JPH0420149A - Radio equipment - Google Patents

Abstract

PURPOSE:To receive a signal in an excellent way even under an environment with much fading by providing a discrimination means confirming it as the presence of a data and extending a sampling period in a receiver when signals of a prescribed number or over exist in a sampled data number and providing a control means reducing a data pulse width for a prescribed time only and sending the resulting pulse at application of power in a transmitter. CONSTITUTION:The receiver R is provided with a sampling means 9 sampling a data pulse for plural number of times for a sufficiently shorter period than a data pulse width, a discrimination means 9 confirming it as the presence of data when signals of a prescribed number of over exist in a sampled data number by the sampling means 9, and the transmitter T is provided with a control means 23 reducing a data pulse width for a prescribed time only and sending the resulting pulse at application of power to the transmitter. Then the width of the data pulse sent from the transmitter T to the receiver R is reduced and the receiver R receives a data pulse whose pulse width is reduced thereby causing the same state as that with deteriorated reception sensitivity and the communication is confirmed. Thus, a signal is received in an excellent way even under an environment with much fading.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wireless device used in a so-called wireless security system, which uses wireless for signal transmission in a security and disaster prevention monitoring system.

[Prior Art] Fig. 7 shows a configuration diagram of a wireless security system, in which a receiver R receives monitoring signals for crime prevention, disaster prevention, etc. transmitted wirelessly from a transmitter T, and monitors crime prevention, disaster prevention, etc. ing.

In the security system, the identification code of the transmitter T is registered in advance in the receiver R in order to distinguish the transmitter T that transmits sensor information and should be monitored.

FIG. 8 shows a block diagram of the receiver R, which is roughly divided into a receiving section Ra that receives a signal from the transmitter T, and a receiving section Ra that receives a signal from the transmitter T.
It is comprised of an identification display section Rb that registers the identification code of and determines the identification code. The receiving unit Ra includes an antenna 1 that receives a signal from a transmitter T, a front end 3 that high-frequency amplifies the output of the antenna 1 and converts it to a predetermined frequency, and a demodulator 4 that demodulates the output of the front end 3.
and a waveform shaping section 5 that shapes the waveform of the output of the demodulator 4. And, in the front stage of front end 3,
Attenuator (ATT) to operate when installing receiver R
2 are provided. In addition, the identification display section Rb indicates that each transmitter T
Display 1 to display the status of! e6, a registration switch 8 that is operated when registering the identification code of the transmitter T, and the transmitter T.
It is comprised of an arithmetic processing unit 9 that identifies the identification code and sensor information for each transmitter Tf)wA, and a memory 10 that records data indicating the transmitter Tf)wA separate code and one type of sensor. Furthermore, an installation switch 7, which will be described later, is provided.

(Problem to be Solved by the Invention) Here, the installation switch 7 and the attenuator 2 are provided for the following reasons. That is, there is a margin in the received transmitter signal level with respect to the reception sensitivity of the receiver R during normal transmission. In order to have a The level is attenuated and communication is confirmed.

However, when a signal is input to the front end 3 without applying attenuator 2 when the installation is removed after installation, there is through attenuation of attenuator 2, which reduces the receiving input and degrades the original sensitivity of receiver R. There was a problem.

Further, as shown in FIG. 9, when the receiving section Ra and the identification display section Rb of the receiver R are disposed separately, there is a problem in that a control line 11 is required. Furthermore, there is also the problem that the attenuation rate of the attenuator 2 cannot be changed arbitrarily.

The present invention has been provided in view of the above-mentioned points, and eliminates the attenuation caused by the attenuator by eliminating the need for an attenuator.The present invention also provides an apparent deterioration in sensitivity during installation, and provides a good signal even in an environment where there is usually a lot of fading. The purpose of this invention is to provide a wireless device that is capable of receiving.

[Means for Solving the Problems] The present invention provides sampling means for sampling data pulses multiple times at a sufficiently short period compared to the data pulse width, and a method in which a predetermined number or more of signals exist from the number of data sampled by the sampling means. The receiver is equipped with a determination means for determining the existence of data when the power is turned on, and the transmitter is equipped with a control means for shortening the width of the data pulse and transmitting it for a certain period of time when the power is turned on.

[Function] Therefore, when installing the transmitter and receiver, the width of the data pulse sent from the transmitter to the receiver is shortened, and the receiver side receives the data pulse with the shortened pulse width. This creates a state that is apparently the same as degrading the reception sensitivity, and by checking communication in this state, it is possible to communicate well even in an environment where normal communication has a lot of fading.

[Example 1] Hereinafter, an example of the present invention will be described with reference to the drawings. In wireless communications, data pulse-width-modulated with a two-tone subcarrier NRZ signal from a transmitter is demodulated by a receiver having a configuration similar to the conventional one. As the distance between the transmitter and the receiver increases, the data pulse width of the signal becomes narrower, as shown in FIG. 2, and the signal is shortened. In the receiver, the arithmetic processing unit 9 samples at a sufficiently short cycle (for example, about 1/10 cycle) compared to the data pulse width, detects the presence or absence of data, and performs sampling at a preset number of times relative to the data pulse width. If there is a predetermined number or more of H level signals (for example, several tens of percent of H level signals is a reference value), the H level or L level is determined as being equal to or greater than the reference value. Note that the sampling means for sampling and the determination means for determining the existence of data are constituted by the arithmetic processing section 9 of the receiver R.

FIG. 3(a) shows the data pulse of the transmitter, and the same 1! I
(b) shows the reception input of the receiver. When sampling the received data pulse, the pulse width is 75
% is the limit of judgment. For example, when data pulses are sampled, if the number of signals present is 60% or more, it is determined that data exists. and,
If the distance between the transmitter and receiver is 30m, the second
As shown in the figure, the data pulse width of the receive input is reduced by 80%. Then, as shown in FIG. 3(b), sampling is performed on the shortened data pulse width, and the determination standard is set at 60% as described above.

Here, if the pulse width of the data pulse of the transmitter itself is set to be narrow, in the above judgment method, the pulse width will be narrower than during normal input, so it is likely to fall below the reference value.
Therefore, the receiver appears to be in the same state as if its upper sensitivity has deteriorated, and the communication distance becomes shorter as shown in FIG.

Therefore, in the present invention, when the transmitter is initially driven (only when the power is turned on), communication is possible within this time by narrowing the pulse width of the data pulse sent from the transmitter for a certain period of time. In this case, it can be determined that communication is reliably possible in subsequent normal times.

FIG. 1 shows a block diagram of the transmitter T, with the ID switch 2
1, memory 22, arithmetic processing unit 23, sensor input terminal 2
41 oscillation section 25, amplification modulation section 26, antenna 27, etc. FIG. 5 shows an operation flow of the arithmetic processing section 23, and FIG. 6 shows an operation waveform diagram.

When installing the transmitter T and receiver R, the arithmetic processing section 23 operates as follows. That is, when the power is turned on, the arithmetic processing section 23 constituting the control means is activated by the memory 22.
It is activated by the program inside and resets the timer. After the timer is initialized, the H tone pulse modulated signal (data 1) is sent as shown in FIG. 6(a) in order to shorten α time with respect to the normal pulse width T. (80% width of the regular data width), then only the carrier is transmitted for 2α time. Thereafter, a pulse width modulated signal (data 0) of the white tone is sent out for (T-α) time. This is output continuously for a certain period of time set by the timer, and after the time set by the timer has elapsed, the mode shifts to the normal input warning mode.

When this is received by receiver R, as shown in Figure 6 (b) and (e), the pulse width is shorter than the actual pulse width at that distance, which is equivalent to deterioration of the sensitivity of receiver R. It turns out. Therefore, by confirming communication in this state, good communication is possible even in an environment where fading is common in normal times. In addition, Fig. 6 (b
) (The broken line shown in e> shows the pulse width at long distances, and the data width is shortened to 55% compared to the regular data width, so even if it is detected by sampling, it will not be judged as 60%. , the data will be identified as not present.

[Effects of the Invention] As described above, the present invention includes a sampling means for sampling a data pulse multiple times at a sufficiently short period compared to the data pulse width, and a method in which a predetermined number or more of signals exist from the number of data sampled by the sampling means. The receiver is equipped with a determination means for determining the existence of data when the power is turned on, and the transmitter is equipped with a control means that shortens the width of the data pulse and transmits it for a certain period of time when the power is turned on. When installing the receiver, the width of the data pulse sent from the transmitter to the receiver is shortened, and the receiver side receives the data pulse with the shortened pulse width, which improves the appearance and improves reception. By setting the sensitivity to the same state as degraded and confirming communication in this state, it is possible to achieve good communication even in an environment where there is a lot of fading in normal communication. By setting it on the program, you can increase the degree of freedom, and furthermore, you can adjust the sensitivity without using an attenuator, which degrades the original sensitivity of the receiver due to the use of an attenuator. This has the effect of not causing any damage.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a transmitter according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of the same, FIG. 3 is an explanatory diagram of the same, FIG. 4 is an explanatory diagram of the same, and FIG. 5 is a flowchart of the same. , FIG. 6 is an explanatory diagram of the same as above, FIG. 7 is a system configuration diagram, FIG. 8 is a block diagram of a conventional receiver, and FIG. 9 is an explanatory diagram of the same. T is a transmitter and R is a receiver. Agent Patent Attorney Ishi 1) Chief 7th 1 Figure T...Transmitter Figure 9

Claims (1)

[Claims] (1) In a radio device consisting of a transmitter that sends out a predetermined data pulse and a receiver that receives the data pulse from the transmitter and demodulates the data signal, the frequency is sufficiently short compared to the data pulse width. The receiver is equipped with a sampling means for sampling data pulses multiple times and a determination means for determining the existence of data when a predetermined number or more of signals exist from the number of data sampled by the sampling means, and the receiver is equipped with A wireless device characterized in that a transmitter is provided with a control means for transmitting a data pulse with a width shortened.