JPH0553410B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is based on a single radio frequency (speech channel)
The present invention relates to an automatic radio relay device capable of simultaneously operating radio relay for each of a plurality of call channels.

(Prior Art) Conventionally, a wireless relay device has been used as a means for relieving a dead zone or expanding a communication range in a wireless communication line. Automatic radio relay devices generally use a two-wave relay system that uses two different radio frequencies for transmission and reception, but there are also those that use a single radio frequency and those that use a multiplex radio system.
In addition, there are two types of communication methods: the press-talk method, in which the press button is pressed when transmitting a call, and transmitting radio waves are emitted only during that time, and the simultaneous transmitting and receiving method, in which different frequencies are assigned to each transmitter and receiver, and radio waves are constantly emitted while talking. However, most mobile communications are based on the press-to-talk system, so this will be explained below as an example.

First, as shown in Figure 3, the two-frequency two-way relay system for the press talk line allocates two waves with different frequencies for upstream and downstream transmission and reception, and relays the line in both directions. If a single channel is relayed, the received signal is once demodulated and then used as a modulation signal for the other transmitter, and a radio wave with a frequency different from that of the received radio wave is re-radiated.

When relaying multiple channels using this method, each channel is equipped with a transmitter/receiver, or the received wave is directly frequency-converted without demodulating the high frequency wave in the frequency band that includes the channel, and then amplified and re-radiated.

The latter method is generally called a booster relay method and is used in television broadcast satellites and the like.

As a single radio frequency two-way press talk line system, for example,
No. 11936 (Patent No. 815196) ``Two-way automatic relay device for press talk lines using the same radio frequency'' exists, and this device makes it possible to relay two-way press talk lines using a single radio frequency. In this method, two sets of transmitters and receivers are placed on both sides of mountains or buildings, and each intermediate frequency signal and the local oscillation signal used to generate the intermediate frequency are transmitted to a local transmitter. After being transmitted, the two are mixed again and the same frequency signal as the received wave is re-radiated via the transmitter.

According to this method, since the local oscillation signals of the transmitter and receiver are the same, even if the local oscillation frequency or the reception frequency fluctuates, the re-radiated radio waves will be exactly the same as the reception frequency, and direct waves and relay waves will be mixed. There is no risk of beat failure even if the

In order to create multiple call channels using this method, as in the case of the two-way radio frequency two-way press-talk line system described above, a large number of circuits for a single radio frequency two-way press-talk line are arranged to share antennas, etc. It is common to do so.

AM, FM, SSB are multiplexed wireless communication methods.
FDM method, TDM method, or PCM in waves etc.
There are two TDM systems, all of which use a two-way press talk line using a single or radio frequency.

Furthermore, in the simultaneous transmission/reception system (duplex system), relaying is performed using the various methods mentioned above, but in this case, since the uplink and downlink frequencies are different, one system of transmitting and receiving equipment is required for each frequency. The system becomes even more complicated.

(Problems to be Solved by the Invention) However, the conventional wireless relay device as described above has various problems as described below.

First of all, because the two-way radio frequency two-way press talk line system uses two different waves for transmission and reception, it is difficult to expand installations in the current radio wave situation. Since it requires a transmitter and a transmitter, it has economical and electrical problems such as increased equipment size, more complicated circuit configuration, and increased power consumption.

In addition, since the booster method amplifies and relays all signals within a wide band, it has the disadvantage of relaying not only radio waves other than the desired channel but also noise, and can only be used in extremely limited areas or cases.

In the single radio frequency two-way press-to-talk line system, there are no radio wave problems caused by using two waves on one line, but
Multiple channels have the same economic and electrical drawbacks as two radio frequencies.

With multiplex communication, it is possible to send multiple signals in a superimposed manner using one transmission path, but the modulation circuit and demodulation circuit become complicated, the equipment becomes larger, and the facility cost increases significantly. It has the disadvantage that it is difficult to use with small-scale wireless lines.

These points similarly pose problems in relay devices in simultaneous transmission and reception lines.

(Object of the Invention) The present invention has been made in view of the above, and is a wireless relay using exactly the same frequency, which enables simultaneous operation of multiple channels, and further simplifies and downsizes the configuration circuit of the device. In particular, it is an object of the present invention to provide a wireless relay device that has a simpler and more compact overall equipment configuration.

(Summary of the invention) In order to achieve this object, the present invention includes:
A transmitting device and a receiving device are placed facing each other across a structure such as the top of a mountain, a tomb, or a building, and the intermediate frequency signal derived from the receiving device and the local oscillation signal used to generate the intermediate frequency signal are coaxially transmitted. The signal is transmitted to the transmitting device via a cable, etc., and the intermediate frequency signal and the local oscillation signal are mixed to extract the same frequency signal as the signal input to the receiving device. In a multi-channel repeating device that re-radiates within a level range that does not cause interference between transmitting and receiving devices using a structure or the like as a shield, a distributor that branches the intermediate frequency signal into a required number of channels in the intermediate frequency signal transmission path. and a combiner for combining the branched signals into one signal again, and furthermore, a bandpass filter having at least a required passband and an intermediate frequency amplifier are inserted in each of the channels.

In addition, the second invention of the present application makes a transmitting device and a receiving device each equipped with a local oscillator that oscillates the same frequency face each other across a structure such as a mountain top, a tomb, or a building, and The derived intermediate frequency signal is transmitted to a transmitter via a coaxial cable, etc., and the transmitter mixes the intermediate frequency signal and a local oscillation signal from a local oscillator to generate a signal with the same frequency as the signal input to the receiver. In the multi-channel relay device, the intermediate frequency signal is transmitted by extracting it, amplifying it as necessary, and re-radiating it within a level range that does not cause any looping between the transmitting and receiving devices using the mountain or building as a shield. a distributor that branches the intermediate frequency signal into a required number of channels in the path;
The present invention is characterized in that a combiner is provided to combine the branched signals into one signal again, and furthermore, a bandpass filter having at least a required passband and an intermediate frequency amplifier are inserted in each channel.

The third invention of the present application provides a local oscillation signal having a frequency different from that used for generating the intermediate frequency signal by making a transmitting device and a receiving device face each other, and transmitting an intermediate frequency signal derived from the receiving device via a coaxial cable or the like. is transmitted to a transmitting device equipped with a local oscillator that oscillates the intermediate frequency signal, and the transmitting device mixes the intermediate frequency signal and a local oscillation signal from the local oscillator to produce a signal with a frequency different from that input to the receiving device. A multi-channel repeater that performs necessary amplification and re-radiation after conversion includes a splitter that branches the intermediate frequency signal into a required number of channels during transmission of the intermediate frequency signal, and a splitter that converts the branched signal into one signal again. The present invention is characterized in that a synthesizer for synthesizing is provided, and furthermore, a bandpass filter having at least a required passband and an intermediate frequency amplifier are inserted in each channel.

The fourth invention of the present application is to arrange the two systems of radio relay devices opposite to each other and to stop the operation of the receiving device attached to it when one of the transmitting devices operates. It is characterized by being able to perform both wireless relays.

(Example) Hereinafter, a wireless relay device of the present invention will be described in detail.

FIG. 1 is a configuration diagram showing an embodiment in which the present invention is applied to a bidirectional relay device for a press talk line;
FIG. 2 is a block diagram showing an example of the configuration of the transmitter and receiver in FIG. be.

As shown in Fig. 1, this two-way radio relay device is installed on a first block A and a second block B, which are placed on both sides of a mountain top, a tomb, or a building. It consists of a group of housed circuits and a coaxial cable that connects the two. Block A is antenna 10
and a matching box 11 connected thereto, and a receiving section 12 and a transmitting section 13 connected to the matching box 11, respectively.
and a DC amplifier 14 that detects and amplifies the received signal.
The transmitter 13 receives the signal received from the DC amplifier 14.
A switch circuit 15 for turning on and off the power supply to the receiver of the block body B, and a power supply circuit 16 for supplying power to each part are provided.

Another block B is composed of the same circuit as block A. That is, a matching box 51 connected to the antenna 50, a receiving section 52 and a transmitting section 53 connected to the matching box 51, a DC amplifier 54 that detects and amplifies the received signal, and a received signal from the DC amplifier 54. A switch circuit 55 that turns on and off the power supply to the transmitting section and the receiving section 53 of the block body A.
and a power supply circuit 56 that supplies power to each part.

Receiving section 12 and transmitting section 13 in block body A
and the receiving section 52 and transmitting section 53 in the block body B.
means that the output of each receiving section is connected to the other transmitting section, and the output of a local oscillator provided in one block body A is connected to the other block body through a coaxial cable 4.
Input via 0.

First block body A and second block body B
In order to obtain the necessary communication range (service area) and to prevent the radio waves emitted from one transmitter via the antenna from reaching the receiver of the other block and making operation unstable, the Arrangements should be made taking into account the topography or shape of buildings such as lines or buildings.

Next, one route of the apparatus shown in FIG. 1 will be described in detail using FIG. 2. Note that the same parts as in FIG. 1 are given the same reference numerals, and redundant explanation will be omitted.

The receiving unit 12 includes a BPF (band pass filter) 70 whose passband is only the frequency band to be relayed among the output signals of the matching box 11 connected to the antenna 10.
and a high frequency amplification circuit 7 that amplifies its output without distortion.
1. The output of the high frequency amplifier circuit 71 is connected to the local oscillator 7.
3, a distributor 74a that distributes the mixed output into a required number of channels, and a combiner 74d that combines the distributed channel signals into one signal again. Between each channel of 74d, there is an IF/BPF (intermediate frequency bandpass filter) 74b that corresponds to each channel frequency and has a band limiting function suitable for the communication system, and a sufficient amplification degree (for example, 120
dB) saturation type intermediate frequency amplifier 74c
These are inserted and connected in series.

On the other hand, the transmitter 53 of block B includes a mixing circuit 81 which receives the local oscillation signal sent from block A as one input, a BPF 82 which has the same pass frequency as the receiving frequency band among the mixed outputs, and a distortion filter. A few linear high frequency power amplifiers 83 are connected in series, and a coaxial cable 4 is connected from block A to
The intermediate frequency signal transmitted through the mixing circuit 8
A signal having the same frequency as the desired signal received by block A and amplified to the required level is obtained by inputting it to the other input end 40b of block A and outputting it from a high-frequency power amplifier 83 with excellent linearity, and mixing this signal. It is configured to re-radiate via the antenna 51 and the antenna 50.

Note that the intermediate frequency signal passing through the transmission line 40 is converted to an intermediate frequency lower than the received signal frequency, thereby reducing the loss on the transmission path to the other block. In addition, in order to prevent spurious reception during reception and to reduce transmission loss to the block, the local oscillation frequency is oscillated at a low frequency and multiplied within each mixing circuit to convert it to the target intermediate frequency. do.

Each of these circuit sections operates as follows as a whole.

That is, the received signal of the antenna 10 is the block body A.
It is converted into an intermediate frequency by the receiving section 12 of the block body B, and transmitted to the block body B via a transmission line such as a coaxial cable 40, and then converted to the same receiving frequency again by the transmitting section 53, and then relayed to be re-radiated from the antenna 50. Perform the action. In the device of the present invention, the receiving section 1
Since the signal frequency of the local oscillation circuit 73 for mixing 2 is also used in the transmitter 53, the same conversion frequency can be obtained. Therefore, even if the oscillation frequency changes due to the temperature or aging of the crystal oscillator used in the local oscillation frequency circuit 73, the receiving signal frequency and the transmitting frequency change in the same way, and direct waves and relay waves are mixed. Even in the case where the transmission line 40
As mentioned above, it has the advantage of reducing transmission loss.

In the above explanation of the operation, the relay operation from the block pair A to the block pair B has been described, but the operation is exactly the same in the opposite direction. However, when relaying on the same frequency for each channel as in this embodiment, if the transmitting section of the same block operates while the receiver section is operating, the relaying operation will occur due to the transmitted waves going around to the receiving section. There is a risk that it may become unstable.

Therefore, it is desirable to configure such a structure that while one of the transmitting and receiving sections is in operation, the other of the same block stops operating.

Various methods can be considered for this purpose, but for example, if the limiter current of the intermediate wave amplifier circuit is detected when the desired wave signal is input to the receiving section and the power supply to the transmitting section of the same block is stopped. This operation is often performed using DC amplifiers 14 and 5 provided in each block.
4 and switch circuits 15 and 55. At the same time, the operation of the transmitter in the other block is detected by its current consumption or the DC voltage obtained by rectifying a part of the transmitted radio wave, and the operation of the receiver in the same block is detected. Stop.

Another method is to operate only the receiving sections of both blocks in the relay standby state, and monitor the limiter current, intermediate frequency signal level, or noise level inside and outside the voice band (so-called carrier squelch, noise squelch function). Based on this, the transmitter of the other block is activated and the function of the receiver is stopped.

Since these means are techniques commonly used in conventional relay devices, detailed explanation thereof will be omitted.

FIG. 4 is a schematic diagram showing the mode of transmission and reception using the single radio frequency bidirectional press-to-talk line system of the present invention. A coaxial cable 40 connects both blocks. At this time, in the case of a mountaintop or the like, by burying the cable underground, it is possible to prevent various radio waves such as heat, lightning, and high frequency waves from entering and superimposing the cable 40.

According to experiments, it is possible to easily obtain a wrap-around attenuation of about 120 dB to 150 dB in the VHF band, depending on the frequency used, by arranging the mountain peak or ridge line narrowly. Furthermore, if the minimum operating input level of the high-frequency amplifier or intermediate-frequency amplifier is set high, that amount can be added to the wrap-around attenuation amount, so that A level diagram may be designed as appropriate.

According to the relay device configured in this way, it is possible to carry out wireless relay using exactly the same frequency for each of a plurality of preset channels.

In the embodiments detailed above, a bidirectional relay device is illustrated, but the present invention is not limited to this example, and various modifications can be made to the operational form and device configuration.

For example, in broadcast communication, only one-way relay is required, so each block needs only a transmitting device or a receiving device.

Furthermore, if different frequencies can be used in uplink and downlink lines, there is no need to use buildings such as mountain peaks or buildings as shields, so they can be set on the same support.

Furthermore, if the communication method is a simultaneous transmission and reception method, the first
In a relay device having almost the same configuration as that shown in Figs. It is easy to understand that if it is modified so that it can operate, it is possible to relay at exactly the same frequency as each line frequency.

Furthermore, various modifications can be made to the device configuration.

For example, an intermediate frequency circuit is divided into multiple stages, part of which is divided into A blocks, and other parts are arranged into B blocks, and these are connected using the same number of coaxial cables as the number of channels. You may do so. This is done as appropriate depending on the installation conditions.
This is intended to improve the S/N ratio by amplifying the intermediate frequency signal to a required level within the A block, taking into account the transmission loss of the connecting coaxial cable.

Furthermore, the relay device of the present invention is not limited to mountains, etc., but can be used in large cities, for example, by arranging block bodies A and B on both sides of the building and connecting them with a coaxial cable, using a high-rise building in a city area as a shield. It is possible to relieve dead zones in various communication lines between high-rise buildings.

Additionally, if the transmission path between blocks A and B becomes long and this loss increases, the loss can be significantly reduced by using an optical fiber as the transmission cable between blocks and using an optical signal as the intermediate frequency signal. sell.

(Effects of the Invention) As explained above, the present invention converts a received signal into an intermediate frequency using one local oscillation signal, and then separates and amplifies each of the multiple channels using a band-limiting filter and an intermediate amplifier circuit. Therefore, it is possible to simultaneously relay only a plurality of desired channel signals with an extremely simple configuration.

In particular, if applied to the method proposed by the same applicant for relaying at exactly the same frequency as the received signal,
Furthermore, a relay system that is extremely convenient for effective use of radio waves without causing beat disturbance even when direct waves and relay waves are present can be made available for multiple channels at the same time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of an embodiment of the present invention, FIG. 2 is a block diagram showing one path of the receiver and transmitter in FIG. 1, and FIG. FIG. 4 is a schematic diagram showing a mode of transmission and reception using a two-way press-to-talk line system using a single radio frequency. Code, 10... Antenna, 11... Matching box, 12
... Receiving section, 13 ... Transmitting section, 14 ... DC amplifier, 15 ... Switch circuit, 16 ... Power supply circuit,
40... Coaxial cable, 40a... Output end, 40
b... Input end, 50... Antenna, 51... Matching box, 52... Receiving section, 53... Transmitting section, 54...
DC amplifier, 55...Switch circuit, 70...
BPF (band pass filter), 71...High frequency circuit, 72...Mixing circuit, 73...Local oscillation circuit, 74...Intermediate frequency amplifier circuit, 74a...Distributor, 74b...BPF, 74c... amplifier, 74
d...Synthesizer, 82...BPF, 83...Power amplifier.

Claims (1)

[Claims] 1. A transmitting device and a receiving device are placed opposite to each other across a structure such as a mountain top, a tombstone or a building,
The intermediate frequency signal derived from the receiving device and the local oscillation signal used to generate the intermediate frequency signal are transmitted to the transmitting device via a coaxial cable or the like, and the intermediate frequency signal and the local oscillation signal are mixed. A multi-channel relay that extracts the same frequency signal as the signal input to the receiving device, performs the necessary amplification, and re-radiates it within a level range that does not cause interference between the transmitting and receiving devices using the mountain or building as a shield. In the apparatus, the intermediate frequency signal transmission path is provided with a distributor that branches the intermediate frequency signal into a required number of channels, and a combiner that combines the branched signals into one signal again, and further includes at least one for each of the channels. A wireless relay device characterized in that a bandpass filter having a required passband and an intermediate frequency amplifier are inserted. 2. A transmitting device and a receiving device, each equipped with a local oscillator that oscillates the same frequency, are placed facing each other across a structure such as a mountain top, a tomb, or a building, and the intermediate frequency signal derived from the receiving device is transmitted over a coaxial cable. At the same time, the intermediate frequency signal and the local oscillation signal from the local oscillator are mixed in the transmitting device to extract the same frequency signal as the signal input to the receiving device, and then the necessary amplification is performed. In a multi-channel repeater that re-radiates within a level range that does not cause interference between transmitting and receiving devices using mountains, buildings, etc. as a shield, the intermediate frequency signal is transmitted into the intermediate frequency signal transmission path. A splitter that branches into the required number of channels and a combiner that combines the branched signals into one signal again are provided, and a bandpass filter and an intermediate frequency amplifier having at least the required passband are inserted in each channel. A wireless relay device characterized by: 3. A local oscillator is provided in which a transmitting device and a receiving device are made to face each other, and the intermediate frequency signal derived from the receiving device is transmitted through a coaxial cable or the like to oscillate a local oscillation signal frequency different from that used to generate the intermediate frequency signal. At the same time, the intermediate frequency signal and the local oscillation signal from the local oscillator are mixed in the transmitter and converted into a frequency signal different from the signal input to the receiver, and then the necessary amplification is performed. A multi-channel repeater that performs and re-radiates the intermediate frequency signal includes a distributor that branches the intermediate frequency signal into a required number of channels during transmission of the intermediate frequency signal, and a combiner that combines the branched signals into one signal again. What is claimed is: 1. A wireless relay device, further comprising: a bandpass filter having at least a required passband and an intermediate frequency amplifier inserted into each channel. 4. By arranging the two systems of wireless relay devices opposite to each other and stopping the operation of the receiving device attached to it when one of the transmitting devices operates, it is possible to perform both upstream and downstream wireless relays. The wireless relay device according to any one of claims 1 to 3, characterized in that the wireless relay device is made to be smoothed.