JPH02114725A - Wireless transmitter - Google Patents

Abstract

PURPOSE:To increase the reception sensitivity at a receiver side and to evade a reception mistake by arranging two arched loop antennas orthogonally so that the polarized planes of radiated radio wave signals differ from each other and outputting radio wave signals from the two loop antennas alternately when a call operation switch is operated. CONSTITUTION:Two loop antennas 31, 32 formed to be arch are arranged on a circuit board 3 so that lateral plates 31a, 32a are made orthogonal. A switching circuit to operate the said antennas 31, 32 for each prescribed time alternately is provided to a transmission control circuit mounted on the circuit board 3. The switching circuit outputs a one-frame signal with an urgent signal to a house cord alternately from the antennas 31, 32 when the transmission operation switches 4, 4 are once operated. Since the radio wave signal with different polarized plate is sent alternately, the effect of radio wave interference in the radio wave path till the arrival of the receiver is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in wireless transmitters for portable use.

[Prior Art] This type of wireless transmitter is worn around the neck of an elderly or sick person who requires nursing care when they are away from the patient, and when an emergency occurs, the transmitter cannot be operated. Operate a switch to send weak radio waves to a separate receiver to alert you to an emergency situation.

Fig. 2 shows the exterior structure of such a conventional wireless transmitter with a part cut away. It has a structure that allows it to be carried by hanging it around the neck with a handle 11.A pair of operation switches 4゜4 are provided on both sides of the upper part of the main body, and in the event of an emergency, the pair of operation switches 4, 4 can be activated. It is configured so that it can be transmitted in the form of a radio wave signal to a separately placed receiver by operating the .

Figure 3 shows an exploded view of the inside.

12.2 is the back cover and front cover of the main body, and these two covers 1. A main body A is formed by aligning the two covers 1 and 2, and a circuit board 3 on which a transmission control circuit is formed is accommodated between the back and front covers 1.2.

Both the back cover 1 and the front cover 2 have lower ends rounded with a predetermined curvature, and openings 11° 21 are formed at both shoulders, tapering upward.

Window holes 10a and 10b are formed at appropriate locations on the back cover 1, and are divided into upper and lower sections by a partition 10c.
A cover (not shown) is removably attached. window l
When the cover installed at O is opened, the dip switch 3a mounted on the circuit board 3 is exposed through the upper window hole 10a, and the battery 3b is exposed through the lower window hole 10b, and the house code can be set. Then, the battery 3b is replaced.

Further, one front cover 2 has a circular convex spherical portion formed in the center according to the curvature of the lower end.

On the other hand, the above-mentioned dip switch 3 is mounted on the circuit board 3.
In addition to a, there is an electromagnetic shielding case 3 f that covers the circuit elements consisting of the coil and capacitor that constitute the LC resonant circuit.
, loop antenna 3 e erected in an arch shape,
A battery 3b connection part +J'3c, 3d and a set of drive switches 5, 5 are mounted, and the latter drive switch 5
I5 is provided opposite to each other at both ends of the dip switch 3a so that operating pieces 5a which are pressed and operated by the switches 4, 4 are directed outward from each other.

A pair of operation switches 4 attached to the sides of both shoulders of the main body
, 4 is the pivot 11'1114. a, 4. a, and these pivot shafts 4a, 4a are fitted into corresponding recesses 21a on the back 5 and front covers 1.2 of the main body A. Operation switch 4
, 4 are provided with operating portions 41, 41, and further below the switches 4, 4 are thin plate tongues 42, 42 for applying elastic force when the switches 4, 4 return. It has a formed structure.

However, in the conventional wireless transmitter configured as described above, the radio wave signal is emitted from one arched loop antenna 3c provided on the circuit board, so it is difficult to identify the polarization plane of the emitted radio wave. If it receives radio wave interference on the way to the receiver, the receiver may not be able to detect it as a subordinate.

[Problems to be Solved by the Invention] The present invention has been made in view of the above circumstances, and provides a wireless transmitter that alternately transmits radio signals with different polarization planes from the wireless transmitter. The purpose is to

[Means for Solving the Problems] A wireless transmitter of the present invention provided to achieve the above object has a transmission operation switch, and has an arch-shaped loop antenna inside the main body and a transmission control for the loop antenna. This is an improvement of a portable wireless transmitter that includes a built-in circuit board on which a control circuit is mounted. includes a switching circuit that alternately outputs radio signals from each of the loop antennas, and when the transmission operation switch is operated, the signal processed by the transmission control circuit is output as a radio signal from the two loop antennas. It is characterized by a configuration in which the outputs are output alternately.

[Function] According to the wireless transmitter of the present invention, when the transmission operation switch is operated, the switching circuit included in the transmission control circuit is activated, and radio signals are alternately transmitted from two loop antennas arranged orthogonally to each other. Since the signal is transmitted, the plane of polarization of the radio wave signal at the time of transmission changes, reducing the influence of radio wave interference along the transmission path, and increasing the apparent range of radio waves.

[Example code] The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is an exploded configuration diagram showing the configuration of a wireless transmitter A of the present invention.

To explain the different parts from the configuration shown in FIGS. 2 and 3, on the circuit board 3, two arch-shaped loop antennas 31 and 32 are arranged on the horizontal plate 31a of the circuit board 3.
, 32a are arranged so that they are perpendicular to each other, and a jumper chip is used as a house code setting means instead of a dip switch.

ICs with house codes set in advance during assembly and manufacturing by disconnecting and shorting jumper wires, etc.
A tip 6a is mounted.

In addition, an opening 1a is provided in the center of the front cover 2 for inserting and removing the battery 8.
The hole 1e is formed so that the operating piece 9a of the reset switch 9 provided on the circuit board 3 is exposed even when the cover 1b is removably attached and the opening 1a is closed by the cover 1b.
, If are provided to match. Note that 7 is an operation display switch that lights up when the transmission operation switch 4.4 is operated.

The transmission control circuit mounted on the circuit board 3 includes
It is equipped with a switching circuit for alternately operating the arch-shaped loop antennas 31 and 32 at predetermined time intervals,
This switching circuit causes the respective antennas 31 and 32 to alternately output one-frame signals of (-1) to the house code when the transmission operation switches 4, 4 are operated. The output is from the reset switch 9 exposed through the hole 1e of the front cover 1 of the main body.
The signal continues to be transmitted when the activation piece 9a is activated.

According to such a configuration, when the transmission operation switch 4°4 is operated, the switching circuit is activated, and the circuit board 3],
In order to operate the loop antennas mounted on 32 alternately,
Due to the so-called polarization diversity effect, radio wave signals with horizontal and vertical polarization planes are radiated from the loop antennas 31 and 32 arranged orthogonally to each other, so that these radio waves with different polarization planes complement each other. , it is possible to increase the reception sensitivity on the receiver side and eliminate reception errors.

[Effects of the Invention] According to the wireless transmitter of the present invention, when the transmission operation switch is operated, radio wave signals with different polarization planes are transmitted alternately, so that the radio wave signals are transmitted along the radio wave path until reaching the receiver side. The effect of radio wave interference is small, making it possible to create a highly reliable and secure wireless system.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing an embodiment of the wireless transmitter of the present invention, FIG. 2 is a partially cutaway external view of a conventional portable wireless transmitter, and FIG. 3 is an exploded perspective view thereof. [Explanation of symbols] A... Wireless transmitter 3... Circuit board 4... Transmission operation switch 31.32... Loop antenna

Claims (1)

[Scope of Claims] 1) A wireless transmitter having a transmission operation switch and having a built-in arch-shaped loop antenna and a circuit board on which a transmission control circuit for the loop antenna is mounted inside the main body, the above-mentioned arch-shaped The loop antennas are arranged orthogonally to each other so that the planes of polarization of the radio signals they radiate are different, and the transmission control circuit includes a switching circuit that alternately outputs radio signals from each of the loop antennas, When operated, the wireless transmitter is configured to alternately output signals processed in the transmission control circuit as radio signals from the two loop antennas.