GB2145259A - Paging receivers - Google Patents

Abstract

In a paging receiver comprising a radio unit receiving a paging code and a test code and demodulating these codes, a controller including a central processing unit supplied with an output of the radio unit for supplying control signals to various circuit elements, and a ringing tone signal generator, there is provided a reset switch, and the controller is responsive to an external signal from the reset switch to generate first, second and third switch signals, responsive to the first switch signal to transfer the receiver to a first test mode with continuous supply of power to the radio unit, responsive to the second switch signal to transfer the receiver to a second test mode from the first test mode, and responsive to the third switch signal to enable reception of a paging code sent to the receiver among a plurality of paging codes sent out at a predetermined period with intermittent supply of the power source to the radio unit. With this construction, by merely operating the reset switch of the receiver, test modes are set so that a series of tests can be efficiently performed. <IMAGE>

Description

SPECIFICATION Paging receivers Background of the invention This invention relates to a paging receiver, and more particularly test means for such a receiver.

In the testing or checking of such a receiver, there are the following problems.

Firstly, in a receiver operating under battery saving, it is necessary to stop the battery saving operation with some means at the time of adjusting the receiver. To this end, the circuit for battery saving is typically short-circuited by utilizing a battery cover.

In a receiver, in which paging number data are stored in a read only memory device (ROM), the ROM is exchanged.

In any case, it is necessary to exchange the battery cover or the ROM. Such a method lacks reliability and easiness of operation.

Secondly, considerable time is necessary for checking the characteristic of the receiver. For example, in a paging code scheme of four-group construction with one frame requiring 20 seconds, at least 15 seconds are necessary to call a receiver whose paging number is inserted in the fourth group so that measurement of the receiving characteristic requires much more time. As the paging numbers are different for respective receivers, it is necessary to change the paging number for different receivers, thus aggravating the tendency to time consuming operation.

For obviating these problems, an improvement has been disclosed in British Patent Publication No.

2124001 entitled "Paging Receiver Having a Plurality of Test Modes", published February 8, 1984. According to this proposal, however, reception of a test code from a testing encoder is needed to begin the test mode and to this end, time-consuming adjustments of the testing encoder and a reset switch of the receiver are required.

Thirdly, as the types of the test modes are displayed by a display device, the types of the test modes can not be discriminated from each other when the receiver is not provided with a display device.

Summary of the invention It is an object of this invention to provide a novel paging receiver wherein the test mode can be set only by the operation of a reset switch of the receiver and a series of checks can be efficiently performed.

In one embodiment there is provided a paging receiver of the type comprising a radio unit receiving a paging code and a test code and demodulating these codes, a controller including a central processing unit supplied with the output of the radio unit for supplying control signals to various elements, and alert tone signal generating means, wherein a reset switch is provided and the controller is responsive to an external signal from the reset switch to generate first, second and third switch signals, responsive to the first switch signal to transfer the receiver to a first test mode with continuous supply of power source to the radio unit, responsive to the second switch signal to transfer the receiver to a second test mode from the first test mode, and responsive to the third switch signal to enable reception of a paging code sent to the receiver among a plurality of paging codes sent out at a predetermined period with intermittent supply of the power source to the radio unit.

Specifically, the controller is responsive to confirmation of the transfer to the first test mode by the first switch signal and transfer to the second test mode from the first test mode by the second switch signal to drive the alert tone signal generating the second switch signal means, and responsive to the test code at the time of the second test mode to drive the ringing tone signal generating means for a predetermined interval.

Brief description of the drawing In the accompanying drawings; Figure 1 is a block diagram showing one embodiment of this invention; Figure 2 is a block diagram showing the controller shown in Figure 1; Figure 3 is a flow chart for explaining the operation of this invention; and Figures 4A, 4B and 4C are diagrams showing the construction of paging signal trains.

Description of the preferred embodiment As shown in Figure 1, the paging receiver of this invention comprises a receiving antenna 1, a radio unit 2 constituted by a high frequency circuit, an intermediate frequency circuit, a frequency discriminating circuit, and a waveform shaping circuit. The radio unit 2 converts a received electromagnetic wave into a digital signal. The receiver also comprises a controller 3 which effects bit-synchronization with a received signal.

The controller 3 receives a frame synchronization signal and a paging signal, generates an alert tone signal and a battery saving timing signal, receives display information, corrects errors in the received signal, controls a display unit and controls read-out of a programmable read only memory (P-ROM) 6.

There are also provided a display unit 4 including a 7-segment liquid crystal display device, an amplifier 5 for amplifying the alert tone signal from the controller 3 to a level sufficient to drive a loudspeaker 7. The P-ROM 6 stores the paging signal of the receiver, and information regarding designation of the performance of the receiver, for example, presence or absence of automatic reset performance as well as the presence or absence of the battery saving performance. The loudspeaker 7 is driven by the amplifier 5 for producing an audible tone to inform the paging. There are also provided a source controller 8 responsive to the battery saving signal from the controller 3 for connecting and disconnecting the radio unit 2 to and from a power source 10, a crystal oscillator 9 for producing a clock signal that operates the controller 3, and a reset switch 11.

The operation of the receiver will be briefly described. The carrier wave received by antenna 1 is subjected to frequency conversion, amplification, demodulation, and waveform shaping by the radio unit 2 to form a digital signal which is sent to the controller 3 in which the received digital signal is compared with a paging signal of the receiver prestored in the P-ROM 6 so as to check whether there is a paging or not. When the paging is confirmed, the controller 3 sends an alert tone signal to the amplifierS to drive the loudspeaker 7.

Where display information is added to the paging signal, the display information is displayed on the display unit 4. This display is manually erased by the reset switch 11 or automatically erased after about 8 sec. by the operation of the controller 3.

The basic construction and operation of the controller 3 will now be described with reference to Figure 2.

The controller 3 comprises a central processing unit (CPU) of one chip construction. A series of operation instructions of the controller is written into a program memory 301 and a test mode instruction to be described later and characterizing the invention in also written into this memory.

The content of the program memory 301 which is addressed by a program counter 302 is outputted to a control unit 303 which sends out control signals to various parts in accordance with the content. The count of the program counter 302 is usually incremented by plus one each time the content of the program memory 301 is sent to the control unit 303. However, upon receipt of a jump instruction, the count of the program counter varies accordingly. The interface between the external circuits and a data bus 308 is effected through input ports a304, d307 and output ports b305 and c306. The data bus 308 is also connected to the program counter 302, a data memory 309, an accumulator 310 and an arithmetic and logic unit (ALU) 311 for transferring data.

A synchronizing clock pulse necessary for taking in data is generated by a quartz oscillating element 9, an oscillator 313 and a timer 312. A display data in the data memory 309 is supplied to and displayed on the display unit 4 through a display controller/driver 314.

Figure 3 is a flow chart showing a test mode of the receiver operation characterizing the invention. In Figure 3, SC designates the synchronizing code and IDL an idle code.

The flow of a normal paging reception will be briefly described. When the power source switch of the receiver is closed in step 101, a check is made in step 102 as to whether the reset switch is in its depressed state or not. When the result of check is NO, a check is made in step 103 as to whether a preamble signal has been detected or not. When the result is YES, a check is made in step 1 04a as to whether a synchronizing code has been detected or not. Where the synchronizing code is detected, the receiver waits for its own group signal in step 104b. Then, the receiver detect, the two types of paging signals, s.e., own address of the receiver, in this embodiment, an A call number and a B call number.Upon detection of the call number of the A or B call, after sending out one group of 20 words, an alert tone is generated and in a case of display information (message) added, the information is displayed, in steps 105 to 108. During the alerting and display operations, the receiver detects an idle code and counts up one group of 20 words in steps 109 and 110. When the result of step 110 is YES, the program is returned to step 103. When the results of checks at steps 105 and 106 show that no own address has been received, the program is returned to step 103 only when the idle code has been received or the time of one 20-word group has elapsed.

The program for bringing the receiver to the test mode will now be described. When the source switch is closed while the reset switch is being depressed (see steps 101 and 102) at step 111, a timer begins to operate in step 111. At step 112, a check is made as to whether the timer time is over or not. When the result of check at step 112 is YES, the receiver is brought into a test mode I in step 113. When the result of check in step 112 is NO, the receiver is brought to a preamble signal waiting state. In other words, the receiver is placed in a condition for receiving a normal paging signal.

The timer is set to 3 to 4 sec. within which it would never be used even when the reset switch is inadvertently depressed, so that when the timer is used for normal paging operation, no test mode would result. The test mode of this embodiment comprises the following two modes which are used for a series of tests of the receiver.

The test mode I will first be described. More particularly, the timer is started in step 111, and when its time is over (see step 112), the mode is immediately transferred to the test mode in step 113. Then, an alert tone continuing for one second is generated once, and where a display unit 4 is provided, an "E1-" display is made. In this mode, the battery power of the radio unit 2 of a receiver provided with a battery saving performance is continuously connected, thus relieving the battery saving performance. Accordingly, it becomes possible to adjust the radio unit and to measure the characteristics thereof, detection of the lowering of the battery voltage is continuously performed and when the voltage restores to its normal value, after finish of an alarm signal informing lowering of the battery voltage, such an alarm signal can be automatically stopped. Consequently, measurement of the battery voltage can be made readily.

The test mode II will now be described. In the test mode I (see step 113), when the reset switch 11 is depressed (see step 114), the test mode II is started at step 115. When alert tone continuing for one second is generated twice at an interval of 0.5 sec., "E2-" would be displayed on the display unit 4. In this mode, a receiving operation utilizing a test code is made. Upon receipt of the test code, an alert tone is generated which is stopped after 0.32 sec. Accordingly, when the sensitivity of the receiver is measured in this mode, one paging is made for about 2 seconds so that it is not necessary to manually stop the alert tone. Thus, the receiving sensitivity can be measured readily and in a short time.

Since the test code is common to all receivers, it is not necessary to change the paging numbers of the test encoders for respective receivers.

Under the state of test mode II (see step 115), when the reset switch is depressed (see step 116), the test mode is released.

Although, in this embodiment, there are two test modes, four test modes can also be used as disclosed in the aforementioned British Patent Publication No. 2124001.

In the embodiment described above, in the test mode I, an alert tone continuing for one second is generated once, while in the test mode II, the alert tone continuing for one second is generated twice at an interval of 0.5 sec. so that the test mode can be discriminated in accordance with the alert tone. Thus, the test mode can be discriminated even in a receiver other than those in which the type of the test mode is discriminated by a display device.

The test code will now be described.

As has been described hereinwhen a receiver to be tested is brought into the test mode II, the test code is not different from an ordinary paging signal since the test code is a paging signal common to all receivers. In other words, the test code is different from ordinary paging number in that it is common to all receivers.

For this reason, according to this invention, among paging signals, a code 1009268(decimal) is used which is larger than one million and in which "1" and "0" are well balanced. This code is never used as a paging number and expressed as follows by binary designation.

01111011001100111010010101001000 MSB LSB Where MSB denotes the most significant bit and the least significant bit.

With reference to Figures 4A to 4C, a train of paging signal sent out from a test encoder utilized in the embodiment of this invention will be described as follows. In these Figures, PS designates a preamble signal, SC a synchronizing code, SUB a subscribers paging signal, IDL an idle signal and TEST a test code.

Figure 4A shown a train of a paging signal when a paging test is made for a receiver having a paging number belonging to group G1. As shown, the preamble signal PS and the group G1 code of 20 words are repeatedly sent out at a predetermined interval. In this case, the sent out group is added with G1 alone and since the length of one frame is equal to (preamble + SC + 1 group), the paging test can be made in a relatively short time.

Figure 4B shows a train of paging signals when a paging test is made for a receiver having a paging number belonging to group G4. In this case, G1 to G4 are added to the sent out group and the length of one frame is (preamble + SC + 4 groups), so that a considerably long time (about 16 seconds) is required for completing the paging test. As has been pointed out before, this is a remarkable defect of the prior art.

Figure 4C shows a train of the paging signals utilized for a simplified paging test in the test mode II. A receiver which has been brought to the test mode II by the operation of the reset switch can be paged once when it receives this train of codes so that at least the sensitivity can be checked in a very short time.

As described above, according to this invention, since a test mode can be readily obtained by merely operating a reset switch of a receiver, the battery saving operation can readily be stopped.

Since the measurement of the characteristic of the receiver and the paging test can be made with the paging number common to all the receivers, the measurement time can be greatly shortened.

Moreover, as the check of the type of the test mode is made with the alert tone, the system of this invention can also be applied to a receiver other than a paging receiver.

Claims (10)

1. In a paging receiver of the type comprising a radio unit receiving a paging code and a test code and demodulating these codes, a controller including a central processing unit supplied with an output of said radio unit for supplying control signals to various circuit elements of said receiver, and an alert tone signal generating means, the improvement wherein said receiver further comprises a reset switch, and said controller is responsive to an external signal from said reset switch to generate first, second and third switch signals; responsive to said first signal to transfer said receiver to a first test mode with continuous supply of power source to said radio unit; responsive to said second switch signal to transfer said receiver to a second test mode from said first test mode; and responsive to said third switch signal to enable reception of a paging code sent to said receiver among a plurality of paging codes sent out at a predetermined period with intermittent supply of the power source to said radio unit.

2. The paging receiver according to claim 1 where said controller is responsive to confirmation of the transfer to said first test mode by said first switch signal and transfer to said second test mode from said first test mode by said second switch signal, to drive said alert tone signal generating means; and responsive to said test code at the time of said second test mode to drive said alert tone signal generating means for a predetermined interval.

3. Apaging receiver comprising: means for receiving a carrier wave modulated with a preamble and paging signal; Power source means for supplying power to said receiver; means for demodulating the receiver carrier wave to provide a demodulated signal; power supply control means for supplying power from said power source means to said receiving and demodulating means in response to a control signal; control unit means for consecutively supplying said control signal to said power control means when a switch signal is continuously supplied to said control unit means for a predetermined period of time after said power source means is turned on; and switch means for manually providing said switch signal.

4. A paging receiver as claimed in claim 3 further comprising: memory means for storing a paging number signal assigned to said receiver; means responsive to an alert tone for generating an audible tone; wherein said control unit means compares said paging number signal and a paging signal included in said demodulated signal and generates said alert tone when they coincide with each other or when the control unit means continuously receives said switch signal for said predetermined period of time after said power source means is turned on.

5. A paging receiver as claimed in claim 4, wherein said carrier wave is further modulated with a message, and wherein said control unit means displays said message on said display means.

6. A test or adjustment method for a receiver with battery saving function, said method comprising the steps of; (a) suspending said battery saving function and shiftng said receiver to a first test mode when said receiver is continuously supplied with a switch signal for a predetermined period of time after the power source of said receiver is turned on; and (b) providing said switch signal by means of a switch incorporated in said receiver.

7. A method as claimed in claim 6 further comprising the step of: (c) shifting said receiver from said first test mode to a second test mode in response to another switch signal from said switch.

8. A method as claimed in claim 7 further comprising the steps of: (d) conducting the test or adjustment of a radio unit of said receiver under said first test mode; and (e) conducting the test or adjustment of the receiving sensitivity of said receiver under said second test mode.

9. A method as claimed in claim 7 further comprising the step of: (f) generating an audible alert tone when said receiver is shifted to said first and second test modes.

10. A paging receiver as claimed in claim 1 substantially as described herein with reference to the accompanying drawings.