JPH0612586A - Wireless transmitter and wireless security system utilizing the same - Google Patents

Abstract

PURPOSE:To reduce the probability of generating mutual interference and to improve reliability by providing a random number generator for changing transmission cycles for repeatedly transmitting security signals at random. CONSTITUTION:A sensor signal transmitted from a signal processing part 4 is added to an ID code set by an ID code setting device 6 as data at a signal code generation circuit 5. In this case, since the signal processing part 4 is operated to start a timer circuit 2 when an additionally connected sensor outputs abnormal signals, the timer circuit 2 successively receives random number data outputted from the random number generator 3 and operates a front end part 1 at the cycle corresponding to the random number data. Thus, for a period when the sensor outputs the abnormal signals, the security signals are transmitted from an antenna 1a while the transmission cycles are successively changed every time the front end part 1 is operated.

Description

Detailed Description of the Invention

The present invention relates to a wireless transmitter using weak radio waves and an improvement in a wireless security system using this wireless transmitter.

[0002]

2. Description of the Related Art Recently, security wireless systems utilizing weak radio waves have been developed and used. In such a system, as shown in FIG. 5, individual wireless transmitters 100 and 100 'are added to a crime prevention sensor Sa and a disaster prevention sensor Sb such as a fire sensor, and these sensors Sa and Sb detect an abnormality. Wireless transmitter 100, 100 '
A security signal is transmitted in the form of a radio wave signal from the device, and the common wireless receiver 200 performs reception processing to issue an alarm and activate necessary external equipment.

By the way, as a wireless transmitter used in such a wireless security system, a security signal is transmitted only once when a sensor detects an abnormality (single transmission type) or a predetermined number of times. In addition to the continuous transmission type (continuous transmission type), as long as the sensor outputs an abnormal signal (ON time in FIG. 6), as shown in FIGS.
There is one that repeatedly transmits the security signal S at a predetermined cycle T (repeated transmission type), and in a normal proper security system, the battery is likely to be consumed, but the latter type has less reception errors on the wireless receiver side. It is highly reliable.

However, in the case where the wireless security system is configured to include a large number of repetitive transmission type wireless transmitters such as the latter, when a plurality of wireless transmitters operate simultaneously and the transmission timings of the security signals coincide with each other. As shown in FIG.
The security signals S1 and S2 transmitted from both wireless transmitters may interfere with each other, and the wireless receivers may not be able to receive them correctly, which in turn reduces the reliability of the security system. Has brought about the result.

[0005]

DISCLOSURE OF THE INVENTION The present invention is proposed to solve the problems in such a wireless security system, in which security signals are simultaneously transmitted from a plurality of wireless transmitters constituting the wireless security system. Even in such a case, it is intended to reduce the probability of mutual interference and improve the reliability of the wireless security system.

[0006]

Therefore, the present invention proposed to achieve the above object proposes a wireless transmitter having a novel structure and a wireless security system using the wireless transmitter. Here, the wireless transmitter relates to the improvement of a plurality of wireless transmitters that repeatedly transmit a security signal in the form of a radio signal when a sensor detects an abnormality, etc. A random number generator for changing at random is provided (Claim 1).

A wireless security system proposed at the same time combines a plurality of wireless transmitters according to claim 1 with a wireless receiver for receiving and processing radio wave signals transmitted from these wireless transmitters. The system is characterized in that the repeating transmission cycle of abnormal signals repeatedly transmitted in the form of radio signals from individual wireless transmitters is set at random (claim 2).

[0008]

According to the wireless transmitter of the present invention, the random number generator randomly changes the repeating transmission cycle of the security signal. Further, according to the wireless security system of the present invention, since the transmission cycle is changed each time a security signal is transmitted from each wireless transmitter, a plurality of wireless transmitters operate at the same timing, and the security signal is transmitted. Since the probability of mutual interference is low even if both are transmitted at the same time, there is no reception error on the wireless receiver side and the reliability is improved.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing the basic configuration of a wireless transmitter A according to the present invention. In the figure, 1 is a front end section having an antenna 1a for transmitting a radio wave signal, 2 is a cycle of the front end section 1 according to random number data output from a random number generator 3 (for example, 7 seconds to 15 seconds). The timer circuit 4 driven at intervals) is driven by receiving an abnormal signal from the sensor, a transmission command signal from the transmission switch SW, and the like, and a signal processing unit for transmitting a sensor signal to a signal code generation circuit 5 described later, and 6 is a wireless An ID code setting device for setting an ID code assigned to the transmitter A.

In the signal code generation circuit 5, the ID
The ID code set by the code setting unit 6 is added with the sensor signal sent from the signal processing unit 4 as data to form the security data in the format as shown in FIG. There is. According to the wireless transmitter A of the present invention having such a configuration, when the sensor (not shown) additionally connected outputs an abnormal signal, the signal processing unit 4 is activated and the timer circuit 2 is activated. 2 sequentially receives random number data output from the random number generator 3, and operates the front end unit 1 at a cycle according to the random number data. Therefore, as shown in FIG. 3, during the period in which the sensor outputs an abnormal signal (ON time in the same figure a), the security signal S is output from the antenna 1a each time the front end unit 1 is activated. However, as shown in FIG.
b, Tc, and Td are sequentially changed and transmitted.

FIG. 4 shows how a security signal is transmitted in the wireless security system of the present invention. A conventional security system (Fig. 7a) in which two wireless transmitters are simultaneously activated to repeatedly transmit a security signal at a predetermined fixed period.
Compared with b)), in the system of the present invention, the security signal may be interfered at the first time, but thereafter, the security signal is transmitted at a random cycle defined by the random number generator 3. Therefore, there is no risk of mutual interference, the probability of a reception error on the wireless receiver side is reduced, and it is understood that the security signals S1 and S2 transmitted from both sides can be properly received by the wireless receiver in the system. It should be done.

[0012]

As described above, according to the wireless transmitter of the present invention, when a security signal is transmitted in response to an abnormal signal from a sensor or the like, the repetition transmission cycle thereof randomly changes, so that a large number of wireless transmissions can be performed. Even when used in a wireless security system including a transmitter, the probability of mutual interference with a security signal transmitted from another wireless transmitter is reduced, so that the reliability of the wireless security system can be improved.

Further, according to the wireless security system of the present invention, even if the wireless transmitters in the system emit security signals at the same time, there is no possibility of mutual interference, and the reliability of the system is improved accordingly.

[Brief description of drawings]

FIG. 1 is a block diagram showing an internal configuration of a wireless transmitter of the present invention.

FIG. 2 is a format diagram of a security signal.

FIG. 3 is a time chart showing the operation of transmitting a security signal in the wireless transmitter of the present invention.

FIG. 4 is a diagram showing a transmission situation of a security signal in a wireless security system using the wireless transmitter of the present invention.

FIG. 5 is an explanatory diagram of a basic concept of a security wireless system.

FIG. 6 is a time chart showing a security signal transmission operation in a conventional wireless transmitter.

FIG. 7 is a time chart explaining a problem of mutual interference of security signals in a conventional wireless security system.

[Explanation of symbols]

A ... Wireless transmitter of the present invention 1 ... Front end unit 2 ... Timer circuit 3 ... Random number generator 4 ... Signal processing unit 5 ... Signal code generation circuit 6 ... ID Code setting device S, S1, S2 ... Security signal Ta, Tb, Tc, Td ... Security signal transmission cycle

Front page continuation (72) Inventor Hideaki Okada 1048, Kadoma, Kadoma-shi, Osaka Prefecture Matsushita Electric Works, Ltd.

Claims (2)

[Claims] 1. A plurality of wireless transmitters for repeatedly transmitting a security signal in the form of a radio signal when a sensor detects an abnormality, etc., and a random number generator for randomly changing a transmission cycle for repeatedly transmitting a security signal. A wireless transmitter comprising: 2. A plurality of wireless transmitters that repeatedly transmit a security signal in the form of a radio wave signal when a sensor detects an abnormality, and receive and process the security signals transmitted from these wireless transmitters. In a wireless security system configured by combining with a wireless receiver, the wireless security system is characterized in that the repeating transmission cycle of the security signal repeatedly transmitted in the form of a radio wave signal from each wireless transmitter is set at random. .