JP2008017226A - Radio relay apparatus and system switching method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio relay apparatus with redundant constitution seamlessly switching an SC signal, and a system switching method. <P>SOLUTION: The SC signal whose speed is converted by a speed converter which is provided on a branching switch 2 and common to active and standby modulating units 3a and 3b is input to the active and standby modulating units 3a and 3b, and multiplexed with a main signal to be transmitted. The SC signal whose speed is converted has its speed converted with an active CLK2 generated from the clock MCLK of the main signal. A CLK2 which slaves to an SCLK generated by conversion from an active CLK1 generated from the MCLK as well is supplied to the speed converter 22 from the standby modulating unit to synchronize with the CLK2 generated by the active system, so taht even when the branching switching device 2 performs system switching, neither the clock nor the SC signal changes in bit timing and the SC signal output from the speed converter 22 can be seamlessly switched. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radio relay apparatus using a microwave or the like and a system switching method thereof.

  A wireless relay device that wirelessly relays a program signal from a studio in a broadcasting station to a transmitting station uses two wireless transmitters and switches as active and standby devices in order to prevent disruption of broadcast waves. Such a radio relay apparatus transmits a main signal for transmitting a program signal (TS signal) and an SC (service channel) signal used for a transmitter at a transmitting station, a control monitor of the radio relay apparatus, and the like.

FIG. 4 is a system diagram for explaining the concept of SC signal transmission of a conventional radio broadcast apparatus for digital broadcast program signals, and FIG. 5 is a functional block diagram for explaining a conventional SC signal system switching method.
The outline of the SC signal system switching process will be described below with reference to FIGS. In FIG. 4, in the radio relay apparatus, the main signal and SC signal input from the center side of the broadcasting station are branched into two systems, that is, the active system and the standby system (systems are distinguished by subscripts a and b), respectively. The signal is input to the modulation units 30a and 30b and becomes a superimposed relay signal. The relay signal is further input to TX (transmitters) 40a and 40b, converted into a transmission radio wave, and then input to SW (switch) 5s.

  Then, for example, by a system switching signal from a distribution switching unit (not shown), for example, TX40a of one system is connected to the antenna 5t as an active system, and a transmission radio wave output from the TX 40a is transmitted toward the antenna 5r. . Then, the transmission radio wave received by the antenna 5r is divided into two by H (hybrid) 7 and becomes a relay signal that is processed in parallel by two RX (receivers) 80a and 80b and demodulators 90a and 90b. The SC signal demodulated from the relay signal passes through SW100 and the main signal passes through SW110, and either one of the signals is selected and taken out as the active system.

  Switching between the working side and the spare side on the transmitting side and the receiving side is performed independently, and when a problem occurs on the transmitting side, the working side and the spare side are switched only on the transmitting side.

  Although not shown, the main signal on the transmission side is synchronized between the two modulators, and the bit timing of the TS signal and the carrier signal are aligned so that there is no noise generation or signal interruption even when the system is switched. . Then, seamless switching is performed in which even if the transmitter is switched, the bit drop of the relay signal of the transmission radio wave does not occur.

  On the other hand, since the SC signal handled by the conventional relay radio apparatus is an auxiliary signal that does not require timing processing for transmitting low-speed data, contact signals, etc. independent of the main signal, seamless switching is not considered.

  FIG. 5 is a functional block diagram for explaining the SC signal system switching method in the modulation unit 30a. In FIG. 5, a modulation unit 30a includes a speed converter 310 that converts the data rate of the SC signal, a digital processing unit 320 that performs processing such as adding error correction information to the input main signal, a clock generator 330, and a MOD 340. , A mixer 350 and an oscillator 360.

  The SC signal input to the modulation unit 30a is, for example, a 128 kbps signal set by external specifications, and a plurality of contact information and the like are multiplexed and transmitted on the bit rate signal. Then, the SC signal is input to the speed converter 310 and converted into a bit rate (here, 160 kbps) adapted to the multiplexing processing in the relay apparatus.

  The clock generator 330 of the modulation unit 30a receives a clock (hereinafter referred to as MCLK) as a main signal, and the clock generator 330 generates an IF signal from the MCLK and a clock for processing the TS signal of the main signal. (Hereinafter referred to as CLK1) and an integer multiple of 160 kbps (for example, 16 times) clock (hereinafter referred to as CLK2) for processing the SC signal are generated and output.

  CLK2 is input to the speed converter 310, and the speed converter performs a process such as converting the input 128 kbps SC signal into a frame in which empty bits are added by an amount corresponding to a higher speed of 160 kbps. Output to. In the MOD 340, the TS signal and SC signal of the main signal are multiplexed, and modulation of a predetermined encoding method is performed.

  CLK1 is used as a processing clock in the MOD 340 and a reference clock of the oscillator 360 that supplies the local oscillation signal of the IF signal. The modulation signal output from the MOD 340 and the local oscillation signal from the oscillator 360 are mixed by the mixer 350. The Then, the relay signal generated by mixing is amplified by the amplifier 370, and for example, the relay signal is output to the TX 40a as an IF (intermediate frequency signal) output of 130 MHz. The operation is the same in the modulation unit 30b of the other system.

  Although CLK1 is not shown in the figure, timing matching is performed between the modulation unit 30a and the modulation unit 30b, as described above, so that the carrier phase of the transmission radio wave and the TS signal of the main signal are changed even when the system is switched. Is seamlessly switched.

  If synchronization is required with the SC signal, since the transmitted data is low speed, the synchronous signal is added to the SC signal together with the low speed data (for example, Patent Document 1). However, since the SC signals processed by the two modulation units are independent from each other in terms of timing, the frame configuration of the SC signal output from the speed converter changes when the active and standby switching is performed. Seamless switching conditions such as missing bits are not satisfied.

The SC signal itself is a medium speed data signal such as 128 kbps, and a signal such as voice can be transmitted. However, since not only the conventional low-speed data but also the middle speed control and the seamless switching of the monitor signal are required along with the start of digital broadcasting, the SC signal cannot be seamlessly switched in the baseband. There was a problem that the data signal was interrupted.
Japanese Examined Patent Publication No. 4-57253 (page 5, Fig. 2)

  Conventionally, a radio relay apparatus using microwaves or the like has a problem that SC signals cannot be switched seamlessly in the baseband.

  The present invention has been made to solve the above problems, and an object thereof is to provide a wireless relay apparatus and a system switching method having a redundant configuration capable of seamlessly switching SC signals.

  In order to achieve the above object, the relay radio apparatus of the present invention transmits a main signal of an input broadcast radio wave and an SC signal as a relay signal, and shares a transmission antenna with a system of two transmission facilities. In the radio relay apparatus that operates by switching alternately between the standby system and the standby system, either the first distribution means for branching and outputting the input main signal to the two transmission facilities, or any of the two transmission facilities One is set as the active system and the other is set as the standby system, and the converted SC signal obtained by converting the speed of the inputted SC signal by the clock information inputted from the transmission equipment is branched and output to the two transmission equipments. Distribution switching means for transmitting, and transmission means for transmitting a relay signal obtained by multiplexing and modulating the input main signal and the converted SC signal, each of which is a master of the input main signal A first clock for processing the main signal converted from a clock to a first frequency; a second clock converted to a second frequency for processing a speed conversion of the SC signal; First and second transmission equipment including clock generation means for generating and outputting a third clock obtained by restoring one clock to the frequency of the master clock, and the distribution switching means includes the first clock When the transmission facility is set to the active system, the first transmission facility sends the third clock generated from the input main signal to the second transmission facility via the distribution switching means. The second transmission facility outputs the first and second clocks as signals to be generated, and receives the converted SC signal generated by the distribution switching unit at the output destination of the second clock, and Relay message The second transmission means generates the first clock and the second clock slaved to the first transmission facility by the input third clock, and outputs the relay signal. It is characterized by generating and waiting.

  Further, the system switching method of the relay radio apparatus according to the present invention transmits a relay signal obtained by multiplexing and modulating a distribution means, a switching means for setting a working or standby system, and an input main signal and an SC signal. In a system switching method for a radio relay apparatus, comprising a first transmission facility and a second transmission facility, wherein the system of the first and second transmission facilities is alternately switched between an active system and a standby system using a common transmission antenna The first distribution means branches and outputs the input main signal to the two transmission facilities, and the first transmission means receives the first signal from the master clock of the main signal from the first distribution means. A first clock for processing the main signal converted to the frequency of the second clock, and a third clock obtained by restoring the second clock and the first clock from the master clock to the frequency of the master clock. And The relay means including the SC signal input from the switching means is output while being output to the switching means, and the switching means to which the second clock is input is the SC signal of the first transmission rate. Is always input, and the first transmission equipment is set to be an active system, the master clock of the main signal is input to the first transmission equipment, and the first transmission equipment is output from the first transmission equipment. The third clock is set to be input to the second transmission facility, and the first transmission rate is changed to the second transmission rate by the second clock input from the first transmission facility. The second transmission means that converts and outputs the new SC signal to the first and second transmission facilities and receives the third clock, and the second transmission means slaves to the first transmission facility. And equivalent to the second clock Characterized in that it stands by Generate the clock.

  According to the present invention, it is possible to provide a wireless relay apparatus and a system switching method having a redundant configuration capable of seamless switching of SC signals.

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a system diagram illustrating the concept of SC signal transmission using a radio relay apparatus according to an embodiment of the present invention, and FIG. 2 is a functional block diagram illustrating a system switching method of the SC signal.
The outline of the SC signal system switching process will be described below with reference to FIGS.
In FIG. 1, the wireless relay device includes DIV (distributor) 1, modulator 3 a, modulator 3 b, TX (transmitter) 4 a, TX 4 b, SW (switch) 5 s, antenna 5 t, and distribution switching as transmission side equipment. 2 is provided. Further, the receiving side equipment includes an antenna 5r, H (hybrid) 7, RX (receiver) 8a, RX 8b, demodulator 9a, demodulator 9b, SW10, and SW11.

  Also in the wireless relay device according to the embodiment, switching between the active side and the standby side on the transmission side and the reception side is performed independently, and when a problem occurs on the transmission side, the switching is performed only on the transmission side.

Also in this embodiment, the operation on the receiving side is the same as the conventional one. On the transmission side, the description of the same part as in the prior art will be omitted, and the operation related to seamless switching of the SC signal will be described below.
The main signal input from the center side of the broadcasting station is branched by DIV1 and input to the active and standby modulators 3a and 3b. The relay signal multiplexed with the SC signal is further input to TX (transmitters) 4a and 4b, converted into a transmission radio wave, and then input to SW (switch) 5s. The SC signal in the conventional wireless relay device is simply branched and then further input to each of the modulation units 3a and 3b, and the speed is converted. In this embodiment, the SC signal is speed-converted by the distribution switch 2. To the modulators 3a and 3b.

  In FIG. 2, the distribution switching device 2 includes a switch 21, a speed converter 22, and a distributor (DIV) 23. The switch 21 selects and outputs the CLK2 from the working system to the speed converter 22 among the clock signals (hereinafter referred to as CLK2) input from the modulation units 3a and 3b. System switching with the M / S (master / slave) switching unit of the clock generator is performed. Further, for example, a 128 kbps SC signal is input to the speed converter 22, and the bit rate is converted to, for example, 160 kbps by CLK 2 input via the switch 21.

  Since the transmission rate of 128 kbps is sufficient for encoding and decoding (or demodulating) the baseband SC signal, if the SC signal of 128 kbps (or converted to 160 kbps) is seamlessly switched, The baseband SC signal is also seamlessly switched.

  Each of the modulation units 3a and 3b includes a digital processing unit 32, a clock generator 33, a MOD 34, a mixer 35, an oscillator 36, and an amplifier 37. Conventionally, the speed converters respectively provided in the two modulation units. Is eliminated by being installed in the distribution switching device 2 as a speed converter 22 shared by both systems.

  In the conventional case, since the SC signal is speed-converted by the modulation units of both systems, the difference in processing speed of the speed converters 310 of the modulation units 30a and 30b in FIG. A difference occurs in the propagation delay time due to the difference between the two. Therefore, the phase (timing) with respect to the same pulse differs between the two SC signals subjected to the speed conversion, and seamless switching cannot be performed when the active standby system is switched.

  On the other hand, in the embodiment, the speed converter 2 is shared between the two systems, and CLK2 for processing the SC signal is generated from the same clock MLCK, so that the clock generators of the two modulators 3a and 3b are generated. The difference in clock timing between 33 is small. Since the clock generator 33 of the active modulation unit always operates the speed converter 22, the pulse timing between the SC signals converted to 160 kbps also matches, so that seamless switching is possible.

  In addition, the clock timing between the clock generators 33 of the two modulation units 3a and 3b is synchronized with the clock generator 33 of the modulation unit (for example, 3a) operating as the active system by making the other slave. I am letting. Therefore, since the pulse timing further matches at the time of switching, more perfect seamless switching is possible.

FIG. 3 is a block diagram showing a functional configuration of the clock generator.
In FIG. 3, the main signal clock MCLK is fed to the master input terminal m of the M / S (master / slave) switching unit 331. If the modulation unit 3a is operating as an active system (that is, a master) according to the setting of the distribution switch 2, the MCLK is input to the 1 / N-minute period 332 and further branched.

  One of the MCLKs is input to the input side of a generation circuit of a clock signal CLK2 for main signal processing such as an SC signal including a 1 / n-minute period 336, a phase detector 337, and an oscillator 338. As described above, the switch 21 is connected to the switch 21 of the distribution switching device 2, and the speed converter 22 is connected from the common terminal of the switch 21.

  The other MCLK is input to a main signal processing clock CLK1 generation circuit such as a TS signal, which includes a 1 / M frequency divider 333, a phase detector 334, and an oscillator 335. The output clock CLK1 is input to the MOD 34 and the converter 39. Converter 39 is a clock frequency converter, and converts the output frequency of clock CLK1 to SCLK having the same frequency as main signal MCLK.

  The output of SCLK is input to the s terminal of the M / S switch 331 of the clock generator 33 of the modulation unit 3b operating as the other standby system, and the clock generator 33 is slaved to the active (master). Works.

  The M / S switch 331 of the clock generator 33 of the modulation unit 3b selects and outputs SCLK from the modulation unit 3a to the 1 / N divided cycle 332. The current / spare (M / S) setting is set by the switch 21 of the distribution switching unit 2. The operation of the modulation unit 3b after SCLK is input is the same as that of the modulation unit 3a. That is, the main signal (TS signal or the like) is processed by CLK1 generated from SCLK generated by the modulation unit 3a, and the SC signal is similarly processed by CLK2 generated from SCLK.

  With the above processing, the main signal and the speed-converted SC signal are also synchronized between the active system and the standby system, and the standby modulation unit 3b and TX4b also generate relay signals in preparation for switching to generate a hot standby state. Wait at. And even if switching between active and standby is performed, seamless switching is performed without shifting the phase timing.

  In the receiving-side equipment antennas 5r, RFs 8a, 8b, etc., even if there is a system switching on the transmitting side, the system on the receiving side is maintained as it is, in other words, the active / standby switching is not performed in conjunction with the relay signal. Seamless transmission is maintained. Further, the baseband SC signal demodulated to speed conversion and further demodulated to the original contact signal is also transmitted seamlessly.

  As described above, in the radio relay apparatus according to the embodiment of the present invention, the baseband signal of the SC signal input to the modulation unit separately from the main signal can be switched seamlessly.

The systematic diagram of the radio relay apparatus by the Example of this invention. The functional block diagram explaining the system | strain switching of SC signal. The block diagram which shows the function structure of a clock generator. The systematic diagram of the radio relay apparatus of the program signal of the conventional digital broadcasting. The functional block diagram explaining the system switching process of the conventional SC signal.

Explanation of symbols

1 DIV (distributor)
2 Distribution switch 21 Switch 22 Speed converter 23 Distributor 3a, 3b Modulator 33 Clock generator 34 Digital processor 35 Mixer 36 Oscillator 37 Amplifier 331 M / S switch 332 1 / N divider 333 1 / M Peripherals 334, 337 Phase detector 335, 338 Oscillator 336 1 / n minute period 4a, 4b TX (transmitter)
5s SW (switch)
5t antenna
7 H (hybrid)
8a, 8b RX (receiver)
9a, 9b Demodulator 10, 11 SW

Claims (2)

In a radio relay apparatus that transmits a main signal of an input broadcast radio wave and an SC signal as a relay signal, and uses a transmission antenna in common and switches between two transmission facilities between an active system and a standby system.
First distribution means for branching and outputting the input main signal to the two transmission facilities;
Either one of the two transmission facilities is set as an active system and the other is set as a standby system, and the converted SC signal is obtained by converting the speed of the SC signal input according to clock information input from the transmission facility. Distribution switching means for branching and outputting to the two transmission facilities.
Transmitting means for transmitting a relay signal obtained by multiplexing and modulating the input main signal and the converted SC signal, each being converted from a master clock of the input main signal to a first frequency A first clock for processing the main signal, a second clock converted to a second frequency for speed conversion processing of the SC signal, and the first clock at the frequency of the master clock A first and second transmission equipment comprising clock generating means for generating and outputting a restored third clock;
When the distribution switching unit sets the first transmission facility to the active system,
The first transmission facility transmits the third clock generated from the input main signal to the second transmission facility via the distribution switching means. The second transmission facility includes the first and second clocks. And outputting the relay signal by receiving the converted SC signal generated by the distribution switching means at the output destination of the second clock,
The second transmission unit generates the first clock and the second clock slaved to the first transmission facility by the input third clock, generates the relay signal, and waits A relay radio apparatus characterized by: A distribution means; a switching means for setting a working or standby system; and first and second transmission equipment for transmitting a relay signal obtained by multiplexing and modulating an input main signal and an SC signal, and a transmission antenna. In the system switching method of the radio relay apparatus that operates by switching the system of the first and second transmission equipment in common to the active system and the standby system in common,
The first distribution means branches and outputs the input main signal to the two transmission facilities,
The first transmission means generates a first clock for processing the main signal converted from a master clock of the main signal from the first distribution means to a first frequency, and the master clock The second clock and the third clock obtained by restoring the first clock to the frequency of the master clock are generated and output to the switching means, and the relay including the SC signal input from the switching means Output signal,
The switching means to which the second clock is input includes:
When the SC signal of the first transmission rate is always input and the first transmission facility is set to be an active system, the setting of inputting the master clock of the main signal to the first transmission facility; The third transmission output from the first transmission facility is set to be input to the second transmission facility, and the first transmission is performed by the second clock input from the first transmission facility. Convert the speed to the second transmission speed and output it as a new SC signal to the first and second transmission equipment,
The second transmission means to which the third clock is input is:
A system switching method for a relay radio apparatus, wherein a clock corresponding to the first and second clocks slaved to the first transmission facility is generated and waited.

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