JPH03209950A - Hot and stand-by systems - Google Patents

Abstract

PURPOSE:To prevent the instantaneous disconnection caused by switching by giving the same data selected by a data selecting circuit by a switching control signal to phase modulating circuits provided on a hot system and a stand-by system, respectively, and synthesizing and outputting them. CONSTITUTION:PLL circuits 2, 3 phase-locked to an output of a reference oscillator 1 generate carrier waves of a hot system and a stand-by system, respectively and give them to phase modulating circuits 4, 5. To the circuits 4, 5, I, Q data (1), (2) subjected to phase modulation in common from a data selecting circuit 10 are given, and in the circuit 10, the I, Q data of the hot system and the I, Q data of the stand-by system are selected in accordance with a switching control signal. In such a state, each output from the circuits 4, 5 is amplified by amplifiers 6, 7, respectively and synthesized by a synthesizer. In this case, since the hot system data and the stand-by data are the same base band, both phase modulation outputs become modulation outputs having the same phase angle and amplitude, therefore, an output of the synthesizer 8 obtains an output of the amplitude of two folds.

Description

[Detailed Description of the Invention] [Summary] Regarding a hot-standby system in a transmitter, the purpose of the present invention is to realize a system that can smoothly switch between hot-standby systems without using a changeover switch. A reference oscillator, a PLL circuit, a phase modulation circuit, and an amplifier provided in the hot system and the standby system, respectively, and a combining section that combines the outputs of both amplifiers in phase, A data selection circuit is connected to select I and Q data of the same baseband in the standby system using a switching control signal.

[Industrial application field]

TECHNICAL FIELD The present invention relates to hot-standby systems, and more particularly to bot-standby systems at transmitters.

Currently, in digital wireless systems, a working-standby switching system is used on the main line, and in this case the switching mechanism is complicated, but a hot-standby system, which has a relatively simple switching mechanism, is used on branch lines. Even in such hot-standby systems, further simplification is required.

[Conventional technology]

FIG. 4 schematically shows a conventional hot-standby system, in which the hot system includes a local oscillator 21,
The carrier wave from this oscillator 21 is used as a hot system data
, Q, (phase, amplitude data), and an amplifier 6 that amplifies the modulated output from the phase modulation circuit 4. Similarly, the standby system is approximately the same as the local oscillator 21. - local oscillator 22 set to the frequency;
, a phase modulation circuit 5 that phase-modulates the carrier wave from the oscillator 22 using standby system data Is and Qs, and an amplifier 7 that amplifies the modulated output from the phase modulation circuit 5.

The outputs of the amplifiers 6 and 7 are outputted from the duplexer 9 via the changeover switch 23.

In such a system, hot system data 1,,Q
, and standby system data I8. The QS is originally the same data, but it is asynchronous to each other because it is synchronized by the master clock of each system, and is given to the phase modulation circuit 4.5 as separate data, and the data from the oscillators 21 and 22 is The carrier waves are each phase-modulated, amplified by amplifiers 6 and 7, and applied to the switch 23.

A switching control signal is applied to the switch 23, and a modulated signal of a system selected by this switching control signal is output.

[Problem to be solved by the invention]

In such a hot-standby system,
For example, since a switching diode is used as the switch 23, there is a problem that there is a momentary interruption as shown in FIG. 5 at the time of switching, and the transmitted signal becomes in an error state.

Another problem is that the switch 23 must be selected depending on the output power of the transmitter.

Therefore, an object of the present invention is to realize a system that can smoothly switch between hot and standby systems without using such a changeover switch.

[Means to solve the problem]

In order to solve the above problems, the pot-standby system according to the present invention, as shown in principle in FIG.
A common reference oscillator 1, PLL circuits 2, 3, phase modulation circuits 4, 5, and amplifiers 6.7 provided in the hot system and standby system, respectively, and a combining section 8 for in-phase combining the outputs of both amplifiers. In each phase modulation circuit 4.5,
I of the same baseband in the pot system or standby system
A data selection circuit 10 for selecting Q data using a switching control signal is connected.

[For production]

In FIG. 1, P
The LL circuits 2.3 generate carrier waves for the hot system and the standby system, respectively, and supply them to the phase modulation circuits 4, 5 (see FIG. 2).

The phase modulation circuit 4.5 is supplied with I and Q data (■, ■) that are commonly phase modulated from the data selection circuit 10.
The data selection circuit 10 selects I and Q data of the hot system and I and Q data of the standby system in accordance with a switching control signal.

Then, each output from the phase modulation circuits 4 and 5 is input to an amplifier 6.
7 and are respectively amplified and synthesized by a synthesizer 8.

At this time, since the hot system data and standby system data have the same baseband, both phase modulation outputs have the same phase angle and amplitude (A shown in FIG. 2), so the output of the synthesizer 8 As shown in FIG. 2, an output with twice the amplitude can be obtained.

In this way, a system without momentary interruptions can be realized without using a changeover switch.

〔Example〕

FIG. 3 shows an embodiment of the data selection circuit shown in FIG.
Three-chie 1...Buffer J1 for opening and closing,
Three-state buffer 12 for opening/closing standby system data ■5, three-state buffer 13 for opening/closing pot system data Q□, and three-state buffer 13 for opening/closing standby system data Q.
a buffer 14, a buffer 15 that provides the output of the buffer 11 or 12 to the phase modulation circuit 4, and a buffer that provides the output of the buffer 13 or 14 to the phase modulation circuit 5;
The inverter 17 inverts the switching control signal and supplies it to the buffer 1214.

In this embodiment, as shown in FIG. 3, when the switching control signal is at the "L°° level, the buffers 11 and 13
becomes passable and the data of the hot system TH and Q)
is selected and sent to the phase modulation circuits 4 and 5 in common, and when the switching control signal is at "H" level, the buffers 12 and 14, which have been inverted by the inverter 17, become passable and the standby system data 3 and Q can be selected and sent to the phase modulation circuits 4 and 5 in common.

Note that the above phase modulation circuit can be used as various multiphase/multilevel phase modulation circuits such as 4-phase PSK, QAM, etc.

〔Effect of the invention〕

As explained above, in the hot-standby system according to the present invention, the same data selected by the data selection circuit is given to the phase modulation circuits provided in the hot system and the standby system respectively by the switching control signal, Since the phase modulation outputs are combined and output by a combiner without a switching mechanism, there is no instantaneous interruption time due to switching, and furthermore, the combining operation has the unique effect of increasing the output power by 6 dB.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the principle of a hot-standby system according to the present invention, FIG. 2 is a diagram for explaining the operation of the hot-standby system according to the present invention, and FIG. , a diagram showing an embodiment of the data selection circuit used in the present invention, FIG. 4 is a block diagram showing the configuration of a conventional hot-standby system, and FIG. 5 is a diagram for explaining the drawbacks of the conventional example. It is a graph diagram. In FIG. 1, 1... Reference oscillator, 23... PLL circuit, 4.5... Phase modulation circuit, 6.7... Amplifier, 8... Synthesizer, 10... Data selection circuit. In the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A common reference oscillator (1) and Ps provided in the hot system and the standby system, respectively.
It includes LL circuits (2) (3), phase modulation circuits (4) (5), amplifiers (6) (7), and a combining section (8) that combines the outputs of both amplifiers in the same phase. The circuits (4) and (5) include a data selection circuit (10
) is connected to the hot-standby system.