JPS587728Y2 - Micro-electric field mobile radio communication device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a device that uses a plurality of transmitters and receivers that utilize weak electric fields to establish a fixed station-to-mobile radio station service area over a relatively wide area and having an arbitrary shape.

Wireless communication between a fixed station and a mobile station by emitting weak electric field waves (
Conventionally, in order to perform mobile radio (hereinafter referred to as mobile radio), information was transmitted from the fixed station to the mobile station by guided radio using guided wires extended and erected in the area to obtain the required service area. A device is used in which the transmitted waves are received and demodulated by radio receivers installed at several locations along the guide line, and then sent to a fixed station via the guide line. Disadvantages include poor call quality in places with a lot of noise in the radio frequency band and limited allocated frequencies.

There are also mobile radio devices that use small transceivers,
When the service area includes factories, buildings, underground malls, etc., there is a problem with information dissemination, there is a lot of interference, and in the case of Breathtalk, it is difficult to handle, making it impractical.

The device of the present invention eliminates the above-mentioned drawbacks, and the distance between transmitters and receivers for generating weak electric fields (hereinafter referred to as distributed transmitters and receivers) installed at multiple appropriate locations in the service area is, for example, about 100 m, and the distance between all the devices is approximately 100 m. It is appropriate that the number of distributed transceivers included in the system be approximately 15 on average.

The present invention will be explained in detail below with reference to the drawings.

The drawing is a communication line configuration diagram of an example of a mobile radio communication device for simultaneous mutual communication in which the present invention is implemented, where A is a fixed station (master station), B is a fixed station (master station),
, B2...Bn is a distributed transceiver, C is a mobile station (
(Slave station).

L is a high frequency coaxial cable, which generally connects the fixed station A, the 81 distributed transmitters and receivers closest to it, and the distributed transmitters and receivers together in cascade.

Through this cable, high frequency, low frequency, and direct current power is transmitted as described later.

First, when transmitting information from a fixed station to a mobile station, a modulated input signal 1 oscillates, passes through a modulator 2, and a high-frequency amplifier 3, and then becomes a modulated wave (hereinafter referred to as T1 wave) with a carrier frequency f1 and is transmitted to the adjacent distributed transceiver B1. Sent out.

UHF-HF can be used for fl, but in practice, a VHF band such as 50 MHz is often selected.

The T1 wave sent to the distributed transceiver B1 is sent to the transmission amplifier 7
The signal is multiplied to a frequency mf1 (m is an integer of 2 or more, mfl is a frequency in the VHF-UHF band, although UHF such as 450 MHz is mainly selected, but is generally a frequency in the VHF-UHF band), and is transmitted from the antenna 9 via the antenna duplexer 8 to the mobile station. The mobile station receives this mf1 wave.

The T1 wave manually input from the cable L to the distributed transmitter/receiver B1 is also applied to the line amplifier 10, which is an F1 wave amplifier, and is amplified, and is further away from the fixed station via the output terminal of the line amplifier 10 via the cable L. , that is, sent to the lower-order distributed transceiver B2 (not shown).

The T1 wave sent to the distributed transceiver B2 generates an mf1 wave that is radiated from its antenna to the mobile station and an f0 wave that is sent to the 83 lower-order devices, respectively, just like the B1 device.

In this way all distributed transceivers B1-Bn are mf
□ It radiates the wave to the surrounding service area, and except for the lowest Bn machine, the amplified T1 wave is sent to the next distributed transmitter/receiver via cable L.

Mobile station C receives mf sent from each distributed transceiver in this way.
For example, the strongest wave may be selected and received, but there is no practical problem even if all the mf1 waves are summed and received, since this is a relatively short-distance, low-power simultaneous transmission.

Next, the T3 wave (T3 is VHF-
UHF is commonly used, for example 400 MH
z) is received and demodulated by the f3 wave receiving receiver 11 of each distributed transmitter/receiver, becomes a low frequency signal T2 wave of 0.3 to 3 kHz, and is sent to the fixed station via the coaxial cable L via the transformer T1□.

In this case, in a distributed transmitter/receiver other than B1, the output of the cable L passes through the upper distributed transmitter/receiver in order, proceeds to the further higher distributed transmitter/receiver, and finally passes through the fixed station transformer T1 to the low frequency amplifier 4. Since it is amplified and the demodulated output becomes 5, simultaneous transmission and reception between the fixed station and the mobile station becomes possible.

In this case, the high-frequency wave f2 sent to the fixed station through the coaxial cable L is a particularly low-frequency version of the received wave f3 of the mobile station as described above, but this is because transmission loss increases with frequency (for example, when high-frequency coaxial Cable 10 D 2
Transmission loss of V (JIS-C-3501) is 4 dB at IMHz per lKm, 15 dB at 10 MHz, 50 M
(33 dB at Hz) This is to reduce this.

Further, the power supply voltage for operating each amplifier and receiver of each distributed transmitter/receiver is supplied from each power supply circuit 12,
This DC power for each power supply circuit is sent from the power supply 6 of the fixed station A through the coaxial cable L.

That is, high frequency (f. wave), low frequency (T2 wave), and direct current flow in a superimposed manner through the coaxial cable L, but the following circuit is provided to separate them.

The fixed station capacitor C1 is a high-pass filter HPF that passes only the T1 wave, and the inductance L1 and capacitor C3 are T
Low-pass filter LP that passes 2 waves and DC and blocks T1 waves
F. The transformer T1 and the capacitor C2 induce and output the T2 wave to the secondary side of T1 and allow the direct current to pass through.

Also, on the distributed transmitter/receiver side, there are inductances L1□ and Ll.

, capacitor CI2 operates as an LPF, passes the T2 wave and DC, and blocks the T1 wave.

C1o has the same HPF as C1, T10. C1 serves to pass DC to the power supply circuit 12 and send out the T2 wave from the receiver 11 to the cable L.

According to the communication device of the present invention as described above, it is possible to form a required service area in an area of arbitrary shape, and to perform simultaneous transmission and reception with good call quality between the master station and slave stations, and each distributed transmission and reception is possible. The transmitted waves from the machine are all MF1 waves multiplied by the stable frequency T1 wave from the fixed station, so they are extremely stable, and the power to operate each distributed transceiver is all transmitted from the fixed station via a coaxial cable. By transmitting cables through cables, maintenance is extremely easy, and transmission loss within the cables can be reduced, which has significant practical effects.

[Brief explanation of the drawing]

The drawing is a line configuration diagram of an example of a mobile radio communication device capable of simultaneous two-way communication in which the present invention is implemented. A: Fixed station, B: Distributed transceiver,
C...Mobile station, L...High frequency coaxial cable, 2...Oscillation, modulator, 3...Amplifier, 4...Low Frequency amplifier, 6...DC power supply, 8...Antenna duplexer, 10...
...Line amplifier, 11...Receiver, 12...
...Power circuit.

Claims (1)

[Scope of utility model registration request] As a device that performs simultaneous transmission and reception communication using a weak electric field between a fixed station and a mobile station, multiple distributed transceivers are connected in cascade to the fixed station via coaxial cables at multiple locations within the required service area for the above communication. They are installed in a distributed manner, and the fixed stations are modulated with the DC power supply power and the information signal for the mobile station to each distributed transmitter/receiver via the above-mentioned coaxial cable, and are sent to the mobile station with high-frequency power of an integer fraction of the transmission frequency. At the same time, each distributed transmitter/receiver is provided with means for receiving the demodulated and low-frequency mobile station information signal from each distributed transmitter/receiver, and each distributed transmitter/receiver is provided with a means for receiving the above-mentioned high frequency input from a fixed station or a distributed transmitter/receiver closer to the fixed station to a constant value. At the same time, the high-frequency input is amplified and sent to another adjacent distributed transmitter/receiver, and the radio waves from the mobile station are received and demodulated to lower the frequency. A micro-electric field mobile radio communication device, each comprising means for transmitting a signal to a fixed station via the coaxial cable.