JP3421712B2 - Receiver - Google Patents

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 used in a satellite communication earth station.

[0002]

2. Description of the Related Art The structure of a conventional receiving apparatus of this type is shown in FIG. In FIG. 2, the signal received by the antenna 20 is selectively derived to two paths via the switch 21c. One of the paths is selectively supplied to the working system and standby system amplifiers 6a and 6b of the first frequency band via the switch 21a, and the other path is provided to the switch 21.
It is alternatively supplied to the working system and standby system amplifiers 6c and 6d of the second frequency band via b.

The outputs of the active and standby system amplifiers 6a and 6b in the first frequency band are selectively derived by the switch 21d and supplied to the channel demultiplexer 7a, and the plurality of channel demultiplexers 8a to 8a. It is distributed to 8n respectively.

The outputs of the active and standby system amplifiers 6c and 6d in the second frequency band are selectively derived by the switch 21e and supplied to the channel demultiplexer 7b, and the plurality of channel receivers 9a to 9n. Are distributed to each.

The control unit 22 controls the switching of each of the switching units 21a to 21e, and switches the switching unit 21c of the amplifier input unit according to the reception frequency to select the amplifier that matches the reception frequency. ing. Further, when the working / standby system amplifier is selected, the switching devices 21a, 2
1b, 21d, and 21e are switched to select the input / output unit of the amplifier.

Japanese Utility Model Laid-Open No. 60-139355 discloses channel receivers 8a-8n and 9a-9 in the configuration of FIG.
In the case where a spare channel receiver is provided for n, a technique for simplifying the configuration by providing a single spare channel receiver instead of arranging the spare channel receivers in parallel for each channel receiver is shown. Has been done.

With this configuration, the input signal frequencies of the channel demultiplexers 7a and 7b of FIG. 2 are frequency-converted by a frequency synthesizer, so that a single spare channel receiver can cope with all frequencies in a wide band. What made it possible is disclosed.

[0008]

In the above-described conventional example of FIG. 2 and the example of Japanese Utility Model Laid-Open No. 60-139355, the reception frequency band is wide (for example, 11 GHz to 13 GHz).
z), the amplifier has a narrow pass band (eg, 11 GHz to 13 GHz in the 500 MHz amplification band).
It is necessary to arrange a large number of (adjusted to an arbitrary frequency band of 1) in parallel to configure the receiving device.

That is, the active system amplifiers (6a, 6a) of FIG.
It is necessary to arrange a large number of c) (two in the example of FIG. 2, but at least four in the above frequency example), and a large number of standby system amplifiers are arranged accordingly for each amplifier. There is a need to.

As a result, the switching device (2
1c) and switching devices (21a, 2) for the active / standby system
1b, 21d, 21e) increases, the control of these switching devices becomes complicated, and the maintenance / operation of the system becomes complicated.

An object of the present invention is to provide a receiving apparatus capable of coping with an amplifier having a narrow pass frequency band even if the received frequency is wide, with only one set of the active system and the standby system.

[0012]

According to the present invention, a conversion path having a frequency conversion means for performing frequency conversion of an antenna reception signal, a non-conversion path for directly deriving the antenna reception signal, and this conversion path First switching means for selectively deriving the antenna received signal to the conversion path, working system and standby system amplifying means for respectively amplifying the received signal, and respective inputs of these working system and standby system amplifying means Second switching means for selectively connecting the conversion path and the non-conversion path to each other, and output levels of the working system and standby system amplifying means, and detecting the output levels according to these output levels. A receiving device is obtained which includes a switching control of the first and second switching means and a control means for controlling the local oscillation frequency of the frequency conversion means.

[0013]

The frequency of the antenna reception signal can be freely converted by the frequency converter, and the frequency-converted output and the non-converted output are selectively supplied to the narrow band working / standby system amplifier. When the output level of these amplifiers is below a predetermined value, the local oscillation frequency of the frequency converter is controlled to be swept, and the output level of the amplifier is monitored. When the output level reaches a predetermined value, the frequency sweep is stopped. As a result, even a wide band signal can be handled by a single narrow band amplifier.

Further, the switching between the working / spare mode may be carried out by switching control when a decrease in the amplified output of the working system is detected.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, and the same portions as those in FIG. 2 are designated by the same reference numerals. The reception signal of the antenna 20 is passed through the switch 1 to the frequency converter
Are derived alternatively to the conversion path 4 and the non-conversion path 3. The frequency converter 5 includes a local oscillator 51 and a frequency mixer 52, and the local oscillator 51 is capable of frequency sweeping by a control signal from the control unit 10.

The signal that has passed through the non-conversion path 3 and the signal whose frequency has been converted through the conversion path 4 are input to the working amplifier 6a and the backup amplifier 6b via the working / standby input switcher 2, respectively. The outputs of these amplifiers 6a and 6b are selectively output via the working / standby output switch 13 and supplied to the channel demultiplexers 7a and 7b. The structure after this channel demultiplexer is the same as that of the conventional example of FIG.

The control unit 10 includes an active system amplifier 6 and a standby system amplifier 6.
a comparator 11 which detects each carrier level of a and 6b and compares it with a predetermined reference level; and a switching control of each of the switching devices 1, 2 and 13 by judging the comparison result, and a local part of the frequency converter 5. Performs sweep control of the oscillation frequency.

First, at the initial stage when the power is turned on,
The control unit 10 controls the switching unit 1 so that the antenna reception signal is supplied to the non-conversion path 3 in the illustrated state, and controls the switching units 2 and 13 to select the active amplifier 6a. .

In this state, if the carrier level which is the output of the amplifier 6a is higher than the reference value, this is detected by the comparator 11, and thereafter, the states of the respective switching devices 1, 2 and 13 are maintained in this state. It will be.

If the carrier level output from the amplifier 6a is smaller than the reference value, it is considered that the reception frequency is outside the pass frequency band of the amplifier 6a.
Controls the switches 1 and 2 so that the antenna reception signal is input to the amplifier 6a via the conversion path 4. In this state, the sweep start command is issued from the control unit 10 to the frequency converter 5
And the local oscillation frequency is swept.

The output carrier level of the amplifier 6a at the time of this frequency sweep is monitored by the comparator 11 of the control unit 10. When it becomes larger than the reference value, the frequency sweep is stopped and the local oscillation frequency at that time is maintained. This state is maintained.

The signal frequency from the communication satellite is, for example, 1
It is an arbitrary one of the 500 MHz band of the wide band of 1 GHz to 13 GHz, and once the 500 MHz band is set, it is not switched on the way, so the initial setting is sufficient as described above.

In this way, the operational state is reached, but if the active amplifier 6a fails during this operation, the output carrier level will drop, so this will be detected by the comparator 11, and the switching devices 2 and 13 will be switched by the standby amplifier 6b. Will be controlled to select.

[0025]

As described above, according to the present invention, even if the received signal frequency is outside the pass band of the amplifier, a converter is provided at the input portion of the amplifier to detect and detect a decrease in the amplifier level. Since the pass frequency of the converter is made to match the pass frequency of the amplifier by the signal, even if the received signal frequency is wide band (for example, 11 GHz to 13 GHz), the pass frequency band is narrow band (for example, 11 GHz to 11.5 GHz).
Since the z band amplifier can be used in the working / standby configuration, the control section can be simplified and the operation and maintenance can be facilitated.

[Brief description of drawings]

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

FIG. 2 is a block diagram of a conventional receiving device.

[Explanation of symbols]

1, 2, 13 switch 3 Unconverted route 4 conversion paths 5 frequency converter 6a, 6b amplifier 7a, 7b channel demultiplexer 8a-8n, 9a-9n receiver 10 Control unit 11 comparator 12 Judgment device 20 antenna 51 Local oscillator 52 mixer

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04B 1/74

Claims (5)

(57) [Claims] 1. A conversion path having frequency conversion means for performing frequency conversion of an antenna reception signal, a non-conversion path for directly deriving the antenna reception signal, and the antenna reception signal selected to the conversion path and the non-conversion path. First to derive one
Switching means, working system and standby system amplifying means for respectively amplifying received signals, and the conversion path and the non-conversion path are selectively connected to respective inputs of these working system and standby system amplifying means. Second switching means for detecting the respective output levels of the active system and the standby system amplifying means, and switching control of the first and second switching means and a local part of the frequency converting means in accordance with these output levels. A receiving device, comprising: a control unit that controls an oscillation frequency. 2. The first control unit controls the first and second switching units so that the antenna reception signal is supplied to the working system amplification unit via the non-conversion path at the initial stage. The receiving device according to claim 1, further comprising: controlling the second switching means. 3. The control means, in the initial stage,
When the output level of the working system amplifying means is lower than a predetermined value, the first switching means is controlled so that the antenna reception signal is supplied to the working system amplifying means via the converting path, and the converting path is also provided. 3. The receiving apparatus according to claim 2, wherein change control of the local oscillation frequency of the frequency conversion means is performed. 4. The control means stops the change of the local oscillation frequency when the output level of the active system amplifying means increases during the change control of the local oscillation frequency. 3. The receiving device according to item 3. 5. The control means controls the second switching means in response to a decrease in the output level of the active system amplifying means to make the standby system amplifying means the active system. The receiving device according to any one of claims 2 to 4.