JPH09200069A - High sensitivity radio receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a fault of the high sensitivity receiver installed outdoor like a mobile radio base station due to lightening surge. SOLUTION: A receiving band-pass filter 3 is made of a superconducting material, a reception signal of an antenna 1 is amplified by a low noise amplifier 4 via the filter 3 and outputted to an output terminal 5 and the filter 3 and the amplifier 4 are contained in a heat shield case 6 air-tightly, cooled by a cooling means 7 to bring the filter 3 to a superconducting state. An arrester 11 provided to an input of the filter 3 outside the heat shield case 6, an arrester 12 is provided to an output of the amplifier 4, an arrester 13 is provided to a power supply line 8 of the amplifier 4, and an arrester 14 is provided to the power supply line 9 of the cooling means 7 respectively and the heat shield case 6 and the arresters 11-14 are contained in a case 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-sensitivity wireless receiver which is applied to a base station receiver for mobile communication, satellite communication, etc. and cools a high frequency receiver to receive a desired signal.

[0002]

2. Description of the Related Art The basic structure of a conventional high sensitivity wireless receiver is shown in FIG. In this conventional receiver, an antenna 1, an antenna feeder 2 for transmitting a signal received by the antenna 1, a reception band filter 3 for selecting a signal in a desired band, and an output of the reception band filter 3 are desired. The reception low-noise amplifier 4 that amplifies with low noise up to the level and the reception signal output end 5 for outputting the reception signal amplified by the reception low-noise amplifier 4. Further, the reception band filter 3 and the reception low noise amplifier 4 are enclosed by a heat shield box 6, are insulated from the outside, and are cooled by the cooling means 7. Further, a first power supply line 8 for supplying operating power to the reception low noise amplifier 4 and a second power supply line 9 for supplying operating power to the cooling means 7 are provided respectively. Although not shown here, in order to achieve matching between the reception band filter 3 and the reception low noise amplifier 4, the reception band filter 3
An isolator may be provided between the receiving low noise amplifier 4 and the receiving low noise amplifier 4.

The reception band filter 3 and the reception low noise amplifier 4 are enclosed in a heat shield box 6 such as a Dewar bottle,
The cooling means 7 stably cools to an extremely low temperature of, for example, about several tens of K for a long time. Here, the cooling means 7 is constituted by a cryogenic refrigerator capable of stably maintaining an extremely low temperature such as several tens of K for a long time by utilizing a heat exchange cycle by compression / expansion of helium gas. These are commercially available products. Can be used.

As described above, the reception band filter 3 and the reception low noise amplifier 4 are cooled stably for a long period of time to the limit, so that the thermal noise generated in the reception band filter 3 and the reception low noise amplifier 4 is limited. In addition to the reduction, the insertion loss of the reception band filter 3 can be reduced and the attenuation characteristic of the reception filter 3 can be sharpened. As a result, the noise figure of the receiver shown in FIG. 6 is greatly improved,
The reception sensitivity is greatly improved. Therefore, by using the high-sensitivity radio receiver shown in FIG. 6, it is possible to obtain a reception output of, for example, a prescribed C / N (carrier power / noise power) even for a received signal of a low level. It is possible to obtain the effect that the transmission power on the transmission side required to obtain the received output of the C / N is small. The high-sensitivity wireless receiver is often installed outdoors or near the top of the antenna tower in order to reduce the loss due to the antenna feeder 2.

[0005]

When a conventional high-sensitivity wireless receiver is installed outdoors, it is necessary to consider avoiding a failure caused by lightning discharge. The obstacle caused by this lightning discharge is that the lightning discharge path and the communication line are electrically and magnetically coupled,
It is caused by abnormally high energy called lightning surge entering a communication line. Therefore, when the high-sensitivity wireless receiver is installed outdoors, lightning surge may intrude from the antenna or antenna feeder, and the high-sensitivity wireless receiver may be burned down, or a failure such as shock may occur.
Although it is necessary to protect the high-sensitivity wireless receiver from this lightning surge, there is a problem that the conventional high-sensitivity wireless receiver cannot protect the high-sensitivity wireless receiver from these lightning surges.

Further, when the high-sensitivity wireless receiver is installed outdoors, a method of detecting an operation abnormality of the high-sensitivity wireless receiver is to observe the level of a received signal, and if there is a decrease in the level, the operation is abnormal. There is something to detect. In this way, the abnormality detection function depending on the level of the received signal is, for example,
In a fixed line where the transmission / reception equipment does not move, the received signal level is constant, so it is possible to detect an abnormal operation of the high-sensitivity wireless receiver due to the lowered received signal level. In the base station device for use, the reception signal level changes greatly because the communication partner is constantly moving, so there is a problem that the operation abnormality of the high-sensitivity wireless receiver cannot be detected by the decrease in the reception signal level. .

An object of the present invention is to protect the high-sensitivity wireless receiver from lightning surge even when the high-sensitivity wireless receiver is installed outdoors, and the high-sensitivity wireless receiver is damaged. In case of abnormality in the transmission line,
It is an object of the present invention to provide a high-sensitivity wireless receiver that can detect a fault immediately and surely.

[0008]

According to the invention of claim 1, as in the prior art, an antenna, a reception band filter made of a superconducting material, a reception low noise amplifier, a reception signal output terminal, and A heat shield box enclosing the reception band filter and the reception low noise amplifier; cooling means for cooling the reception band filter and the reception low noise amplifier; a first power supply line connected to the reception low noise amplifier; A high-sensitivity radio receiver having a second power supply line connected to a cooling means, wherein first lightning surge protection means is provided between the antenna and the reception band filter and outside the heat shield box. A second lightning surge protection means provided between the reception low noise amplifier and the reception signal output terminal and outside the heat shield box, and on the second power supply line, and , The above A third lightning surge protection means provided outside the shielding box and a fourth lightning surge protection means provided on the first power supply line and outside the thermal shielding box are provided. The heat shield box, the cooling means, the first lightning surge protection means, the second lightning surge protection means, the third lightning surge protection means, and the fourth lightning surge protection means are in one housing. The receiving band filter is housed, and the reception band filter is made of a superconducting material, and the superconducting material is brought into a superconducting state by the cooling.

According to the invention of claim 2, the first power supply line and the fourth lightning surge protection means in the high-sensitivity radio receiver of claim 1 are omitted, and instead of this, the receiving low noise amplifier. A power separation filter in series between the second lightning surge protection means and the reception signal output terminal, and the power stabilization means for stabilizing the power separated by the power separation filter is provided in the heat shield box. Operating power is supplied to the reception low noise amplifier through the power stabilizing means, which is provided outside and inside the housing.

According to the third aspect of the present invention, the first or second aspect is provided.
In the high-sensitivity wireless receiver, the pilot signal generating means for generating a pilot signal within the range of the attenuation band of the reception band filter is provided outside the heat shield box and inside the housing, and the reception low noise is provided. An amplifier and a power supply source are shared, and pilot signal injection means for injecting the pilot signal between the reception band filter and the reception low noise amplifier is provided, and the reception signal and the pilot signal from the reception signal output end are provided. Demultiplexing means for demultiplexing, level detecting means for detecting the level of the demultiplexed pilot signal, and comparing the pilot signal detected by the level detecting means with a predetermined threshold value, Monitoring means for sending an alarm signal when the level of the detected pilot signal is below a threshold value. And said that you are.

According to the invention of claim 4, in the high-sensitivity radio receiver according to claim 3, the temperature detecting means for detecting the temperature in the heat shield box, and the pilot according to the output signal of the temperature detecting means. A pilot signal modulating means for modulating a signal is provided both outside the heat shield box and inside the housing, and the pilot signal modulating means shares a power supply source with the receiving low noise amplifier, The temperature monitoring means for demodulating the waved pilot signal to obtain temperature information in the heat shield box and sending a temperature alarm signal when the temperature information has a predetermined temperature abnormality. .

According to the invention of claim 5, claims 1 to 4
In any one of the high-sensitivity wireless receivers, the superconducting material is composed of a high temperature superconductor. According to the invention of claim 6, in the high-sensitivity wireless receiver according to any one of claims 1 to 4, the antenna and the first lightning surge protection means are connected through an antenna feeder provided outside the housing. Characterize.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the invention according to claim 1, and parts corresponding to those in FIG.
In this embodiment, a first lightning surge protection means 11 is provided between the antenna feeder 2 and the reception band filter 3 and outside the heat shield box 6, and between the reception low noise amplifier 4 and the reception signal output terminal 5. The second lightning surge protection means 12 is provided outside the heat shield box 6, the third lightning surge protection means 14 is provided on the second power supply line 9, and the fourth lightning surge protection means 14 is provided on the first power supply line 8.
The lightning surge protection means 13 is provided, the heat shield box 6, the cooling means 7, the first lightning surge protection means 11, the second lightning surge protection means 12, the third lightning surge protection means 14, and the fourth lightning protection means. The surge protection means 13 is housed in one housing 15, the reception band filter is made of a superconducting material, and the superconducting material is brought into a superconducting state by the cooling, which is different from FIG. Here, the first to fourth lightning surge protection means are composed of a safety element called a lightning arrester that protects the line, the equipment and the building from electrical damage, and abnormalities such as impact voltage due to lightning, contact between power line and communication line, etc. It is equipped with the function of discharging electricity to the ground when a voltage is applied and quickly returning to the current state. This arrester includes a carbon arrester,
There are vacuum arresters, paper arresters, gapless arresters, etc., all of which are applicable. It should be noted that none of the first lightning surge protection means 11, the second lightning surge protection means 12, the third lightning surge protection means 14, or the fourth lightning surge protection means 13 was provided inside the heat shield box 6. Is to reduce the load on the cooling means 7. As shown in FIG. 1, by providing lightning surge protection means on the communication line and the power supply line, the high-sensitivity wireless receiver can be protected from lightning surge. Further, the reception band filter 3 is formed of, for example, a microstrip line, and the ground layer and the signal line forming the microstrip line are both formed of a superconducting material, and these are in a superconducting state. The loss of the filter 3 is significantly smaller and the noise figure of the receiver is improved.

As shown in FIG. 2, the antenna 1 may be directly connected to the housing 15 without the antenna feeder 2. By removing the antenna feeder 2 in this manner, the loss of the antenna feeder 2 can be reduced, and as a result, the noise figure of the entire receiver can be improved, so that the reception sensitivity is further improved. FIG. 3 shows an embodiment of a high-sensitivity wireless receiver according to the invention of claim 2. In the present invention, as compared with the embodiment of FIG. 1, instead of the first power supply line 8 and the fourth lightning surge protection means 13, a portion between the reception low noise amplifier 4 and the second lightning surge protection means 12, In addition, the power separation filter 21 is provided outside the heat shield box 6 and inside the housing 15, and the power stabilizing means 22 for stabilizing the output power of the power separation filter 21 is provided outside the heat shield box 6. Moreover, it is different in that it is provided inside the housing 15. Neither the power separation filter 21 nor the power stabilizing means 22 is provided inside the heat shield box 6 in order to reduce the load on the cooling means 7.

As a method of supplying electric power to the reception low noise amplifier 4, a method of superimposing a direct current or a low frequency current on a reception signal and sending it out from the room, that is, a phantom power supply method can be used. In this embodiment, as a method of supplying power to the reception low noise amplifier 4, indoor reception signal demodulation means or the like is provided through a transmission line (not shown) connected to the reception signal output end 5 when phantom power supply is performed. A direct current or a low frequency current is supplied to the power separation filter 21 from the reception signal output end 5 through the transmission line. The power separation filter 21 is composed of a simple duplexer that separates a received signal from a direct current or a low frequency current. The power stabilizing unit 22 is a unit that stabilizes the direct current or the low frequency current separated by the power separating filter 21 and stably outputs the direct current of a predetermined voltage, and uses a DC-DC converter, a switching power supply, or the like. It is configurable. By doing so, there is an advantage that it is possible to configure a high-sensitivity wireless receiver while reducing the number of power cables from indoors. Although the power separation filter 21 is provided between the reception low noise amplifier 4 and the second lightning surge protection means 12 in FIG. 3, the power separation filter 21 does not include an active element and has a simple structure, and has an instantaneous withstand voltage. However, since a relatively expensive one can be manufactured at low cost, it may be provided between the second lightning surge protection means 12 and the reception signal output terminal 5. Of course, the example of FIG. 3 is preferable. The present embodiment may be applied to a configuration in which the antenna feeder 2 is removed and the antenna 1 is directly connected to the housing 15 as shown in FIG.

FIG. 4 shows an embodiment of a high-sensitivity wireless receiver according to the invention of claim 3. This embodiment is different from the embodiment of FIG. 1 in that it is connected to the output side of the fourth lightning surge protection means 13 and generates pilot signals within the range of the attenuation band of the reception band filter 3 in the pilot signal generation means 31. Is provided outside the heat shield box 6 and inside the housing 15, and the pilot signal injection means 32 for injecting the pilot signal generated by the pilot signal generation means 31 between the reception band-pass filter 3 and the reception low noise amplifier 4. And a demultiplexing means 33 for demultiplexing the received signal and the pilot signal on the transmission line 24 for transmitting the received signal from the received signal output end 5.
And the level detection means 34 for detecting the level of the demultiplexed pilot signal, and the pilot signal detected by the level detection means 34 and a predetermined threshold value are compared, and the level of the detected pilot signal is The difference is that it has a monitoring means 35 which sends out an alarm signal when it is lower than the threshold value. The reason why the pilot generating means 31 is not provided inside the heat shield box 6 is to reduce the load on the cooling means 7. Level detection means 34
Can use a selection level meter. Further, the monitoring means 35 is composed of a reference voltage generating means for generating a preset threshold voltage and a comparator or the like, or an A / D converter as a basic circuit, a microprocessor, a ROM, a RAM, etc. In any of the configurations, while monitoring the level of the pilot signal, it is determined whether or not the predetermined threshold value is exceeded, and if it is lower than the threshold value, an alarm signal is sent out. It is composed.

The pilot signal generated by the pilot signal generating means 31 is injected by the pilot signal injecting means 32. At this time, since the frequency of the pilot signal is set to fall within the attenuation band of the reception band filter 3, the injected pilot signal is reflected by the reception band filter 3 and input to the reception low noise amplifier 4, The pilot signal is not radiated from the antenna 1 and there is no fear of disturbing other systems. The reception signal to which the pilot signal is added is amplified by the reception low noise amplifier 4 and output from the reception signal output terminal 5. Therefore, for example, indoors, the received signal and the pilot signal are demultiplexed by the demultiplexing means 33, the level of the pilot signal is detected by the level detecting means 34, and the pilot signal level detected by the monitoring means 35 is a predetermined value. If you monitor whether it is low compared with, immediately if there is a failure in the high-sensitivity wireless receiver installed outdoors,
And it can be detected reliably.

Although FIG. 4 shows an example in which the pilot signal generating means 31 and the pilot signal injecting means 32 are provided in the configuration example of FIG. 1, the pilot is similarly applied to the configuration example shown in FIG. 2 or FIG. Signal generating means 31
And a pilot signal injection means 32 can be provided. Further, in FIG. 4, pilot signal injection means 3
Although the example in which 2 is not cooled by the cooling means 7 is described, the pilot means 32 may be cooled by the cooling means 7. Of course, this is the same when the pilot signal generating means 31 and the pilot signal injecting means 32 are provided in the configuration example shown in FIG. 2 or 3.

FIG. 5 shows an embodiment of the high-sensitivity radio receiver of the invention according to claim 4. This embodiment is different from the embodiment of FIG. 4 in that the temperature detecting means 41 for measuring the temperature inside the heat shield box 6 is provided inside the heat shield box 6, and is output by the pilot signal generating means 31. Modulating means 42 for modulating the pilot signal according to the output signal of the temperature detecting means 41.
Is provided outside the heat shield box 6 and inside the housing 15, and the demodulation means 43 for demodulating the modulated pilot signal is provided at the output side of the demultiplexing means 33. The modulation means 42 has a function of modulating the pilot signal when the temperature inside the heat shield box 6 detected by the temperature detection means 41 becomes higher than a predetermined threshold value. Any of amplitude modulation, phase modulation, and frequency modulation can be applied. Further, the demodulation means 43 demodulates the signal modulated by the modulation means 42 and sends out a temperature alarm when there is a modulated signal. Since it is the same as the case of FIG. 4 to judge whether or not a failure has occurred in the high sensitivity receiver by monitoring the level of the pilot signal,
The operation of modulating the pilot signal will be described below.

When the temperature inside the heat shield box 6 rises above the threshold value, the modulation means 42 frequency-modulates the pilot signal with a tone signal of 1 kHz, for example. The pilot signal thus frequency-modulated is demodulated by the demodulation means 43.
Is demodulated and a 1 kHz tone signal is detected. When there is a modulated signal in this way, it corresponds to an increase in the temperature inside the heat shield box 6, so the demodulation means 43 sends out a temperature alarm. If there is no modulated signal, the demodulation means 43 does not demodulate anything, so no temperature alarm is sent out. That is, the demodulation means 43 is a temperature warning means for obtaining temperature information in the heat shield box 6 and issuing a temperature warning when the temperature information exceeds a predetermined value. As described above, one pilot signal can be used to monitor the temperature abnormality in the heat shield box 6 and the operation abnormality of the amplifier. The modulating means 42 may modulate the pilot signal by the output signal of the temperature detecting means 41, and may issue a temperature alarm when the temperature information demodulated by the demodulating means 43, that is, the temperature alarming means becomes a predetermined temperature or higher. Although FIG. 5 is based on the configuration example of FIG. 1,
It is exactly the same as the case of the invention of claim 3 that the same effect can be obtained based on the configuration example shown in FIG. 2 or 3. Here, FIG. 5 shows an example in which the pilot signal injection means 32 is not cooled by the cooling means 7, but the pilot means 32 may be cooled by the cooling means 7. Of course, this is the same when the pilot signal generating means 31 and the pilot signal injecting means 32 are provided in the configuration example shown in FIG. 2 or 3.

Although not shown, a material containing a high temperature superconductor as a component can be used as the superconducting material when forming the reception band-pass filter 3. Examples of high-temperature superconductors include superconductors containing copper oxide as a component. Some high-temperature superconductors have a critical temperature at which the superconducting state is achieved over 100K. In such superconductors, the superconducting state can be achieved by simply cooling the liquid nitrogen to a boiling point of about 77.3K. Therefore, the cooling capacity of the cooling means 6 can be relaxed, and a smaller and cheaper cryogenic refrigerator can be used. As a result, the high-sensitivity wireless receiver can be made small and inexpensive.

[0022]

As described above, according to the present invention, even when the high-sensitivity wireless receiver is installed outdoors, the high-sensitivity receiver can be protected from a lightning surge and the high-sensitivity wireless receiver can be protected. It is possible to immediately and surely detect the failure that has occurred in 1.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing an embodiment of the invention of claim 6;

FIG. 3 is a block diagram showing an embodiment of the invention of claim 2;

FIG. 4 is a block diagram showing an embodiment of the invention of claim 3;

FIG. 5 is a block diagram showing an embodiment of the invention of claim 4;

FIG. 6 is a block diagram showing a conventional high-sensitivity wireless receiver.

Claims (6)

[Claims] 1. A reception signal from an antenna is passed through a reception band filter, an output of the reception band filter is amplified by a reception low noise amplifier and output to a reception output end, and the reception band filter and the reception low noise amplifier are provided. Is enclosed in a heat shield box, and the reception band-pass filter and the reception low noise amplifier are cooled by a cooling means, and operating power is supplied to a power supply terminal of the reception low noise amplifier through a first power supply line to the cooling means. In a high-sensitivity wireless receiver in which operating power is supplied through a second power supply line, a first lightning surge protection means provided outside the heat shield box and inserted on the input side of the reception band filter, Second lightning surge protection means provided outside the shielding box and inserted between the output side of the receiving low noise amplifier and the receiving output end, and provided outside the heat shielding box. A third lightning surge protection means inserted into the second power line, a fourth lightning surge protection means provided outside the heat shield box and inserted into the first power line, the heat shield box, It comprises one housing containing the first to fourth lightning surge protection means and the cooling means, the reception band filter is made of a superconducting material, and the cooling makes the superconducting material in a superconducting state. A high-sensitivity wireless receiver characterized in that 2. A reception signal from an antenna is passed through a reception band filter, an output of the reception band filter is amplified by a reception low noise amplifier and output to a reception output end, the reception band filter and the reception low noise amplifier. Is enclosed in a heat shield box, and the reception band-pass filter and the reception low-band noise amplifier are cooled by cooling means, and operating power is supplied to a power supply terminal of the reception low-noise amplifier through a first power supply line, and the cooling means is provided. A high-sensitivity wireless receiver in which operating power is supplied through a second power line to the first lightning surge protection means, which is provided outside the heat shield box and is inserted into the input side of the reception band filter; Second lightning surge protection means provided outside the heat shield box, inserted between the output side of the reception low noise amplifier and the reception output end, and provided outside the heat shield box The third lightning surge protection means inserted into the second power supply line and the third lightning surge protection means provided outside the heat shield box and inserted in series with the second lightning surge protection means to separate a high frequency signal and electric power. A power separation filter; power stabilization means for supplying the power separated by the power separation filter and supplying stabilized operating power to a power supply terminal of the reception low noise amplifier; the heat shield box; To a third housing for accommodating the third lightning surge protection means, the power separation filter, the power stabilization means, and the cooling means, the reception band filter is made of a superconducting material, and the superconducting material is provided by the cooling. High-sensitivity wireless receiver characterized in that the material is in a superconducting state. 3. The high-sensitivity radio receiver according to claim 1, wherein pilot signal generating means for generating a pilot signal within the attenuation band of the reception band filter is provided between the heat shield box and the housing. Pilot signal injecting means for injecting the pilot signal into a signal path between the reception band-pass filter and the reception low noise amplifier, the pilot signal injection means being provided for the operation of the reception low noise amplifier and the power supply source. Demultiplexing means for demultiplexing the received signal from the output end and the pilot signal, level detecting means for detecting the level of the demultiplexed pilot signal, and the pilot signal detected by the level detecting means It compares with a predetermined threshold value and warns if the detected pilot signal level is lower than the threshold value. High sensitivity radio receiver which is characterized in that a monitoring unit is provided for delivering the items. 4. The high-sensitivity wireless receiver according to claim 3, wherein the temperature detecting means for detecting the temperature in the heat shield box and the temperature detecting means provided between the heat shield box and the housing are provided. Pilot signal modulating means for modulating a pilot signal supplied to the pilot signal injecting means in accordance with an output signal, the pilot signal modulating means sharing a power supply source with the receiving low noise amplifier, and the receiving signal output By demodulating the demultiplexed pilot signal from the end to obtain temperature information in the heat shield box, and when the temperature information exceeds a predetermined temperature, temperature monitoring means for sending a temperature alarm signal is provided. A high-sensitivity wireless receiver, comprising: 5. The high sensitivity wireless receiver according to claim 1, wherein the superconducting material is a high temperature superconductor. 6. The high-sensitivity wireless receiver according to claim 1, wherein the antenna and the first lightning surge protection means are connected to each other through an antenna feeder provided outside the housing. And a high-sensitivity wireless receiver.