JP2558006B2 - Wireless device - Google Patents

Description

The present invention relates to a wireless device (hereinafter referred to as a transponder) mounted on an artificial satellite and usable for communication with an earth station and communication between artificial satellites.

[Prior Art] In a conventional transponder, each received frequency signal is converted into an IF signal having the same intermediate frequency (hereinafter referred to as IF), and then supplied to an IF band switch and switched by the IF band switch. Then, it is sent to each transmitter. In each transmitter, the IF signal is converted into a radio signal and transmitted to the earth station or another satellite for communication.

[Problems to be Solved by the Invention] In such a configuration, each received signal is converted into an IF signal, and
Since each local oscillator for converting a signal into a transmission signal is required, i) the number of local oscillators increases, ii) the transmission capacity that can be transmitted depends largely on the IF frequency, and the electrical characteristics of the IF switch Also, because the IF frequency cannot be increased due to mechanical performance and there is an upper limit to the transmission capacity, iii) even when light waves are transmission and reception signals, a local oscillator is required for each transmission and reception, which complicates the device configuration. There is a problem that there are limits to applicable frequency bands and communication services.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a transponder in which the range of operating frequencies of the transponder and the transmission capacity are expanded.

[Means for Solving the Problems] The present invention provides a transponder that performs communication using a plurality of frequencies, and a plurality of receiving units capable of receiving different predetermined frequency bands and a signal received by the receiving unit. A converter that converts light waves, a plurality of transmitters that convert the light waves into radio frequency signals of a predetermined frequency band, respectively, and transmit the light waves supplied from the converter to the transmitters instructed by a control signal. And an optical switch for switching.

[Operation] The conversion unit, the transmission unit, and the optical switch can be configured by an optical circuit, and act so as to simplify the device configuration and reduce the size. Further, since the optical switch has an ultra-wide band characteristic, using the switch acts to increase the transmission capacity.

[Embodiment] In FIG. 1 showing an embodiment of the transponder of the present invention, antennas 1 to 3 are antennas for receiving received signals of respective frequency bands transmitted from an earth station or a satellite. Although only three antennas are shown in the drawing, there are actually as many antennas as the number of divided frequency bands. These antennas 1 to 3 are connected to high-frequency amplifiers 5 to 7, respectively, and the high-frequency amplifiers 5 to 7 are connected to electro-optical conversion circuits 8 to 10 for converting electric signals into optical signals, respectively.
Through 10 are connected to the optical switch 11.

The antenna 4 for receiving the control information signal transmitted from the earth station or satellite is connected to the high frequency amplifier 33,
The high frequency amplifier 33 is connected to the modulator / demodulator 34, and the modulator / demodulator 34 is connected to the optical switch 11 and the high frequency amplifier 35.

The optical switch 11 switches a plurality of optical signals supplied from the electro-optical conversion circuits 8 to 10 in accordance with an instruction of the control information signal demodulated by the modulator / demodulator 34 and corresponds to a desired direction. It is a switch that transmits a lightwave signal to a transmitter.

The output side of the optical switch 11 is an antenna corresponding to each direction.
To create the signals transmitted by 21 to 23, they are first connected to frequency converters 12, 14, 16. Although only three transmitting antennas are shown, more antennas are actually provided, and the same number of frequency converters 12 and the like are provided. The local converter lasers 13, 15, 17 are connected to the respective frequency converters 12, 14, 16 and the frequency converters 12, 1, 16 are connected.
Reference numerals 4 and 16 frequency-convert the light wave signal sent from the optical switch 11 to create a radio frequency signal.

The frequency converters 12, 14, 16 are connected to high-frequency amplifiers 18 to 20 for amplifying signals up to a predetermined level, and
18 to 20 are connected to the antennas 21 to 23.

The high frequency amplifier 35 described above is connected to the antenna 24.

The operation of the transponder thus configured will be described below.

Received signals 25 to 27 of each frequency band transmitted from the earth station or satellite are received by antennas 1 to 3 corresponding to each frequency band and amplified by respective high frequency amplifiers 5 to 7, Electro-optical conversion circuit 8 to 10
Is converted into a light wave signal and supplied to the optical switch 11.

In the optical switch 11, the lightwave signal is selected by the control information signal transmitted from the base station, received by the antenna 4 and demodulated by the modulator / demodulator 34, and the selected lightwave signal corresponds to the desired direction. Frequency converters belonging to
Is transmitted to at least one of the sixteen. Frequency converter 12,14,
The supplied lightwave signal is frequency-converted in 16 and the local oscillator lasers 13, 15, 17 to create a radio frequency signal. This radio frequency signal is amplified to a predetermined level by the high frequency amplifiers 18 to 20 and then transmitted via the antennas 21 to 23.

In such a transponder, since the optical switch 11 has an ultra-wide band characteristic with respect to the signal band, it is possible to perform a switching operation on the modulated signal at a high speed, and there is an advantage that the wide band signal can be transmitted by one radio frequency signal. is there.
In addition, since the components of the electro-optical conversion circuits 8 to 10, the optical switch 11, and the frequency converters 12, 14, 16 are all configured by optical circuits, the device configuration can be simplified, downsized, and lightened. And is suitable as a transponder for mounting on a satellite.

In FIG. 2 showing another embodiment of the present invention, the same components as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

For example, the wavelength converters 38 and 39 which are supplied with the light wave signals transmitted from the satellite and condensed by the optical lenses 36 and 37 and which convert the wavelengths of the light wave signals are connected to the optical switch 11. Although only two sets of the optical lens 36, the optical amplifier 38 and the like are shown, a plurality of sets more than this are actually provided.

Some output sides of the optical switch 11 are connected to wavelength converters 40 and 41 that perform wavelength conversion on the lightwave signal sent from the optical switch 11. The lightwave signals sent from the wavelength converters 40 and 41 are sent to other satellites, for example, via the optical lenses 42 and 43. Although only two sets of the wavelength converter 40 and the optical lens 42 are shown in the figure, more sets are actually provided.
The operation of the transponder configured in this way is the same as that of the above-described transponder, but the radio signals compatible with this transponder can include microwaves, millimeter waves, and even light waves.

For example, if the supplied signal is other than a light wave, it is received by the antenna 1 or the like, and if it is a light wave, it is received by the optical lens 36 or the like, and each signal subjected to predetermined conversion processing is supplied to the optical switch 11. To be done. Then, the optical switch 11 performs the switching instructed by the control information signal supplied from the base station as described above. For example, when connected to the frequency converter 12 or the like according to the instruction of the control information signal, a wireless signal is transmitted from the antenna 21. On the other hand, when connected to the wavelength converter 40 or the like, the light wave signal is transmitted from the optical lens 42 or the like.

In general, the communication between the earth station and the satellite is performed by a radio frequency signal, and the communication between the satellites is often performed by a light wave. The transponder of this embodiment has an advantage that a plurality of earth stations and a plurality of satellites can be connected by one optical switch 11 by using radio waves and light waves.

Further, since the frequency range from microwaves, millimeter waves to light waves can be processed by one optical switch 11, there is an effect that the apparatus can be greatly simplified. Further, since the transmission capacity can be increased with such a simple configuration and a plurality of earth stations and a plurality of satellites can be connected, the application area of the system using the satellites can be expanded.

[Effects of the Invention] As described in detail above, according to the present invention, since the optical switch having the ultra-wide band characteristic is provided, it is possible to expand the range of the operating frequency and the transmission capacity of the transponder,
Further, since the conversion unit, the transmission unit, and the optical switch are configured by an optical circuit, simplification of the device configuration of the transponder,
It can be miniaturized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration in one embodiment of the transponder of the present invention, and FIG. 2 is a block diagram showing a configuration in another embodiment of the transponder of the present invention. 1 to 4 ... Antenna, 8 to 10 ... Electro-optical conversion circuit, 11 ... Optical switch, 12,14, 16 ... Frequency converter, 21 to 24 ... Antenna, 34 ... Modulator / demodulator, 36, 37 ...... Optical lens, 38 to 41 …… Wavelength converter, 42,43 …… Optical lens.

Claims (2)

(57) [Claims] 1. A radio apparatus for communicating using a plurality of frequencies, comprising: a plurality of receiving sections capable of receiving different predetermined frequency bands; and a converting section for converting a signal received by the receiving section into a light wave. A plurality of transmitters for converting the light waves into radio frequency signals each having a predetermined frequency band and transmitting the radio waves, and an optical switch for transmitting the light waves supplied from the converter to the transmitters instructed by a control signal. A wireless device characterized by the above. 2. The wireless device according to claim 1, further comprising a receiving unit for directly receiving the light wave and transmitting the light wave, and a transmitting unit.