WO2018113742A1

WO2018113742A1 - Signal transmission method and network system

Info

Publication number: WO2018113742A1
Application number: PCT/CN2017/117748
Authority: WO
Inventors: 雷俊鹏; 罗俊; 鲁珣; 刘杰
Original assignee: 华为技术有限公司
Priority date: 2016-12-24
Filing date: 2017-12-21
Publication date: 2018-06-28
Also published as: CN106657070A; CN106657070B

Abstract

A network system, comprising a decoding unit, an optical transmitter (TX), a digital/analogue converter, an FM modulator, an optical receiver (RX) and an FM receiver. The decoding unit is used for receiving a transmission stream, obtaining a pulse code modulation (PCM) code stream according to the transmission stream, and providing the PCM code stream to the TX. The TX is used for converting the PCM code stream into a digital optical signal, and sending the digital optical signal to the RX via a digital optical fibre. The RX is used for receiving the PCM code stream, and performing photoelectric conversion on the PCM code stream to obtain a digital electrical signal. The FM modulator is used for modulating the digital electrical signal, and sending the digital electrical signal to the digital/analogue converter. The digital/analogue converter is used for converting the digital electrical signal into an analogue signal, and providing the analogue signal to the FM receiver. The FM receiver is used for receiving the analogue signal.

Description

Signal transmission method and network system

Technical field

The present application belongs to the field of communication technologies, and relates to a method and network system for transmitting signals.

Background technique

The Community Antenna Television (CATV) is used to carry broadcast television signals. As shown in FIG. 1 , in a Hybrid Fiber-Coaxial (HFC) network, a Frequency Modulation (FM) modulator receives a Transport Stream (TS), and modulates the TS to obtain a radio frequency. (Radio Frequency, RF) signal, the optical transmitter TX1 sends the RF signal to the optical receiver RX1, RX1 in the optical node (Finter Node, FN) via the analog optical fiber, and photoelectrically converts the received RF signal to the modulation device. The FM signal is obtained after modulation, and the FM signal arrives at the FM receiver 1 and/or the FM receiver 2 via an amplifier and a coaxial cable.

As network technology shifts from analog technology to digital technology, cable television networks are also used to implement Internet services. As shown in Figure 2, the HUB room equipment receives FM signals and data. The data, such as video and broadband data, is modulated into an RF signal, and the RF signal is mixed with the RF signal corresponding to the data in the RF signal mixer, and after electrical/optical conversion, is sent to the RX1 of the FN through the TX1 and the analog fiber. After the FN completes the optical/electrical conversion, it is transmitted to the user through the coaxial distribution network. The branch distributor separates the FM signal from the RF signal, sends the FM signal to the FM receiver, and sends the RF signal to the Cable Modem (CM). The CM demodulates the received RF signal and sends it to the user. The CM also modulates the data sent by the user to the HUB equipment room and sends it to the FN. The TX2 of the FN performs electrical/optical conversion on the data sent by the user, and then sends it to the RX2 and HUB equipment room through the analog optical fiber, thereby providing video and broadband access to the user. Business. A coaxial network is a network that shares media. The coaxial network consists of a coaxial cable, an amplifier, and a branch distributor.

With the development of technology, the analog optical fiber is replaced by a digital optical fiber or a passive optical network (PON), and an optical line terminal (OLT) communicates with an optical network unit (ONU) through a PON. As shown in FIG. 3, in order to transmit the FM signal through the PON transmission of the HFC network, the FM modulator modulates the received TS to obtain an RF signal corresponding to the TS, and a Narrowband Digital Forward (NDF) device NDF. -1 samples the RF signal output by the FM modulator for analog/digital (A/D) conversion to obtain a digital signal, and sends the obtained digital signal to the OLT, and the OLT transmits the digital signal through the digital optical fiber. To FN. After the optical receiver in the FN receives the optical signal sent by the OLT, the NDF-2 of the FN performs a digital/analog (Digital/Analog, D/A) conversion on the received digital signal to obtain an analog signal, and the analog signal arrives through the amplifier. The FM receiver, which broadcasts the received analog signal to the user.

However, in this technology, network costs are increased due to the need to increase NDF-1 and NDF-2.

Summary of the invention

Embodiments of the present invention provide a network system and method of transmitting signals.

A first aspect of an embodiment of the present invention provides a network system including a decoding unit, an optical transmitter TX, an FM modulator, a digital/analog converter, an optical receiver RX, and an FM receiver. The decoding unit receives the transport stream and obtains a pulse code modulated PCM code stream according to the transport stream and provides the PCM code stream to the TX; the TX converts the PCM code stream into a digital optical signal and transmits it to the RX via the digital optical fiber Receiving, by the RX, the digital optical signal and photoelectrically converting the digital optical signal stream to obtain a digital electrical signal, and transmitting the digital electrical signal to the FM modulator; the FM modulator modulating the digital electrical signal And transmitting the modulated digital electrical signal to the digital to analog converter, the digital to analog converter converting the modulated digital electrical signal into an analog signal and providing the analog signal to the FM receiver; The FM receiver receives the analog signal.

In the network system, the decoding unit decodes the received transport stream to obtain a PCM code stream, and uses the digital optical fiber to transmit the digital optical signal corresponding to the PCM code stream to the peer device, and can fully utilize the existing network system to transmit the transport stream. In particular, FM audio helps reduce the cost of FM audio transmission. In addition, the network system can support the full digital transformation of the HFC network, save the trunk fiber, save the investment of analog equipment, reduce the construction and operation and maintenance costs of the customer, and support the flexible planning of the FM signal spectrum on the Cable network.

In an embodiment, the network system may further include a frequency shifter between the FM modulator and the digital-to-analog converter and an FM between the digital-to-analog converter and the FM receiver Adapter; the frequency shifter carries the digital electrical signal in a digital signal carried by a first spectrum segment; the digital-to-analog converter receives a digital electrical signal carried by the first frequency segment obtained by the frequency shifter Converting to an analog signal carried by the first spectrum segment; the FM adapter is configured to convert the analog signal carried by the first spectrum segment into an analog signal carried by the second spectrum segment that the FM receiver can receive. In this way, the idle spectrum segment can be flexibly used to carry the analog signal sent to the FM receiver, especially the FM audio signal; when the analog signal is about to reach the FM receiver, the analog signal carried on the idle spectrum segment is converted by the FM adapter. The spectrum segment can be received by the FM receiver so that the FM receiver can receive the analog signal.

In an embodiment, the transport stream includes signals of a plurality of programs, the network system further includes a demultiplexing unit, the demultiplexing unit is configured to demultiplex the transport stream to obtain the plurality of The signal of each program in the signal of the program is forwarded to the decoding unit for processing the audio signal of each program.

In one embodiment, the transport stream comprises a Moving Picture Experts Group MPEG audio signal. More specifically, the format of the audio signal follows MPEG-1 or MPEG-2 or MPEG-4 or MPEG-7 or MPEG-21.

A second aspect of the embodiments of the present invention provides a method for transmitting a signal, according to which a local device including an optical line terminal OLT receives a transport stream, and obtains a PCM code stream according to the transport stream, the local device is digital fiber-optic The peer device including the optical network unit ONU transmits a message including the PCM code stream, so that the peer device that receives the message converts the PCM code stream into an analog signal and sends the analog signal to the FM receiver. In an embodiment, the message is an Ethernet message or an Internet Protocol IP message or a User Datagram Protocol UDP message or a Real-Time Transport Protocol (RTP) message.

In an embodiment, before the local device receives the transport stream, the method further comprises: demultiplexing the transport stream to obtain a signal of a single program, the transport stream comprising signals of a plurality of programs;

In one embodiment, the local device obtains a PCM code stream from the transport stream, comprising: obtaining the PCM code stream by decoding a signal of the single program.

In one embodiment, the transport stream comprises a Moving Picture Experts Group MPEG audio signal. Specifically, the format of the audio signal follows MPEG-1 or MPEG-2 or MPEG-4 or MPEG-7 or MPEG-21.

Optionally, in an embodiment of the present application, a network system includes a decoding unit, an optical line terminal OLT, an optical network unit ONU, a frequency modulation FM modulator, a digital/analog converter, and an FM receiver, where: The decoding unit is configured to receive a transport stream, obtain a pulse code modulated PCM code stream according to the transport stream, and provide the PCM code stream to the TX; the OLT is configured to encapsulate the PCM code in a message and send To the ONU, the message is an Internet Protocol IP packet or a real-time transport protocol RTP message or an Ethernet packet; the ONU is configured to receive an Ethernet packet or an IP packet or an RTP packet that carries the PCM code stream. And converting the Ethernet message or the IP message or the RTP message into a digital electrical signal, sending the signal to the digital-to-analog converter, and transmitting the digital electrical signal to the FM modulator; An FM modulator for modulating the digital electrical signal and transmitting the modulated digital electrical signal to the digital to analog converter; the digital to analog converter for converting the digital electrical signal to an analog signal and to the An FM receiver provides the analog signal; according to the FM receiver Receiving the analog signal.

Optionally, the OLT includes a communication interface and a package module, where the communication interface is configured to receive a pulse code modulated PCM code stream and send the PCM code stream to the package module; The PCM code stream is encapsulated into a message; the communication interface is further configured to send the message to the optical network unit ONU of the opposite end.

Optionally, the optical network unit ONU includes a communication interface and a decapsulation module, wherein the communication interface is configured to receive a packet sent by the optical line terminal OLT, where the packet includes a pulse code modulated PCM code stream; The module is configured to parse the message to obtain the PCM code stream; the communication interface is further configured to send the PCM code stream to the FM receiver after frequency modulation FM modulation and digital-to-analog conversion.

Optionally, the packet is an Ethernet packet or an Internet Protocol IP packet or a User Datagram Protocol UDP packet or a Real-Time Transport Protocol (RTP) packet.

DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the present invention, Those skilled in the art can also obtain other drawings based on these drawings without paying for creative labor.

1 is a schematic diagram of an HFC network;

2 is a schematic diagram of another HFC network;

3 is a schematic diagram of a network including a PON;

4a is a schematic flow chart of a method of forming a transport stream;

4b is a schematic structural diagram of a transport stream packet;

4c is a schematic structural diagram of a header of a transport stream packet in FIG. 4b;

FIG. 5 is a schematic structural diagram of a network system according to an embodiment of the present application;

FIG. 5b is a schematic structural diagram of another network system according to an embodiment of the present application;

FIG. 5c is a schematic structural diagram of still another network system according to an embodiment of the present application;

FIG. 5 is a schematic structural diagram of still another network system according to an embodiment of the present application;

5e is a schematic structural diagram of still another network system according to an embodiment of the present application;

FIG. 5f is a schematic structural diagram of a packet according to an embodiment of the present application;

FIG. 6 is a schematic flowchart diagram of a method for transmitting a signal according to an embodiment of the present application.

detailed description

The technical solutions in the embodiments of the present invention will be described below with reference to the accompanying drawings in the embodiments of the present invention.

As shown in FIG. 4a, in the multimedia information and communication system, after the video and audio data are encoded by the source, the program must be multiplexed with the auxiliary data to form an elementary stream (ES). The ES is packaged to form a packetized Elementary Stream (PES). Subsequently, PESs representing different video and audio signals are sent to a transport multiplexer for system multiplexing, which are combined into a program stream (PS) in a Program Stream (PS) multiplexer, or in a transport stream (Transport) The Stream, TS) multiplexers are combined into TSs. PS and TS are two types of data streams in digital video systems, defined by the MPEG-2 system layer. H.264 uses the same system layer as MPEG-2, and thus uses both PS and TS data streams. The PS is composed of PES, a set of basic components of video, audio and data, and the basic components in the PES have the same relative time relationship. The PS packet length is variable and relatively long, and is generally used in an environment where transmission errors, storage, and local playback are relatively small. TS is a collection of PS or ES. The PS or ES can be multiplexed together in a non-specific relationship. The TS packet length is 188 bytes. TS is usually used in environments with relatively large bit errors such as network transmission, such as storage or transmission in packet loss and noise media. TS and PS can be converted to each other. But TS is not a subset or superset of PS, and PS is not a subset or superset of TS. The transport stream referred to in this application can be applied to ITU-T Rec. H.262 or ISO/IEC 13818-2 or ISO/IEC 13818-3 or other environments with relatively large bit errors.

Optionally, as shown in Figure 4b, the TS packet is 188 bytes in length. The TS packet includes a 4-byte TS packet header and data. The TS packet header is typically 4 bytes and the data portion is up to 184 bytes. As shown in FIG. 4c, the TS packet header includes a 1-byte sync byte, a 1-bit transmission error indicator, a 1-bit payload unit start indicator, a 1-bit transmission priority identifier, and a 13-bit packet. A Pid, a 2-bit transmission scrambling control field, a 2-bit adaptive control field, and a 4-bit continuous counter are identified. Alternatively, the TS packet may further include a 1-byte extended self-applied area and a 1-byte adaptive area flag.

As shown in FIG. 5a, the present application provides a network system including a decoding unit, an optical transmitter TX, a digital/analog converter (D/A converter), an optical receiver RX, an FM modulator, and an FM receiver. machine. The optical transmitter TX communicates with the optical receiver RX via a digital optical fiber or PON. When only the audio stream is included in the transport stream, the decoding unit receives the transport stream, and decodes the transport stream to obtain a Moving Pictures Experts Group (MPEG) audio signal, and performs MPEG audio decoding on the MPEG audio signal to obtain a pulse. Pulse Code Modulation (PCM) code stream. The decoding unit sends the PCM bitstream to the optical transmitter TX, and the optical transmitter TX converts the PCM code stream into a digital optical signal and sends it to the passive optical network (PON) or digital optical fiber. Optical receiver RX. The optical receiver RX performs optical/electrical conversion on the received digital optical signal to obtain a digital electrical signal corresponding to the TS. The optical receiver RX sends the digital electrical signal to the FM modulator, and the FM modulator modulates the digital electrical signal to a frequency band that the FM receiver can receive and sends it to the D/A converter. The D/A converter performs D/A conversion on the digital electrical signal to obtain an analog electrical signal, and transmits the analog electrical signal to the FM receiver.

In the network system, the decoding unit decodes the received transport stream to obtain a PCM code stream, and uses the digital optical fiber to transmit the PCM code stream to the peer device, and can fully utilize the existing network system to transmit the transport stream, especially the FM audio. Helps reduce the cost of FM audio transmission. In addition, the network system can support the full digital transformation of the HFC network, save the trunk fiber, save the investment of analog equipment, reduce the construction and operation and maintenance costs of the customer, and support the flexible planning of the FM signal spectrum on the Cable network.

Optionally, the decoding unit comprises an audio decoder. The audio decoder is configured to decode the audio data in the received TS packet, obtain corresponding audio data, and send the corresponding audio data to the MPEG decoder, and the MPEG decoder performs MPEG decoding on the received audio data to obtain a PCM code stream, and The PCM code stream is sent to the optical transmitter TX.

For legal reasons or other reasons, FM receivers can only receive analog signals in a specific spectrum range. For example, FM radio receivers in China can only receive FM signals in the frequency range between 88MHz and 108MHz in Japan. The FM receiver of the FM broadcast can only receive FM signals with a spectral range between 76MHz and 90MHz. In addition, there may be other signals transmitted through the frequency domain carrier frequency within the spectrum range that the FM receiver can receive, so that the FM receiver may not receive the FM signal transmitted by the source. In this case, optionally, as shown in FIG. 5b, the network system may further include a frequency shifter and an FM adapter. The frequency shifter is located between the FM modulator and the D/A converter, the FM adapter being disposed between the D/A converter and the FM receiver. The FM modulator is configured to perform FM modulation on the digital electrical signal obtained by photoelectrically converting the optical receiver RX, and then send the digital electrical signal to the frequency shifter, and the frequency shifter carries the digital electrical signal in the first frequency spectrum segment, and the first frequency spectrum segment is different. In the spectrum segment that is already occupied. The frequency shifter modulates the digital electrical signal to the first frequency spectrum segment, sends the first frequency spectrum segment to the D/A converter, and the D/A converter performs D on the digital electrical signal carried by the first frequency spectrum segment. /A conversion, the analog signal carried by the first spectrum segment is obtained. The D/A converter transmits the analog signal carried by the first spectrum segment to the FM adapter. The FM adapter performs spectrum adaptation on the analog signal carried by the first spectrum segment, that is, the FM adapter converts the analog signal carried by the first spectrum segment into an analog signal carried by the second spectrum segment that the FM receiver can receive, And sent to the FM receiver. In this way, the idle spectrum segment can be flexibly used to carry the analog signal sent to the FM adapter, especially the FM audio signal; before the analog signal arrives at the FM receiver, the FM adapter converts the analog signal carried on the idle spectrum segment to the FM receiver. The spectrum segment that the machine can receive is carried so that the FM receiver can receive the analog signal.

Optionally, if the transport stream TS includes audio signals of multiple programs, as shown in FIG. 5c, the network system may further include a demultiplexing unit, where the demultiplexing unit is configured to receive the transport stream, and demultiplex transmission The audio signals of the plurality of programs in the stream obtain audio signals of each of the audio signals of the plurality of programs, and then forward the audio signals of the respective programs to the decoding unit for processing. Optionally, the demultiplexing unit may be implemented in software. Optionally, the demultiplexing unit may also adopt an Application Specific Integrated Circuit (ASIC) or a Field Programmable Gate Array (Field Programmable Gate Array). FPGA) or digital signal processor (DSP) implementation.

Optionally, the demultiplexing unit and the decoding unit may be located in the same module or component, for example, a Transport Stream demultiplex and decoder (TSDD) may include a demultiplexing unit and a decoding unit. A transport stream containing a plurality of programs, after reaching the TSDD, the TSDD demultiplexes the transport stream to obtain data of a single program, and further performs audio decoding to obtain a decoded decoded audio signal. The TSDD can be implemented in software. Alternatively, the TSDD can also be implemented by using an ASIC or an FPGA or a DSP.

Optionally, in order to enhance the strength of the analog signal emitted by the D/A converter, the network system may further include one or more amplifiers based on the network system shown in FIGS. 5a to 5c, as shown in FIG. 5d. The amplifier is disposed between the D/A converter and the FM receiver. This amplifier is used to enhance the received analog signal. The D/A converter enhances the analog signal obtained after the D/A conversion by the amplifier and transmits it to the FM receiver.

In an embodiment, as shown in FIG. 5e, the network system may include a demultiplexing unit, a decoding unit, a TX, an RX, an FM modulator, a frequency shifter, a D/A converter, an amplifier, an FM adapter, and an FM. Receiver. The components and functions of the various components in the network system of FIG. 5e have been described in the foregoing embodiments, and are not described herein again. Alternatively, the network system of Figures 5a-5e may also include one or more filters (not shown in Figure 5e). For the network system of Figures 5a - 5c, the filter can be located between the D/A converter and the FM receiver. For the network system of Figure 5d, the filter can be located between the D/A converter and the amplifier. For the network system of Figure 5e, the filter can be located between the D/A converter and the amplifier or between the D/converter and the FM adapter. The filter is used to filter the analog signal obtained after the D/A conversion to obtain an analog signal that meets the requirements. The filter can be a high pass filter or a low pass filter.

Alternatively, the TS packet may be sent by other devices to the decoding unit or demultiplexing unit in Figures 5a-5e. The "other device" herein may be any device capable of providing audio and/or video data, such as a router, switch, server, computer or portable device. The portable device can be a cell phone or laptop or a personal digital assistant PDA.

Alternatively, the TS packet may be an audio signal or a video signal, or the TS packet may also be a combination of an audio signal and a video signal. The format of the audio signal is Motion Picture Experts Group MPEG-1 or MPEG-2 or MPEG-4 or MPEG-7 or MPEG-21 format. Alternatively, the format of the audio signal may be MP3 (MPEG-3 Layer 3).

Optionally, the optical receiver RX is located in the fiber node FN.

Optionally, in an implementation manner of the present application, the PCM code stream may be carried by using an xPON, where the xPON is an APON defined by ITU-T G.983 or a GPON defined by ITU-T G.984 or IEEE 802.3. Ah defined EPON. Taking the EPON to carry the PCM code stream as an example, the TX in the network system of FIG. 5a to 5e can be replaced by an Optical Line Terminal (OLT), and the RX can be replaced by an Optical Network Unit (ONU). . The EPON is an Ethernet-based passive optical network that carries packets in an Ethernet encapsulation format. The OLT is used to encapsulate the PCM code into a packet and send the packet to the ONU via a digital optical fiber. The message is a Real-time Transport Protocol (RTP) packet or a UDP packet or an IP packet or an Ethernet packet. The format of the RTP packet encapsulated with the PCM code stream is as shown in FIG. 5f. The OLT can broadcast Ethernet data to the RX in the ONU by the TX. The OLT can also allocate bandwidth for the ONU, and control the start time and the send window size of the ONU to send data. The ONU is a user equipment in the network system and is placed at the user end to cooperate with the OLT to implement Layer 2 and Layer 3 functions of the Ethernet to provide voice, data, and multimedia services for users. The ONU receives and parses the RTP packet or the IP packet or the Ethernet packet sent by the OLT, obtains the PCM code stream carried in the RTP packet or the IP packet or the Ethernet packet, and sends the PCM code stream to the FM modulator.

Alternatively, the ONU can be an active ONU or a passive ONU. Optionally, the ONU may also include an optical transmitter.

The present application further provides a method for transmitting a TS packet, in combination with the network system of FIG. 5a, as shown in FIG. 6, the method includes:

S10. The first network device receives the transport stream, and obtains a PCM code stream according to the transport stream.

Specifically, the local first network device may include the decoding unit in FIG. 5a, and after the first network device receives the TS packet, the first network device decodes the TS packet to obtain a PCM code stream. Specifically, the decoding unit of the first network device decodes the TS packet to obtain a PCM code stream.

S12. The first network device converts the PCM code stream into a digital optical signal, and sends the digital optical signal to the second network device via the digital optical fiber, so that the peer device that receives the message is received (ie, in FIG. 6 The second network device converts the digital optical signal into an analog electrical signal and transmits the analog electrical signal.

Specifically, the first network device device may further include an optical transmitter TX, and the TX converts the PCM code stream decoded by the decoding unit into a digital optical signal, and sends the digital optical signal to the second network device at the opposite end via the digital optical fiber. . The second network device can include an RX, a D/A converter, and an FM modulator. The RX receives the digital optical signal and performs optical/electrical conversion on the received digital optical signal to obtain a digital electrical signal corresponding to the TS.

And transmitting, by the first network device, the packet including the PCM code stream to the second network device by using the digital optical fiber, where the first network device sends the packet including the PCM code stream to the second network device by using the xPON to the EPON. For example, the PCM code stream may be encapsulated into a packet, and the encapsulated packet is sent to the second network device by using an xPON, and the packet is an RTP packet or a UDP packet or an IP packet or an Ethernet packet. The format of the RTP packet encapsulated with the PCM stream is as shown in Figure 5f. Where xPON is APON defined by ITU-T G.983 or GPON defined by ITU-T G.984 or EPON defined by IEEE 802.3ah.

S14. The second network device performs FM modulation on the received digital optical signal to obtain an analog signal.

Specifically, the optical receiver RX of the second network device converts the digital optical signal into a digital electrical signal and sends the digital electrical signal to an FM modulator, and the FM modulator modulates the digital electrical signal to an FM receiver capable of receiving The band is sent to the D/A converter. The D/A converter performs D/A conversion on the digital electrical signal to obtain an analog signal.

S16. The second network device sends the obtained analog signal to the FM receiver.

Optionally, based on FIG. 5b, a frequency shifter is further included between the FM modulator and the D/A converter, and an FM adapter is further included between the D/A converter and the FM receiver. The method further includes: the frequency shifter can transmit a digital electrical signal sent by the FM modulator, and the frequency shifter carries the digital electrical signal in a first frequency spectrum segment, the first frequency spectrum segment being different from the already occupied spectrum segment. After the frequency shifter modulates the digital electrical signal to the first frequency spectrum segment, the digital electrical signal is sent to the D/A converter through the first frequency spectrum segment, and the D/A converter carries the first frequency spectrum segment. The digital electrical signal is D/A converted to obtain an analog signal carried by the first spectrum segment. The D/A converter transmits the analog signal carried by the first spectrum segment to the FM adapter. The FM adapter performs spectrum adaptation on the analog signal carried by the first spectrum segment, that is, the FM adapter converts the analog signal carried by the first spectrum segment into an analog signal carried by the second spectrum segment that the FM receiver can receive, And sent to the FM receiver.

Optionally, if the transport stream TS includes audio signals of multiple programs, as shown in FIG. 5c, the network system may further include a demultiplexing unit, where the demultiplexing unit is configured to receive the transport stream, and demultiplex the transport stream. The audio signals of the plurality of programs are obtained, and the audio signals of each of the audio signals of the plurality of programs are obtained, and the audio signals of each of the programs are forwarded to the decoding unit for processing.

Optionally, based on FIG. 5d, the method may further include: amplifying the analog signal sent by the D/A converter and transmitting the analog signal to the FM receiver, so that the signal strength received by the FM receiver can be enhanced.

Optionally, based on FIG. 5e, the method may further include: the frequency shifter receives the digital electrical signal sent by the FM modulator to the D/A converter, and the frequency shifter carries the digital electrical signal in the first frequency spectrum segment, where A spectrum segment is different from a spectrum segment that has already been occupied. After the frequency shifter modulates the digital electrical signal to the first frequency spectrum segment, the digital electrical signal is sent to the D/A converter through the first frequency spectrum segment, and the D/A converter carries the first frequency spectrum segment The digital electrical signal is D/A converted to obtain an analog signal carried by the first spectrum segment. The D/A converter sends the analog signal carried by the first spectrum segment to the amplifier for amplification, and then sends the analog signal to the FM adapter. The FM adapter performs spectrum adaptation on the analog signal carried by the first spectrum segment, that is, the FM adapter converts the analog signal carried by the first spectrum segment into an analog signal carried by the second spectrum segment that the FM receiver can receive, And sent to the FM receiver.

Optionally, in an embodiment of the present application, a network system includes a decoding unit, an optical line terminal OLT, an optical network unit ONU, a frequency modulation FM modulator, a digital/analog converter, and an FM receiver, where: The decoding unit is configured to receive a transport stream, obtain a pulse code modulated PCM code stream according to the transport stream, and provide the PCM code stream to the TX; the OLT is configured to encapsulate the PCM code in a message and send To the ONU, the message is an Internet Protocol IP packet or a real-time transport protocol RTP message or an Ethernet packet; the ONU is configured to receive an Ethernet packet or an IP packet or an RTP packet that carries the PCM code stream. And converting the Ethernet message or the IP message or the RTP message into a digital electrical signal, sending the signal to the digital-to-analog converter, and transmitting the digital electrical signal to the FM modulator; An FM modulator for modulating the digital electrical signal and transmitting the modulated digital electrical signal to the digital to analog converter; the digital to analog converter for converting the digital electrical signal to an analog signal and to the An FM receiver provides the analog signal; according to the FM receiver Receiving said analog signal.

In the several embodiments provided by the present application, it should be understood that the disclosed system, apparatus, and method may be implemented in other manners. For example, the device embodiments described above are merely illustrative. For example, the division of the unit is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, each functional unit/module in each embodiment of the present invention may be integrated into one processing unit/module, or each unit may exist physically separately, or two or more units/modules may be integrated into one unit. . The above integrated unit can be implemented in the form of hardware or in the form of hardware plus software functional units. For example, an OLT, an optical transmitter, an optical receiver, a communication interface, an ONU, an FM modulator, a decoding unit, a package module, a demultiplexing unit, and the like may all be implemented by a general-purpose CPU or an application specific integrated circuit (Application Specific Integrated Circuit, ASIC) or Field-Programmable Gate Array (FPGA).

The above-described integrated unit implemented in the form of a software functional unit can be stored in a computer readable storage medium. The software functional units described above are stored in a storage medium and include instructions for causing a computer device (which may be a personal computer, server, or network device, etc.) to perform portions of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and the like, and the program code can be stored. Medium.

The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that The technical solutions are described as being modified, or equivalent to some of the technical features, and the modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

A network system, comprising: a decoding unit, an optical transmitter TX, a digital/analog converter, an optical receiver RX, a frequency modulated FM modulator, and an FM receiver, wherein:

The decoding unit is configured to receive a transport stream, obtain a pulse code modulated PCM code stream according to the transport stream, and provide the PCM code stream to the TX;

The TX is used to convert the PCM code stream into a digital optical signal and send it to the RX via a digital optical fiber;

The RX is configured to receive the digital optical signal and photoelectrically convert the digital optical signal to obtain a digital electrical signal, and send the digital electrical signal to the FM modulator;

The FM modulator is configured to modulate the digital electrical signal and transmit the modulated digital electrical signal to the digital/analog converter;

The digital to analog converter is configured to convert the modulated digital electrical signal into an analog signal and provide the analog signal to the FM receiver;

The FM receiver is configured to receive the analog signal.
The network system of claim 1 further comprising a frequency shifter between said FM modulator and said digital to analog converter and said digital to analog converter and said FM receive FM adapter between machines;

The frequency shifter is configured to convert the digital electrical signal to obtain a digital electrical signal carried by the first spectrum segment;

The digital-to-analog converter is specifically configured to convert a digital electrical signal carried by the first spectrum segment obtained by the frequency shifter into an analog signal carried by the first spectrum segment;

The FM adapter is configured to convert the analog signal carried by the first spectrum segment into an analog signal carried by the second spectrum segment that the FM receiver can receive.
The network system according to claim 1 or 2, wherein said transport stream comprises signals of a plurality of programs, said network system further comprising a demultiplexing unit, said demultiplexing unit being for demultiplexing The transport stream is described to obtain a signal for each of the signals of the plurality of programs.
A network system according to any one of claims 1 to 3, wherein said transport stream comprises a Moving Picture Experts Group MPEG audio signal.
The network system according to claim 4, characterized in that the format of the audio signal follows MPEG-1 or MPEG-2 or MPEG-4 or MPEG-7 or MPEG-21.
A method for transmitting a signal, comprising:

The local device including the optical line terminal OLT receives the transport stream;

The local device obtains a pulse code modulated PCM code stream according to the transport stream;

Transmitting, by the local device, a packet including the PCM code stream to a peer device that includes the optical network unit ONU, so that the peer device that receives the packet converts the PCM code stream into an analog signal and Sending the analog signal.
The method according to claim 6, wherein the message is an Ethernet message or an Internet Protocol IP message or a User Datagram Protocol UDP message or a Real-Time Transport Protocol (RTP) message.
The method according to claim 6 or 7, wherein before the local device receives the transport stream, the method further comprises: demultiplexing the transport stream to obtain a signal for each program, the transmission The stream includes signals of a plurality of programs;

Obtaining, by the local device, the PCM code stream according to the transport stream, comprising: obtaining the PCM code stream by decoding a signal of the single program.
A method according to any one of claims 6-8, wherein said transport stream comprises a Moving Picture Experts Group MPEG audio signal.
The method of claim 9 wherein the format of the audio signal follows MPEG-1 or MPEG-2 or MPEG-4 or MPEG-7 or MPEG-21.
An optical line terminal OLT, comprising: a communication interface and a package module, wherein

The communication interface is configured to receive a pulse code modulated PCM code stream and send the PCM code stream to the package module;

The encapsulating module is configured to encapsulate the PCM code stream into a packet;

The communication interface is further configured to send the message to the optical network unit ONU of the opposite end.
The OLT according to claim 11, wherein the message is an Ethernet message or an Internet Protocol IP message or a User Datagram Protocol UDP message or a Real-Time Transport Protocol (RTP) message.
An optical network unit ONU, comprising: a communication interface and a decapsulation module, wherein

The communication interface is configured to receive a message sent by an optical line terminal OLT, where the message includes a pulse code modulated PCM code stream;

The parsing module is configured to parse the packet to obtain the PCM code stream;

The communication interface is further configured to send the PCM code stream to the FM receiver after frequency modulation FM modulation and digital-to-analog conversion.
The ONU according to claim 13, wherein the message is an Ethernet message or an Internet Protocol IP message or a User Datagram Protocol UDP message or a Real-Time Transport Protocol (RTP) message.
A network system, comprising: a decoding unit, an optical line terminal OLT, an optical network unit ONU, a frequency modulation FM modulator, a digital/analog converter, and an FM receiver, wherein:

The decoding unit is configured to receive a transport stream, obtain a pulse code modulated PCM code stream according to the transport stream, and provide the PCM code stream to the TX;

The OLT is configured to encapsulate the PCM code in a packet and send it to the ONU, where the packet is an Internet Protocol IP packet or a real-time transport protocol RTP packet or an Ethernet packet;

The ONU is configured to receive an Ethernet packet or an IP packet or an RTP packet that carries the PCM stream, and convert the Ethernet packet or the IP packet or the RTP packet into a digital electrical signal, and send the packet to the a digital-to-analog converter and transmitting the digital electrical signal to the FM modulator;

The FM modulator is configured to modulate the digital electrical signal and transmit the modulated digital electrical signal to the digital/analog converter;

The digital to analog converter is configured to convert the digital electrical signal into an analog signal and provide the analog signal to the FM receiver;

The FM receiver is configured to receive the analog signal.
The network system according to claim 15, wherein the OLT is the OLT according to claim 12 or 13, and the ONU is the ONU according to claim 14 or 15.