition transmission system adaptable to multiple signal sources of the present invention;

[0056] Figure 3 It is a schematic diagram of the transcoder of a terrestrial digital TV high-definition transmission system adaptable to multiple signal sources of the present invention. Detailed Description of the Embodiments

[0057] The following will describe in detail the embodiments of the present application. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals indicate the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and should not be construed as a limitation of the present application.

[0058] As Figure 1 shown is a terrestrial digital TV high-definition transmission system adaptable to multiple signal sources of the present application, including: a signal source receiving module, an encoder, a transcoder, a switch, and a transmitter. The design of this system aims to solve the deficiencies of existing terrestrial digital TV transmission systems in aspects such as signal source adaptation, signal processing, transmission stability, and system reliability. By integrating multiple key modules, the system can efficiently process multiple signal sources and ensure stable signal transmission and high-quality broadcasting.

[0059] The signal source receiving module is responsible for receiving high-definition fiber optic signals and high-definition satellite signals. The high-definition fiber optic signal adopts the HD-SDI format, and the video format of the high-definition satellite signal is AVS+ and the audio format is Dolby AC-3. The signal source receiving module is the first checkpoint of the system, and its function is to accurately receive high-definition signals from different channels. Due to its stability and high-bandwidth characteristics, the high-definition fiber optic signal is commonly used for high-quality signal transmission over short distances; while the high-definition satellite signal has a wide coverage range and is suitable for long-distance transmission. The receiving capabilities of these two signal sources enable the system to adapt to different transmission environments and requirements.

[0060] The encoder is connected to the signal source receiving module and is used to encode the HD-SDI signal into a video signal in the AVS+ format. As Figure 2 shown, the encoder includes a first power module, a first heat dissipation module, a first monitoring and display module, a first communication module (including a gigabit network interface, a USB interface, a hundred-megabit network control port, and an RS232 serial port), and a first signal processing module. The first signal processing module includes an HD-SDI / ASI board. The encoder separates the video, audio, and metadata information in the signal through an internal de-embedding module, encodes and compresses the video signal in the AVS+ format, encodes and compresses the audio signal in the DRA format, and finally synchronously multiplexes the encoded video and audio signals to generate a standard DTMB (Digital Television Multimedia Broadcasting) stream signal. The encoder is mainly responsible for converting the received HD-SDI signal into an AVS+ video signal that meets the terrestrial digital television broadcast standard. This process involves multiple complex steps, including signal de-embedding, encoding compression, and synchronous multiplexing. Through these steps, the encoder can ensure that the signal maintains high quality during the conversion process and meets the transmission standard.

[0061] The transcoder is connected to the signal source receiving module and is used to transcode the Dolby AC-3 audio into the DRA format. As Figure 3As shown in the figure, the transcoder includes a second power module, a second heat dissipation module, a second monitoring and display module, a second communication module (including a gigabit network interface, a USB interface, a hundred-megabit network control port, and an RS232 serial port), and a second signal processing module. The second signal processing module includes an AC-3 / PCM board and a PCM / DRA board. The transcoder decodes the AC-3 signal into a PCM digital baseband through the AC-3 / PCM board, and then encodes the PCM audio into the DRA format through the PCM / DRA board, and multiplexes it synchronously with the video signal to generate a standard DTMB bitstream signal. The main task of the transcoder is to process the audio signal and convert the Dolby AC-3 format accompaniment into the DRA format. This process requires precise signal processing capabilities to ensure that the audio signal does not suffer from distortion or quality degradation during the conversion process. The design of the transcoder takes into account the efficiency and stability of signal processing to meet the strict requirements for audio quality in terrestrial digital television broadcasting.

[0062] The switcher is connected to the encoder and the transcoder, and is used to receive the DTMB bitstream signals output by the encoder and the transcoder, and perform signal switching according to the preset switching logic to ensure the stable transmission of the signals. The function of the switcher is to select and switch between the signals output by the encoder and the transcoder. This function is crucial for ensuring the stable transmission of the signals. Especially when the main signal link fails or the signal quality deteriorates, the switcher can quickly switch to the backup link, thus ensuring the continuity of the signals.

[0063] The transmitter is connected to the switcher and is used to transmit the switched DTMB bitstream signal to achieve terrestrial digital television broadcasting of high-definition signals. The transmitter is responsible for transmitting the processed signal in the form of terrestrial digital television broadcasting. The design of the transmitter needs to consider the signal coverage, transmission quality, and compatibility with different receiving devices to ensure that viewers can receive high-quality high-definition television signals.

[0064] In the implementation manner of this application, the main function of the encoder is to encode the HD-SDI signal into a video signal in the AVS+ format and perform DRA encoding compression on the audio signal. Among them, the AVS+ encoding compression process of the encoder includes:

[0065] Frame types are allocated, including I-frames (key frames), P-frames (forward prediction frames), and B-frames (bidirectional prediction frames). Intra-frame prediction is performed to generate residual data. Inter-frame prediction is carried out to reduce temporal redundancy. Integer discrete cosine transform is applied to the residual data to separate low-frequency and high-frequency components. Dynamic quantization is performed to compress high-frequency video redundancy and control the bit rate. Entropy coding is carried out to further compress the bit rate. During the encoding process, frame type allocation is the basic step, which determines the encoding method of the video signal in the time series. Intra-frame prediction and inter-frame prediction techniques are used to reduce redundant information in the video signal, thereby improving the encoding efficiency. Discrete cosine transform and dynamic quantization are key steps, which can effectively compress the data volume of the video signal while maintaining the image quality. Entropy coding is the last step, which further optimizes the encoded data stream to make it more suitable for transmission.

[0066] In an embodiment of the present application, the DRA audio encoding and compression process of the encoder includes:

[0067] Preprocessing, including stereo channel mapping, dynamic range compression, and loudness normalization. The time-domain PCM signal is converted to the frequency domain through an improved discrete cosine transform. Dynamic bit allocation is performed, giving priority to retaining the mid-low frequency bands that are more sensitive to the human ear. Non-uniform quantization of the frequency-domain coefficients is carried out and compressed using Huffman coding. The DRA frame header is encapsulated to complete the audio encoding. The audio encoding process first performs preprocessing to optimize the characteristics of the audio signal. The improved discrete cosine transform converts the audio signal from the time domain to the frequency domain, which helps to encode more effectively. Dynamic bit allocation and non-uniform quantization techniques ensure that key information can be retained in the audio signal during the encoding process while removing unnecessary redundancy. Huffman coding further compresses the audio data to make it more suitable for transmission.

[0068] Timestamps are generated based on the time codes extracted from the HD-SDI signal, the AVS+ video and DRA audio are multiplexed, and independent PIDs (Packet Identifiers) are allocated to identify the audio and video. PSI / SI tables are inserted to indicate the encoding format and synchronization information. After encoding, the video and audio signals need to be synchronously multiplexed to ensure that they can be correctly synchronized during transmission. The generation and insertion of timestamps are key steps in synchronous multiplexing, which ensures that the video and audio signals can be accurately restored at the decoding end. The insertion of PSI / SI tables provides the necessary information for the decoding device to correctly parse and display the signals.

[0069] In an embodiment of the present application, the main function of the transcoder is to transcode Dolby AC-3 audio to the DRA format. The AC-3 decoding PCM digital baseband process of the transcoder includes:

[0070] Find the start position of the frame through the synchronization code 0x0B77 in its fixed 16-bit synchronization header. Parse the static metadata to obtain the channel configuration and sampling rate of the audio. Separate the frequency-domain coefficients and reconstruct the spectral envelope of the signal. Dynamically allocate bits and decode the mantissa. Use the inverse modified discrete cosine transform on the frequency-domain coefficients to convert them into time-domain PCM samples. Overlap and add windowing to eliminate blocking artifacts. During the decoding process, the identification of the synchronization header is a crucial step, which ensures the correct decoding of the signal. The parsing of metadata provides the basic information of the audio signal, which is crucial for subsequent processing. The separation and reconstruction of the frequency-domain coefficients are the core of the decoding process, which ensures the quality of the audio signal. The inverse modified discrete cosine transform converts the audio signal from the frequency domain back to the time domain, preparing for subsequent encoding.

[0071] In an embodiment of the present application, the process of encoding PCM audio into the DRA format by the transcoder includes:

[0072] Encode the PCM audio into the DRA format, and the specific process is the same as the audio DRA encoding process in the encoder. The AVS+ video and metadata demultiplexed from the AC-3 / PCM board are sent to the PCM / DRA board for caching. When constructing the DRA signal, the original timestamp is restored to the DRA frame header. According to the timestamp of the read video and the DRA audio frame header after encoding, the bitstreams corresponding to the same timestamp are merged to ensure audio-video synchronization. During the encoding process, the PCM audio signal is converted into the DRA format, and this process needs to ensure the quality and synchronization of the audio signal. The restoration of the timestamp and the merging of the bitstreams are the key steps to ensure audio-video synchronization, which guarantee the integrity of the signal during transmission and reception.

[0073] In an embodiment of the present application, the main function of the switch is to receive the DTMB bitstream signals output by the encoder and the transcoder, and perform signal switching according to the preset switching logic to ensure the stable transmission of the signals. The switch has an automatic switching function, which can automatically select the optimal link for signal transmission according to the signal quality of the main link and the backup link, ensuring the stability and continuity of the signal. The design of the switch takes into account the stability and reliability of signal transmission. The automatic switching function enables the system to quickly switch to the backup link when the main link fails, thus ensuring the uninterrupted transmission of the signal.

[0074] In an embodiment of the present application, the automatic switching function of the switch is implemented based on a signal quality evaluation module. The signal quality evaluation module can monitor the signal strength, bit error rate, and delay of the main link and the backup link in real time, and automatically trigger the switching operation according to the preset threshold. The signal quality evaluation module includes: a signal parameter acquisition unit, a signal quality scoring unit, and a switching decision unit.

[0075] The signal parameter acquisition unit is used to collect the signal strength, bit error rate, and latency of the primary link and the backup link in real time.

[0076] The signal quality scoring unit calculates the signal quality scores of the primary link and the backup link according to the collected parameters and the preset weights. The signal quality scoring unit obtains the comprehensive score of the signal quality through weighted calculation of the collected parameters. This scoring mechanism enables the system to quantify the signal quality and provide a basis for handover decisions.

[0077] The handover decision unit decides whether to trigger a handover operation according to the signal quality score and the preset handover threshold, and controls the switch to perform the corresponding handover action.

[0078] When the signal quality score of the primary link is lower than the preset threshold, the switch automatically switches the signal to the backup link to ensure the stability and continuity of the signal.

[0079] In the embodiment of the present application, the system further includes an intelligent fault diagnosis module, which can monitor the operating status of each component of the system in real time, and automatically perform fault diagnosis and alarm when an anomaly is detected, so as to repair the fault in time and ensure the stable operation of the system.

[0080] In the embodiment of the present application, the intelligent fault diagnosis module has a self-learning function, which can automatically optimize the fault diagnosis algorithm according to historical fault data, improve the accuracy and efficiency of fault diagnosis. The self-learning function includes: a fault data collection unit, a fault mode analysis unit, and an algorithm optimization unit.

[0081] The fault data collection unit is used to collect the fault data of each component of the system, including the fault type, occurrence time, and duration. The fault data collection unit is the basis of the self-learning function, and it provides the fault data of each component of the system. These data are crucial for subsequent fault mode analysis and algorithm optimization.

[0082] The fault mode analysis unit analyzes the collected fault data to identify common fault modes and associated factors. The fault mode analysis unit identifies common fault modes and associated factors by analyzing the collected fault data. This analysis process provides a basis for algorithm optimization, enabling the system to better handle faults.

[0083] The algorithm optimization unit automatically adjusts the parameters of the fault diagnosis algorithm according to the results of the fault mode analysis, optimizes the diagnostic logic, and improves the accuracy and response speed of the fault diagnosis. The algorithm optimization unit automatically adjusts the parameters of the diagnostic algorithm according to the results of the fault mode analysis. This optimization process improves the accuracy and response speed of the fault diagnosis, thereby further improving the reliability of the system.

[0084] In an embodiment of the present application, the intelligent fault diagnosis module can also communicate with an external maintenance system, transmit fault information to maintenance personnel in real time, and receive remote instructions from maintenance personnel to achieve remote fault handling and system maintenance. The communication function includes: a communication interface unit, a fault information transmission unit, and a remote instruction receiving unit.

[0085] The communication interface unit provides a communication interface with the external maintenance system and supports wired or wireless communication methods. The communication interface unit is the basis of the communication function. It provides a communication interface with the external maintenance system. This interface supports multiple communication methods, enabling the system to communicate with the maintenance system flexibly.

[0086] The fault information transmission unit transmits the fault diagnosis results and related data to the external maintenance system in real time, including the fault location, fault type, and recommended repair measures. The fault information transmission unit is responsible for transmitting the fault diagnosis results and related data to the external maintenance system in real time. This function enables maintenance personnel to understand the system status in a timely manner, thereby improving the maintenance efficiency.

[0087] The remote instruction receiving unit receives remote instructions sent by maintenance personnel through the external maintenance system and executes corresponding operations, such as restarting components, adjusting parameters, and running diagnostic programs. The remote instruction receiving unit enables maintenance personnel to send remote instructions through the external maintenance system, thereby achieving remote fault handling and system maintenance. This function improves the maintenance efficiency of the system and reduces the maintenance cost.

[0088] Through the above detailed technical solutions, the ground digital TV high-definition transmission system of the present invention can achieve the adaptation of multiple signal sources, efficient signal processing, stable transmission, and intelligent fault diagnosis, significantly improving the reliability and maintenance efficiency of the system, and providing more stable and efficient technical support for ground digital TV broadcasting.

[0089] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art of this industry should understand that the above embodiments do not limit the present invention in any form. Any technical solutions obtained by using equivalent replacements or equivalent transformations fall within the protection scope of the present invention.

Claims

1. A terrestrial digital television high-definition transmission system adapted to multiple signal sources, characterized in that, Including: A signal source receiving module, which is used to receive high-definition fiber optic signals and high-definition satellite signals. The high-definition fiber optic signal is an HD-SDI signal, and the video format of the high-definition satellite signal is AVS+ and the audio format is Dolby AC-3; An encoder, connected to the signal source receiving module, which is used to encode the HD-SDI signal into a video signal in AVS+ format. The encoder includes a first power supply module, a first heat dissipation module, a first monitoring and display module, a first communication module, and a first signal processing module. The first signal processing module includes an HD-SDI / ASI board. The encoder separates the video, audio, and metadata information in the signal through an internal de-embedding module, encodes and compresses the video signal in AVS+, encodes and compresses the audio signal in DRA, and finally synchronously multiplexes the encoded video and audio signals to generate a standard DTMB stream signal; A transcoder, connected to the signal source receiving module, which is used to transcode the Dolby AC-3 audio into DRA format. The transcoder includes a second power supply module, a second heat dissipation module, a second monitoring and display module, a second communication module, and a second signal processing module. The second signal processing module includes an AC-3 / PCM board and a PCM / DRA board. The transcoder decodes the AC-3 signal into a PCM digital baseband through the AC-3 / PCM board, then encodes the PCM audio into DRA format through the PCM / DRA board, and synchronously multiplexes it with the video signal to generate a standard DTMB stream signal; A switch, connected to the encoder and the transcoder, which is used to receive the DTMB stream signals output by the encoder and the transcoder, and perform signal switching according to a preset switching logic to ensure stable signal transmission; A transmitter, connected to the switch, which is used to transmit the switched DTMB stream signal to realize terrestrial digital TV broadcasting of high-definition signals.

2. The terrestrial digital TV high-definition transmission system adapted to multiple signal sources according to claim 1, characterized in that The AVS+ encoding and compression process of the encoder includes: Allocating frame types, including I frames, P frames, and B frames; Performing intra-frame prediction to generate residual data; Performing inter-frame prediction to reduce temporal redundancy; Performing integer discrete cosine transform on the residual data to separate low-frequency and high-frequency components; Performing dynamic quantization to compress high-frequency video redundancy and control the bit rate; Performing entropy encoding to further compress the bit rate.

3. The terrestrial digital TV high-definition transmission system adapted to multiple signal sources according to claim 1, characterized in that The DRA audio encoding and compression process of the encoder includes: Preprocessing, including stereo channel mapping, dynamic range compression, and loudness normalization; Converting the time-domain PCM signal to the frequency domain through an improved discrete cosine transform; Performing dynamic bit allocation, preferentially retaining the mid-low frequency bands that are more sensitive to the human ear; Performing non-uniform quantization of the frequency domain coefficients and compressing them with Huffman coding; Encapsulating the DRA frame header.

4. The terrestrial digital TV high-definition transmission system adapted to multiple signal sources according to claim 1, characterized in that The AC-3 decoding to PCM digital baseband process of the transcoder includes: Find the start position of the frame through the synchronization code 0x0B77 in its fixed 16-bit synchronization header; Parse the static metadata to obtain the channel configuration and sampling rate of the audio; Separate the frequency-domain coefficients and reconstruct the spectral envelope of the signal; Dynamically allocate bits and decode the mantissa; Use the inverse modified discrete cosine transform on the frequency-domain coefficients to convert them into time-domain PCM samples; Overlap and add an overlapping window to eliminate block effects.

5. The terrestrial digital TV high-definition transmission system adapted to multiple signal sources according to claim 1, wherein The process of encoding the PCM audio of the transcoder into the DRA format includes: Encode the PCM audio into the DRA format, and the specific process is the same as the audio DRA encoding process in the encoder; The AVS+ video and metadata de-embedded in the AC-3 / PCM board are sent to the PCM / DRA board for caching; When constructing the DRA signal, restore the original timestamp to the DRA frame header; According to the timestamp of the read video and the DRA audio frame header after encoding, merge the bitstreams with the corresponding timestamps to ensure audio-visual synchronization.

6. The terrestrial digital TV high-definition transmission system adapted to multiple signal sources according to claim 1, wherein The switch has an automatic switching function and can automatically select the optimal link for signal transmission according to the signal quality of the main link and the backup link to ensure the stability and continuity of the signal.

7. The terrestrial digital TV high-definition transmission system adapted to multiple signal sources according to claim 6, wherein The automatic switching function of the switch is implemented based on a signal quality evaluation module. The signal quality evaluation module can real-time monitor the signal strength, bit error rate, and delay of the main link and the backup link, and automatically trigger a switching operation according to a preset threshold. The signal quality evaluation module includes: A signal parameter acquisition unit for real-time acquiring the signal strength, bit error rate, and delay of the main link and the backup link; A signal quality scoring unit for calculating the signal quality scores of the main link and the backup link according to the acquired parameters according to preset weights; A switching decision unit for deciding whether to trigger a switching operation according to the signal quality score and a preset switching threshold, and controlling the switch to perform the corresponding switching action.

8. The terrestrial digital TV high-definition transmission system adapted to multiple signal sources according to claim 1, wherein The system further includes an intelligent fault diagnosis module that can real-time monitor the operating status of each component of the system and automatically perform fault diagnosis and alarm when an abnormality is detected, so as to repair the fault in time and ensure the stable operation of the system.

9. The terrestrial digital TV high-definition transmission system adapted to multiple signal sources according to claim 8, wherein The intelligent fault diagnosis module has a self-learning function and can automatically optimize the fault diagnosis algorithm according to historical fault data to improve the accuracy and efficiency of fault diagnosis. The self-learning function includes: A fault data collection unit for collecting the fault data of each component of the system, including the fault type, occurrence time, and duration; A fault mode analysis unit for analyzing the collected fault data to identify common fault modes and associated factors; The algorithm optimization unit automatically adjusts the parameters of the fault diagnosis algorithm according to the results of the fault mode analysis, optimizes the diagnosis logic, and improves the accuracy and response speed of fault diagnosis.

10. The ground digital TV high-definition transmission system adapted to multiple signal sources according to claim 9, characterized in that the intelligent fault diagnosis module can also communicate with an external maintenance system, transmit fault information to maintenance personnel in real time, and receive remote instructions from maintenance personnel to achieve remote fault handling and system maintenance. The communication function includes: A communication interface unit provides a communication interface with an external maintenance system and supports wired or wireless communication methods; A fault information transmission unit transmits the fault diagnosis results and relevant data to an external maintenance system in real time, including the fault location, fault type, and recommended repair measures; A remote instruction receiving unit receives remote instructions sent by maintenance personnel through an external maintenance system and performs corresponding operations, such as restarting components, adjusting parameters, and running diagnostic programs.

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