JP7353880B2 - Digital broadcast transmitter and digital broadcast system - Google Patents

Description

Embodiments of the present invention relate to a digital broadcast transmitting device and a digital broadcast system.

In next-generation terrestrial digital broadcasting, expansion of transmission capacity by polarized MIMO (Multi Input Multi Output) is being considered. Polarized MIMO is a technology that doubles the transmission capacity by using horizontal (H) polarized signals and vertical (V) polarized signals and carries different information on each polarized wave.

A digital broadcasting transmitting device to which polarized MIMO is applied transmits a main signal using, for example, H polarization, and a sub signal using V polarization. A receiving device that receives the signal demodulates the main signal and the sub signal, synthesizes the information, and reproduces the broadcast content. Although technically it is still under consideration, for example, a 2K signal and a part of the 4K signal can be transmitted as the main signal, a part of the 4K signal can be transmitted as the sub signal, and then the receiving side can transmit 2K or 4K video. We can expect applications such as playing .

Japanese Patent Application Publication No. 2009-124361 Japanese Patent Application Publication No. 11-27181

With existing technology, video content itself cannot be transmitted using only V-polarized waves, that is, sub-signals. Therefore, if the H-polarized transmitter in the transmitting device fails, the receiving side will not be able to reproduce the video, and in the worst case, the signal will stop.

An object of the present invention is to provide a digital broadcast transmitting device and a digital broadcast system with improved fault tolerance.

According to the embodiment, the digital broadcast transmitting device includes a first antenna, a second antenna, a modulation section, a first transmitter, a second transmitter, a switching section, a detection section, and a switching control section. Equipped with. The modulation section generates a first modulation signal modulated by the main signal and a second modulation signal modulated by the sub-signal of the main signal. The first transmitter converts the input signal into a broadcast band and transmits it from the first antenna in a first polarized wave. The second transmitter converts the input signal into a broadcast band and transmits it from a second antenna with a second polarization. The switching unit inputs the first modulated signal to the first transmitter and inputs the second modulated signal to the second transmitter during normal times. The detection unit detects a failure of the first transmitter. The switching control unit controls the switching unit to input the first modulated signal to the second transmitter when a failure of the first transmitter is detected.

FIG. 1 is a functional block diagram showing an example of a digital broadcast transmitting device according to an embodiment. FIG. 2 is a functional block diagram showing an example of the H polarization transmitter 13 shown in FIG. 1. FIG. 3 is a diagram illustrating an example of the operation of the digital broadcast transmitting device according to the embodiment during normal operation. FIG. 4 is a schematic diagram showing a state in which the H polarized wave transmitter 13 shown in FIG. 1 has failed. FIG. 5 is a diagram for explaining the operation of the digital broadcast transmitting device according to the embodiment.

Next, embodiments of this invention will be described. In the following, assuming a next-generation terrestrial digital broadcasting system using MIMO transmission technology, a transmitting device applicable to this type of system will be described. In particular, a device that transmits a main signal with horizontal polarization (H) and a sub signal with respect to the main signal with vertical polarization (V) will be described. By transmitting 2K definition broadcast content using the main signal, the receiving side can demodulate the 2K broadcast as long as the main signal can be received. If a sub signal containing additional data to the main signal can also be received, the 4K broadcast can be demodulated on the receiving side. The same applies to 8K broadcasting.

FIG. 1 is a functional block diagram showing an example of a digital broadcast transmitting device according to an embodiment. In FIG. 1, a modulator 11 generates a main IF signal (first modulation signal) modulated with a main signal and a sub IF signal (second modulation signal) modulated with a sub signal. Both the main IF signal and the sub-IF signal are in an intermediate frequency band, and are input to the IF switch 12. The IF switch 12 inputs the main IF signal to the H polarization transmitter 13 and inputs the sub IF signal to the V polarization transmitter 15 in normal times.

The H polarization transmitter 13 up-converts the input signal to an RF (Radio Frequency) broadcast band and amplifies it to a transmission level. The transmission RF signal (H) thus obtained is transmitted from the antenna 20 via the RF switch 14 as an H polarized wave.

The V-polarization transmitter 15 up-converts the input signal to an RF broadcast band and amplifies it to a transmission level. The transmission RF signal (V) thus obtained is transmitted via the RF switch 14 from the antenna 20 as a V-polarized wave.

Further, the digital broadcast transmitting device 10 includes a control section 16. The control unit 16 realizes its functions by having a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit) execute calculation processing based on a program stored in a memory.

The control unit 16 includes a detection unit 16a and a switching control unit 16b as processing functions according to the embodiment. The detection unit 16a detects a failure of the H polarized wave transmitter 13 as the first transmitter. When a failure of the H polarization transmitter 13 is detected, the switching control unit 16b controls the IF switch 12 to input the main IF signal to the V polarization transmitter 15 as a second transmitter. . Furthermore, in a state in which a failure of the H polarization transmitter 13 is detected, the switching control unit 16b connects the output of the V polarization transmitter 15 to the antenna 20, and transmits in H polarization. That is, if a failure occurs in the H-polarized transmitter 13, the main signal will be transmitted from the antenna 20 via the V-polarized transmitter 15.

FIG. 2 is a functional block diagram showing an example of the H polarization transmitter 13 shown in FIG. 1. The configuration of the V-polarized wave transmitter 15 is also similar. In FIG. 2, an IF signal input to the H-polarized transmitter 13 is up-converted to a transmission band by an exciter 31, and then divided into a plurality of systems by a distributor 32. The RF signals of each system are individually amplified by transmission power amplifiers (PA: power amplifiers) 33-1 to 33-n, and then combined by a combiner 34. The output of the synthesizer 34 is band-limited by a filter 35 and output.

The states of the H polarization transmitter 13 and the V polarization transmitter 15 are constantly monitored by the control unit 16 in FIG. 1 (health check). Further, as shown in FIG. 1, the status of each transmitter 13 and 15 can also be known by monitoring the output of each of the H polarization transmitter 13 and the V polarization transmitter 15. Next, the operation of the above configuration will be explained.

As shown in FIG. 3, during steady state, the main signal is amplified by the H polarization transmitter 13 and transmitted from the antenna 20 as H polarization. The sub-signal is amplified by the V-polarized wave transmitter 15 and transmitted from the antenna 17 as a V-polarized wave.

In this state, if a failure occurs in the H-polarized transmitter 13 and it stops functioning, it will no longer be possible to deliver video to the receiving side, as shown in FIG. 4. This is based on the specification that the main content of broadcast content is stored in the main signal, and the sub signal stores additional data to the main signal. In other words, if only the main signal can be received, the broadcast content can be restored (albeit at a lower resolution), but if only the sub signal can be received, the broadcast itself cannot be received and demodulated in the first place.

Therefore, in the embodiment, the control unit 16 monitors the state of the H-polarized transmitter 13 that amplifies the main signal. When a failure of the H polarization transmitter 13 is detected, the control unit 16 controls the IF switch 12 and the RF switch 14 to switch the main signal path as shown in FIG. That is, the main signal is input to the V-polarized wave transmitter 15, amplified through a path that amplifies the sub-signal during steady state, and transmitted from the H-polarized antenna 20.

In this way, in a transmitting device for MIMO transmission that consists of a main signal and a sub signal, if the transmitter that amplifies the main signal fails, the transmitter that amplifies the sub signal is used to transmit the main signal. The signal was amplified and radio waves were output from an H-polarized antenna. As a result, although the video resolution is lower than the original resolution (for example, 4K broadcast becomes 2K broadcast), information can be transmitted without interruption. Therefore, according to the embodiment, it is possible to provide a digital broadcast transmitting device and a digital broadcast system with improved fault tolerance.

Note that this invention is not limited to the above embodiments. For example, in the above explanation, the exact same argument holds even if horizontally polarized waves are read as vertically polarized waves and vertically polarized waves are read as horizontally polarized waves. In short, it is sufficient that the plane of polarization of the transmitted wave of the main signal and the plane of polarization of the transmitted wave of the sub-signal are orthogonal to each other. Furthermore, it is also conceivable to transmit the main signal with right-handed polarization and the sub-signal with left-handed polarization, for example. Furthermore, the digital broadcast transmitting device 10 according to the embodiment can also be used as a relay station.

Although an embodiment of the invention has been described, this embodiment is presented by way of example and is not intended to limit the scope of the invention. This novel embodiment can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. This embodiment and its modifications are included within the scope and gist of the invention, as well as within the scope of the invention described in the claims and its equivalents.

10... Digital broadcast transmitting device, 11... Modulator, 12... IF switch, 13... H polarization transmitter, 14... RF switch, 15... V polarization transmitter, 16... Control section, 16a... Detection section, 16b...Switching control unit, 17...Antenna, 20...Antenna, 31...Exciter, 32...Distributor, 33-1 to 33-n...Transmission power amplifier, 34...Synthesizer, 35...Filter.

Claims (6)

a first antenna that transmits radio waves of a first polarization ;
a second antenna that transmits radio waves of a second polarization ;
a first switch that switches a route of a broadcast band signal to either the first antenna or the second antenna;
a modulation unit that generates a first modulation signal modulated with a main signal and a second modulation signal modulated with a sub-signal of the main signal;
a first transmitter that converts the input signal into a broadcast band;
a second transmitter that converts the input signal into a broadcast band;
a second switch that inputs the first modulation signal to the first transmitter and inputs the second modulation signal to the second transmitter during normal times;
a detection unit that detects a failure of the first transmitter;
When a failure of the first transmitter is detected, the second switch is controlled to input the first modulated signal to the second transmitter , and the first switch is controlled to transmit the second signal. a switching control unit that connects a broadcast band signal from a broadcasting device to the first antenna . The digital broadcast transmitting device according to claim 1, wherein the polarization plane of the first polarized wave and the polarization plane of the second polarized wave are orthogonal to each other. The digital broadcast transmitting device according to claim 1, wherein the main signal includes broadcast content data. 4. The digital broadcast transmitting apparatus according to claim 3, wherein the sub signal includes additional data to the main signal. The digital broadcast transmitting device according to claim 1, wherein the first antenna and the second antenna are compatible with polarized MIMO (Multiple-Input Multiple-Output). A digital broadcast transmitting device comprising a first antenna that transmits radio waves of a first polarization and a second antenna that transmits radio waves of a second polarization, and the radio waves of the first polarization and the radio waves of the second polarization. A digital broadcasting system comprising a digital broadcasting receiving device that receives
The digital broadcast transmitting device includes:
a first switch that switches a route of a broadcast band signal to either the first antenna or the second antenna;
a modulation unit that generates a first modulation signal modulated with a main signal and a second modulation signal modulated with a sub-signal of the main signal;
a first transmitter that converts the input signal into a broadcast band;
a second transmitter that converts the input signal into a broadcast band;
a second switch that inputs the first modulation signal to the first transmitter and inputs the second modulation signal to the second transmitter during normal times;
a detection unit that detects a failure of the first transmitter;
When a failure of the first transmitter is detected, the second switch is controlled to input the first modulated signal to the second transmitter , and the first switch is controlled to transmit the second signal. a switching control unit that connects a broadcast band signal from a broadcasting device to the first antenna .