JPS5890834A - Radio equipment - Google Patents

Abstract

PURPOSE:To obtain a satellite station near a high voltage line with easy maintenance, by dividing the satellite station into a frequency conversion section under and on the tower, connecting the both with a radio line, and eliminating a power supply for the frequency conversion section on the tower. CONSTITUTION:A reception signal fR from an antenna ANT1 and a local oscillation signal fLO from an antenna ANT2 are synthesized at a mixer MIX1 in the 1st frequency converter CONV1 to obtain sum and difference signals fLO+ or -fR, which are transmitted from the ANT2. Since the local oscillation signal fLO used for this frequency cnversion is supplied from the 2nd frequency conversion section CONV2, no local oscillator requiring power supply is provided for the CONV1. Further, the input of the CONV2 is applied to an MIX2, where the input is mixed with the local oscilltion signal fLO leaked from the local oscillator LO by making use of the imcompleteness of a common device DUP and the reception signal is repoduced. This signal is amplified at an amplifier AMP and transmitted to a satellite station with a coaxial cable 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wireless device that is effective when applied to, for example, a satellite station that relays television signals near high-voltage lines.

High-voltage power transmission lines become obstacles to the propagation of radio waves, and if they are interposed in the propagation path of, for example, television signals (radio waves), they cause diffuse reflection, which impedes normal reception within the service area. For this reason, generally, as shown in Fig. 1, radio waves (Vat) from a broadcasting station 1 are first received at a satellite station 2R, and then sent to a satellite station 2YK via a coaxial or optical cable 3.
From there, measures are taken to avoid the problem, such as relaying the signal to the service area 4 where there is a reception problem using UHF. However, in this method, the installation location of the satellite station is a problem. That is, since the high-voltage line tower 5 is about 100 meters high and is built on the top of a mountain, the range of interference caused by the high-voltage line 6 is wide (
%), an appropriate installation position for satellite station 21 cannot be found, and satellite station receiving antenna A
If the NTI is low, it will naturally receive the disturbed radio waves, and even if it is relayed, it will not be possible to reproduce a good television image within Area 4. Therefore, the receiving antenna ANT should be raised higher than the transmission line tower. is a problem in terms of cost.

By the way, it was found that the radio waves on the high-voltage line tower were in good condition. Focusing on this point, it is conceivable to install a relay device on the high-voltage line tower. One such relay method is to install only the receiving antenna A N T t on the high-voltage line tower 5, and transmit the received signal to the satellite station 2 below the tower using a coaxial cable.
This is a method of transmitting to m.

However, this method is difficult to implement because the coaxial cable is electrically conductive, so there are serious problems with lightning strikes and electromagnetic induction. Another method is to install a receiving antenna and a receiver with an amplification function that operates on batteries on the steel tower 5, and make this a satellite station 2m. This method connects the two using an optical cable 3.

According to this method, there is no need to worry about lightning strikes due to the insulation properties of the optical cable, and there is no effect of electromagnetic induction.

However, since maintenance and inspection such as battery replacement at high places is not easy, this is also difficult to implement.

The present invention is intended to enable radio wave relaying, which is subject to various restrictions as described above, to be carried out stably and reliably for a long period of time without problems due to segregation. In the present invention, as shown in FIG. 2, the satellite station 2 is connected to the receiving antenna ANT on the tower, the first frequency converter C0NV, and the second frequency converter C0 below the tower.
It is divided into NV2 and an output section, and the two are coupled via a wireless line, and the first frequency conversion section is constructed of passive circuit elements so that no power source is required. The VHF signal received by the first antenna ANT is converted into millimeter waves (for example, 50 GHy) by the frequency converter C0NV, and then transmitted to the frequency converter C0NV by the second antenna ANT*, where it is frequency converted. In the CONV unit, the third antenna ANTs receives this 50 GHz millimeter wave, converts it back to a VHF wave, and sends it to two satellite stations via the coaxial cable 3. In this system, the first frequency converter C0NV does not include an active element, and the local oscillator signal is transferred to the second frequency converter C0NV.
, it is important that the signal is supplied from the antennas ANTs and ANTt to the frequency converter C0NVI side.

As a result, the first frequency converter C0NVI on the υ tower is powered off (sometimes a bias power source is used), resulting in durability and easy maintenance.

Additionally, the top and bottom of the tower are connected via wireless lines, so there is no need to worry about lightning strikes.

The radio device of the present invention includes a mixer including first and second antennas and a passive circuit element, and mixes a received signal received by the first antenna and a local signal supplied via the second antenna. The present invention is characterized in that the mixer is added to the mixer to obtain the sum and difference signals thereof, and at least one of the signals is sent out from the second antenna. This will be further explained.

Figure 3 shows an embodiment of the present invention applied to the satellite station 2m in Figure 2, where fm is a received signal such as VHF, and ft and . be.

The first frequency converter C0NV is a bandpass filter BPF that passes the received signal from the antenna ANTI.
and the local oscillator signal ft,6 supplied from the antenna NT word.
and - are mixer M composed of passive elements (diodes, etc.)
IX, and the sum and difference signal fLOfl
is obtained and transmitted from antenna AN'h.

The local oscillator signal fL· used for this frequency conversion is externally transmitted, in this example, to the second frequency converter C0NV! Since the power is supplied from the converter C0NV side, there is no need to provide a local oscillator that requires a power source on the converter C0NV side. Further, since the converter C0Nv1 simply converts the frequency and does not perform amplification, no amplifier is provided.

For these reasons, the converter C0NVI is composed entirely of passive elements and basically functions without a power source. mixer MI
If an appropriate bias current needs to flow through the diodes used in the be able to.

The second frequency converter C0NVffi includes a local oscillator LO, which generates a local oscillation signal f in the j IJ waveband. This local oscillation signal ft, is sent out from the antenna ANT via the antenna duplexer DUP, and is sent out from the antenna ANT.

received at Antenna ANT, , ANT, is 50
With a parabola of 5 wφ, the gain in the 50 GHz band is +
45dB, and antennas ANTt and ANT1
If the distance between the
If so, the fL input level of the converter C0NVI is +20+45-110+45=OdBm, which can sufficiently drive the mixer MIX. Then, the received signal fl
If the level of -15d Bm - and the conversion loss at the converter CONV is 10dB, then the input level (ft, o±f虱) at the converter CONV is 15-10 + 45-110
+45=-45 dBm, which is quite practical. When this input level is low, the gain can be increased by increasing the diameter of the antennas ANT, , ANT.

The input of the converter C0NVs (which may be one of fLo+fm with a filter) is input to the converter C0NVs through the duplexer DUP.
*, and here it is mixed with the local oscillator signal fL· (dashed arrow) leaking from the local oscillator LO@ by utilizing the imperfection of the duplexer DUP, and the received signal fm is regenerated. After this signal passes through a 1m (VHF band) band pass filter BPF, it is amplified by an amplifier AMP, and is connected to a coaxial (or optical) cable 3 to the satellite station 2 in FIG. transmitted to. Satellite station 2! converts the received signal to, for example, the UHIP band and transmits it from the antenna ANT4 to the service area 4 (Figure 1).
Send to.

FIG. 4 shows the passive type mixer MIX used in the frequency converter C0NV of FIG. 1. In this circuit example, HPF is a high-pass filter, D is an indexing diode, and LPF is a low-pass filter. This circuit operation is known and
The received signal f, is supplied to the diode DK through the LPF as shown by the arrow F1, and the local oscillation signal fLfl is supplied to the diode DK as shown by the arrow F1.
As shown in (supplied to diode D through HPF).

Then, they are mixed by diode D and their sum and difference fz
The signal with 6±fm has a high frequency, so the FIPF side,
In other words, it is output to the antenna ANT3 side. FIG. 5 is a diagram showing a main part of a modification of the second frequency converter C0NV.

In the example of Fig. 3, the duplexer DU is used for the second mixer MIXI.
fL6 is given by utilizing the imperfection of P, but in this example, a coupler CPL is interposed between the oscillator LO and the duplexer DUP, and the coupler divides fL@i to mixer M I
! K fx, .

The frequency used between the antennas ANT and ANTs is originally arbitrary, but if it is set to 50 GH, (1) it is easy to transmit a wide band multi-channel signal f, and (2) the antenna It is advantageous in terms of high gain, etc.

As described above, according to the present invention, a received signal can be frequency-converted and transmitted using a circuit configuration that does not include any active elements, so a power source is not required at all, or only a bias source is required. Therefore, it is suitable as a relay radio device installed on a steel tower at a satellite station near a high-voltage line.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of a conventional television satellite station.
Fig. 2 is an explanatory diagram showing an overview of the present invention, Fig. 3 is a schematic diagram showing an embodiment of the invention, Fig. 4 is a circuit diagram of a mixer using passive elements, and Fig. 5 is a diagram similar to Fig. 3. FIG. 7 is a block diagram of main parts showing a modified example. In the figure, ANT, -ANT, box 1 to 3rd antenna, M
IXI. M I Xs is the first. Second mixer, C0NVI,
C0NV! is the first. The second frequency converter, LO, is a local oscillator. Applicant Fujitsu Ltd. Representative Patent Attorney Minoru Aoyagi Figure 1

Claims (1)

[Claims] A mixer including first and second antennas and a passive circuit element is provided, and the received signal received by the first antenna and the local oscillation signal supplied via the antenna of fiJc2 are added to the mixer and the sum of them is calculated. A relay radio device characterized in that it obtains a difference signal and transmits at least one of the scissor signals from the second antenna.