Note: Descriptions are shown in the official language in which they were submitted.
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Specification
Title of the Invention
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 cas~, 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
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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 Wo. 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.
According to this invention, 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
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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.
In a specific embodiment, 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.
According to another aspect, the present invention pro-
vides a paging 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
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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.
According to a further aspect, the present invention
provides a test or adjustment method for a receiver with battery
saving function, said method comprising the steps of; (a) sus-
pending said battery saving function and shifting 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.
Brief Description of the Drawing
In the accompanying drawings;
Fig. 1 is a block diagram showing one embodiment of this
invention;
Fig. 2 is a block diagram showing the controller shown
in Fig. l;
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Fig. 3 is a flow chart for explaining the
operation of this invention; and
Figs. 4A, 4B and 4C are diagrams showing the
construction of paging signal trains.
Description of the Preferred Embodiment
As shown in Fig. 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 unitd 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 e~ample, presence or absence of
automatic reset performance as well as the presence or
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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 recieved 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 amplifier 5 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 teh 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 t Fig.
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 connnected to the program counter 302, a data memory
309, an accumulator 310 and an arithemetic 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.
Fig. 3 is a flow chart showing a test mode of the
receiver operation characterizing the invention. In Fig.
3, SC designates the synchronizing code and IDL an idle
code.
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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 104a as to whether a synchornizig code has been
detected or not. Where the synchornizing code is
detected, the receiver waits for its own group signal in
step 104b. Then, the receiver detect, the two types of
paging signals, i.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 "El-" 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
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thereof, detection of the lowering of the battery voltage
is continously 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
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modes, four test modes can also be used as disclosed in
the aforementioned British Patent Publication No. 21240Q1.
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,
20 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
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significant bit.
With reference to Figs. 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.
Fig. 4A shows a train of a paging signal when a
paging test is made for a receiver having a paging number
belonging to group Gl. As shown, the preamble signal PS
and the group Gl code of 20 words are repeatedly ~ent out
at a predetermined interval. In this case, the sent out
group is added with Gl alone and since the length of one
frame is equal to (preamble + SC + l group), the paging
test can be made in a relatively short time.
Fig. 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, Gl 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.
Fig. 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
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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 teh 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.
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