JPS59161932A - Transmitting and receiving radio device - Google Patents

Abstract

PURPOSE:To prevent the connection between the radiation component generated by the standing wave of a coaxial cord and a receiver by shielding the input/ output cord of a radio equipment at the part existing within a housing of the radio equipment with a metallic pipe, a wire net, a conductive coating material, etc. CONSTITUTION:A part (a'-b) of a coaxial cord (a-b) which is led into a storing part I is enclosed by a wire net 17 of a cylindrical form through the outer circumference of the part (a'-b). This net 17 is set outside the outer insulator of the cord (a-b) and earthed to the part I via a cord 18. Thus the function of an antenna attained by the standing wave is prevented for the part (a'-b) led into the part I. As a result, the image frequency, etc. radiated into the part I are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to transmitting/receiving radio equipment, particularly to two-wave simplex radio equipment and two-wave duplex radio equipment.

Conventional Structure and Problems Conventionally, in mobile communications, a two-wave simplex system has been used in which the transmission frequency fT and the reception frequency fm are set such that fT≠f. In the above-mentioned communication radio equipment that uses frequencies in the UHF band, the intermediate frequency f1 of the receiver is set to fi = f, -f, or fi = fT - f, -fυ (However, on the moon, there is a frequency), but fi”=
If fTfB is used, the device configuration is simple and economical, so the former method is widely used and 4L is used.

FIG. 1 shows the circuit configuration of this conventional shelf radio.

(1) is the transmitting/receiving antenna, (2) is the antenna switching section,
A low pass filter [hereinafter referred to as LPF] (3) for removing spurious components of the transmission frequency (fT), a band pass filter [hereinafter referred to as BPF] (4) for the reception frequency (fR), It consists of an electronic switch (5) that turns on and off the transmission output, and these (3), (4), and (5) are assembled into one piece. (6) is a receiver whose reception frequency is fR, and (7) is a sound device such as a speaker. (8) is a transmitter whose transmission frequency is fT, and (9) is a telephone transmitter for making calls, and calls are made using the breath-talk system. Reference numeral 01 denotes an oscillation unit, which serves as both the local oscillator of the receiver and the original oscillator of the transmitter. If the frequency used is one channel, a single crystal oscillator is sufficient, but if switching multiple channels, f is #
JI & number synthesizers etc. are used. The circle is the oscillator θ
When transmitting the output, send it to the transmitter (8), and when receiving it, send it to the receiver (8).
6) side.

(Incorporated) is the main power regulator for radio equipment, which is connected to the power cord by the power cord, and the regulator □
The output of □□ supplies power to the control unit θQ via the transmitter (8) and sub-source regulator α. The control unit - performs transmission control, channel switching, and communication control. The function is sealed. 0 (9 is the operation section of the controller 00, and the control section 11j (D) has the function of setting the operating conditions. During standby (receiving), turn off the electronic switch (5).
During transmission, the electronic switch (5) is turned on.

This operation is normally performed by a switch (not shown) in the playsuit.

The radio housing has a control section (5) and an antenna switching section (2).
It consists of a part (1) for storing the wireless device and a part (1) for storing the radio, and the parts (I) and (1) are separated into front and back sides by a metal partition plate. Receiver input and transmission output are connected through the holes in the housing partition plate respectively B P F (4)
Output and electronic switch (5) input code (d-e) (f
-g) are directly connected. The antenna input is connected to the antenna switch (3) and the LPF (2) by a coaxial cord (a-b).

The 21st is the transmission frequency fT, the reception frequency fR and L P
The frequency relationship between F (3) and BPF (4) is shown. Here, fT−fkL=fi, and B P F (4)
limits the band used by the receiver (6) to prevent unnecessary signals from flowing into C1.

) = pF (3) removes the harmonic components of the transmitter h4 (8) and gives a large attenuation at 2 fT or more, and the passive unit (6
) has a characteristic of giving almost no attenuation to the image frequency f1M. - When the switch is OFF, the child switch (5) applies attenuation of about 20 aB to the transmitter side and disconnects the transmitting 45J4 (8J output).

Next, cut the antenna and receive IM 6 from the national strength of the city (2).
Looking at the m-image characteristics, we can see that due to the selection characteristics of BPF (4), from point e, the receiver image characteristics have a number of 1.0 d.
However, the receiver image characteristics from the antenna input terminal a are significantly degraded to about -60 dB. Since the receiver image characteristics must be kept below -80 dB, some kind of improvement≠n countermeasure has been required.

In the 1st g circuit, when transmitting S, the transmitting output is turned ON and OFF.
When the FF electronic switch (5) is turned on and the transmitter (8) is operated, its output passes through the LPF (3) and is output to the transmitting/receiving antenna (1). At this time, the transmitting/receiving antenna (1) and the transmitter (8) are in a matching state.On the other hand, at the time of reception, the electronic switch (5) is turned OFF, so that the image frequency f1M of the received pJ (e) also becomes an open impedance.On the other hand, when viewed from point C), B
Since PF (4) also has an open impedance with respect to f□, the point b has an open impedance. Now, if the electrical length of the coaxial cord from the antenna input a to the input point b of the LPF (a) is an odd multiple of V/4, the coaxial cord (a-b) in the storage section (1) Some are standing waves VS
Acts as an antenna for W, transmitting/receiving antenna (1)
The energy of the fIM input from is radiated into the housing. This radiant energy (Pr) is B P F (4)
Output (d) of BPF (4) and receiver (6)
, the selection characteristics of the BPF (4) do not work and the image characteristics of the receiver (6) deteriorate.

In addition, in reality, the radiated energy (Pr) from the coaxial cord (a-b) is not only direct as mentioned above, but also
It infiltrates the receiver by combining with the power supply wiring (hi) and various control signal wiring. Therefore, in order to reduce or prevent unnecessary sensitivities such as fIM, it is necessary to add a filter to each of these wirings, but if the control signal is a physical signal, the waveform may be distorted or the signal may not be transmitted completely. become unable. For this reason, there are problems such as loss of the radio equipment's original functions, and it is technically and economically inappropriate to rely solely on such countermeasures.

OBJECTS OF THE INVENTION An object of the present invention is to provide a transmitting/receiving radio device that can prevent radiation from being coupled to a transmitter due to a fixed number of coaxial cords drawn into a housing without adding a filter to each signal path. do.

Structure of the Invention The transmitting/receiving radio device of the present invention includes a high-frequency coaxial cord that is inserted into the housing of a radio device and serves as a transmitting/receiving input/output, and its surroundings are covered with a conductive material over a certain length. It is characterized in that at least one point of the conductive material is grounded to the casing.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. . Components having the same function as those in the m1 diagram are given the same symbols and their explanations will be omitted.

In Figure 48, Qη is a cylindrical wire mesh that surrounds the outer periphery of the part (a'-b) of the coaxial cord (a, tb) drawn into the other storage part (1), and this wire mesh Qη is the coaxial cord (a
-b) It is arranged outside the jacket insulator and is grounded to the housing part (1) by a cord (g).

With this configuration, it is possible to prevent the part (a'-b) of the coaxial cord (a-b) drawn into the storage part (1) from acting as an antenna due to standing waves.
The flM etc. radiated into the storage section (1) are reduced. According to actual measurements, the image characteristics can be improved by about 20 dB depending on the degree of shielding of a part of a'-b, and the image characteristics can be brought to a value extremely close to the characteristics measured from the 0 point of BPF (4). did it. FIG. 4 shows the VSW characteristics before shielding as in the present invention.

In the above embodiment, the outer periphery of the coaxial cord is surrounded by a cylindrical wire mesh, but the same effect can be obtained even if the wire mesh is as follows.

O Metal pipe, coated with conductive paint, rectangular wire mesh or metal plate bent into a U shape and bound at both ends with fasteners In the above example, the outer station of the coaxial cord was completely surrounded with conductive material. This can be done by providing a conductive material along the length of a part of the outer periphery of the coaxial cord and grounding it. A mitigation effect can be expected.

In the above embodiment, a two-wave simplex system was explained as an example, but ctt7 has BP for transmitting and receiving input/output.
A similar effect can be obtained in a wireless device using a simultaneous transmission/reception method using F.

Effects of Investigation As explained above, according to the transmitting/receiving radio device of the present invention, at least the portion of the input/output coaxial cord of the radio that exists inside the radio device housing is shielded with a metal pipe, wire mesh, conductive paint, etc. Since the shield part is grounded to the housing at at least one point, the standing wave component due to the mismatch of the coaxial cord is shielded and this part can be prevented from operating as an antenna, and the radiation component due to the standing wave is prevented from entering the housing. generation and coupling to the receiver can be prevented or reduced at the source. Therefore, it is low cost, simple, and can be implemented effectively compared to the method that uses filters, etc. for each path to prevent the components from being coupled to the receiver through multiple paths after being radiated into the housing. . In addition, the arrangement of the built-in components of the radio device housing is determined under conditions suitable for manufacturing. Totoga℃;
A secondary effect is also obtained that arrangement with a large degree of freedom can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional wireless device, and the second factor is transmission. FIG. 8 is a diagram for explaining the reception frequency and image frequency, FIG. 8 is a diagram showing the main part of an embodiment of the wireless device according to the present invention, and FIG. 4 is a Vsw characteristic diagram before implementing the present invention. (1)...Transmitting/receiving antenna, (2) antenna switching section, (3)...low pass filter, (4)...band pass filter, (5)...kameko switch, (6) ...
Receiver, (8)...Transmitter, Q cable...Cylindrical wire mesh [
conductive material], (1)...storage section [casing], (a-b
)...High frequency coaxial cord agent Shigehiro Morimoto

Claims (1)

[Scope of Claims] 1. The outer insulator of the high-frequency coaxial cord, which is inserted into the housing of the radio and serves as the transmitting and receiving input/output, is covered with a conductive material over a certain length, and the conductive material is A transmitting/receiving radio device in which at least one point of a conductive material is grounded to the housing. 2. Conductive paint is applied to the outer periphery of the jacket insulator of the high-frequency coaxial cord over a certain length so as to surround the high-frequency coaxial cord, and at least one part of the applied paint is grounded. A transmitting/receiving radio device according to claim 1.