JPH10154973A - Communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a relation station hold the phase synchronization of a basic frequency even when a transmitting station intermittently operates by holding an input voltage to a voltage control oscillator when in data propagation and applying a hold input voltage to the oscillator when in non-propagation. SOLUTION: A flip-flop circuit 16 samples transmission data 100 by the output signal of the voltage control oscillator 14, synchronizes it with a synchronizing frequency, and generates reproducing transmission data 102a. In this state, if the propagation of the transmission data 100 is stopped on a transmission path 3, the output of a multivibrator 8 keeps a high level, so that both switch circuits 9 and 12 are kept being switched on a II and a IV sides, respectively. Thus, like the output signal of a circuit 12, a constant voltage which is charged in a capacity 11 is applied to the oscillator 14. Since this constant voltage is an input voltage to the voltage control oscillator 14 at the time when phase synchronization is performed based on the transmission data propagated before, the output of the voltage control oscillator 14 maintains the phase synchronization state even if transmission data is not inputted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication apparatus for relaying transmission data from a transmitting station, and more particularly to a relay station capable of maintaining phase synchronization of a fundamental frequency in an intermittent operation of the transmitting station. Related to a communication device.

[0002]

2. Description of the Related Art A conventional communication apparatus synchronizes a synchronization frequency in a relay station with a fundamental frequency of the transmission station from a reference clock of transmission data transmitted from a transmission station on a transmission line, and based on the synchronization frequency, transmits the transmission data. Is reproduced and propagated to other relay stations, receiving stations, and the like using a transmission path.

FIG. 3 is a configuration block diagram showing an example of such a conventional communication device. In FIG. 3, 1a and 1b
Is a fundamental frequency oscillator, 2a and 2b are transmission data transmitters, 3 and 6 are transmission lines, 4 is a phase synchronization circuit, 5 is a transmission data reproduction circuit, 52 is a receiving station, 100 and 101 are transmission data, and 102 is reproduction. This is transmission data.

[0004] Further, 1a and 2a designate a transmitting station 50a as 1
b and 2b constitute a transmitting station 50b, and 4 and 5 constitute a relay station 51, respectively.

The output of the fundamental frequency oscillator 1a is a transmitter 2a
And the output of the fundamental frequency oscillator 1b is
Connected to. The outputs of the transmitters 2a and 2b are connected to one end of the transmission path 3.

The other end of the transmission line 3 is connected to a relay station 51,
The output of the relay station 51 is connected to one end of the transmission line 6, and the other end of the transmission line 6 is connected to the receiving station 52.

Here, the operation of the conventional example shown in FIG. 3 will be described. In the transmitting station 50a, the transmitter 2a uses the fundamental clock "f" based on the output frequency "F1" of the fundamental frequency oscillator 1a.
The transmission data 100 including the 1 ″ component is generated and propagated to the transmission path 3.

The relay station 51 causes the phase synchronization circuit 4 to synchronize the phase of the synchronization frequency “F2” with the basic frequency “F1” based on the basic clock “f1” component included in the transmission data 100 propagated on the transmission line 3.

The transmission data reproducing circuit 5 reproduces the transmission data in synchronization with the synchronization frequency “F2” from the phase synchronization circuit 4 and propagates the reproduction transmission data 102 to the transmission line 6. In addition, the receiving station 52 receives the reproduced transmission data 102 transmitted through the transmission path 6.

Similarly, in the transmitting station 50b, the transmitter 2b
Generates transmission data 101 including a basic clock “f2” component based on the output frequency “F1” of the basic frequency oscillator 1 b and propagates the transmission data 101 to the transmission line 3.

The relay station 51 synchronizes the phase of the synchronization frequency “F2” with the basic frequency “F1” based on the basic clock “f2” component included in the transmission data 101 transmitted through the transmission line 3 in the phase synchronization circuit 4.

The transmission data reproducing circuit 5 reproduces the transmission data by synchronizing the phase with the synchronizing frequency "F2" from the phase synchronizing circuit 4 and propagates the reproduction transmission data 102 to the transmission line 6. In addition, the receiving station 52 receives the reproduced transmission data 102 transmitted through the transmission path 6.

As a result, the fundamental frequency "F"
By generating 102 the reproduced transmission data based on the synchronization frequency “F2” synchronized with “1” and transmitting it to the receiving station 52, the transmission data can be relayed.

[0014]

However, in the prior art, when the transmission data 100 from the transmitting station 50a does not propagate, the synchronization frequency "F2" in the relay station 51 is phase-synchronized with the fundamental frequency "F1". There is a problem that data errors easily occur and communication quality cannot be maintained.

In the above situation, if the signal including the basic clock component "f1" is always propagated on the transmission path 3, the phase synchronization of the synchronization frequency "F2" in the relay station 51 can be maintained. I can do it.

However, as shown in the conventional example of FIG.
When the transmission path 3 is shared by a plurality of transmission stations 0a and 50b, the transmission data intermittently propagates in the transmission path 3 every time the transmission station is switched.

As a result, the transmission data does not always propagate to the transmission line 3, the synchronization frequency "F2" in the relay station 51 is not phase-synchronized with the fundamental frequency "F1", and a data error is likely to occur, so that the communication quality is maintained. There is a problem that I did not say. Therefore, an object of the present invention is to realize a communication device capable of maintaining phase synchronization of a fundamental frequency at a relay station even when a transmitting station intermittently operates.

[0018]

According to the present invention, there is provided a communication apparatus for relaying transmission data from a transmitting station, wherein the oscillation frequency of a voltage controlled oscillator is determined based on the transmission data. Phase synchronization means for performing phase synchronization with a frequency, and holding means for holding an input voltage to the voltage-controlled oscillator when the transmission data is input, and applying the held input voltage to the voltage-controlled oscillator when the transmission data is not input And transmission data reproducing means for reproducing and outputting the transmission data in synchronization with the output of the phase synchronization means.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration block diagram showing one embodiment of a communication device according to the present invention.

In FIG. 1, 1a, 2a, 3, 6, 50a
And 100 have the same reference numerals as in FIG.
Is a flip-flop circuit, 8 is a monomultivibrator, 9 and 12 are switch circuits, 10 is a resistor, 11 and 13 are capacitors, 14 is a voltage controlled oscillator, 15 is an inverter circuit, and 102a is reproduced transmission data.

Reference numerals 7 to 16 denote relay stations 51a and 7, 1
Reference numerals 3 and 14 denote the phase synchronization means 53, 8, 9, 10, 11
And 12 constitute a holding means 54, and 15 and 16 constitute a transmission data reproducing means 55, respectively.

The output of the fundamental frequency oscillator 1a is a transmitter 2a
, And the output of the transmitter 2 a is connected to one end of the transmission line 3.

The other end of the transmission line 3 is connected to a flip-flop circuit 7
, The input terminal of the monomultivibrator 8 and the input terminal of the flip-flop circuit 16.

The output of the flip-flop circuit 7 is connected to the input terminal of the switch circuit 9 and one input terminal of the switch circuit 12, and one output terminal of the switch circuit 9 is connected to one end of the resistor 10.

The other end of the resistor 10 is connected to one end of the capacitor 11 and the other input circuit of the switch circuit 12, and the output of the switch circuit 12 is connected to one end of the capacitor 13 and the voltage controlled oscillator 14
Is connected to the input terminal.

The output of the voltage controlled oscillator 14 is connected to the input terminal of the flip-flop circuit 7 and the input terminal of the inverter circuit 15, and the output of the inverter circuit 15 is connected to the clock terminal of the flip-flop circuit 16.

The output of the flip-flop circuit 16 is connected to the transmission line 6 as reproduced transmission data 102a, and the output of the monomultivibrator 8 is connected to the switch circuits 9 and 1.
2 control terminals. Further, the capacity 11
And 13 are grounded, and the other output terminals of the switch circuit 9 are opened.

The operation of the embodiment shown in FIG. 1 will now be described with reference to FIG. FIG. 2 is a timing chart showing the operation of the embodiment.

FIG. 2A shows a voltage-controlled oscillator 14.
(B) is the transmission data 100, (c) is the output signal of the mono-multi vibrator 8, (d) is the output signal of the flip-flop 7, (e) is the output signal of the switch circuit 12, and (f) is The output signal of the flip-flop circuit 16 which is the reproduction transmission data 102a, and (g) is the switch circuit 12 when the transmission data 100 is not propagated to the transmission path 3.
Is the output signal.

(A) The output signal of the voltage controlled oscillator 14 has a synchronizing frequency "F" which is phase-synchronized with the fundamental frequency "F1".
2 "and its frequency is the reference clock of the transmission data"
f1 ″ is about 10 to 20 times.

The mono-multivibrator 8 generates (b) a narrow negative pulse at the rising timing of the transmission data 100. When the output signal of the mono multivibrator 8 is at a low level, the switch circuits 9 and 11
It switches to the middle "i" and "c" sides, and in the case of the high level, switches to the "b" and "d" sides in FIG.

Therefore, (d) flip-flop circuit 7
(C) When the output signal of the monomultivibrator 8 is at a low level, the switch circuit 9 and the resistor 10
And the switch circuit 1
2 is applied to the capacitor 13 and the voltage-controlled oscillator 14.

At this time, the voltage value currently applied to the voltage controlled oscillator 14 is held in the capacitor 11.

On the other hand, in the case of the high level, (d) the output signal of the flip-flop circuit 7 is not applied anywhere, and the constant voltage charged in the capacitor 11 is supplied via the switch circuit 12 to the capacitor 13 and the voltage controlled oscillator 14. Is applied to

The voltage controlled oscillator 14 changes its oscillation frequency based on the voltage applied from the switch circuit 12 and smoothed by the capacitor 13. That is, when the voltage increases, the oscillation frequency increases, and when the voltage decreases, the oscillation frequency decreases.

Here, (d) the output signal of the flip-flop circuit 7 is obtained by sampling (b) the output signal of the voltage-controlled oscillator 14 at the rising timing of the transmission data 100.

For example, when the synchronization frequency "F2" is phase-synchronized with the fundamental frequency "F1", (d) when the output signal of the flip-flop circuit 7 goes high as shown in FIG. As shown in "", a high level voltage of a narrow pulse is applied from the switch circuit 12 to the voltage controlled oscillator 14 to increase the oscillation frequency.

Next, when the output signal of the voltage-controlled oscillator 14 is sampled at the timing shown by "c" in FIG. 2, the oscillation frequency rises at the high-level voltage and the phase is shifted. The output signal of the loop circuit 7 becomes low level as shown by "d".

For this reason, the switch circuit 12 outputs “
Since the low-level voltage of the narrow pulse indicated by "e" is applied to the voltage controlled oscillator 14, the voltage controlled oscillator 14 lowers the oscillation frequency and returns the synchronization frequency "F2" to the phase synchronization state.

The flip-flop circuit 16 is composed of (a)
(B) the transmission data 10 by the output signal of the voltage controlled oscillator 14
Since 0 is sampled, (f) reproduced transmission data 102a as shown in the output signal of the flip-flop circuit 16 is generated in synchronization with the synchronization frequency "F2".

In this state, the transmission data 100 on the transmission path 3
When the propagation of the signal ceases, the output of the mono-multivibrator 8 maintains the high level, so that both the switch circuits 9 and 12 remain switched to the "low" and "d" sides.

For this reason, a constant voltage charged in the capacitor 11 is applied to the voltage controlled oscillator 14 like the output signal of the switch circuit 12 in FIG.

This constant voltage is applied to the voltage controlled oscillator 14 at the time of phase synchronization based on the transmission data 100 that has propagated previously.
Therefore, the output of the voltage controlled oscillator 14 maintains the phase-synchronous state even when transmission data is not input.

As a result, the transmission voltage from the transmitting station 50a is intermittent by maintaining the input voltage to the voltage controlled oscillator 14 during transmission of transmission data and applying the input voltage maintained during non-propagation to the voltage control oscillator. The relay station 51a can maintain the phase synchronization of the fundamental frequency even if it is input in a random manner, preventing the occurrence of a data error and maintaining the communication quality.

Even when a plurality of transmitting stations share a transmission line, a data error occurs because the synchronization frequency "F2" of the relay station 51a maintains the phase synchronization state with the fundamental frequency "F1". Prevention and maintain communication quality.

[0046]

As is apparent from the above description,
According to the present invention, the following effects can be obtained. By holding the input voltage to the voltage-controlled oscillator during transmission of transmission data and applying the input voltage to the voltage-controlled oscillator during non-propagation, the relay station can synchronize the phase of the fundamental frequency even if the transmitting station operates intermittently. A communication device that can be held can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram showing an embodiment of a communication device according to the present invention.

FIG. 2 is a timing chart showing the operation of the embodiment.

FIG. 3 is a configuration block diagram illustrating an example of a conventional communication device.

[Explanation of symbols]

 1a, 1b Fundamental frequency oscillator 2a, 2b Transmitter 3, 6 Transmission line 4 Phase synchronization circuit 5 Transmission data reproduction circuit 7, 16 Flip-flop circuit 8 Monomultivibrator 9, 12 Switch circuit 10 Resistance 11, 13 Capacitance 14 Voltage controlled oscillator 15 Inverter circuit 50a, 50b Transmitting station 51, 51a Relay station 52 Receiving station 53 Phase synchronization means 54 Holding means 55 Transmission data reproducing means 100, 101 Transmission data 102, 102a Reproduced transmission data

Claims (1)

[Claims] 1. A communication device for relaying transmission data from a transmitting station, comprising: phase synchronization means for phase-locking an oscillation frequency of a voltage controlled oscillator to a fundamental frequency based on the transmission data; Holding means for holding the input voltage to the control oscillator, applying the held input voltage to the voltage controlled oscillator when the transmission data is not input, and reproducing the transmission data in synchronization with the output of the phase synchronization means. And a transmission data reproducing means for outputting the transmission data.