JPH0588574B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to the field of paging devices using battery powered portable pagers.

Prior Art Paging devices use various methods to reduce power consumption in order to miniaturize the pager device. One such method is broadcasting data related to a particular pager device. There is a method of supplying power to the receiving circuit only during a predetermined time slot. Without precise synchronization between transmitter and receiver, longer time slots are required to ensure that relevant data is received, consuming more power.

Apart from paging devices, there are methods by which the clock can be reset remotely by means of a transmitted signal. For example, U.S. Pat. No. 4,358,836 to Toyama et al. shows a method for setting a clock from a transmitted time announcement signal.

A combination of a pager and a resettable clock using time slot transmission is disclosed in U.S. Pat.
No. 3937004. Natori's device shows a clock controlled by a counter that is periodically reset by a transmitted signal. The use of an internal counter causes the error to accumulate because the counter has some error and the error for each count is added to the time indication. Therefore, the clock deviates from the correct time. This offset requires the use of large time slots to accommodate time errors in powering the pager receiver.

SUMMARY OF THE INVENTION The present invention is a method and apparatus for transmitting paging and time information from a central station and receiving the information at a remote electronic clock and pager device during short time slots assigned to the pager device. In pager devices, an oscillator is connected to a timer that generates a time display. This function is always powered. The timer periodically powers the receiver and message decoder during short time slots during which transmitted data is to be received. A receiver detects and reconstructs the transmitted signal. The transmitted signal is processed through a decoder that extracts paging and time update data. If the paging data includes the pager device's ID number, the device audibly and/or visually indicates to the user that it has received a page.

A time update signal extracted from the transmitted signal is used to synchronize the paging device timer. The timer serves the dual function of providing an accurate time indication to the clock function and, as described above, providing power during the time slots.

By sending time updates rather than resetting internal counters, the clock functions remain precisely synchronized and do not fluctuate. In addition to indicating accurate time, the synchronized timer powers the receiver during the pager device's allotted time slot, allowing the use of very short time slots.

In a preferred embodiment, the system corrects its time slot alignment by comparing the transmit time slot position to its assigned time slot position. If not, this means that the timer causes the receiving circuit to power up at an incorrect time, so the timer is adjusted by the time difference between the received time slot and its assigned time slot. Thereafter, the timer powers the receiving circuit during its allotted time slot.

In the preferred embodiment, the end-of-message signal powers down the paging device early when the time slot is not filled with data, reducing power consumption beyond that obtained by powering the receiver circuitry only during the short slot. Different reductions can be achieved. Because of its low cost and compactness, and therefore its wide applicability, the present invention is suitable for applications where either the person's employer (office, hospital, etc.) to be paged is the subscriber or each person with a pager clock is the subscriber. Can be used with a wider range of devices that can be called arbitrarily.

Embodiment FIG. 1 illustrates a pager clock according to the invention. The watch face shows a number of indicator lights 7 assigned to desired messages such as "home call", "office call", etc. Digital display 8 shows the called telephone number. In addition, the display 9 indicates the time and other functions of a normal watch.

The preferred embodiment of the present invention provides a method for transmitting specific data, although a large number of data formats are available.
It can be best understood by referring to the format. FIG. 2 shows the preferred time slot frame format for the transmitted signal. The time frame (FIG. 2A), designated by double-headed arrow 10, consists of 100 time slots, each designated by 12. In the preferred embodiment, the time frame length is 10 minutes and each time slot is therefore 6 seconds long. The time frame is restarted every 10 minutes. The first, ie, the "0" time slot shown at 14, contains time update information. The remaining time slots numbered 1-99 contain paging information in the format shown in expanded time slot 12.

The time slots 12 are each represented by 16.
Up to 125 identical message channels (second
Figure B) and the first time slot represented by 18.
Consists of address channels. The time slot address is a digital representation of one of the numbers from 0 to 99, depending on which time slot it represents. Each message channel is 40 milliseconds long, except for the time slot address channel, which is 1 second long.

Message channel 16 is shown in enlarged form in FIG. 2C. The first portion 20 of message channel 16 includes synchronization bits. Second part 22
contains the identification number of the particular clock/pager device.
The third portion 24 contains functional data indicating the type of message to be displayed on the face of the watch/pager device. Alternatively, the capability data can indicate that the next message channel contains a telephone number to be displayed rather than an identification number. The final portion 26 of the message channel contains error correction data.

FIG. 3A is a block diagram of the central paging station transmitter. The paging information of the present invention can be transmitted by using traditional low power transmission, by using FM or AM side channels, or
This can be accomplished in a variety of ways, such as by using the TV vertical blanking interval. As shown in FIG. 3A, a series of input telephone lines 28 provide paging data to a telephone line concentrator 30. Concentrator 30 buffers relatively slow data from a caller in the form of a ditone multifrequency signal (DTMF). The device is fully automatic and requires no operator or caller. The call must include the subscriber identification number of the caller (user's office, hospital, etc., as appropriate), the page ID number of the person to be paged, and a predetermined message function number (to instruct "call office," etc.) , a computer voice prompt asking for an arbitrary telephone number, etc. This information is then provided to computer 32, which numerically sorts the messages by ID number and stuffs them into their assigned time slots. The data blocks are evaluated and error correction data is added to each block by computer 32. The computer 32 is connected to a master clock 34 so that when the master clock reference time reaches a particular time slot, the data in that time slot is
The blocks are broadcast by transmitter 36 after being coded with a suitable modulation technique, such as frequency shift keying. In the preferred embodiment, the transmitter 36 is
At the FM transmitter, the data block is used to modulate the FM broadcast bandwidth carrier channel.

If a particular time slot is not filled with data, computer 32 adds an end message code after the last unit of data in the time slot, which instructs the individual pager device to power off early. The computer also performs other functions, such as preparing billing data for pager subscribers.

FIG. 3B shows a block diagram of the preferred embodiment of the clock and pager device. An arm loop antenna 38 picks up the transmitted signal and is connected to a receiver 40. Receiver 40 is tuned to the transmit frequency by an oscillator 42. The oscillator 42 is also a timer 44
It is connected to the. Timer 44 provides a time signal to clock face time display section 46 . The oscillator 42, timer 44, and clock face time display 46 are constantly powered by a battery 48 (like the display described below). The receiver and decoder sections of the pager device to the right of dashed line 49 are powered only when timer 44 provides an energizing signal to switch 50. The timer is programmed to transmit the activation signal only during the time slots assigned to the pager device. A pager device is assigned, for example, to time slot 12 shown in FIG.

The signal sent to receiver 40 is reconstructed as a digital signal. The reconstructed digital signal is passed to a decoder 5 which converts it to its original digital form.
Sent to 2. The digital information is then processed through error correction circuit 54 and detected errors are corrected. The corrected data is applied to identification number detection module 56 and function decoder 58 simultaneously. Module 56 determines whether the correct time slot location has been received and then examines each received pager device ID number to determine whether it matches the ID number assigned to the receiving pager device.

If the received time slot address is not aligned with the time slot location assigned to the pager device, module 56 calculates to the correct time slot by subtracting the received time slot location from the pager device's assigned time slot location;
A correction signal is sent to timer 44 to cause the timer to open switch 50 and remove power from the receiver and message decoder until the correct time slot.

Function decoder 58 is activated by module 56 only when there is a match between the received ID number and the pager device ID number. If there is time slot alignment and ID number alignment on each pager device, module 56 sends an activation signal to page alarm 60. Module 56 then also energizes the output of function decoder 58, which determines the function following the pager ID number and displays a plurality of clock function displays 62.
send a signal to one of the

If the functional data indicates that a preassigned message on the watch face should be illuminated, the functional decoder 58 sends an activation signal to the appropriate display 62. If the feature data indicates that the phone number continues in the next message channel,
The decoder output is energized during the next message channel to transmit the received telephone number to the watch telephone number display 64.

If module 56 and decoder 58 receive an early stop message because there are no more data messages in the time slot, decoder 58
sends a signal to timer 44 indicating that power to the receiver and message decoder should be removed.
send to The timer 44 operates the switch 50,
Remove power to the receiver and message decoding portion of the pager device.

If the received time slot address is the first address "0" assigned to the time update information, the decoder 52, error correction unit 54, and function decoder 58 decode the time update information and set the timer to the correct time. The update signal to be set is sent to the timer 44.
send to

In operation, each pager device is programmed to provide power to the receiver and message decoding section only during its allotted time slot.
By turning on only one of the slots every 10 minutes for 100 hours, power consumption is reduced by a factor of 100:1. After starting power supply and receiving the transmission signal,
The pager device first compares its assigned time slot to the time slot position appearing in the first channel of time slots, time slot position 18 in FIG. In the preferred embodiment, this first message channel is one second long and the time slot locations either appear at the end of the time slot address channel or are repeated throughout. Therefore, the clock and pager device operate for about 1 second every 10 minutes, or about 144 seconds a day, and correct the time by updating the time data every 10 minutes.
This is still synchronized enough to receive paging information.

If the pager device determines that it was turned on during different time slots, the difference between the detected time slot position and its assigned time slot position is calculated. The pager device is de-energized and then re-energized at the correct time slot.

In theory, a pager device would need to be powered long enough to receive its paging information, so instead of large time slots allocated to blocks of pager devices, each time frame should be It can be divided into many small time slots representing pager devices. However, current cost-effective commercial electronic technology cannot maintain the timer accuracy necessary to achieve such precise alignment.

As mentioned above, each pager device is also powered during the first time slot to receive time update information. To achieve further power savings, if the pager device strays from its allotted time slot, it is powered only during this first time slot, while the time it receives the time slot position is used to make small corrections to the timer. Do this.

If the paging information is small and the time slots are not completely filled with data, messages after the last message channel containing data
The channel contains a power outage message. This instructs the individual pager to cease powering for the remainder of the time slot since there is no other information for the remainder of the time slot. Therefore, if the message end signal appears 4 seconds after the 6 second time slot, an additional 1/3 power saving is realized.

Upon recognizing the ID number, the individual clock and pager device emits a sound alerting the user that a page has been received. Next comes the functional data,
Contains an instruction to illuminate a predetermined message assignment marker, such as "Home Call" or "Office Call," or indicates the next message channel, including a telephone number to be displayed on the face of the clock and pager device. .

Additional features may be added to the invention to enhance its capabilities or reduce power consumption. For example, each pager device can be programmed to turn off during unattended hours, such as after midnight and before 7 a.m.
In another variation, if a subscriber does not wish to be given a 10 minute delay before receiving a paging message, the paging device may be assigned two time slot positions, It is also possible to make the increase only require a 5 minute delay.

As will be understood by those skilled in the art, the invention may be embodied in other specific forms without departing from its spirit or essential characteristics. Therefore, the disclosure of the preferred embodiments of the invention is intended as a non-limiting illustration of the scope of the invention as set forth in the appended claims.

[Brief explanation of drawings]

1 is a perspective view of a preferred embodiment of the pager clock of the present invention; FIGS. 2A to 2C are time slot diagrams of a preferred embodiment of the time slot format of the present invention; and FIG. 3A is a transmission diagram of the present invention. Time Slot Diagram of the Preferred Embodiment of the Station. FIG. 3B is a block diagram of the preferred embodiment of the clock and pager device. 28...Telephone line, 30...Concentrator, 32...Computer, 34...Master clock, 36...Transmitter, 38...Loop antenna, 40...Receiver, 4
2... Oscillator, 44... Timer, 46... Time display section,
48...Battery, 50...Switch, 52...Decoder,
54...Error correction circuit, 56...Identification number detection module, 58...Function decoder, 60...Page alarm.

Claims (1)

Claims: 1. In a paging system that selectively communicates information with a plurality of receivers, each frame is divided into a plurality of time slots, the time slots are assigned a time slot number, and each frame is divided into a plurality of time slots. The time slot number of the slot includes a device for transmitting successive frames of information to be transmitted within the assigned time slot, and a plurality of receivers that are activated periodically to receive said information. each receiver being assigned one of the time slots, the plurality of receivers being powered and activated during the assigned time slot, each of the plurality of receivers receiving a comparison device responsive to the received information, comparing the allocated time slot number with the received time slot number to determine whether the received time slot number was activated during the allocated time slot; If it is determined that the receiver is not activated, change the activation interval required for the receiver to be activated during the allocated time slot based on the difference between the allocated time slot number of the receiver and the received time slot number. A paging system with a device that calculates the total amount and varies the time of activation of the receiver. 2. The device according to claim 1, wherein the device transmitting the information frame transmits a registration number identifying a particular one of the receivers and information directed to the particular receiver. transmitting during a time slot allocated to the receiver, and the receiver determines, based on the registration number, that the information transmitted during the allocated time slot is transmitted to the receiver; A paging system that determines whether something is a thing or not. 3. In the device according to claim 1,
A paging system in which the device for transmitting the information frame periodically transmits frames in which each time slot in each frame appears after a predetermined time from the beginning of the frame.