JP2002050970A - Hot-standby wireless apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a phase deviation of transmission output occurring in switching from an active system to a nonactive system, and an instantaneous cutoff of a transmission signal occurring in a switching operation. SOLUTION: In a hot-standby wireless apparatus, a modulated-carrier frequency oscillator 3 and a carrier local oscillation frequency oscillator 4 are used in common in both an active system 1 and a nonactive system 2 for a modulating part and a transmission part which are each provided in both systems, thereby, a phase variation of a received signal before and after the changeover can be suppressed within a range of pulling-in phase on demodulation. Further, switches 6, 7 of a system changeover part 5 are controlled by separate change-over signals for each system, the active system is cut off after the nonactive system starts a transmission, the instantaneous cut-off of a signal as a transmitting line is eliminated by overlapping the transmitting time of the two systems, thus, the line failure which involves an instantaneous cutoff in changing the hot-standby can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot standby system for digital radio communication having two radio transmission devices, an operation system and a non-operation system.

[0002]

2. Description of the Related Art Conventionally, this type of radio apparatus having two radio transmission / reception apparatuses, an operation system and a non-operation system, is, for example, as shown in FIG. 1
And a protection unit 2 comprising a modulation unit-2 and a transmission unit-2. The modulation unit-1 and the transmission unit-1 of the operation system 1 have a modulated carrier frequency oscillator 13-1 and a carrier local frequency oscillator 14 respectively. -1 is provided to the modulator 2 and the transmitter 2 of the protection system 2, respectively, the modulated carrier frequency oscillator 13-2 and the carrier local oscillator 14-2.
Is provided.

When the system is switched from the working system 1 to the protection system 2, the transmission of the protection system 2 is output after the transmission output of the working system 1 is turned off, and the changeover switch 12 of the switching unit 11 is disabled. This is performed by switching to the operation system 2.

[0004]

As described above, in the conventional hot standby type wireless transmission / reception apparatus, the transmission output of the protection system 2 is output after the transmission output of the operation system 1 is cut off when the system is switched. Since the switching is performed, both outputs stop when the switching is performed, and an instantaneous interruption of the signal occurs as a transmission path.

[0005] The switching operation in the hot standby system is assumed to be a case of equipment failure in the active system 1. In this case, since a line failure has already occurred in the active system 1, there is no particular problem even in the conventional switching control. However, in the switching operation when the device is operating normally, such as at the time of maintenance of the device, there is a problem that a line failure accompanied by an instantaneous interruption occurs in the operating line that is operating normally.

An object of the present invention is to provide a means for preventing a momentary interruption of a transmission signal from occurring during a switching operation when the apparatus is operating normally, such as during maintenance of the apparatus.

Another object of the present invention is to provide means for preventing occurrence of a transmission output phase shift when switching from the working system to the non-working system.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a hot standby system for digital radio communication, in which the phases of transmission signals of an active system and a non-operating system are kept within a pull-in phase range at the time of demodulation and an operation is performed in switching control. Switching is performed without causing a line failure with an instantaneous interruption by overlapping the transmission times of the active and non-operational systems.

More specifically, the radio communication apparatus of the present invention provides a common modulation carrier frequency oscillator and a common carrier wave local oscillation frequency to a modulation section and a transmission section provided in an active system and a non-active system, respectively. An oscillator is provided. By sharing these modulated carrier frequency oscillators and carrier local oscillators in the working system and the non-working system, it is possible to suppress the phase fluctuation of the received signal before and after the switching within the range of the pull-in phase during demodulation. Become.

[0010] Further, the switch of the system switching unit is controlled by an individual switching signal for each system, and after the non-operating system starts transmission, the active system is cut off, and the transmission time of the two systems is overlapped so that transmission is performed. As a path, instantaneous interruption of signal is eliminated, and switching can be performed without causing a line failure accompanied by instantaneous interruption in switching of hot standby.

[0011]

FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, a modulation unit-1 modulates input data to an intermediate frequency by a modulation carrier frequency oscillator 3 and outputs the intermediate data to a transmission unit-1. In the transmitting section-1, the intermediate frequency is converted into a carrier frequency by the carrier local oscillator 4 and output to the switching section 5.

The modulating section-2 modulates input data to an intermediate frequency by the same modulation carrier frequency oscillator 3 as the modulating section-1, and outputs the modulated data to the transmitting section-2. In the transmission unit-2,
The intermediate frequency is converted to a carrier frequency by the same carrier local frequency oscillator 4 as that of the transmission unit 1 and output to the switching unit 5.

The switching section 5 has a switch 6 for switching a signal of the transmission section-1 and a switch 7 for switching a signal of the transmission section-2. The switch 6 is a switching control signal 1 (SW CONT 1).
The switch 7 controls the switching control signal 2
Switch control is performed by (SW CONT 2).

[0014] Also, from the input of the modulation unit-1 to the transmission unit-1,
The difference between the absolute delay time of the signal path leading to the antenna 8 via the switch 6 and the absolute delay time of the signal path leading from the input of the modulation section-2 to the transmission section-2 and the antenna 8 via the switch 7 is constant. It is configured to be within.

This is to prevent a phenomenon in which a phase difference occurs between a received signal before switching and a received signal after switching as a cause of signal deterioration in a switching operation, and the phase synchronization is lost when demodulating the signal. is necessary.

That is, in the hot standby system,
A phase difference occurs because two different signal systems are switched in the transmission system. Therefore, in the present invention, in order to suppress a phase difference in the transmission system, the same data is input to the modulation unit-1 and the modulation unit-2 at the same timing. Then, the modulation unit-1
From the input to the antenna 8 via the transmission unit-1 and the switch 6.
The difference between the absolute delay time of the signal path leading to the antenna and the absolute delay time of the signal path leading from the input of the modulation section-2 to the antenna 8 via the transmission section-2 and the switch 7 is kept within a certain value. Is suppressed.

Further, at the time of modulation, the modulation unit-1 and the modulation unit-2
By using the same modulated carrier frequency oscillator 3, the phase difference of the modulated signal is suppressed. Similarly, in the frequency conversion in the transmitting unit, the same carrier-station-generated frequency oscillator 4 is used in the transmitting unit-1 and the transmitting unit-2 to suppress the phase difference after the frequency conversion.

Thus, the phase difference between the transmission signals generated in the two paths can be suppressed, and the phase fluctuation of the signal at the time of switching the transmission unit is suppressed at the reception unit, so that the phase synchronization is not lost.

Next, the operation of switch switching control in the switching unit 5 of the present invention will be described with reference to the block diagram of FIG. 1 and the timing chart of FIG.

A state in which the signal of the transmission unit-1 is in the active system and the signal of the transmission unit-2 is in the non-operational system (TX-1 output in FIG. 2).
In the case where the control of switching the signal of the transmission unit-2 to the active system is performed, first, the switch 7 is turned on (transmission state) by the switching control signal 2 (SW CONT 2), so that the signal of the transmission unit-1 is transmitted. The signal of the section -2 is output in an overlapping manner for a predetermined time (“TX-1 output + TX-2 output” in FIG. 2).
State). Thereafter, the switch 6 is turned off (transmission is cut off) by the switching control signal 1 (SW CONT 1), and the switching is completed.

As described above, according to the present invention, the transmission output times of the active system and the protection system are set so as to overlap each other, so that both the transmissions of the working system and the protection system are performed in the switching process. In this case, there is no time for disconnection, and instantaneous interruption as a line can be avoided.

FIGS. 3 and 4 are timing charts showing another embodiment of the switch switching control operation in the switching section 5 of the present invention.

In the switch switching control operation shown in FIG. 2, while the transmission output of the active system and the transmission output of the non-operating system are output in duplicate, the transmission output is doubled, and the transmission output may increase during that time. Therefore, in the switch switching control of FIGS. 3 and 4, the switch switching control operation is slightly complicated, but it is possible to avoid an instantaneous interruption of the line at the time of switch switching and to suppress the fluctuation of the transmission output at the time of switch switching. It is characterized by doing.

That is, in the switch switching control of FIG. 3, while the transmission outputs of the active system and the protection system are output in an overlapping manner, the transmission outputs of the working system and the protection system are controlled to be １ ／. , So that the transmission output when one system is transmitting alone and when both systems are transmitting at the time of switch switching are controlled to be equal to suppress the transmission output fluctuation at the time of switch switching operation I do.

In the switch switching control shown in FIG. 4, while the transmission outputs of the active system and the protection system are output in an overlapping manner, the transmission output of the working system is gradually reduced and the transmission output of the protection system is gradually reduced. , The transmission output obtained by adding both of them is controlled to be constant, and the transmission output fluctuation at the time of the switch switching operation is suppressed.

FIG. 5 is a block diagram showing another embodiment of the present invention. In FIG. 5, the modulation unit-1 includes a modulation carrier frequency oscillator 3-1. The oscillation output is branched and output to the modulation unit-2. Similarly, the modulation unit-2
Has a modulated carrier frequency oscillator 3-2, and its oscillation output is branched and output to the modulation section-2.

Further, the modulation section-1 has a selection switch 9-1 for selecting the output of the modulation carrier frequency oscillator 3-1 provided and the modulation carrier frequency signal output from the modulation section-2. Similarly, the modulation section-2 has a selection switch 9-2 for selecting the output of the modulation carrier frequency oscillator 3-2 provided and the modulation carrier frequency signal output from the modulation section-1.

Selection switch 9-1 and selection switch 9-2
Are synchronized, and by selecting the same modulation carrier frequency oscillator (3-1 or 3-2), the modulation unit
The same modulated carrier frequency oscillator is used for 1 and the modulation section-2.

In the transmitting section-1 or the transmitting section-2, similarly to the modulating section, the carrier-station-generated frequency oscillator (4-1 or 4-2) and the selection switch (10-1 or 10-).
2), and the transmission unit-1 is selected by the selection switch.
And the transmission unit 2 are configured to perform frequency conversion using the same carrier-station-generated frequency oscillator.

Modulation section selection switches (9-1, 9-2)
The switching of the selection switches (10-1 and 10-2) of the transmission unit can be independently performed independently of the switching of the signal system. Switching unit 5 for switching the signal system
Is the same as that of the embodiment shown in FIG.

In this embodiment, it is not necessary to provide an oscillator as a common system separately from each of the modulation units and the transmission unit, and the oscillators provided in each of the modulation units and the transmission unit are shared with each other. When a failure occurs in one of the oscillators, the failure of the oscillator can be avoided by switching to the other oscillator by switching the selection switch.

It should be noted that the modulated carrier frequency oscillator and the carrier local frequency oscillator according to the present invention are not limited to the case of using the oscillator of the frequency itself, but the phase locked loop (P
The same effect can be obtained by sharing the reference frequency oscillator in the case of using LL).

[0033]

According to the present invention, when switching between the active system and the non-active system, the transmission time of the active system and the non-active system are overlapped by switching off the active system after transmitting the non-active system. -There is no instantaneous interruption of the line when switching the protection system.

In addition, the signal line length (absolute delay time) of the transmission system is adjusted to be within a certain value in the working system and the non-working system, and the modulated carrier frequency oscillator and the carrier local frequency oscillator are shared by the two systems. As a result, the phase fluctuation of the received signal before and after the switching is suppressed within the pull-in phase range at the time of demodulation, so that the phase synchronization of the received signal does not deviate when switching between the active system and the non-active system.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a time chart showing a switching control operation between an active system and a non-active system in the present invention.

FIG. 3 is another time chart showing a switching control operation between an active system and a non-active system in the present invention.

FIG. 4 is another time chart showing a switching control operation between an active system and a non-active system in the present invention.

FIG. 5 is another block diagram showing an embodiment of the present invention.

FIG. 6 is a block diagram showing a conventional example.

[Explanation of symbols]

1 working system 2 non-working system 3,3-1,3-2,13-1,13-2 modulated carrier frequency oscillator 4,4-1,4-1,14-1,14-2 carrier catastrophic frequency oscillator 5, 11 switching section 6, 7 switch 8 antenna 9-1, 9-2, 10-1, 10-2 selection switch 12 switching switch

Claims (5)

[Claims] 1. A modulating section for modulating input data to an intermediate frequency by a modulating carrier frequency oscillator and a transmitting section for converting the intermediate frequency modulated by the modulating section to a carrier frequency by a carrier local oscillator and transmitting the same. An active system and a protection system, respectively, and a hot standby radio apparatus including a switching unit that selects one of the transmission outputs of the operation system and the protection system and outputs the transmission output to an antenna, wherein the modulated carrier frequency oscillator and the carrier wave The local oscillator is shared between the working system and the protection system, and when the switching unit switches the transmission output between the working system and the protection system, the transmission output of the working system and the protection system are predetermined. A hot standby wireless device that performs switch switching control so as to overlap in time. 2. A modulation section for modulating input data to an intermediate frequency by a modulation carrier frequency oscillator, and a transmission section for converting the intermediate frequency modulated by the modulation section to a carrier frequency by a carrier local oscillator and transmitting the same. An active system and a protection system, respectively, and a hot standby wireless device including a switching unit that selects any one of the transmission outputs of the operation system and the protection system and outputs the transmission output to an antenna, wherein the operation system and the protection system include: The modulation carrier frequency oscillator and the carrier local oscillation frequency oscillator provided respectively are shared by the operating system and the non-operating system, and any one of the modulation carrier frequency oscillator and the carrier oscillation frequency oscillator is used in the switching unit. When switching the transmission output between the active system and the protection system, the transmission output There hot standby radio apparatus and performs switching control so as to overlap a predetermined time. 3. An absolute delay time of a signal path from the active modulation section and the transmission section to the antenna via the switching section and the switching section, and an absolute delay time of the non-operational modulation section and the transmission section via the switching section. 3. The hot standby wireless apparatus according to claim 1, wherein a difference from an absolute delay time of a signal path to the antenna is set within a predetermined range. 4. The switching unit, wherein the transmission output of the active system and the transmission output of the protection system are overlapped and output, and the transmission output of the operation system and the protection system are individually transmitted by one of the systems. 4. The hot standby wireless device according to claim 1, wherein the switch switching control is performed so that the output is reduced to a half of the output when the device is present. 5. The switching unit gradually reduces the active transmission power and gradually increases the non-active transmission output while overlappingly outputting the active and non-active transmission outputs. The hot standby wireless device according to any one of claims 1 to 3, wherein the switch switching control is performed so that the transmission output obtained by adding both systems is constant.