JPH036132A - Shf band same frequency repeating system - Google Patents

Abstract

PURPOSE:To control the gain of a repeating amplifier by using the corresponding voltage by detecting and calculating the turn-in quantity from a transmitting output to a receiving input from a spurious component generated in the output of a transmission band and displaying it. CONSTITUTION:A repeating amplifying part 13 leads a receiving signal of an antenna 1 to an antenna 6 through a BPF 2, an amplifier 3, a directional coupler 4 and a BPF 5. A part thereof branches in the coupler 4, passes through a band eliminating filter BEF 7 and converted into a DC voltage by a high frequency DC converting circuit 8. An arithmetic circuit 9 makes the gain of the amplifier 3 lower enough than a gain control circuit 12, a voltage V1 from the DC converting circuit 8 is held in a storage circuit 10, and by increasing the gain of the amplifying circuit 3 by (a), V2 is obtained, and it is compared with V1. By adding an energy increase S by a spurious component in a deterioration allowable limit by a turn-in wave, the gain A of the amplifier 3 is controlled as V1+a+S=V2. Subsequently, a ratio to a desired wave is denoted as K, and the turn-in quantity (M=A-K) is derived and shown by a display arithmetic circuit 11. According to this constitution, no oscillation is executed, and an optimum mutual position of a transmitting/receiving antenna can be determined easily.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a same frequency repeating system that directly amplifies received waves in the SHF band and transmits them at the same frequency.

(Summary of the Invention) This invention relates to a relay method that directly amplifies received waves in the 5IIF band and transmits them at the same frequency. By utilizing the phenomenon that spurious components are generated in increasing profits.

This simplifies the repeater circuit configuration and makes effective use of radio waves.

(Prior art) In relays that receive SHF band transmission waves, directly amplify the received waves, and transmit them at the same frequency, there is a risk that the transmission output will wrap around the receiver's power and cause oscillation, and due to the influence of the wraparound waves. This could lead to deterioration of frequency phase characteristics.

Conventionally, in order to prevent these problems, the amount of wraparound has been reduced by isolating the transmitting and receiving antennas depending on the topography, or by installing a shielding plate between the transmitting and receiving antennas, and by spatially mutually coupling the transmitting and receiving antennas.

(Problem to be Solved by the Invention) In order to implement the conventional prevention method and reduce the amount of radio waves that cross over from the transmitting output to the receiver's power, there is a large gap based on conventional experience, and it is difficult to carry out the actual installation. The drawback was that it was subject to many restrictions.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an SHF band same frequency repeating system which eliminates the above-mentioned drawbacks, has a relatively simple repeater circuit configuration, and allows effective use of radio waves.

(Means for Solving the Problems) In order to achieve this object, the SHF band same frequency relay system of the present invention is a relay system that receives an SHF band transmission wave, directly amplifies the received wave, and transmits it at the same frequency. , detects and calculates the amount of wrap-around from the transmission output to the receiver's power from spurious components occurring in a band outside the transmission band, and displays it, and uses the voltage corresponding to the amount of wrap-around determined by the calculation. , the gain of the relay amplifier is controlled.

(Function) The amplification repeater system according to the present invention detects the amount of interference and controls the gain of the amplifier, so it is possible to prevent oscillation of the amplification section, and also to reduce the amount of interference of the transmission output to the receiver's power, thereby reducing the deterioration of relay characteristics. Since it is possible to detect and control the gain before this occurs, it is possible to operate the amplifier gain to the maximum within the range allowed by the amount of spatial mutual coupling determined by the installation conditions of the transmitting and receiving antennas without considering margin. Furthermore, the wraparound amount detection and display function makes it possible to easily find the optimal mutual positional relationship of the transmitting and receiving antennas.

(Example) In a relay method in which received radio waves are directly amplified in the SIIF band and transmitted at the same frequency, oscillation does not occur until the amplifier gain and the amount of spatial mutual coupling between the transmitting and receiving antennas are approximately the same. but,
Even if oscillation does not occur, as the amount of wraparound waves increases, the frequency phase characteristics will be affected and the transmitted signal will deteriorate.

Regarding the amount of wrap around the detection limit of this deterioration, band 27
In the case of MHz FM modulated waves, according to the literature, Satellite Broadcasting CATV Technology, published by the Radio Technology Association, pages 27 to 29 (February 1980), a delay of 0.01 p sec causes a delay of approximately It is sufficient if the level is 10 dB lower.

5) In the IF (B, C band) frequency bands, the bandwidth is different and the delay time also varies depending on the amplifier characteristics and antenna installation spacing, but experimentally it has been shown that even if the wrap-around wave is about 6 dB lower than the desired wave. For example, this is the detection limit for relay characteristic deterioration. Near this usage limit, detectable spurious components occur. The method of the present invention detects this spurious energy, measures and calculates the level, detects the amount of interference, and controls the gain of the amplifier.

Hereinafter, the present invention will be described in detail by way of examples with reference to the accompanying drawings.

FIG. 1 shows a block diagram of the main body of the relay amplifying section 13 according to the method of the present invention. The part surrounded by the broken line in the figure is the main circuit section of the present invention.

The basic function of the relay amplification section 13 is to guide the relayed signal received by the receiving antenna 1 to the high gain amplifier 3 via a band pass filter (BPP) 2 and amplify it there.

The amplified signal is guided to a transmitting antenna 6 via a directional coupler 4 and a BPP 5.

A part of the transmission output branched from the one-way coupler 4 is
Band Elimination Filter
After the relayed signal is removed via Filter BEF) 7, it is converted into a DC voltage by a high frequency DC conversion circuit 8.

The voltage comparison calculation circuit 9 calculates the increase in the energy of the spurious component that occurs due to the increase in the amount of wraparound.
Compare the voltage with the energy when there is no influence of wrap-around waves.

This voltage comparison method first sets the gain of the high-gain amplifier 3 sufficiently low using the gain control circuit 12, and then compares the DC voltage from the high-frequency DC conversion circuit 8 (this V, (dB)) is the voltage recording circuit 1
Record to 0. Second, the gain of the high gain amplifier 3 is a (d
B), and the DC voltage at this time is V, (dB
), the first DC voltage Vt and the second DC voltage v2 are compared.

At this time, the DC voltage v1 is determined by the increase in gain a (dB) of the high gain amplifier 3 and the increase in energy due to spurious components at the limit where the transmission characteristics do not deteriorate due to an increase in wrap-around waves or at the permissible limit of deterioration (this S
(dB)) is used.

In the comparison operation, the gain of the high gain amplifier 3 is controlled via the gain control circuit 12 so that the condition (v, +a+5)=V is satisfied.

The gain of the high gain amplifier 3 at this time (this is referred to as A (dB)) can be known from the control voltage of the gain control circuit 12, and the value of the detection limit or permissible limit of transmission characteristic deterioration is If the pre-calibrated ratio of the wrap-around wave to the desired wave is K (d[l), the wrap-around amount (this is M (dB)) is obtained from M=A-, and the display calculation circuit 11 Perform calculations and display.

Normally, by automatically applying this gain restriction, the function of the repeater will not be impaired even if the amount of wrap-around waves increases due to a moving body or some other cause. Furthermore, by displaying the detected amount of wraparound, it becomes possible to easily determine the optimal mutual positional relationship between transmitting and receiving antennas in close proximity.

Although this embodiment has been described using an example of bands B and C of the SHF band, the present invention is not limited thereto, and can be applied to other frequency bands.

(Effects of the Invention) As explained in detail above, according to the relay system of the present invention, the amount of wraparound of the transmitting output to the receiving input is detected and displayed, and the amplifier gain is controlled without causing oscillation. It is also very easy to determine the optimal mutual positions of the transmitting and receiving antennas by displaying the amount of wraparound. Therefore, if the relay distance is limited, a relay station can be configured with normal transmitting and receiving antennas placed close to each other, and the optimal relative positions of the close transmitting and receiving antennas can be easily determined, making it highly useful as a mobile relay station.

Furthermore, since the same frequency is used for transmission and reception, it is possible to use radio waves effectively, and the circuit configuration of the relay section is also simplified, which is particularly effective when the relay lines are congested.

[Brief explanation of drawings]

FIG. 1 shows a configuration block diagram of an embodiment according to the system of the present invention. ■...Receiving antenna 2.5...Band pass filter 3...High gain amplifier 4...Directional coupler 6...
・Transmission antenna 7...Band removal filter・
・High frequency DC conversion circuit 9... Voltage comparison calculation circuit 10... Voltage storage circuit 1
1... Display calculation circuit 12... Gain control circuit 1
3...Relay amplification section

Claims (1)

[Claims] 1. In a repeating method that receives an SHF band transmission wave, directly amplifies the received wave, and transmits it at the same frequency, the amount of wraparound from the transmission output to the reception input is determined by the frequency band outside the transmission band. The SHF band same frequency relay is characterized in that it detects and calculates and displays the spurious components generated in the SHF band, and controls the gain of the relay amplifier using the voltage corresponding to the amount of wrap-around determined by the calculation. method.