JP2005039550A - Gap filler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gap filler which ensures a sufficient isolation between a receiving antenna and a retransmitting antenna without using a separate measuring instrument. <P>SOLUTION: A control program of a controller CPU for controlling a circuit for processing received signals is changed to use the controller as an oscillation detector circuit 16. The gap filler comprises a reporting means 17. If a retransmission signal detected by a detector circuit 15 exceeds a reference value set by the program, the circuit 16 decides that it is in an oscillating state, operates the reporting means 17, and minimizes the gain of a second amplifier circuit 4 to maximize the attenuation values of a first and second variable attenuator circuits 10, 11. The reference value is set, based on a possible maximum value of signals in view of operation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a gap filler device that retransmits a received signal to a dead area where a radio wave from a satellite or the like does not reach directly.

  Broadcasting or communication using artificial satellites is widely used. The frequency used in such large-scale broadcasting is, for example, the S band (2.6 to 4 GHz) and a frequency that is straight ahead, so if there is an obstacle such as a building, the other side Radio waves are difficult to reach and a so-called insensitive area occurs. Therefore, when such satellite broadcasting is to be used for a moving body such as a vehicle, it is necessary to eliminate the insensitive area, and as a countermeasure, a gap filler device is installed in each insensitive area. . This gap filler device is intended to eliminate the dead area by installing a receiving antenna in a place where radio waves from satellites can be received well, and re-radiating the received signal with a retransmission antenna installed in the dead area. is there. (For example, patent document 1).

JP 2001-230718 A

Such a gap filler device includes, for example, a method of retransmitting at the same frequency as the transmission frequency from the satellite. In that case, the space between the receiving antenna and the retransmitting antenna is sufficient because the retransmit signal does not circulate in the space where the satellite signal does not reach at all, such as an underground shopping center or underground parking lot. Can be ensured and can be made to act satisfactorily.
However, it is difficult to ensure isolation between the receiving antenna and the retransmitting antenna in places such as in the shade of a building or in the semi-underground, and the radio waves re-radiated by the gap filler device are reflected and enter the receiving antenna. In this case, an oscillation phenomenon occurs, which adversely affects the gap filler device and other receiving devices. Therefore, in such an environment, sufficient attention should be paid to the arrangement and direction of both antennas, but it is difficult to predict the reflection of radio waves, and it is installed while checking the presence or absence of oscillation using a separate measuring instrument. It was.

  In view of the above problems, an object of the present invention is to provide a gap filler device that can ensure sufficient isolation between a reception antenna and a retransmission antenna without using a separate measuring instrument.

In order to solve the above-mentioned problem, the invention of claim 1 processes a received signal in a gap filler device that receives a satellite signal or a terrestrial signal and retransmits the signal at the same frequency as the reception frequency toward an area where direct reception is not possible. A signal processing unit including an amplification circuit, an attenuation circuit, and the like, a control unit that controls the signal processing unit, a detection circuit that detects a retransmission signal, and a magnitude of a detection signal of the detection circuit An oscillation detection circuit for detecting oscillation and an informing means for informing of the occurrence of oscillation when the oscillation detection circuit detects oscillation.
With this configuration, it is possible to know the presence or absence of oscillation without using a separate measuring instrument, and it is possible to easily isolate the receiving antenna and the retransmitting antenna and arrange the receiving antenna and the retransmitting antenna that do not oscillate. it can.

According to a second aspect of the present invention, in the first aspect of the invention, the oscillation detection circuit determines that the oscillation has occurred when the detection signal of the detection circuit exceeds the reference value, and operates the reference value with the input level maximized. It is characterized by being set to a maximum value that is possible or slightly larger than the maximum value.
With this configuration, since the reference value is set based on the maximum value that can be used in operation, there is no malfunction that detects the received signal as oscillation, and the operator can reliably ensure isolation by relying on the operation of the notification means. .

According to a third aspect of the present invention, in the first or second aspect of the present invention, the oscillation detection circuit is a control unit that controls the signal processing unit. When the CPU of the control unit detects oscillation, the notification unit is operated to perform a notification operation, and further amplified. The circuit is programmed to turn off the operating power of the circuit, maximize the attenuation of the attenuation circuit, or perform at least one circuit protection operation.
With this configuration, the present invention can be configured without providing a new circuit simply by providing a notification means and changing the program of the control unit, and the internal circuit and peripheral wireless devices are not adversely affected by oscillation.

According to a fourth aspect of the invention, in the third aspect of the invention, the oscillation detection circuit automatically cancels the circuit protection operation after a predetermined time has elapsed after the circuit protection operation, and performs an operation of outputting a retransmission signal.
With this configuration, even if the circuit protection operation is performed, it automatically returns after a predetermined time, so that the gap filler device can be installed smoothly.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the notification means includes a wireless transmission means for wirelessly reporting the occurrence of oscillation, and a monitoring device for receiving the wireless signal of the wireless transmission means is separately provided. It is provided that the occurrence of oscillation can be monitored remotely.
With this configuration, it is possible to centrally manage a plurality of gap filler devices in one place, so that the occurrence of oscillation can be recognized early.

Thus, according to the present invention, it is possible to know the presence or absence of oscillation without using a separate measuring instrument, and it is possible to easily implement isolation between the receiving antenna and the retransmission antenna.
Further, since the reference value is set to the maximum possible value in operation, there is no malfunction that detects the received signal as oscillation, and the operator can reliably ensure the isolation by relying on the operation of the notification means.
Furthermore, by changing the CPU control program of the control unit so that the control unit is also used as an oscillation detection circuit, the gap filler device of the present invention can be configured with a simple change by simply providing a notification means, and oscillation can be performed. By performing a circuit protection operation to turn off the output when detected, the internal circuit and peripheral wireless devices are not adversely affected.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described in detail with reference to the drawings. FIG. 1 is a circuit block diagram of a gap filler apparatus main body according to the present invention. 1a is a signal input unit for connecting a satellite signal receiving antenna 1, and 2a is a signal output unit for connecting a retransmission antenna 2 that radiates a retransmission signal. In the meantime, a signal processing unit for processing the received signal is provided.

  Specifically, the signal processing unit includes first to fifth amplifier circuits 3 to 7 for amplifying signals (of which the second amplifier circuit 4 is a variable amplifier circuit), and a bandpass for removing noise outside the band. Filters 8 and 9, first and second variable attenuation circuits 10 and 11, and an attenuator 12 are provided. Further, a coupler (branch circuit) 14 for taking out an output signal is provided immediately before the signal output unit 2, 15 is a detection circuit that converts the signal from the coupler into a DC voltage, and 16 is oscillated from the output of the detection circuit 15. An oscillation detection circuit 17 for detecting is a notification means that performs a notification operation when oscillation is detected, and is provided with a light emitting diode. However, the oscillation detection circuit 16 also serves as a control unit that controls the signal processing unit.

  FIG. 2 is a block diagram of the oscillation detection circuit 16. The oscillation detection circuit 16 is mainly configured by a CPU 20 provided in the control unit, and a function such as oscillation detection is added by changing a control program of the CPU 20. As described above, since the control unit also serves as the oscillation detection circuit 16, the CPU 20 receives the output signal of the detection circuit 15 through the A / D conversion circuit 21 and operates the notification signal output unit that operates the notification unit 17. The control signal output units 10a and 11a for controlling the first and second variable attenuation circuits 10 and 11 and the control signal output unit 4a for controlling the gain of the second amplifier circuit 4 are provided. The first and second variable attenuation circuits 10 and 11 and the second amplification circuit 4 are connected to the first and second variable attenuation circuits 10 and 11 via D / A conversion circuits 22, 23, and 24, respectively.

The output signal of the detection circuit 15 converted into a digital signal by the A / D conversion circuit 21 is input to the CPU 20, and the presence or absence of oscillation is determined. Then, the CPU 20 performs an oscillation detection operation as follows.
When the CPU 20 compares the input signal with the set reference value and determines that there is oscillation, the CPU 20 first operates the notifying means 17 to turn on or blink the light emitting diode. The reference value is programmed to a maximum value that can be used in the operation of the retransmission signal, or a value slightly larger than each. Here, the maximum value is obtained in a state where the attenuation amount of the first and second variable attenuation circuits 10 and 11 is minimized, the gain of the second amplification circuit 4 which is a variable amplification circuit is maximized, and the input level is maximized. The value is a value that further anticipates temperature fluctuations. The notification means 17 may be a buzzer that outputs a notification sound, or it is effective to combine both light and sound.

  If it is determined that oscillation has occurred, the operation power supply for the second amplifier circuit 4 is turned off, and a circuit protection operation is performed to maximize the attenuation amounts of the first and second variable attenuation circuits 10 and 11. Then, after the circuit protection operation, the program is programmed to start the re-transmission operation by performing a return operation after a predetermined time (for example, after 50 mS). Note that the notification means 17 continues the notification operation until the oscillation stop is confirmed.

As described above, since the oscillation detection circuit is provided, it is possible to know the presence or absence of oscillation without using a separate measuring instrument, and it is possible to easily isolate the reception antenna and the retransmission antenna.
Further, since the reference value is set to the maximum possible value in operation, there is no malfunction that detects a signal as oscillation, and the operator can reliably ensure isolation by relying on the operation of the notification means.
Furthermore, by changing the CPU control program of the control unit so that the control unit is also used as an oscillation detection circuit, the gap filler device of the present invention can be configured with a simple change by simply providing a notification means, and oscillation can be performed. By performing a circuit protection operation to turn off the output when detected, the internal circuit and peripheral wireless devices are not adversely affected. And even if it performs circuit protection operation | movement, since it resets automatically after the predetermined time, the installation operation | work of a gap filler apparatus can be implemented smoothly.

  Specifically, when the received satellite signal is 2.6 GHz in the S band, the detection circuit 15 is capable of detecting a band from DC to 3 GHz. When the gain of the amplifier circuit is high, noise increases. Therefore, a band-pass filter 9 is provided in front of the coupler 14 so that the power of the signal component can be measured as accurately as possible. In the above-described embodiment, the control unit of the input signal processing circuit is also used as the oscillation detection circuit, but an oscillation detection circuit may be provided separately.

FIG. 3 shows another example of the gap filler device of the present invention. The configuration of the notification unit is different from the configuration of FIG. 1 and includes a wireless transmission unit. As shown in FIG. 3, the notification unit 17 includes a display unit 17a including a display unit such as a light emitting diode, and a transmission unit 17b that includes a transmission antenna 17c and receives a signal from the CPU and performs a wireless transmission operation. The receiving device 18 serving as the monitoring device is configured to receive the notification signal of the notification unit 17 at a remote location. In addition, the same code | symbol is provided to the component similar to FIG. 1, and description is abbreviate | omitted.
In this way, by providing a transmission unit as a wireless transmission means to notify the occurrence of oscillation wirelessly and to be able to receive the notification at a remote location, a plurality of gap filler devices can be centrally managed at one place, and the occurrence of oscillation is prevented. Recognize early and reliably. In particular, when a large signboard, etc. is installed in the re-transmission area, the gap filler device may suddenly oscillate due to the reflected wave. In such a case, it is possible to respond quickly by monitoring wirelessly. Become.

Note that the form of wireless transmission may use a public telephone line. In this case, if the transmission unit is a mobile phone and the reception device is a personal digital assistant (PDA), remote monitoring can be performed using an existing device. Become.
Moreover, although the said embodiment demonstrated the satellite reception, it is effective also for terrestrial broadcasting, and can be effectively utilized for the elimination of the dead area especially for terrestrial digital broadcasting.

It is a circuit block diagram showing an example of an embodiment of a gap filler device concerning the present invention. FIG. 2 is a block diagram of the oscillation detection circuit of FIG. 1. It is a circuit block diagram which shows the other example of a gap filler apparatus.

Explanation of symbols

1 .. Receiving antenna 2.. Retransmission antenna 4.. Second amplifier circuit 10.. First variable attenuation circuit 11.. Second variable attenuation circuit 14. 16 .. Oscillation detection circuit (control unit), 17 .. Notification means, 17 b... Transmission unit (wireless transmission means), 18.

Claims (5)

In a gap filler device that receives satellite signals or terrestrial signals and retransmits them at the same frequency as the reception frequency toward an area where direct reception is not possible,
A signal processing unit including an amplification circuit for processing a received signal, an attenuation circuit, and the like, a control unit for controlling the signal processing unit, a detection circuit for detecting a retransmit signal, and a detection signal of the detection circuit A gap filler device comprising: an oscillation detection circuit that detects oscillation from the magnitude of the oscillation; and an informing means for informing the occurrence of oscillation when the oscillation detection circuit detects oscillation. When the detection signal of the detection circuit exceeds the reference value, the oscillation detection circuit determines that oscillation has occurred, and the reference value is a maximum value that is possible in operation with the input level maximized, or a value slightly larger than the maximum value. The gap filler device according to claim 1. The oscillation detection circuit is a control unit that controls the signal processing unit. When the CPU of the control unit detects oscillation, the notification unit is operated to perform notification operation, and the operation power of the amplifier circuit is turned off or the attenuation amount of the attenuation circuit is maximized. 3. A gap filler device according to claim 1 or 2 programmed to perform at least one circuit protection operation. 4. The gap filler device according to claim 3, wherein the oscillation detection circuit automatically cancels the circuit protection operation after a predetermined time has elapsed after the circuit protection operation and outputs a retransmission signal. 5. The notification means according to claim 1, further comprising a wireless transmission means for wirelessly notifying the occurrence of oscillation, and a separate monitoring device for receiving a wireless signal from the wireless transmission means, wherein the oscillation occurrence can be remotely monitored. The gap filler device described.

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