JPH08139963A - Television repeater - Google Patents

Abstract

PURPOSE: To attain light weight and small size and to reduce the intrusion of an undesired wave to the signal band of a received wave by using a transmission circuit and a reception circuit in common a lower frequency band or a higher frequency band in a frequency converter so as to decrease the number of local oscillators. CONSTITUTION: A signal received from an input terminal 4 of a control section 1 is converted into a 130MHz signal and it is outputted to a coaxial cable 3 via a filter type multicoupler 8. The 130MHz signal is extracted by a multicoupler 23 in a high frequency section and the signal is mixed with an oscillated frequency signal (l370MHz) of a local oscillator 22 by a frequency mixer 9 to allow a filter 10 to extract only a desired frequency signal 1500MHz. Furthermore, a mixer 11, the local oscillator 20 and a filter 12 extract a desired frequency band (7GHz) and the extracted signal is given to a high frequency terminal 15 via a power amplifier 13 and a multicoupler 14. On the other hand, a received wave at a 10GHz band from an antenna is given to the terminal 15, the multicoupler 18, and an oscillator 21 and a 230MHz signal is obtained by a mixer 24 and the oscillator 22 and a video signal and an audio signal are outputted from a terminal 5 via the multicoupler 23, the cable 3 and the multicoupler 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave television repeater having a bidirectional function.

[0002]

2. Description of the Related Art In a microwave relay device for television relay, a method of connecting a transmitter and a receiver to two housings of a high frequency section and a control section and connecting the two housings with one coaxial cable is adopted. When converting the frequency to the first intermediate frequency of 130 MHz transmitted in the coaxial cable, there is no need to convert the frequency to the second intermediate frequency (1,500 MHz) and then to the predetermined microwave frequency (7 GHz band, 10 GHz band). It is easy to suppress frequency components (spurious components). In case of reception, the first intermediate frequency (1,500 MH
Since the reception sensitivity can be made high by converting to z) and then to the second intermediate frequency, the above-described frequency conversion of two times is general.

As a conventional technique having a bidirectional function, FIG.
A block diagram of the high frequency section is shown in FIG. The control unit and the coaxial cable are the same as those in FIG. 1 described later and are omitted. When operating as a transmitter, the first intermediate frequency (130 MHz) transmitted from the control unit via the coaxial cable is the duplexer 23.
Is input to the mixer 9, mixed with the oscillation frequency (1,370 MHz) of the first local oscillator 22, and the second intermediate frequency (1,500 MHz) is taken out by the filter 10. . The signal is input to the mixer 11,
A predetermined frequency mixed with the oscillation frequency of the second local oscillator is taken out by the filter 12, amplified by the power amplifier 13, and then connected to the antenna via the duplexer 14 and the high frequency output terminal 15.

On the other hand, the received wave from the antenna is fed to the terminal 15,
After being amplified by the low noise amplifier 16 via the duplexer 14, the filter 17 removes unnecessary components such as the image frequency, and then the mixer 18
Then, only the third intermediate frequency (1,500 MHz) mixed with the oscillation frequency of the third local oscillator 26 is taken out by the filter 19, and the oscillation frequency of the fourth local oscillator 27 (1,27 MHz).
0 MHz) is mixed by the mixer 24, and only the fourth intermediate frequency (230 MHz) is taken out by the duplexer 23 and transmitted to the control unit via the coaxial cable for demodulation. The signals to be transmitted are 1 channel of video signal, 2 channels of audio signal, and 1 channel of audio for meeting line.

[0005]

However, the conventional technique has a drawback in that the device cannot be downsized. An object of the present invention is to provide a compact, lightweight and high performance device.

[0006]

In order to achieve the above object, the present invention commonly uses either a local oscillator for obtaining a first intermediate frequency or a local oscillator for obtaining a second intermediate frequency. It is something that is done.

[0007]

The common use of the above local oscillator enables downsizing. In addition, since the number of local oscillators is reduced, the number of elements by which unnecessary frequency components fall into the band is reduced.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, a control unit 1 and a high frequency unit 2 are connected by a coaxial cable 3. Video and audio input terminal 4 of control unit 1
The signal input from is converted to 130 MHz and output to the coaxial cable 3 via the duplexer 8 of the filter type. In the high frequency section 2, after taking out 130 MHz with the duplexer 23,
The frequency mixer 9 mixes the oscillation frequency (1,370 MHz) of the local oscillator 22 to convert the frequency, and the filter 10 extracts only the desired frequency 1,500 MHz. Further, the desired frequency of 7 GHz band is taken out by the frequency mixer 11, the local oscillator 20, and the filter 12, and after being amplified by the power amplifier 13, the high frequency output terminal 1 is output via the duplexer 14.
5 is output. The terminal 15 is connected to the antenna.

On the other hand, the 10 GHz band received wave from the antenna is input from the terminal 15, amplified by the low noise amplifier 16 via the duplexer 14, and then the filter 17 removes the image frequency component, and the mixer 18, 1,600M with local oscillator 21
Hz is obtained, the second image frequency component is removed by the filter, 230 MHz is obtained by the mixer 24 and the local oscillator 22, and is transmitted to the control unit 1 by the coaxial cable 3 via the duplexer 23 and shared. It is supplied to the video / audio demodulator via the device 8, and the video / audio is demodulated and output from the output terminal 5.

In the above, the local oscillation frequency of the local oscillator 21 is set so that the output frequency of the mixer 18 of the receiving side high frequency section becomes 1,600 MHz, and the mixer 9 of the transmitting side high frequency section and the receiving side high frequency section are set. The local oscillator 22 is shared so that the local oscillation frequencies supplied to the mixer 24 are the same. In addition, reception of 7 GHz band and 1
A configuration similar to that of FIG. 1 capable of transmitting in the 0 GHz band may be used so that transmission and reception can be performed by one opposite.

FIG. 3 shows a high frequency section when the second local oscillator is commonly used. In this case, the oscillation frequency of the local oscillator 28 is 8.5 GHz, which is an intermediate frequency band between the 7 GHz band and the 10 GHz band, and the local oscillator 29 is 1,630 MHz. The oscillation frequency of the local oscillator 30 needs to be a frequency (1,270 MHz) at which 230 MHz is obtained as the conversion frequency of the output of the mixer 24.

In FIG. 4, the transmitting side is in the 7 GHz band and the receiving side is in the 10 GHz band.
This is a high-frequency unit that can switch between the setting of the GHz band and the setting of the transmitting side in the 10 GHz band and the receiving side in the 7 GHz band. Power amplifiers 13 and 34, low noise amplifiers 16 and 35
The above switching is possible by switching and using the local oscillators 39 and 40, respectively. 32, 33, 3
Reference numerals 7 and 38 are coaxial relays.

By utilizing the present invention, the size and weight of the device can be reduced. It is also possible to: In other words, since there are three systems of audio that can be transmitted, information of the received input electric field level is sent back to the transmission side by using one of the three systems, and the received input electric field is controlled to a certain constant level. Paths (interference with reflected waves generated by buildings) can be reduced. Further, as in the above case, the information of the direction adjustment of the antenna can be sent back by using one audio system.

[0014]

According to the present invention, in a high frequency section of a television transmission device, when the transmission system and the reception system are mounted in one housing, the local oscillator is shared, thereby reducing the size of the device,
The cost can be reduced and the performance can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional high frequency unit.

FIG. 3 is a block diagram showing a configuration of a high frequency unit according to another embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a high frequency unit according to another embodiment of the present invention.

[Explanation of symbols]

1 Control part 2 High frequency part 3 Coaxial cable 4 Video / audio input terminal 5 Video / audio output terminal 6 Modulator 7 Demodulator 8, 14, 23, 31, 36 Duplexer 9, 11, 18, 24 Mixer 10, 12, 17 , 19 Filter 13, 34 Power amplifier 15 High frequency output terminal 16, 35 Low noise amplifier 20-22, 25-27, 28-30, 39, 40 Local oscillator 32, 33, 37, 38 Coaxial relay

Claims (2)

[Claims] 1. A control unit and a high-frequency unit are connected to each other by a coaxial cable to transmit a frequency signal of one wave and receive another frequency signal, and the transmitted and received signals are each subjected to predetermined frequency conversion twice. Of the local oscillator for frequency conversion in the high frequency part, in the device for mounting both the control part and the high frequency part in the transmitter / receiver circuit. A television relay device, wherein any one of the above is shared by a transmission circuit and a reception circuit. 2. The television relay apparatus according to claim 1, wherein the received input electric field level signal is sent back to the transmission side using the third voice transmission line.