JP2000188557A - Receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a receiver that is featured with low power consumption and a light weight. SOLUTION: A control signal generator 17 generates a control signal (g) so that output power of a variable gain amplifier 16 is constant on the basis of a DC signal (m) and outputs it to the variable gain amplifier 16 and also to a signal changeover controller 7. The signal changeover controller 7 compares voltages of control signals g-in outputted from reception circuits 1-3 and outputs a control signal (p) to a signal changeover circuit 6 so as to select a reception circuit, e.g. the reception circuit 1, that generates the lowest control voltage, for example. The signal changeover circuit 6 selects and outputs an output signal (j) of the reception circuit 1. A signal Q outputted from the signal changeover circuit 6 is given to a demodulation circuit 50. A detector 19 of the demodulation circuit 50 detects the signal Q on the basis of an output of an original oscillator 5, a low pass filter 10 eliminates an undesired signal to obtain a required demodulation signal which is amplified by an amplifier 51 and outputted to an external device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver, and more particularly, to a receiver mounted on a satellite in satellite communication.

[0002]

2. Description of the Related Art In order to receive an uplink signal from a ground station, an earth orbiting satellite needs to secure a coverage range of an antenna on a full spherical surface (solid angle). Usually, this is achieved by space diversity. That is, a plurality of antennas are provided so as to cover the entire spherical surface, and a receiving / demodulating circuit which is always on is connected to the antennas.
At this time, the installation direction of the antenna is 1 in the + X axis direction of the satellite.
There are many configurations, one in the -X-axis direction, one in the + Y-axis direction, one in the -Y-axis direction, one in the + Z-axis direction, and one in the -Z-axis direction. Are combined with the uplink signal from the minus direction to obtain one
In many cases, demodulation is performed by a demodulation circuit.

As described above, since the receiving circuit is provided for each axis, a plurality of receiving circuits are required as shown in FIG. 2, for example. The conventional receiving apparatus shown in FIG. 2 has +/-
Pairs of antennas 11, 12, 21, 22, 3 corresponding to
1 and 33, and hybrids 13, 23 and 33 that combine antenna reception (uplink) signals a to f for each axis. Further, it is configured to include receiving circuits 1 to 3 for receiving the outputs of the hybrids 13, 23, and 33, respectively, and reference signal generators (local oscillators; original oscillators) 4 and 5 for frequency conversion and detection.

Further, receiving circuits 1 to 3 respectively include low noise amplifiers 14 for pre-amplifying antenna reception signals a to f,
24, 34, and frequency converters 15, 25, 35 for converting the output of the original vibration 4 into an intermediate frequency signal. Furthermore, the variable gain amplifiers 16, 26, 36 for automatic gain control (AGC) for setting the inputs of the detectors 19, 29, 39 to a constant level, and the output levels of the variable gain amplifiers 16, 26, 36 to DC levels Power intensity detectors 18, 28, and 38 for amplitude detection at m to o are provided.

Further, control signal generators 17, 27 and 37 for generating control signals g to i for controlling the variable gain amplifiers 16, 26 and 36 based on the DC signals m to o. Detectors 19 and 2 for detecting and demodulating based on the output of
9,39. Further, a low-pass filter 1 for removing unnecessary signals from the detection outputs of the detectors 19, 29, and 39
0, 20, 30, amplifiers 51 to 53 for transmitting demodulated output
Is configured.

FIG. 2 is explained using an example of a single superheterodyne receiving circuit. It should be noted that the receivers are generally roughly classified into a straight system and a heterodyne system. Currently, most of the heterodyne systems are used for high stability and high selectivity, and a superheterodyne system is also used. Therefore, description will be made using this method, but it is applicable in principle to any method.

In FIG. 2, signals a and b from antennas 11 and 12 are combined by hybrid 13, signals c and d from antennas 21 and 22 are combined by hybrid 23, and signal e of antennas 31 and 32 is combined. , F are synthesized by the hybrid 33. Hybrid 13,23,33
Are connected to the receiving circuits 1 to 3, respectively. Hereinafter, the receiving circuit 1 will be described (the same applies to the receiving circuits 2 and 3).

[0008] The uplink signal a or b received by the antennas 11 and 12 is input to the receiving circuit 1 via the hybrid 13. In the receiving circuit 1, the uplink signal, for example, a is amplified by the low noise amplifier 14,
The frequency is converted into an intermediate frequency signal j by the frequency reduction converter 15, amplified by the variable gain amplifier 16, and output to the power intensity detector 18 and the detector 19.

The power intensity detector 18 is a non-coherent type detector and has a D in proportion to the intensity of the input signal j.
A C signal m is generated. In the control signal generator 17, DC
A control signal g is generated based on the signal m so that the output power of the variable gain amplifier 16 becomes constant, and is output to the variable gain amplifier 16. The output signal j of the variable gain amplifier 16 is
Is detected based on the output of the original vibration 5, and the low-pass filter 1
After the unnecessary signal is removed at 0 to obtain a required demodulated signal, the signal is amplified by the amplifier 51 and output to an external device (not shown).

As described above, independently providing a plurality of, for example, three, receiving circuits 1 to 3 not only increases the amount of circuits but also increases the power consumption, and increases the mounting weight, mounting space,
It is unsuitable for satellite-borne equipment that has a large power consumption limit.

Japanese Unexamined Patent Publication No. 4-158636 proposes a power supply system for a fixed terrestrial digital radio communication device of a working radio system and a redundant radio communication system constituting frequency diversity. That is, as shown in FIG. 3, power consumption is reduced by supplying power to only one of the working system and the redundant system having a high reception level.
Also, power is intermittently supplied to the system in the non-receiving state, and the receiving levels are intermittently compared.

In FIG. 3, the radio apparatus using the proposed frequency diversity has an antenna 11 for transmitting and receiving by radio waves u, and a transmission / reception signal distributor 61 connected to the antenna 11 and distributing transmission / reception signals. Further, a receiver 63, a demodulator 67, a modulator 66, and a transmitter 62 constituting one of the two systems, a receiver 64, a demodulator 69, constituting the other,
It comprises a modulator 70 and a transmitter 65, a reception switch 71 for receiving and selecting signals of two systems, a transmission switch 72, and a power distributor 68 for supplying power to devices of the two systems.

First, in the operation before the two systems, that is, the working system and the standby system, are determined, the radio signal u received by the antenna 11 is transmitted to the receiver 63 of both systems via the transmission / reception signal distributor 61. , 64. Further, the signals transmitted to the demodulators 67 and 69 and demodulated are transmitted to the reception switch 71. The reception switch 71 compares the received signals of both the active system and the standby system, selects a system having a good reception state from these two signals, and selects a device of the selected system (for example, the receiver 63 and the demodulator). Power splitter 6 so that power is supplied only to the
8 is controlled.

At this time, the system selection information v is sent to the transmission switch 72, and this information v is modulated by the modulators 66 and 70, and transmitted from the transmitters 62 and 65 via the antenna 11 to the opposite station (not shown). ). The opposing station controls based on this system selection information v to supply power to its own working system. Also, in the wireless communication apparatus shown in FIG. 3 as well, the power supply to the standby system (the receiver 64 and the demodulator 69) is stopped and the apparatus is put on standby.

In such a state, the receiving switch 71
Supplies power via a power divider 68 to a standby system that is inactive at regular time intervals, receives signals from both systems, and monitors the reception state. If the reception level of the active system being used is equal to or lower than the reference value, the standby system that has been suspended is selected, and power supply is instructed only to this standby system. Also, the reception switch 71 instructs the power distributor 68 to supply power to both systems during a time zone in which the reception status of both systems is not good.

[0016]

Problems to be Solved by the Invention
The proposal described in Japanese Patent Publication No. 6 can reduce power consumption, but does not reduce the number of circuits, and thus cannot reduce the weight. Rather, a circuit for intermittently supplying power and a circuit for comparing reception levels are required, so that an increase in weight cannot be avoided. For this reason, it is not suitable as a satellite-mounted device that requires a weight reduction of several tens g.

[0017] Further, the reception level is compared by intermittently supplying power to the non-selection-side receiving apparatus. However, since the orbiting artificial satellite has a short visible time of about 5 to 10 minutes, it is intermittent. , The possibility that a time in which a system having a weak reception level is selected may occur cannot be denied.
If you increase the intermittent frequency, you can shorten the time, but you can not solve it,
There is a problem that the effect of low power consumption is reduced.

An object of the present invention is to provide a receiving device having both low power consumption and light weight.

[0019]

According to the present invention, an X-axis,
A receiving device that performs signal reception while covering an entire solid angle using antennas provided in each of the Y-axis and Z-axis directions,
Three amplifying means for respectively amplifying the reception outputs in these three directions, level comparison means for comparing the reception output levels in the three directions, and the amplification in the direction in which the reception output level is maximum by the output of the level comparison means. There is provided a receiving apparatus comprising: a selection unit for selectively deriving an output of the unit; and a demodulation unit for detecting and demodulating an alternative derivation output by the selection unit.

The reception output level is a control signal of an automatic gain control circuit of the amplification circuit. The automatic gain control circuit is provided in an intermediate frequency amplification stage.

The operation of the present invention will be described. Focusing on the fact that only one demodulation circuit is actually effective at a given moment, and by reducing the number of demodulation circuits in an invalid state,
Realize weight reduction and low power consumption. In a plurality of systems of receiving devices constituting space diversity, a non-coherent type received power detection circuit and an automatic gain control circuit are arranged in each receiving circuit, and the received signal levels of each system are sequentially compared to be at the maximum received level. Only one system is selected and demodulated by one demodulation circuit. By reducing the number of invalid circuits and integrating them into one system, not only low power consumption but also light weight can be realized.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of a receiving apparatus according to the present invention, and the same parts as those in FIG. 2 are denoted by the same reference numerals. The receiving apparatus according to the present invention shown in FIG. 1 includes three pairs of antennas 11, 12, 21, 22, 31, and 33 corresponding to +/− of each of the XYZ axes, and receives antenna reception (uplink) signals a to f on each axis. It has hybrids 13, 23, and 33 that are synthesized every time. The receiving circuits 1 to 3 receive the outputs of the hybrids 13, 23, and 33, respectively, reference signal generators (local oscillators, original oscillators) 4 and 5 for frequency conversion and detection, and outputs j of the receiving circuits 1 to 3 ~ L
And a signal switch 6 for selecting from the following.

Further, a signal switching controller 7 for comparing the levels of the control signals g to i to generate a control signal p for controlling the signal switch 6 and a demodulation circuit 50 for demodulating the output of the signal switch 6 are provided. It is composed. And also
The receiving circuits 1 to 3 respectively include low-noise amplifiers 14, 24, and 34 for pre-amplifying the antenna reception signals a to f, and frequency converters 15, 25, and 35 for converting the output of the source 4 into intermediate frequency signals. Have.

Also, variable gain amplifiers 16, 26, 36, 16 and 2 for automatic gain control (AGC) for keeping the inputs of detectors 19, 29 and 39 at a constant level.
It has power intensity detectors 18, 28, and 38 for amplitude-detecting the output levels 6, 6, to DC levels m to o. further,
Variable gain amplifiers 16, 26, 3 based on DC signals m to o
And control signal generators 17, 27, and 37 for generating control signals g to i for controlling the control signal generator 6. And also
The demodulation circuit 50 includes a detector 19 that detects and demodulates the intermediate frequency signal q based on the output of the source 5, a low-pass filter 10 that removes unnecessary signals from a detection output of the detector 19, and an amplifier 51 that sends out a demodulation output. It is configured to have.

The operation of the embodiment of the present invention will be described. FIG. 1 is described using an example of a single superheterodyne receiving circuit. It should be noted that the receivers are generally roughly classified into a straight system and a heterodyne system. Currently, most of the heterodyne systems are used for high stability and high selectivity, and a superheterodyne system is also used.
Therefore, description will be made using this method, but it is applicable in principle to any method.

In FIG. 1, signals a and b from antennas 11 and 12 are combined by hybrid 13, signals c and d from antennas 21 and 22 are combined by hybrid 23, and signal e of antennas 31 and 32 is combined. , F are synthesized by the hybrid 33. Hybrid 13,23,33
Are connected to the receiving circuits 1 to 3, respectively. Hereinafter, the receiving circuit 1 will be described (the same applies to the receiving circuits 2 and 3).

Now, the intensity of the uplink signal a received by the antenna 11 is the maximum, and the other antennas 12, 2
Description will be made assuming that the reception intensities of 1, 22, 31, and 32 are lower (including the intensity 0). The uplink signal “a” received by the antenna 11 is input to the receiving circuit 1 via the hybrid 13. In the receiving circuit 1, the uplink signal “a” is amplified by the low-noise amplifier 14, frequency-converted to an intermediate frequency signal “j” by the circumflex converter 15, amplified by the variable gain amplifier 16, Output to the device 18 and the signal switching device 6.

The power intensity detector 18 is a non-coherent detector, and has a D proportional to the intensity of the input signal j.
Generate a C signal m. The control signal generator 17 generates a control signal g based on the DC signal m so that the output power of the variable gain amplifier 16 becomes constant, outputs the control signal g to the variable gain amplifier 16, and simultaneously outputs the control signal g to the signal switching controller 7. I do.

Here, assuming that the control signals h and i of the receiving circuits 2 and 3 have lower uplink signal levels than the receiving circuit 1, the control voltage becomes higher, for example. The signal switching controller 7 compares the voltages of the control signals g to i output from the receiving circuits 1 to 3 and selects, for example, the receiving circuit that generates the lowest control voltage, that is, the receiving circuit 1. Thus, the control signal p is output to the signal switch 6.

The signal switch 6 selects and outputs the output signal j of the receiving circuit 1. The signal q output from the signal switch 6 is input to the demodulation circuit 50. The signal q in the demodulation circuit 50 is detected by the detector 19 based on the output of the original vibration 5, an unnecessary signal is removed by the low-pass filter 10 to be a required demodulated signal, and then amplified by the amplifier 51. Output to an external (separate) device (not shown).

The signal switching controller 7 can be composed of, for example, several operational (0P) amplifier IC (semiconductor integrated circuit) elements in circuit scale, and the signal switch 6 can be composed of several MMIC (monolithic microwave integrated circuit) elements. . Therefore, for example, it can be realized with a weight of about 30 g and a power consumption of about 0.3 W.

On the other hand, the demodulation circuit is composed of, for example, about ten or more 0P amplifier elements. For example, the weight is about 100 g, and the power consumption is about 1 W. Therefore, when three receiving devices (= receiving circuit + demodulating circuit) are mounted, the demodulating circuit is
For example, while the power is 300 g and 3 W, in the embodiment of the present invention, the total is 130 g and 1.3 W, for example, including the signal switching controller, the signal switch, and the demodulation circuit. As a result, for example, it is possible to reduce the weight by 170 g and reduce the power consumption by 1.7 W.

[0033]

As described above, according to the present invention, a plurality of receiving circuits are provided by installing a signal switch and a signal switching controller and selecting a receiving circuit based on the gain control circuit output of each receiving circuit. Even if there is, there is an effect that one demodulation circuit can be used. Therefore, it is possible to reduce the number of demodulation circuits that are only turned on (resting), and to achieve an effect of realizing light weight and low power consumption.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a block diagram illustrating an example of a conventional receiving apparatus.

FIG. 3 is a block diagram of another example of a conventional receiving device.

[Explanation of symbols]

 1, 2, 3 Receiving circuit 4, 5 Original vibration 6 Signal switching device 7 Signal switching controller 10 Low-pass filter 11, 12, 21, 22, 31, 32 Antenna 13, 23, 33 Hybrid 14, 24, 34 Low noise amplifier 15, 25, 35 Frequency converter 16, 26, 36 Variable gain amplifier 17, 27, 37 Control signal generator 18, 28, 38 Power intensity detector 19 Detector 50 Demodulation circuit 51 Amplifier

Claims (4)

[Claims] 1. A receiving apparatus for receiving signals while covering an entire solid angle by using antennas provided in respective directions of an X axis, a Y axis, and a Z axis. Three amplifying means for amplifying, a level comparing means for comparing the received output levels in the three directions, and an output of the amplifying means in a direction in which the received output level is maximum is selectively derived from an output of the level comparing means. And a demodulating means for detecting and demodulating an alternative output derived by the selecting means. 2. The receiving apparatus according to claim 1, wherein said reception output level is a control signal of an automatic gain control circuit of said amplifier circuit. 3. The receiver according to claim 2, wherein the automatic gain control circuit is provided in an intermediate frequency amplification stage. 4. The receiving device according to claim 1, wherein the receiving device is mounted on a satellite, wherein the antenna receives an uplink signal from a ground station.