JPH0357324A - Master station communication equipment - Google Patents

Abstract

PURPOSE:To receive a packet signal from each slave station with a demodulator for conventional continuous wave reception by controlling the output of a burst wave signal from a 2nd demodulator in matching with the timing of a packet sent from a slave station. CONSTITUTION:A master station H uses a continuous wave signal A to send a control signal to slave stations V1, V2 and the stations V1, V2 send a reply control signal to the station H in terms of packet signals B, C. In such a case, the station H controls the output of a burst wave signal E from a 2nd modulator 2 in matching with the timing of packet transmission from an estimated slave station to stop the transmission. Since almost the same state as the state of receiving the signal A is supplied to the demodulator 6 of the station H, a simple demodulator to receive the signal A is enough for the demodulator 6. Thus, the packet signal from the slave stations V1, V2 is received with a conventional continuous wave reception demodulator without using a sophisticated demodulated for conventional continuous wave reception.

Description

[Detailed description of the invention] [Industrial application field] INDUSTRIAL APPLICATION This invention is utilized for the master station communication apparatus of satellite communication.

In particular, the present invention relates to a master station communication device for satellite communication in which control signals from a slave station to a master station are transmitted in the form of packet signals.

〔overview〕

The present invention provides a master station communication device for satellite communication, in which a second modulator that sends out a burst wave signal at a second frequency is provided separately from a first modulator that sends out a continuous wave signal at a first frequency, The second modulator is controlled so that the output signal of the second modulator and the packet signal at the second frequency from the slave station do not collide on the time axis of the communication satellite, and the demodulator converts the continuous wave signal into This allows a normal continuous wave reception demodulator to receive packet signals from slave stations by creating almost the same state as when receiving packet signals.

[Conventional technology]

FIG. 4 is a diagram illustrating the operation of a conventional master station communication device. FIG. 5 is a time chart of each signal of a conventional master station communication device.

Conventionally, a master station communication device has a master station H, as shown in FIG.
It is composed of a plurality of slave stations v, , V2 and a communication satellite S. As shown in the signal waveform shown in Fig. 5, the continuous wave signal A from the master station H to the slave stations V, , V2 and the slave stations V, , V
．． The satellite communication system was controlled by transmitting a control signal using a packet signal BSC from the satellite to the master station.

[Problem that the invention seeks to solve]

However, in such a conventional master station communication device, the slave station V
+ , it is necessary to receive the packet signal from V2,
Since packet signals are generated irregularly on the time axis, they have the disadvantage of requiring special control such as automatic frequency control (AFC).

Therefore, there is a drawback that the master station H needs to be equipped with a special demodulator for receiving the packet signal.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a master station communication device that can receive packet signals from slave stations Vl and V2 using a normal continuous wave reception demodulator.

[Means for solving problems]

The present invention includes a first modulator that modulates and outputs a continuous wave signal of a first frequency with a control signal, and a transmitter that transmits the output signal of the first modulator to a plurality of slave stations via a communication satellite. and,
A master station communication device comprising: receiving means for receiving a second frequency packet signal modulated by the control signal from each slave station via the communication satellite; and a demodulator for demodulating the output signal of the receiving means. In the device, based on a timing signal indicating that a packet signal is input, the above-mentioned timing signal is set so that the packet signal from each slave station and the burst wave signal of the second frequency do not collide on the time axis of the communication satellite. It is characterized in that it comprises a second modulator that outputs to a transmitting means, and the transmitting means includes means for transmitting the output signal of the second modulator as well.

[Effect]

Based on the input timing signal, the second modulator outputs the packet signal from each slave station and the burst wave signal of the second frequency to the transmitting means so that they do not collide on the time axis in the communication satellite. The transmitting means also transmits the output signal of the second modulator. (2) The above operation puts the demodulator in almost the same state as when it is receiving a continuous wave signal, so a normal continuous wave receiving demodulator can receive the packet signal from the slave station.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings. 1st
The figure is a block diagram of a communication device according to an embodiment of the present invention.

In FIG. 1, the communication device includes a first modulator 1 that modulates a continuous wave signal of a first frequency with a control signal and outputs the modulated signal, and an output signal of the first modulator 1 that is transmitted to a plurality of modulators via a communication satellite. A transmitting means 3 and an antenna 4 for transmitting to the station, an antenna 4 and a receiving means 5 for receiving a second frequency packet signal modulated with a control signal from each slave station via the communication satellite, and a receiving means. and a demodulator 6 for demodulating the output signal of No. 5.

Here, the feature of the present invention is that based on a timing signal indicating that a packet signal is input, the packet signal from each of the slave stations and the burst wave signal of the second frequency are arranged on the time axis in the communication satellite. The second modulator 2 is provided to output the signal to the transmitting means 3, and the transmitting means 3 includes a means for transmitting the output signal of the second modulator 2 in order to avoid collisions.

The operation of the master station communication device having such a structure will be explained. FIG. 2 is a diagram illustrating the operation of the master station communication device of the present invention. FIG. 3 is a time chart of each signal of the master station communication device of the present invention.

In FIGS. 2 and 3, H is the master station, v1 and V2 are slave stations, S is a communication satellite, A is the continuous wave signal from the first modulator 1 of the master station H, and E is the continuous wave signal from the first modulator 1 of the master station H. Burst signals from the two modulators 2, B and C represent packet signals from slave stations V+ and V2, and D represents an input signal to the demodulator 6 of the master station H, respectively. For example, the master station H sends a control signal using the continuous wave signal A to the slave stations V+ and V2. At this time, for example, slave station V1
sends a control signal for response to the master station H using the packet signal B.

At this time, the master station H controls the output of the burst wave signal E from the second modulator 2 in accordance with the timing of expected packet transmission from the slave station, and stops transmitting the burst wave signal. The input signal D of the demodulator 6 is as shown in FIG. By controlling in this way, the demodulator 6 of the master station H is given almost the same state as when it is receiving the continuous wave signal 8. Therefore, the demodulator 6 can be a simple demodulator for receiving the continuous wave signal A.

〔Effect of the invention〕

As described above, the present invention has an excellent effect in that a satellite communication device can be constructed using a normal continuous wave reception demodulator without using a complex packet signal reception demodulator.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a master station communication device according to an embodiment of the present invention. FIG. 2 is a diagram explaining the operation of the master station communication device of the present invention. FIG. 3 is a time chart of each signal of the master station communication device of the present invention. FIG. 4 is a diagram illustrating the operation of a conventional master station communication device. FIG. 5 is a time chart of each signal of a conventional master station communication device. DESCRIPTION OF SYMBOLS 1... First modulator, 2... Second modulator, 3... Transmitter, 4... Antenna, 5... Receiver, 6... Demodulator, S... Communication Satellite, H... Master station, V+, V2
... Slave station, A... Continuous wave signal from master station, ESC.
... Packet signal from the slave station, D, F... Input signal of the master station, E... Burst wave signal from the master station. Antenna Embodiment 1st Example (Above) Embodiment Operation Explanation Diagram 2 Embodiment Time Chart of Each Signal Figure 3

Claims (1)

[Claims] 1. A first modulator that modulates and outputs a continuous wave signal of a first frequency with a control signal, and an output signal of the first modulator that is transmitted to a plurality of slave stations via a communication satellite. a transmitting means for transmitting a signal, a receiving means for receiving a second frequency packet signal modulated by a control signal from each slave station via the communication satellite, and a demodulator for demodulating an output signal of the receiving means. In the master station communication device, the packet signal from each slave station and the burst wave signal of the second frequency are aligned on the time axis of the communication satellite based on a timing signal indicating that a packet signal is input. A master station communication device comprising: a second modulator that outputs an output signal to the transmitting means to avoid collision; the transmitting means includes means for transmitting the output signal of the second modulator together.