JPH0612894B2 - Frequency synchronization method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a frequency synchronization system, and more particularly to a polarization-sharing wireless communication device in which a transmission station-origination frequency or a reception-station-origination frequency corresponding to a definite polarization is mutually exchanged. The present invention relates to a frequency synchronization method for synchronizing.

[Prior Art] Due to the degree of separation between two polarizations that are orthogonal to each other (for example, vertical polarization and horizontal polarization), polarization sharing that transmits two pieces of information at the same frequency is effective for effective use of frequency. Has been done.

In such a polarization-communicating wireless communication device, in order to make the frequencies of two polarized waves the same, it is necessary to frequency-synchronize the transmitting station-originated frequency or the receiving station-originated frequency corresponding to each polarized wave.

In the conventional frequency synchronization method, a reference frequency oscillator is provided for each polarization, one of them is frequency-synchronized with the other, and the output frequency of the transmitting station or the receiving station frequency corresponding to each polarization is controlled by the output of each reference frequency oscillator. I was using the means to do.

[Problems to be solved by the invention]

As described above, the conventional frequency synchronization method requires at least two reference frequency oscillators and one frequency synchronization circuit, and in order to improve reliability, all of them require separate spares. However, there is a drawback in that the number of components increases and the cost is high.

An object of the present invention is to provide a frequency synchronization method which is economical and which does not impair reliability.

[Means for solving problems]

The frequency synchronization method of the present invention frequency-synchronizes two transmitting station originating frequencies or two receiving station originating frequencies of a wireless communication device that transmits two pieces of information with two polarized waves that are orthogonal to each other and have the same frequency. In the frequency synchronization method, the master
One is a master and the other is a slave in response to a slave designation signal, and two reference frequency generators having the same configuration are provided, each of which outputs a reference signal serving as a reference of the transmission station-originated frequency or the reception station-originated frequency. One of the two reference frequency generators outputs an oscillation signal having the same frequency as the reference signal and outputs an alarm signal in the event of an oscillation abnormality, and one of the oscillation signals is branched into two, and one of the two is used as the reference frequency. A branch circuit for outputting to the other of the generators, a switching circuit controlled by a control signal to select the output of one of the branch circuits of the two reference frequency generators and output it as the reference signal, the master circuit A control circuit that generates the control signal and the output signal from a slave designation signal, the alarm signal, and the input signal, and outputs the output signal from the two reference frequencies. Configured as the input signal of the other of said control circuit having generator.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating an embodiment.

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

In the embodiment shown in FIG. 1, the vertical polarization (abbreviated as V) side reference signal generating section 1 and the horizontal polarization (abbreviated as H) side reference signal generating section 2 have the same configuration, and the lowest order. Each building block and each signal having a code with the same numeral in each digit are the same.

The V-side reference signal generator 1 includes a crystal oscillator 11 that outputs an oscillation signal 101 and an alarm signal 102, and an oscillation signal 101.
A hybrid 12 that branches into two and outputs one of them to the H-side reference signal generator 2, and the other output of the hybrid 12 controlled by the control signal 105 or the H-side reference signal generator 2.
The switch 13 that selects the output of the hybrid 22 and outputs it as the reference signal 103, and the control circuit 14 that inputs the alarm signal 102 and the designation signal 104 and outputs the control signal 105. The control circuit 14 is connected to the control circuit 24 of the H-side reference signal generator 2 by a signal line 100.

First, both the crystal oscillators 11 and 12 normally generate the oscillation signal 10
The operation of the embodiment shown in FIG. 1 will be described for the case where 1, 201 is output and the alarm signals 102, 202 are not output.

In response to designation signals 104 and 204 input from the outside, (for example) control circuit 14 designates V-side reference signal generator 1 as a master, and control circuit 24 designates H-side reference signal generator 2 as a slave. When specified in this way, the control circuit 1
4 and 24 are switch 1 by control signals 105 and 205
The connections of Nos. 3 and 23 are the connections shown by the solid lines. Therefore, the output of the crystal oscillator 11 is output as the reference signal 103 via the hybrid 12 switch 13 and is output as the reference signal 203 via the hybrid 12 switch 23. The reference signals 103 and 203 serve as a reference for the frequency of the transmitting station or the frequency of the receiving station on the V / H side. On the other hand, the oscillation signal 201 is transmitted through the hybrid 22 to
The crystal oscillator 21 is spared by terminating at one terminal of the switches 13 and 23. If the master / slave designation is reversed from the above, the output of the crystal oscillator 21 becomes the reference signals 103 and 203, and the crystal oscillator 11 becomes a spare.

Next, the operation of the embodiment shown in FIG. 1 will be described for the case where the crystal oscillator 11 or 21 has an oscillation abnormality and outputs the alarm signal 102 or 202. It is assumed that the V-side reference signal generator 1 is designated as the master and the H-side reference signal generator 2 is designated as the slave.

When the crystal oscillator 21 on the slave side becomes abnormal,
The control circuit 24 detects this by the alarm signal 202 and notifies the control circuit 14 via the signal line 100. At this time, the switch 1 by the control circuits 14 and 24
The control of the switches 3 and 23 does not change, and the switches 13 and 23 continue to receive the input from the normal crystal oscillator 11.

When the crystal oscillator 11 on the master side has abnormal oscillation,
The control circuit 14 detects this by the alarm signal 102. Further, the control circuit 14 confirms that the information from the control circuit 24 for detecting the oscillation abnormality of the crystal oscillator 21 is not input, and then notifies the control circuit 24 of the oscillation abnormality of the crystal oscillator 11 via the signal line 100. To do. When the above operation is completed, the control circuits 14 and 24 switch the switches 13 and 23.
The connection is made as shown by the dotted line. Therefore, it is output as the reference signals 103 and 203 of the normal output of the crystal oscillator 21. When the oscillation abnormality of the crystal oscillator 11 is recovered and the alarm signal 102 disappears, the control circuits 14 and 24 return the switches 13 and 23 to the original connection (illustrated by the solid line), and the output of the crystal oscillator 11 changes to the reference signal 103. At 203, the crystal oscillator 21 returns to the standby state.

Although one embodiment of the present invention has been described above, the reference signal may be the transmission station-originated signal itself or the reception station-originated signal itself.

〔The invention's effect〕

As described in detail above, the frequency synchronization method of the present invention is
Since there is no need for a frequency synchronization circuit, but only one oscillation circuit is provided by providing two oscillation circuits, there is an advantage that the number of constituent elements is small, the cost is high, and the reliability is high. Since the two reference frequency generators have exactly the same configuration, there is an effect that the productivity is good.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the frequency synchronization system of the present invention. 1 ... V side reference signal generator, 2 ... H side reference signal generator 11,21 ... Crystal oscillator, 12,22 ... Hybrid, 13,23 ... Switch, 14,24 ... Control circuit

Claims (1)

[Claims] 1. A frequency synchronization system for frequency-synchronizing two transmitting station originating frequencies or two receiving station originating frequencies of a wireless communication device transmitting two pieces of information with two polarized waves which are orthogonal to each other and have the same frequency. In the above, a reference frequency generation unit having the same configuration, one of which is a master and the other of which is a slave according to a master / slave designation signal, and which outputs a reference signal serving as a reference of the transmission station oscillation frequency or the reception station oscillation frequency, respectively. One of the two reference frequency generators includes an oscillation circuit that outputs an oscillation signal having the same frequency as the reference signal and outputs an alarm signal when an oscillation abnormality occurs; A branch circuit for outputting to the other of the two reference frequency generators, and one of the branch circuits of the two reference frequency generators controlled by a control signal. A switching circuit that selects a force and outputs it as the reference signal; and a control circuit that generates the control signal and the output signal from the master / slave designation signal and the alarm signal input signal. A frequency synchronization method, wherein the other input signal of the control circuit of one reference frequency generation unit is used.