JPH11298421A - Synchronization repeater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct stable relay operations by very simply canceling even sneaked part of a broadcast wave sent from a transmission antenna to a reception antenna in the case that the broadcast wave sent from the master station is received by the reception antenna and the transmission antenna sends the broadcast wave with the same frequency after amplifying the received broadcast wave. SOLUTION: The synchronization repeater 1a uses a reception antenna 2 to receive a broadcast wave and generates a received signal, uses a compensation antenna 4 to receive its own sneaked wave that is sneaked to the reception antenna 2 among broadcast waves sent from a transmission antenna 3 and to generate a compensation signal. A relay amplifier section 5 amplifies a broadcast wave component included in the received signal while canceling its own sneaked wave included in the received signal and allows the transmission antenna 3 to send the broadcast wave.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous repeater used in a broadcast or transmission system, and more particularly, to a synchronous repeater for preventing oscillation of a relay amplifier when relaying a broadcast wave of the same frequency. It relates to a relay device.

[0002] The present invention relates to a synchronous relay apparatus for relaying broadcast waves using the same frequency, and receives a broadcast wave from a master station by a receiving antenna having directivity. Is amplified by the relay amplifier and retransmitted from the directional transmitting antenna, a part of the broadcast wave transmitted from the transmitting antenna is received by the directional compensating antenna, and the local station of the receiving antenna is used. By canceling the overlapping wave, even if a part of the broadcast wave transmitted from the transmission antenna goes around to the reception antenna, the relay amplification unit does not oscillate.

[0003]

2. Description of the Related Art For example, in a broadcasting system provided in a place where there are many closed areas surrounded by mountains, such as a community FM broadcast, a synchronous relay device is used to transmit broadcast waves from a master station. In addition, a broadcast wave having the same frequency as the broadcast wave transmitted from the master station is relayed so that the broadcast contents can be received in all homes.

However, such a synchronous relay device receives a broadcast wave transmitted from a master station by a receiving antenna, amplifies the broadcast wave, and transmits the broadcast wave from the transmitting antenna. In some cases, a part of the broadcast wave wraps around to the receiving antenna, and the relay transmitter constituting the synchronous relay device oscillates.

[0005] Therefore, in such a broadcasting system or transmission system, the synchronous repeater 101 shown in FIG.
Using the synchronous relay device 111 shown in FIG. 7 and the synchronous relay device 121 shown in FIG. 8, the relay transmitter does not oscillate even if a part of the broadcast wave transmitted from the transmitting antenna goes around the receiving antenna. I have to.

The synchronous repeater 101 shown in FIG. 5 has one wavelength (eg, 3690 m when λ = 3690 mm).
m), two transmitting antennas 102 that are spaced apart by
103, and each transmitting antenna 102, as shown in FIG.
A receiving antenna 104 installed at a null point (a point at which the electric field strength of a transmitted radio wave becomes almost zero) of the directional characteristic constituted by 103 and a received signal obtained by the receiving operation of the receiving antenna 104 are amplified, Each transmitting antenna 102, 1
And a relay transmitter (not shown) for transmitting broadcast waves from the transmission antennas 103 and 103 so as to prevent the broadcast waves transmitted from the transmission antennas 102 and 103 from wrapping around the reception antenna 104. , 103
While receiving the broadcast wave by the receiving antenna 104 to generate a received signal while preventing the receiving antenna 104 from interfering with each other, the received signal is amplified by the relay transmitter and broadcast from each of the transmitting antennas 102 and 103. Send a signal.

[0007] The synchronous repeater 111 shown in FIG.
Receiving antenna 11 for receiving broadcast waves having a horizontal polarization plane
2 and a relay transmitter 113 that amplifies a reception signal obtained by the reception operation of the reception antenna 112 to generate a transmission signal.
And a transmission antenna 114 for receiving a transmission signal output from the relay transmitter 113 and transmitting a broadcast wave having a vertical polarization plane. The polarization plane of the broadcast wave that can be received by the reception antenna 112 is provided. The broadcast wave is received by the receiving antenna 112 while making the polarization plane of the broadcast wave transmitted from the transmitting antenna 114 orthogonal to each other so that the transmitting antenna 114 and the receiving antenna 112 do not interfere with each other. Is generated, the received signal is amplified by the relay transmitter 113, and the broadcast signal is transmitted from each transmitting antenna 114.

[0008] The synchronous relay device 121 shown in FIG.
A receiving antenna 122 for receiving a broadcast wave, and a broadcast wave component included in the received signal while canceling the local station fogging component included in the received signal obtained by the receiving operation of the receiving antenna 122 And a transmission antenna 124 for receiving a transmission signal output from the relay amplification unit 123 and transmitting a broadcast wave. To generate a received signal, and amplify the broadcast wave component included in the received signal while canceling the local station interference component included in the received signal by the relay amplifier 123. , A broadcast wave is transmitted from the transmission antenna 124.

In this case, the relay amplification section 123 adds a received signal output from the receiving antenna 122 and the fed back inverted signal to generate a combined signal, and outputs the combined signal from the combiner 125. A relay transmitter 126 that amplifies the combined signal to generate a transmission signal, distributes a transmission signal output from the relay transmitter 126, and supplies one transmission signal to a transmission antenna 124 to transmit a broadcast wave. And a variable phase shifter 128 that takes in the other transmission signal distributed by the splitter 127, inverts the phase and generates an inverted phase signal, and a negative phase output from the variable phase shifter 128. A variable attenuator 129 for adjusting the level of the signal. And the receiving antenna 1
When generating the transmission signal by amplifying the reception signal output from 22, the phase and level of the transmission signal are adjusted,
A reverse-phase signal having substantially the same level as that of the local station echo component that wraps around from the transmitting antenna 124 to the receiving antenna 122 side and having a reversed phase is generated.
A broadcast signal component included in the received signal is amplified while generating a transmission signal while canceling the local station interference component included in the received signal, and this is supplied to the transmission antenna 124. Is sent.

[0010] Further, as a synchronous relay device obtained by improving the synchronous relay device 121 shown in FIG. 8, the amplitude included in the received signal output from the receiving antenna 122 (the received signal of the broadcast wave transmitted from the master station). Synchronous repeaters that reproduce a modulated identification signal and precisely control the phase using the identification signal have also been developed. In addition, when only one of the above-described synchronous relay devices 101, 111, and 121 is used, a sufficient D / U [the strength of the broadcast wave from the master station (D) and the strength of the own-station overhead wave (D) are satisfied. U) is not obtained, a synchronous repeater that uses the techniques used in the synchronous repeaters 101, 111, and 121 for canceling the local station overhead wave is used.

[0011]

However, the above-described conventional synchronous repeaters 101, 111, and 121 have the following problems.

First, in the synchronous relay apparatus 101 shown in FIG. 5, a broadcast wave transmitted from each of the transmitting antennas 102 and 103 is prevented from wrapping around the receiving antenna 104, so that the receiving antenna 104 does not include an own-station fogging component. There has been a problem that it is not possible to increase the transmission output of the broadcast wave transmitted from each of the transmission antennas 102 and 103 for outputting the reception signal.

Further, the synchronous relay apparatus 101 has a problem that the null point at which the receiving antenna 104 is installed fluctuates depending on a season or the like and that it is difficult to stabilize a transmission output.

In the synchronous repeater 111 shown in FIG. 7, it is assumed that the broadcast wave transmitted from the master station has a horizontal plane of polarization.
If the polarization plane of the broadcast wave received by the reception antenna 112 and the polarization plane of the broadcast wave transmitted from the transmission antenna 114 fluctuate, there is a problem that a sufficient D / U cannot be obtained.

In the synchronous repeater 121 shown in FIG. 8, even if the oscillation is prevented at the center frequency, the transmission antenna 12
4 returns to the receiving antenna 122, the actual local station overlap wave, the distributor 127, the variable phase shifter 128, and the variable attenuator 1.
The transmission antenna 12 cannot completely match the self-stationary echo component generated electrically by the transmission antenna 12.
4 is the sideband component of the broadcast wave transmitted from receiving antenna 1
In some cases, the signal may wrap around and the relay amplifier 123 may oscillate.

Further, when the attenuation rate of the variable attenuator 129 is reduced and the amount of cancellation is increased, there is a problem that the amplification becomes unstable and the modulation band is narrowed.

Further, in the synchronous relay apparatus 121, when environmental conditions and the like change, the transmission signal output from the relay amplifier 123 fluctuates not only in a short time but also in a long time. In order to stabilize the transmission output, the phase amount of the variable phase shifter 128 and the attenuation rate of the variable attenuator 129 constituting the relay amplification unit 123 are always
There was a problem that had to be adjusted.

The synchronous relay devices 101, 111, 1
In the case of using 21, sufficient D / U can be provided only in a closed space where broadcast waves from the transmitting antennas 102 and 103 do not reach the receiving antenna 104 and the like, for example, in a limited place such as an underground mall or a tunnel. When each of the synchronous relay devices 101, 111, and 121 cannot be secured and is used in an open space, the reception antenna 104 and the like are sufficiently shielded from the transmission antennas 102 and 103, and the reception antenna is not used. It is necessary to install 104 or the like in the shadow of a mountain or the like, so that there is a problem that station installation conditions are limited by that amount and free station installation cannot be performed.

Each of the synchronous relay devices 101, 111, 1
21 and the transmitting antennas 102, 103, etc., are too far apart.
4 and the transmitting antenna 10
There is a time difference between the broadcast waves transmitted from 2, 103 and the like, and the modulation band becomes narrower or the modulation becomes unstable.

In view of the above circumstances, the present invention receives a broadcast wave transmitted from a master station by a receiving antenna, amplifies the broadcast wave, and then transmits the broadcast wave of the same frequency from the transmitting antenna. It is an object of the present invention to provide a synchronous relay apparatus that can cancel a part of a broadcast wave to be received by a receiving antenna very easily and thereby perform a stable relay operation.

[0021]

According to a first aspect of the present invention, a broadcast wave from a master station is received by a receiving antenna, and a received signal obtained by the receiving operation is received. In the synchronous relay device that transmits a broadcast wave having the same frequency as the broadcast wave from the transmission antenna after the amplification, the broadcast receiver is disposed so as to be directed to the transmission antenna side, and among the broadcast waves transmitted from the transmission antenna, A compensating antenna that receives the self-station covering wave wrapping around the antenna and generates a compensation signal, and adjusts the phase and level of the compensation signal output from the compensation antenna to generate a cancel signal, and based on the cancel signal, A relay amplifying unit that removes a local station echo component in a received signal output from the receiving antenna, amplifies the signal, and supplies the amplified signal to the transmitting antenna. It is set to.

According to a second aspect of the present invention, in the synchronous relay apparatus according to the first aspect, a length of a cable for guiding a compensation signal output from the compensation antenna to the relay amplification unit, and a reception output from the reception antenna. By adjusting the length of the cable that guides the signal to the relay amplification unit, the phase of the local station echo component included in the compensation signal is reversed with respect to the phase of the local station echo component included in the received signal. It is characterized by being in phase.

According to a third aspect of the present invention, in the synchronous relay apparatus according to the first aspect, a self-station identification signal is superimposed on a broadcast wave transmitted from the transmission antenna, and the received signal is output from the reception antenna. When removing the own-station echo component, the phase and level of the compensation signal output from the compensation antenna so that the own-station identification signal component included in the received signal from which the own-station echo component has been canceled is minimized. Is adjusted to generate a cancel signal.

According to a fourth aspect of the present invention, in the synchronous relay apparatus according to the third aspect, the own station identification signal superimposed on a broadcast wave transmitted from the transmission antenna is an upper band or a lower band of the broadcast wave. Is a single carrier multiplexed into any one of the above.

According to a fifth aspect of the present invention, in the synchronous relay apparatus according to the third aspect, the own station identification signal superimposed on a broadcast wave transmitted from the transmitting antenna is a signal spread spectrum-spread in the broadcast wave. It is characterized by being.

In the above-mentioned configuration, in the first aspect, of the broadcast waves transmitted from the transmitting antenna, the local station covering wave wrapping around the receiving antenna is received by the compensating antenna arranged so as to be directed to the transmitting antenna side. A compensation signal, and a relay amplifier adjusts the phase and level of the compensation signal output from the compensation antenna to generate a cancellation signal. Based on the cancellation signal,
After removing the local station echo component in the received signal output from the receiving antenna, the signal is amplified and supplied to the transmitting antenna. Thereby, after receiving the broadcast wave transmitted from the master station by the receiving antenna and amplifying it, when transmitting the broadcast wave of the same frequency from the transmission antenna, a part of the broadcast wave transmitted from the transmission antenna is received. Even if it goes around the antenna, it is canceled very easily, and thereby a stable relay operation is performed.

According to the present invention, the length of the cable for guiding the compensation signal output from the compensation antenna to the relay amplification unit and the length of the cable for guiding the reception signal output from the reception antenna to the relay amplification unit are adjusted. Then, the phase of the local station echo component included in the compensation signal is made opposite to the phase of the local station echo component included in the received signal. Thus, by simply adjusting the length of the cable, the phase of the cancellation signal required to cancel the own-station echo component included in the received signal is adjusted, thereby further simplifying the circuit configuration. After receiving the broadcast wave transmitted from the master station by the receiving antenna and amplifying it, when transmitting the broadcast wave of the same frequency from the transmitting antenna, a part of the broadcast wave transmitted from the transmitting antenna turns to the receiving antenna. Even if it does, this is canceled and a stable relay operation is performed.

According to a third aspect of the present invention, when a self-station identification signal is superimposed on a broadcast wave transmitted from a transmitting antenna and a self-station echo component in a received signal output from the receiving antenna is removed, By adjusting the phase and level of the compensation signal output from the compensation antenna so as to minimize the own-station identification signal component included in the received signal in which the echo component has been canceled, and generating a cancellation signal, After receiving the broadcast wave transmitted from the master station by the antenna and amplifying it, when transmitting the broadcast wave of the same frequency from the transmission antenna, a part of the broadcast wave transmitted from the transmission antenna goes around to the reception antenna. However, this is almost completely canceled, a stable relay operation is performed, and the transmission output is further increased.

According to a fourth aspect of the present invention, a single carrier multiplexed in either the upper band or the lower band of the broadcast wave is used as the own station identification signal superimposed on the broadcast wave transmitted from the transmitting antenna. use. Thereby, after receiving the broadcast wave transmitted from the master station by the receiving antenna and amplifying it, when transmitting the broadcast wave of the same frequency from the transmission antenna, a part of the broadcast wave transmitted from the transmission antenna is received. Even if the signal goes around the antenna, it is canceled almost completely by a relatively simple circuit, and a stable relay operation is performed, thereby further increasing the transmission output.

According to a fifth aspect of the present invention, a signal spread spectrum of the broadcast wave is used as a self-station identification signal superimposed on the broadcast wave transmitted from the transmitting antenna. Thereby, after receiving the broadcast wave transmitted from the master station by the receiving antenna and amplifying it, when transmitting the broadcast wave of the same frequency from the transmission antenna, a part of the broadcast wave transmitted from the transmission antenna is received. Even if the signal goes around the antenna, it is canceled almost completely by a relatively simple circuit, and a stable relay operation is performed, thereby further increasing the transmission output.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS << First Embodiment >> FIG. 1 is a block diagram showing a first embodiment of a synchronous repeater according to the present invention. The synchronous relay device 1a shown in this figure is configured by a high-gain antenna whose directivity is directed to the master station side, for example, an eight-element Yagi antenna or the like, receives a broadcast wave transmitted from the master station, and receives a received signal. It is composed of a receiving antenna 2 to be generated, a transmitting antenna 3 for converting a transmission signal into a radio wave and transmitting it as a broadcast wave, and a low-gain antenna whose directivity is directed toward the transmitting antenna 3, such as a low-gain Yagi antenna. A compensating antenna 4 for receiving a local station echo wave wrapping around from the transmitting antenna 3 to the receiving antenna 2 and generating a compensating signal; A broadcast signal included in the received signal is amplified while canceling the local station overlap signal in the received signal to generate a transmission signal, which is supplied to the transmission antenna 3. And a relay amplifier 5 for.

In this case, the relay amplifying section 5 receives a compensation signal obtained by receiving the local station interference wave by the compensation antenna 4 (however, the compensation signal includes a broadcast wave component from the master station).
And a variable attenuator 6 for attenuating the compensation signal at a preset attenuation rate, and a compensation signal output from the variable attenuator 6 and shifting the phase by a preset amount of phase. A variable phase shifter 7 for generating a cancel signal, a cancel signal output from the variable phase shifter 7 and a received signal output from the receiving antenna 2 are added to each other to generate a local station echo component included in the received signal. And a relay transmitter 9 that amplifies a received signal output from the combiner 8 to generate a transmission signal.
And

In the above configuration, the reception antenna 2 receives a broadcast wave from the master station and generates a reception signal,
The compensating antenna 4 receives the local station fogging wave that wraps around the receiving antenna 2 among the broadcast waves transmitted from the transmitting antenna 3, generates a compensation signal, and supplies the generated signal to the relay amplifier 5. The variable attenuator 6 of the relay amplifier 5 takes in the compensation signal and attenuates the compensation signal at a preset attenuation rate. The variable phase shifter 7 takes in the compensation signal output from the variable attenuator 6, shifts the phase by a predetermined amount of phase, generates a cancel signal, and supplies the cancel signal to the synthesizer 8. The combiner 8 adds the cancellation signal output from the variable phase shifter 7 and the reception signal output from the reception antenna 2 to generate a reception signal in which the own-station echo component included in the reception signal is canceled. To the relay transmitter 9. The relay transmitter 9 amplifies the reception signal output from the combiner 8, generates a transmission signal, supplies the transmission signal to the transmission antenna 3, and transmits a broadcast wave from the transmission antenna 3.

As described above, in this embodiment, the broadcast wave is received by the reception antenna 2 to generate a reception signal, and the transmission antenna 3 is generated by the compensation antenna 4.
Of the broadcast wave transmitted from the receiving antenna 2, receives the own-station echo wave wrapping around the receiving antenna 2, generates a compensation signal, and cancels the own-station echo signal component included in the received signal by the relay amplifier 5. Meanwhile, the broadcast wave component included in the received signal is amplified, and the broadcast wave is transmitted from the transmission antenna 3. Therefore, after receiving the broadcast wave transmitted from the master station by the receiving antenna 2 and amplifying it,
When transmitting a broadcast wave of the same frequency from the transmitting antenna 3,
Even if a part of the broadcast wave transmitted from the transmitting antenna 3 goes around the receiving antenna 2, it can be canceled very easily and a stable relay operation can be performed.

At this time, the electric field strength of the broadcast wave transmitted from the transmitting antenna 3 is much larger than the electric field strength of the broadcast wave from the master station received by the receiving antenna 2 in a normal relay broadcasting station. The value of the broadcast wave component in the received signal obtained by receiving the broadcast wave from the master station by the large receiving antenna 2 is “D”, and the broadcast wave from the master station is received by the compensation antenna 4. Assuming that the value of the broadcast wave component in the cancel signal is “D ′” and the value of the local station overlap wave component in the cancel signal is “U”, the value of the broadcast wave component “D” included in the received signal is: The value of the broadcast wave component “D ′” included in the cancel signal has an opposite phase, and has a magnitude relationship represented by the following equation. | D '| << | D | (1) where | X |: a symbol indicating the absolute value of X

Accordingly, even if the cancel signal output from the variable phase shifter 7 and the received signal output from the receiving antenna 2 are added by the simple combiner 8 that performs the adding operation, it is included in the received signal. Without attenuating the value “D” of the broadcast wave component to be received, only the local station fogging component included in the received signal can be canceled.

In this embodiment, the broadcast wave transmitted from the transmitting antenna 3 is guided to the receiving antenna 2 and the compensating antenna 4 via one propagation path. Receiving antenna 2 at null point of wave
Is not received by the receiving antenna 2, even if the environmental conditions change and the characteristics of the propagation path change or the electric field strength of the broadcast wave transmitted from the transmitting antenna 3 changes. The local station interference wave and the local station interference wave received by the compensation antenna 4 can always have the same amplitude and phase relationship, thereby almost attenuating the broadcast wave component contained in the received signal. Without the need to efficiently cancel only the local station's wave component,
Sufficient D / U can be obtained.

In the conventional synchronous repeater, a sufficient D
Since / U cannot be obtained, the transmission output must be reduced to "1 W" or less. In this embodiment, even if the variable attenuator 6 and the variable phase shifter 7 are controlled only to some extent,
D / U can be improved by about dB to 20 dB.
As a result, the transmission output can be increased to “10 W to 100 W”, and the service area can be dramatically expanded. Furthermore, if the variable attenuator 6 and the variable phase shifter 7 are precisely controlled, the D / U can be improved by about 30 dB,
The transmission power can be increased to the kW level.

Also, in this embodiment, the feedback loop when the broadcast wave transmitted from the transmitting antenna 3 is guided to the receiving antenna 2 via one propagation path, and the feedback wave to the compensation antenna 4 via the propagation path. It is possible to eliminate a phase delay caused by the modulation frequency band where there is no path difference between the feedback loop and the feedback loop when guided, and to stabilize the broadcast wave transmitted from the transmission antenna 3 over a wide modulation frequency band. it can.

<< Second Embodiment >> FIG. 2 is a block diagram showing a second embodiment of the synchronous repeater according to the present invention. In this figure, the same parts as those in FIG. 1 are denoted by the same reference numerals.

The difference between the synchronous relay device 1b shown in this figure and the synchronous relay device 1a shown in FIG. 1 is that the length of the cable 11 for guiding the received signal output from the receiving antenna 2 to the combiner 8 of the relay amplifier 5 is shown. With the compensation antenna 4
The length of the cable 10 that guides the compensation signal output from the relay amplifier 5 to the relay amplification unit 5 is adjusted so that the phase of the compensation signal supplied to the relay amplification unit 5 is equal to the phase of the local station interference wave component included in the received signal. That is, the variable phase shifter 6 can be omitted from the relay amplifying unit 5 so that the phase is reversed.

In the above configuration, the directivity of the receiving antenna 2 can be as high as about 25 dB, and the directivity of the compensating antenna 4 is 25 dB.
Degree of directivity can be secured, and 50 dB can be secured as a difference between these levels.
The attenuation of the variable attenuator 6 is adjusted so that the local station echo component included in the received signal output from the receiving antenna 2 and the local station echo component in the cancel signal output from the variable attenuator 6 are matched. By simply adjusting the rate, it is possible to remove the local station fogging component contained in the received signal while hardly attenuating the broadcast wave component in the received signal.

As described above, in this embodiment, the phase of the local station echo component in the received signal input to the relay amplifier 5 and the local station echo component in the compensation signal input to the relay amplifier 5 are described. So that the compensating antenna 4 and the compensating antenna 4
Since the length of the cable 10 connected to the relay amplifying unit 5 is adjusted, the length of the cable 10 is adjusted only, without using a variable phase shifter. Similarly, after receiving a broadcast wave transmitted from the master station by the receiving antenna 2 and amplifying it, when transmitting a broadcast wave of the same frequency from the transmission antenna 3, one of the broadcast waves transmitted from the transmission antenna 3 is transmitted. The part is the receiving antenna 2
Can be canceled, and a stable relay operation can be performed.

Thus, the synchronous repeater 1 shown in FIG.
Compared with a, the configuration of the relay amplification unit 5 can be simplified, and the manufacturing cost of the synchronous relay device 1b can be reduced. As a result, the number of relay stations can be easily increased, and a broadcast service can be provided even in a closed area where broadcast waves from the master station do not reach.

<< Third Embodiment >> FIG. 3 is a block diagram showing a third embodiment of the synchronous repeater according to the present invention. In this figure, the same parts as those in FIG. 1 are denoted by the same reference numerals.

The difference between the synchronous relay device 1c shown in this figure and the synchronous relay device 1a shown in FIG.
To generate a self-station identification signal (for example, a single carrier frequency having a frequency determined for each relay station) from the identification signal generator 12, and transmit a transmission signal output from the relay transmitter 9. Multiplexes the own-station identification signal, superimposes the own-station identification signal on the upper band or the lower band of the broadcast wave transmitted from the transmission antenna 3, and further outputs a detector 13 and a controller on the output side of the synthesizer 8. 14, the detector 13 detects the own-station identification signal included in the received signal output from the combiner 8, and the controller 14 minimizes the level of the own-station identification signal. Thus, the attenuation factor of the variable attenuator 6 and the phase amount of the variable phase shifter 7 are adjusted.

As a result, the attenuation rate of the variable attenuator 6 and the phase amount of the variable phase shifter 7 are always maintained at optimal values,
/ U can be further increased, and the electric field strength of the broadcast wave transmitted from the transmitting antenna 3 can be further increased. As a result, as shown in FIG. Is constructed, the transmission output of each relay station 16 is increased, and an efficient network can be constructed.

As described above, in this embodiment, a carrier signal having a single frequency serving as a self-station identification signal is superimposed on either the upper band or the lower band of the broadcast wave transmitted from transmitting antenna 3. Using the compensation signal output from the compensation antenna 4, the self-station echo component is removed from the reception signal output from the reception antenna 2 and remains in the reception signal from which the self-station echo component has been removed. The level and phase of the compensation signal output from the compensation antenna 4 are automatically adjusted so that the level of the own-station identification signal is minimized, so that a cancellation signal having an optimal phase and level is generated. Therefore, even if a part of the broadcast wave transmitted from the transmitting antenna 3 wraps around the receiving antenna 2, it can be almost completely canceled, thereby stabilizing the relay operation and improving the transmission output. It is possible to increase further.

As a result, when the terrestrial digital broadcasting system 15 is constructed by SFN (single frequency network), the transmission output of each relay station 16 can be increased, and an efficient network can be constructed.

In the third embodiment, a carrier signal having a single frequency and superimposed on the upper band or the lower band of the broadcast wave transmitted from the transmitting antenna 3 is used as the own station identification signal. However, a signal superimposed on a broadcast wave in another multiplexing format, for example, a signal spread spectrum over the entire band of the broadcast wave transmitted from the transmission antenna 3 is used as a self-station identification signal. You may do it.

Even in this case, when a part of the broadcast wave transmitted from the transmitting antenna 3 reaches the receiving antenna 2, this is almost completely canceled to stabilize the relay operation and further increase the transmission output. be able to.

[0052]

As described above, according to the present invention, in the synchronous repeater according to the first aspect, the broadcast wave transmitted from the master station is received by the receiving antenna, and the broadcast wave is amplified and then transmitted from the transmitting antenna. When transmitting a broadcast wave of a frequency, even if a part of the broadcast wave transmitted from the transmitting antenna goes around to the receiving antenna, it can be canceled very easily, and thereby a stable relay operation can be performed.

In the synchronous repeater according to the second aspect, the phase of the cancellation signal necessary to cancel the own-station echo component contained in the received signal is adjusted only by adjusting the length of the cable. This makes it possible to further simplify the circuit configuration, receive a broadcast wave transmitted from the master station by the receiving antenna, amplify the broadcast wave, and then transmit the broadcast wave of the same frequency from the transmitting antenna. Even if a part of the broadcast wave transmitted from the receiver wraps around the receiving antenna, this can be canceled and a stable relay operation can be performed.

Further, in the synchronous repeater according to the third aspect, the broadcast wave transmitted from the master station is received by the receiving antenna,
After amplifying this, when transmitting a broadcast wave of the same frequency from the transmission antenna, even if a part of the broadcast wave transmitted from the transmission antenna goes around the reception antenna, this is almost completely canceled and a stable relay is performed. The operation can be performed to further increase the transmission output.

Further, in the synchronous relay device according to claims 4 and 5,
A single carrier signal or a spread spectrum signal can be used to form a self-station identification signal, whereby a broadcast wave transmitted from a master station by a receiving antenna is received and amplified. When transmitting a broadcast wave of the same frequency from the transmitting antenna, even if a part of the broadcasting wave transmitted from the transmitting antenna goes around to the receiving antenna, it can be canceled almost completely with a relatively simple circuit and stable. , The transmission output can be further increased.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a synchronous relay device according to the present invention.

FIG. 2 is a block diagram showing a second embodiment of the synchronous relay device according to the present invention.

FIG. 3 is a block diagram showing a third embodiment of the synchronous relay device according to the present invention.

4 is a block diagram showing an example of a terrestrial digital broadcasting system using the synchronous relay device shown in FIG.

FIG. 5 is a block diagram showing an example of a conventionally known synchronous relay device.

FIG. 6 is a graph showing a relationship between transmission characteristics of a transmission antenna constituting the synchronous relay device shown in FIG. 5 and an installation position of the reception antenna.

FIG. 7 is a block diagram illustrating another example of a conventionally known synchronous relay device.

FIG. 8 is a block diagram illustrating another example of a conventionally known synchronous relay device.

[Explanation of symbols]

 1a, 1b, 1c: Synchronous repeater 2: Receiving antenna 3: Transmitting antenna 4: Compensating antenna 5: Relay amplifying unit 6: Variable attenuator 7: Variable phase shifter 8: Combiner 9: Relay transmitter 10, 11: Cable 12: identification signal generator 13: detector 14: controller 15: terrestrial digital broadcasting system 16: relay broadcasting station

Claims (5)

[Claims] 1. A synchronous relay for receiving a broadcast wave from a master station by a receiving antenna, amplifying a received signal obtained by this receiving operation, and transmitting a broadcast wave having the same frequency as the broadcast wave from a transmitting antenna. In the device, a compensating antenna that is arranged so as to be directed to the transmitting antenna side, receives a local station covering wave wrapping around the receiving antenna among broadcast waves transmitted from the transmitting antenna, and generates a compensation signal, Adjusting the phase and level of the compensation signal output from the compensation antenna to generate a cancellation signal, and based on the cancellation signal, removing the own-station echo component in the reception signal output from the reception antenna, And a relay amplifying unit that amplifies and supplies the amplified signal to the transmitting antenna. 2. The synchronous relay apparatus according to claim 1, wherein a length of a cable for guiding a compensation signal output from the compensation antenna to the relay amplification unit and a reception signal output from the reception antenna are relay-amplified. Adjusting the length of the cable guided to the section to make the phase of the local station echo component included in the compensation signal opposite to the phase of the local station echo component included in the received signal. A synchronous relay device characterized by the above-mentioned. 3. The synchronous relay apparatus according to claim 1, wherein a self-station identification signal is superimposed on a broadcast wave transmitted from the transmission antenna, and a local station echo in a reception signal output from the reception antenna. When removing the components, the phase and level of the compensation signal output from the compensation antenna are adjusted so that the own-station identification signal component included in the received signal of the own-station fogging component canceled has been minimized, A synchronous repeater for generating a cancel signal. 4. The synchronous relay apparatus according to claim 3, wherein a self-station identification signal superimposed on a broadcast wave transmitted from the transmission antenna is multiplexed in one of an upper band and a lower band of the broadcast wave. A synchronous carrier, wherein the carrier is a single carrier. 5. The synchronous relay apparatus according to claim 3, wherein the own-station identification signal superimposed on a broadcast wave transmitted from the transmission antenna is a signal that is spread spectrum on the broadcast wave. A synchronous relay device characterized by the following.