JP3324254B2 - Transmission equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention is a gas meter and water meters, gas by the power meter or the like, measuring water, the integrated value of the amount of electricity, etc., order to suck up the integrated value from the remote
Related to the transmission device.

[0002]

2. Description of the Related Art In recent years, a so-called automatic meter reading system has been introduced in which an integrated value measured by a meter is remotely fetched using a telephone line or the like. Further, there is an attempt to connect a telephone line and a meter by a wireless line. FIG. 3 shows a block diagram of a conventional automatic meter reading system using wireless communication and a transmission device used in the system. FIG. 3A shows the configuration of the parent device, and FIG. 3B shows the configuration of the child device.

In FIG. 3A, 1 is an antenna, 2 is transmitting means, 3 is channel selecting means, 4 is signal generating means, 5 is receiving means, 6 is clock generating means, 7 is timer means, and 8 is intermittent. It is a control means and constitutes the transmission device 12. 9 is a public telephone line, 10 is a no-ringing network control means (hereinafter referred to as T-NCU) connected to the public telephone line 9, and 11 is an interface means.
Data collection means 1 by U10 and interface means 11
3.

In FIG. 1B, reference numeral 14 denotes an antenna,
5 is transmitting means, 16 is channel selecting means, 17 is signal generating means, 18 is receiving means, 19 is clock generating means,
Reference numeral 20 denotes a timer unit, and reference numeral 21 denotes an intermittent control unit, which constitutes the transmission device 25. Reference numeral 22 denotes a gas pipe installed at home, 23 denotes a gas flow meter (so-called gas meter) provided in the middle of the gas pipe 22 to measure the amount of gas used in the target home, and 24 denotes storage means.

[0005] The parent device and the child device are driven by a battery, and an intermittent reception system is employed to extend the life of the battery.
In the intermittent control means 8 and 21, for example, 20 m at 30 second intervals
Power is supplied to the receiving means 5 and the receiving means 18 for only seconds, and the receiving means 5 enters the receiving state. If it becomes necessary to transmit data to the other party, the radio wave is transmitted at the above-mentioned 30-second interval synchronized with the other party. Radio waves in the 400 MHz band, which has recently been approved for use as low-power radio, are used as radio waves to be used. The channel selecting means 3 and the channel selecting means 16 select the frequency of the radio wave to be transmitted and received. The channel selecting means 3 and the channel selecting means 16 have a so-called PLL (PHASE LOCKEDLOOP) system configuration. Signal generating means 4 and signal generating means 17
Is composed of a crystal oscillator, and serves as a reference frequency for determining the channel frequency of the channel selecting means 3 and 16. ± 4 ppm by law for low power radio
It is specified that the following frequency accuracy is required. Now, in order for the parent device and the child device to perform the transmission operation and the reception operation at the same time in synchronization, the clock generation means 6 for determining the operation time of the intermittent control means 8 and the intermittent control means 21.
And the clock frequency of the clock generation means 19 need to match without any deviation. The timer means 7 and the timer means 20 measure an intermittent operation time interval by counting clock pulses from the clock generating means 6 and the clock generating means 19. Generally, clock generation means 6
Although a crystal oscillator is used as the clock generator 19, the clock frequencies of the clock generator 6 and the clock generator 19 do not match due to the influence of temperature and an initial adjustment error. For this reason, the intermittent operation timing of each other shifts with time. Therefore, a signal for timing adjustment is transmitted from the parent device before the intermittent operation timing is largely shifted. For example, if the frequency accuracy of the crystal oscillator used in the clock generation means 6 and the clock generation means 19 is ± 50 ppm, the worst case will be a deviation of ± 100 ppm between the parent device and the child device. Therefore, for example, a shift of ± 60 msec for 10 minutes. Therefore, the parent device transmits the timing adjustment signal at intervals of 10 minutes by making the preamble signal transmitted at the time of transmission slightly longer so that the child device can receive even if shifted by ± 60 msec. When the slave device receives a signal for timing adjustment from the master device, it controls the timer means 20 and corrects the start time of the timer means 20. The above operation cancels the shift of the intermittent operation timing every 10 minutes, so that the shift of the intermittent operation timing does not accumulate for 10 minutes or more.

[0006]

However, in the configuration of the above-mentioned conventional transmission device, the time interval at which the parent device transmits the timing adjustment signal is determined by the maximum error between the clock frequencies of the parent device and the child device. Therefore, when a normal crystal oscillator is used, it is necessary to transmit and receive a timing alignment signal at a time interval of about 10 minutes, which has been a cause of shortening the battery life. Further, when a crystal oscillator with high frequency accuracy is used, the time interval can be lengthened, but there is a problem that such a high-precision crystal oscillator is very expensive.

[0007] A transmission device according to the present invention solves the above-mentioned problems, and has as its object to realize a transmission device capable of extending a transmission / reception cycle of a timing adjustment signal and thereby extending battery life.

[0008]

In order to achieve the above object, a transmission apparatus according to the present invention comprises: a receiving means for receiving a radio wave;
Clock generating means, timer means for measuring time based on a clock signal from the clock generating means, intermittent control means for intermittently controlling the operation of the receiving means at time intervals controlled by the timer means, A reference signal generating means, a time error detecting means for detecting a time error between a signal from the reference signal generating means and a signal from the clock generating means, and a time error detecting signal from the time error detecting means. It is configured to correct the time measurement of the timer means.

The reference signal generating means used in the above configuration receives a signal from a receiving means for receiving a radio wave from a second transmission device for intermittently transmitting a radio wave at a predetermined time interval as an input. The time interval of the radio wave from the second transmission device is used as an output signal.

The reference signal generating means used in the above configuration is shared with the signal generating means for determining the frequency to be received by the receiving means.

[0011]

According to the transmission apparatus of the present invention, the clock frequency deviation between the parent device and the child device can be detected and the count value of the timer means can be changed in such a direction as to eliminate the clock frequency deviation. Therefore, the transmission / reception interval of the timing adjustment signal can be extended.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1A shows the configuration of the parent device, and FIG. 1B shows the configuration of the child device. The same numbers are assigned to the same functional blocks as in the conventional example. In FIG. 1A, 1 is an antenna, 2 is a transmitting means, 3 is a channel selecting means, 4 is a signal generating means, 5 is a receiving means, 6 is a clock generating means, 7 is a timer means, and 8 is an intermittent control means. The transmission device 29 is provided. 9 is a public telephone line, and 10 is a no-ringing network control means (hereinafter referred to as T-N) connected to the public telephone line 9.
CU), 11 is an interface means, T
The data collection means 13 is constituted by the NCU 10 and the interface means 11;

In FIG. 1B, 14 is an antenna, 1
5 is transmitting means, 16 is channel selecting means, 17 is signal generating means, 18 is receiving means, 19 is clock generating means,
Reference numeral 20 denotes a timer unit, and reference numeral 21 denotes an intermittent control unit, which constitutes the transmission device 30. Reference numeral 22 denotes a gas pipe installed at home, 23 denotes a gas flow meter (so-called gas meter) provided in the middle of the gas pipe 22 to measure the amount of gas used in the target home, and 24 denotes storage means. 26 is a reference signal generating means, and 27 is a time error detecting means.

The parent device and the child device are driven by a battery and employ an intermittent reception system to extend the life of the battery.
That is, similarly to the conventional example, the timing adjustment signal is transmitted from the parent device (A) at intervals of 10 minutes. When the slave unit (B) receives the timing adjustment signal every 10 minutes from the parent device (A) by the receiving unit 18, the reference signal generation unit 26 synchronizes with the timing alignment signal based on the timing adjustment signal received by the receiving unit 18. Output a signal every 10 minutes. The time error detecting means 27 measures the timing alignment signal interval from the reference signal generating means 26 using the signal from the clock generating means 19. For example, it is assumed that a timing alignment signal interval measured by a signal from the clock generation unit 19 is 10 minutes 10 ms. Then, assuming that the timing adjustment signal interval is a correct 10 minute interval, the time error detection means 27 outputs an error signal of 10 msec. This error signal controls the timer means 20 to generate an output from the timer means 20 every 10 minutes and 10 ms in the time measurement by the signal from the clock generation means 19. Therefore, the output of the timer means 20 has the same time interval as the timing adjustment signal. Therefore, the timing of the intermittent operation of the parent device (A) and the child device (B) does not significantly deviate even if the time interval of the timing adjustment signal is increased by 10 minutes or more, for example, about every hour. That is, since the transmission interval of the timing adjustment signal can be lengthened, the transmission power of the timing adjustment signal can be reduced for the parent device (A), and the child device (B)
Therefore, the reception power of the timing adjustment signal can be reduced. Therefore, the battery life is extended for both the parent device (A) and the child device (B).

Another embodiment of the present invention will be described with reference to FIG. FIG. 2A shows the configuration of the parent device, and FIG. 2B shows the configuration of the child device. The same numbers are assigned to the same functional blocks as in the embodiment of FIG. In FIG. 2A, 1
Is an antenna, 2 is a transmitting means, 3 is a channel selecting means,
4 is a signal generating means, 5 is a receiving means, 6 is a clock generating means, 7 is a timer means, and 8 is an intermittent control means, constituting a transmission device 29. Reference numeral 9 denotes a public telephone line, 10 denotes a no-ringing network control unit (hereinafter referred to as T-NCU) connected to the public telephone line 9, and 11 denotes an interface unit. The data collection unit 13 includes the T-NCU 10 and the interface unit 11. are doing.

In FIG. 2B, 14 is an antenna, 1
5 is transmitting means, 16 is channel selecting means, 17 is signal generating means, 18 is receiving means, 19 is clock generating means,
Reference numeral 20 denotes a timer unit, and reference numeral 21 denotes an intermittent control unit, which constitutes the transmission device 30. Reference numeral 22 denotes a gas pipe installed at home, 23 denotes a gas flow meter (so-called gas meter) provided in the middle of the gas pipe 22 to measure the amount of gas used in the target home, and 24 denotes storage means. 27 is a time error detecting means.

The parent device and the child device are driven by a battery and employ an intermittent reception system to extend the life of the battery.
The signal generation means 4 and the signal generation means 17 are intermittent control means 8
It operates intermittently by the intermittent control means 21. The signal generating means 4 and the signal generating means 17 have a frequency accuracy of ± 4.
Generates high-precision signals of less than ppm. The signal frequencies from the signal generating means 4 and 17 and the signal frequencies of the clock generating means 6 and the clock generating means 19 are compared in a time error detecting means 28 and a time error detecting means 27, and the time error signals are compared with each other. Output from the detecting means 28 and the time error detecting means 27. The timer means 7 and the timer means 20 are controlled by the time error signal so that the time intervals measured with the frequency accuracy of the signal generation means 4 and the signal generation means 17 are set. Therefore, the accuracy of the intermittent operation is ± 4 ppm for both the parent device (A) and the child device (B).
It is as follows. Therefore, the time interval of the intermittent operation can be longer than 10 minutes, for example, every hour, and the battery life can be extended.

Note that a clock of a microcomputer may be used as the reference signal generating means.

[0019]

As described above, according to the transmission apparatus of the present invention, receiving means for receiving radio waves, clock generating means, timer means for measuring time based on a clock signal from the clock generating means, An intermittent control unit that intermittently controls the operation of the receiving unit at a time interval controlled by the timer unit, a reference signal generating unit that operates intermittently, and a signal from the reference signal generating unit and the clock generating unit. A time error detecting means for detecting a time error of the signal of the above, and a time error detecting signal from the time error detecting means, wherein the time measurement of the timer means is corrected, so that the intermittent time interval is increased. This has the effect of extending the battery life.
Further, by sharing the signal generating means serving as the reference frequency of the PLL and the reference signal generating means, the absolute accuracy can be improved without increasing the number of components.

[Brief description of the drawings]

FIG. 1 is a block diagram of a transmission device and an automatic meter reading system using the transmission device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a transmission device and an automatic meter reading system using the transmission device according to another embodiment of the present invention.

FIG. 3 is a block diagram of a conventional transmission device and an automatic meter reading system using the same.

[Explanation of symbols]

 Reference Signs List 2 transmitting means 3 channel selecting means 4 signal generating means 5 receiving means 6 clock generating means 7 timer means 8 intermittent control means 10 T-NCU 15 transmitting means 16 channel selecting means 17 signal generating means 18 receiving means 19 clock generating means 20 timer means Reference Signs List 21 intermittent control means 23 flow meter 24 storage means 26 reference signal generation means 27 time error detection means

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masahiro Yamamoto 1006 Kazuma Kadoma, Kadoma City, Osaka Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-63-24793 (JP, A) JP-A-56- 69577 (JP, A) JP 5-30793 (JP, U) JP 3-52279 (JP, B2) JP 4-51796 (JP, B2) (58) Fields surveyed (Int. Cl. ⁷ , DB name) G08C 15/06 G08C 19/00 301 H04M 11/00 301

Claims (1)

(57) [Claims] 1. A receiving means for receiving a radio wave, a clock generating means, a timer means for measuring time based on a clock signal from the clock generating means, and the receiving means intermittently at time intervals controlled by the timer means. Intermittent control means for controlling the operation of the means, reference signal generating means which operates intermittently, time error detecting means for detecting a time error between a signal from the reference signal generating means and a signal from the clock generating means, A transmission device configured to correct the time measurement of the timer means by a time error detection signal from the time error detection means , wherein the reference signal generation means
Is a signal for determining the frequency to be received by the receiving means.
A transmission device shared with signal generation means.