CA1283708C - Radio pager having local- and wide-area reception modes - Google Patents
Radio pager having local- and wide-area reception modesInfo
- Publication number
- CA1283708C CA1283708C CA000505830A CA505830A CA1283708C CA 1283708 C CA1283708 C CA 1283708C CA 000505830 A CA000505830 A CA 000505830A CA 505830 A CA505830 A CA 505830A CA 1283708 C CA1283708 C CA 1283708C
- Authority
- CA
- Canada
- Prior art keywords
- signal
- code
- channel
- code format
- identification
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
- H04W88/02—Terminal devices
- H04W88/022—Selective call receivers
- H04W88/025—Selective call decoders
- H04W88/026—Selective call decoders using digital address codes
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B3/00—Audible signalling systems; Audible personal calling systems
- G08B3/10—Audible signalling systems; Audible personal calling systems using electric transmission; using electromagnetic transmission
- G08B3/1008—Personal calling arrangements or devices, i.e. paging systems
- G08B3/1016—Personal calling arrangements or devices, i.e. paging systems using wireless transmission
Abstract
"Radio Pager Having Local- and Wide--Area Reception Modes"
ABSTRACT OF THE DISCLOSURE
Disclosed is a radio pager wherein a manually controlled channel selector selects a first channel to operate the pager in a local area reception mode and selects a second channel to operate it in a wide area reception mode. A receiving circuit is responsive to the selector for receiving a first paging signal transmitted on the first channel and receiving a second paging signal transmitted on the second channel, the first and second paging signals containing address signals in first and second code formats, respectively. A decoder is responsive to the manual selector for comparing the address signal of the first paging signal with a first identification signal representing a user's identification number in the first code format and comparing the address signal of the second paging signal with a second identification signal representing the same user's identification number in the second code format. The decoder produces a coincidence signal when the address signal of each paging signal coincides with the identification signal of the corresponding code format to generate an audible tone.
ABSTRACT OF THE DISCLOSURE
Disclosed is a radio pager wherein a manually controlled channel selector selects a first channel to operate the pager in a local area reception mode and selects a second channel to operate it in a wide area reception mode. A receiving circuit is responsive to the selector for receiving a first paging signal transmitted on the first channel and receiving a second paging signal transmitted on the second channel, the first and second paging signals containing address signals in first and second code formats, respectively. A decoder is responsive to the manual selector for comparing the address signal of the first paging signal with a first identification signal representing a user's identification number in the first code format and comparing the address signal of the second paging signal with a second identification signal representing the same user's identification number in the second code format. The decoder produces a coincidence signal when the address signal of each paging signal coincides with the identification signal of the corresponding code format to generate an audible tone.
Description
370~
(008A/M3) TITLE OF THE INVENTION
"Radio Pager Having Local- and wide--Area Reception Modes"
BACKGROUND OF THE INVENTION
The present invention relates to a radio pager which is capable of operation in a local-area reception mode and in a wide-area reception mode.
Conventional radio pagers are assigned with an identification code representing the user's idendification number. The identification code is in the Bose-Chaudhuri-Hocquenghem (31,16) format for a given local area andtransmitted on a specified radio frequency channel. The total number of subscribers available with the BCH (31,16) code format is 65,536- Therefore, if the number of subscribers exceeds the limit, an extra radio frequency channel is required to accommodate new subscribers and this procedure must be repeated in units of 65,625 new subscribers.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a radio pager which permits efficient utilization of radio frequency channels.
According to the present invention, a pager transmitting station sends paging signals for each called party on first and second channels for local and wide area services, respectively. The paging signal transmitted on ~i~
NE-71 1~837~8 (008A/M3) the first channel contains an address signal in a first prescribed code format and the paging signal transmitted on the second channel contains an address signal in a second code format, each address signal representing the same identification number assigned to a user of the paging system.
A radio pager according to the invention comprises a manually controlled channel selector for selecting the first channel to operate the pager in a local area reception mode when the user is in the local area and selecting the second channel to operate the pager in a wide area reception mode when the user is outside of the local area. A receiving circuit is responsive to the selector for receiving a first paging signal transmitted on the first channel and receiving a second paging signal transmitted on the second channel, each of the paging signals containing an address signal of the particular code format. A decoder is responsive to the manual selector for comparing the address signal of the first paging signal with an identification signal representing a user's first identification number in the first code format when the first channel is selected and comparing the address signal of the second paging signal with an identification signal representing a user's second identification number in the second code format. The decoder generates a coincidence signal when each address NE-71 1~ ~3 7~
(008A/M3) signal coincides with the associated identification signal.
An audible tone is generated in response to the coincidence signal to call the attention of the user to the reception of a message from a caller. Preferably, the user's first identification number is the same as the user's second identification number. In a further preferred form of the invention, the second code format has a greater number of code bits than the number of code bits available with the first code format.
Preferably, the first code format for local-area reception mode is the BCH (L, M) code format and the second code format for wide-area reception mode is the BCH (L, N) code format (where L > N > M).
In a further preferred embodiment, the address signal in the BCH (L, M) code format undergoes two-bit error corrections and the address signal in the BCH (L, N) code format undergoes l-bit error correction.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be described in further detail with reference to the accompanying drawings, in which:
Fig. 1 is a block diagram of a radio pager according to a preferred embodiment of the invention;
Fig. 2 is a block diagram of the decoder of Fig. 1;
and NE-71 1~7~
(008A/M3) Fig. 3 is a block diagram of a modified embodiment of the invention.
DETAILED DESCRIPT[ON
Referring to Fig. 1, there is shown a multi-channel radio paging receiver, or pager according to the present invention. In Fig. 1, first and second paging signals are frequency-modulated respectively upon first and second channels and transmitted from a transmitting station for local and wide area services, respectively. Each paging signal comprises a selective calling address signal and a message signal. The address signal of the first paging signal is in the Bose-Chaudhuri-Hocquenghem (31, 16) code format for local area service and the address signal of the second paging signal is in the BCH (31, 21) code format for wide area service. The total capacity of codes that can be transmitted on the first channel for local area is 65,536, whereas the total capacity of codes that can be transmitted on the second channel for wide area is 2,097,152, a value 32 times greater than that available for local-area service.
This is best understood by analyzing the BCH (31, 21) code and BCH (31, 16) code as follows. Let it be assumed that generator polynominals are represented by: -Ml(X) = x5 + x2 + 1 M3(x) = x5 + x4 + x3 + x2 + 1 M5(X) = x5 + x4 + x2 + x + 1 NE-71 1~37~
~008A/M3) then the generator poloynomial of the BCH (31, 21) code is given by:
Ml(x) * M3(x) = x10 + x9 + x8 + x6 + 5 + 3 and the generator polynomial of the sCH (31, 16) code is given by:
M (x) * M (x~ * M5(x) = x15 + xll + x + x + x + x + x5 + x3 + x2 + x + 1 Since Ml(x) * M3(X) is a common term of the two generator polynomials, the BCH (31, 16) code is a part of the BCH (31, 21) code.
The paging signal is intercepted by an antenna 1, filtered through a band-pass amplifier 2 and fed to a frequency converter 3 to which is also applied the output of a variable frequency local oscillator 4. The radio-frequency signal is transposed to an intermediate-frequency signal by the frequency converter 3 and fed to a frequency demodulator 5 and thence to a waveshaper 6. Waveshaper 6 comprises a low-pass filter for eliminating undesirable high frequency components of the demodulated signal and a comparator for comparing the output of the low-pass filter with a threshold to generate a dignal signal which is a replica of the original signal comprising a message signal preceded by a selective calling signal.
The output of waveshaper 6 is connected to a display unit 7 and to a decoder 8 which decodes the address signal by NE-71 ~37~
(008A/M3) comparing it with an identification code and activates an audio-frequency oscillator 9 to generate an audible tone by a loudspeaker 10 when the address signal coincides with the identification code. Display unit 7 essentially comprises a message decoder and a liquid-crystal display to provide a visual display of a message following an address signal. A
user carrying the pager is thus alerted of the reception of a page from a caller.
Variable frequency local oscillator 4 includes a crystal-controlled Colpitts circuit which is formed by a transformer 402 in parallel with a capacitor 403, the transformer being coupled by a parallel circuit of a bypass capacitor 406 and a biasing resistor 407 to the emitter of transistor 408. The emitter of transistor 408 is further coupled to its base by a capacitor 409 and the collector of transistor 408 is connected by a bypass capacitor 411 to ground, by a biasing resistor 410 to its base and directly to a DC voltage source 11. The base of transistor 408 is connected through a local-area selecting circuit to a series 20 of a quartz crystal 414 and a variable capacitor 415 and through a wide-area selecting circuit to a series of a quartz crystal 412 and a variable capacitor 413.
A high-frequency tuning circuit is formed by a transformer 404 and a capacitor 405 connected in parallel therewith. The high-frequency tuning transformer 404 has NE-71 1~ ~3 71~
(008A/M3) one end connected through a coupling capacitor 401 to the frequency converter 3. Transformer 402 is connected through an intermediate tap of transformer 404 to ground.
The operating parameters of the local oscillator are determined so that the combined impedance of the two tuning circuits as seen from across the emitter of transistor 408 and ground is capacitive in the variable range of frequencies generated by quartz crystals 412 and 414. In a pract-ical embodiment, each of the quartz cyrstals has an oscillating frequency which is 1/3 of the difference in frequency between the frequency of the respective channel and the intermediate frequency.
The local-area selecting circuit is established when a first area-selecting switch 12 couples the quartz crystal 414 through contacts 106 and 105 to the base of transistor 408 and the wide-area selecting circuit is established when the switch 12 is moved to a position connecting the quartz crystal 412 through contacts 105 and 104 to the base of the transistor.
Decoder 8 comprises a shift register 80 having 31 bit positions into which the address code is sequentially stored, and a local-area memory 84 and a wide-area memory 83. Local-area memory 84 is enabled by DC voltage source 11 when a second area-selecting switch 13, which is ganged to switch 12, couples the DC source thereto through contacts NE-71 ~ ~
(008A/M3) 1~7~
102 and 103 and memory 83 is enabled by DC voltage source 11 when the second switch 13 is moved to a position connecting the source voltage thereto through contacts 102 and 101.
Each of the memories 83 and 84 has memory cells corresponding in number to the bit positions of shift register 80.
As shown in Fig. 2, each memory cell of memories 83 and 84 is formed by a Zener diode 810, a transistor 820, and a protection resistor 830. Each Zener diode has its cathode connected to an associated input bit line 81 and its anode connected to the base of the associated transistor. Each of the transistors 820 has its collector coupled to a common output line 82 and to contact 101 or 103 through a common resistor 840 and has its emitter connected through the respective resistor 830 to ground.
The user's identification code bits are stored into memory cells by destroying particular Zener diodes to transform them into mere resistance elements. This is accomplished by applying a high positive DC potential to associated input bit lines 81 and a negative DC potential to an output line 82. Resistors 830 serve as a means for protecting the associated transistor from being damaged by the high DC potential. An identification number assigned to the user in the BCH (31,16) code format is stored in local-area memory 84 and the same identification number in NE-71 1~ ~37~8 -- g the BCH (31,21) code format is stored in wide-area memory 83.
When a logical "1" input is applied, the memory cell having a destroyed Zener diode develops a logical "0" output at the collector of the associated transistor and the memory cell having a non-destroyed Zener diode develops a logical "1" output, and when a logical "0" input is applied, the memory cell having a destroyed Zener diode develops a logical "1" output and the cell having a non-destroyed Zener diode develops a logical "0" output. Since the transistors 820 of all cells of each memory are connected in parallel, they establish an AND gate to produce a logical "1" output at the output line 82 when there is a one-to-one coincidence between the address code and identification code. The coincidence output from each memory is coupled by an OR gate 85 to oscillator 9 to activate the speaker 10 and to a control terminal of the display unit 7 to provide a display of a message signal following the address signal.
From the transmitting station, two paging signals respectively having BCH (31,16) and BCH (31,21) formatted address signals are respectively transmitted on the local-area channel and wide-area channel. When the user is in his own local service area, switches 12 and 13 are positioned so that quartz crystal 414 and memory 84 are enabled. Oscillator 4 is tuned to the local-area channel to NE-71 ~ 7~
check the BCH ( 31,16) address signal transmitted on the local-area channel against the BCH (31,16) identification code stored in memory 84. When the user enters the wide service area, switches 12 and 13 are moved to wide-area service positions so that quartz crystal 412 and memory 83 are enabled. Oscillator 4 is tuned to receive the wide-area channel to decode the BCH ( 31,21) address signal transmitted on the wide-area channel by comparing it with the BCH
(31,21) identification code stored in memory 83.
It is preferred that error correction circuits be provided respectively for correcting errors in the address signals of the BCH ( 31, 21) and BCH ( 31,16) code formats.
In Fig. 3, a l-bit error correction circuit 86 and a 2-bit error correction circuit 87 are provided to receive the output of waveshaper 6. Each error correction circuit includes a buffer, or shift register into which the received address signal is sequentially loaded in a manner as it is loaded into the shift register of Fig. 2. The address bits stored in the shift register undergo an error correction process known in the art. The l-bit error correction circuit 86 is connected to the contact 101 so that it is enabled simultaneously with memory 83 during wide-area reception mode and the 2-bit error correction circuit 87 is connected to the contact 103 to be enabled with memory 84 during local-area reception mode. During local-area (008A/M3) 1~7~
reception mode, 2-bit error correction is performed by circuit 87 on the address signal of the BCH (31, 16) code format and during wide-area reception mode, l-bit error correction is performed by circuit 86 on the address signal of the BCH (31, 21) code format. The error-corrected 31-bit address signals are applied from error correction circuits 86 and 87 are respectively applied to memories 83 and 84 on input lines 81.
(008A/M3) TITLE OF THE INVENTION
"Radio Pager Having Local- and wide--Area Reception Modes"
BACKGROUND OF THE INVENTION
The present invention relates to a radio pager which is capable of operation in a local-area reception mode and in a wide-area reception mode.
Conventional radio pagers are assigned with an identification code representing the user's idendification number. The identification code is in the Bose-Chaudhuri-Hocquenghem (31,16) format for a given local area andtransmitted on a specified radio frequency channel. The total number of subscribers available with the BCH (31,16) code format is 65,536- Therefore, if the number of subscribers exceeds the limit, an extra radio frequency channel is required to accommodate new subscribers and this procedure must be repeated in units of 65,625 new subscribers.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a radio pager which permits efficient utilization of radio frequency channels.
According to the present invention, a pager transmitting station sends paging signals for each called party on first and second channels for local and wide area services, respectively. The paging signal transmitted on ~i~
NE-71 1~837~8 (008A/M3) the first channel contains an address signal in a first prescribed code format and the paging signal transmitted on the second channel contains an address signal in a second code format, each address signal representing the same identification number assigned to a user of the paging system.
A radio pager according to the invention comprises a manually controlled channel selector for selecting the first channel to operate the pager in a local area reception mode when the user is in the local area and selecting the second channel to operate the pager in a wide area reception mode when the user is outside of the local area. A receiving circuit is responsive to the selector for receiving a first paging signal transmitted on the first channel and receiving a second paging signal transmitted on the second channel, each of the paging signals containing an address signal of the particular code format. A decoder is responsive to the manual selector for comparing the address signal of the first paging signal with an identification signal representing a user's first identification number in the first code format when the first channel is selected and comparing the address signal of the second paging signal with an identification signal representing a user's second identification number in the second code format. The decoder generates a coincidence signal when each address NE-71 1~ ~3 7~
(008A/M3) signal coincides with the associated identification signal.
An audible tone is generated in response to the coincidence signal to call the attention of the user to the reception of a message from a caller. Preferably, the user's first identification number is the same as the user's second identification number. In a further preferred form of the invention, the second code format has a greater number of code bits than the number of code bits available with the first code format.
Preferably, the first code format for local-area reception mode is the BCH (L, M) code format and the second code format for wide-area reception mode is the BCH (L, N) code format (where L > N > M).
In a further preferred embodiment, the address signal in the BCH (L, M) code format undergoes two-bit error corrections and the address signal in the BCH (L, N) code format undergoes l-bit error correction.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be described in further detail with reference to the accompanying drawings, in which:
Fig. 1 is a block diagram of a radio pager according to a preferred embodiment of the invention;
Fig. 2 is a block diagram of the decoder of Fig. 1;
and NE-71 1~7~
(008A/M3) Fig. 3 is a block diagram of a modified embodiment of the invention.
DETAILED DESCRIPT[ON
Referring to Fig. 1, there is shown a multi-channel radio paging receiver, or pager according to the present invention. In Fig. 1, first and second paging signals are frequency-modulated respectively upon first and second channels and transmitted from a transmitting station for local and wide area services, respectively. Each paging signal comprises a selective calling address signal and a message signal. The address signal of the first paging signal is in the Bose-Chaudhuri-Hocquenghem (31, 16) code format for local area service and the address signal of the second paging signal is in the BCH (31, 21) code format for wide area service. The total capacity of codes that can be transmitted on the first channel for local area is 65,536, whereas the total capacity of codes that can be transmitted on the second channel for wide area is 2,097,152, a value 32 times greater than that available for local-area service.
This is best understood by analyzing the BCH (31, 21) code and BCH (31, 16) code as follows. Let it be assumed that generator polynominals are represented by: -Ml(X) = x5 + x2 + 1 M3(x) = x5 + x4 + x3 + x2 + 1 M5(X) = x5 + x4 + x2 + x + 1 NE-71 1~37~
~008A/M3) then the generator poloynomial of the BCH (31, 21) code is given by:
Ml(x) * M3(x) = x10 + x9 + x8 + x6 + 5 + 3 and the generator polynomial of the sCH (31, 16) code is given by:
M (x) * M (x~ * M5(x) = x15 + xll + x + x + x + x + x5 + x3 + x2 + x + 1 Since Ml(x) * M3(X) is a common term of the two generator polynomials, the BCH (31, 16) code is a part of the BCH (31, 21) code.
The paging signal is intercepted by an antenna 1, filtered through a band-pass amplifier 2 and fed to a frequency converter 3 to which is also applied the output of a variable frequency local oscillator 4. The radio-frequency signal is transposed to an intermediate-frequency signal by the frequency converter 3 and fed to a frequency demodulator 5 and thence to a waveshaper 6. Waveshaper 6 comprises a low-pass filter for eliminating undesirable high frequency components of the demodulated signal and a comparator for comparing the output of the low-pass filter with a threshold to generate a dignal signal which is a replica of the original signal comprising a message signal preceded by a selective calling signal.
The output of waveshaper 6 is connected to a display unit 7 and to a decoder 8 which decodes the address signal by NE-71 ~37~
(008A/M3) comparing it with an identification code and activates an audio-frequency oscillator 9 to generate an audible tone by a loudspeaker 10 when the address signal coincides with the identification code. Display unit 7 essentially comprises a message decoder and a liquid-crystal display to provide a visual display of a message following an address signal. A
user carrying the pager is thus alerted of the reception of a page from a caller.
Variable frequency local oscillator 4 includes a crystal-controlled Colpitts circuit which is formed by a transformer 402 in parallel with a capacitor 403, the transformer being coupled by a parallel circuit of a bypass capacitor 406 and a biasing resistor 407 to the emitter of transistor 408. The emitter of transistor 408 is further coupled to its base by a capacitor 409 and the collector of transistor 408 is connected by a bypass capacitor 411 to ground, by a biasing resistor 410 to its base and directly to a DC voltage source 11. The base of transistor 408 is connected through a local-area selecting circuit to a series 20 of a quartz crystal 414 and a variable capacitor 415 and through a wide-area selecting circuit to a series of a quartz crystal 412 and a variable capacitor 413.
A high-frequency tuning circuit is formed by a transformer 404 and a capacitor 405 connected in parallel therewith. The high-frequency tuning transformer 404 has NE-71 1~ ~3 71~
(008A/M3) one end connected through a coupling capacitor 401 to the frequency converter 3. Transformer 402 is connected through an intermediate tap of transformer 404 to ground.
The operating parameters of the local oscillator are determined so that the combined impedance of the two tuning circuits as seen from across the emitter of transistor 408 and ground is capacitive in the variable range of frequencies generated by quartz crystals 412 and 414. In a pract-ical embodiment, each of the quartz cyrstals has an oscillating frequency which is 1/3 of the difference in frequency between the frequency of the respective channel and the intermediate frequency.
The local-area selecting circuit is established when a first area-selecting switch 12 couples the quartz crystal 414 through contacts 106 and 105 to the base of transistor 408 and the wide-area selecting circuit is established when the switch 12 is moved to a position connecting the quartz crystal 412 through contacts 105 and 104 to the base of the transistor.
Decoder 8 comprises a shift register 80 having 31 bit positions into which the address code is sequentially stored, and a local-area memory 84 and a wide-area memory 83. Local-area memory 84 is enabled by DC voltage source 11 when a second area-selecting switch 13, which is ganged to switch 12, couples the DC source thereto through contacts NE-71 ~ ~
(008A/M3) 1~7~
102 and 103 and memory 83 is enabled by DC voltage source 11 when the second switch 13 is moved to a position connecting the source voltage thereto through contacts 102 and 101.
Each of the memories 83 and 84 has memory cells corresponding in number to the bit positions of shift register 80.
As shown in Fig. 2, each memory cell of memories 83 and 84 is formed by a Zener diode 810, a transistor 820, and a protection resistor 830. Each Zener diode has its cathode connected to an associated input bit line 81 and its anode connected to the base of the associated transistor. Each of the transistors 820 has its collector coupled to a common output line 82 and to contact 101 or 103 through a common resistor 840 and has its emitter connected through the respective resistor 830 to ground.
The user's identification code bits are stored into memory cells by destroying particular Zener diodes to transform them into mere resistance elements. This is accomplished by applying a high positive DC potential to associated input bit lines 81 and a negative DC potential to an output line 82. Resistors 830 serve as a means for protecting the associated transistor from being damaged by the high DC potential. An identification number assigned to the user in the BCH (31,16) code format is stored in local-area memory 84 and the same identification number in NE-71 1~ ~37~8 -- g the BCH (31,21) code format is stored in wide-area memory 83.
When a logical "1" input is applied, the memory cell having a destroyed Zener diode develops a logical "0" output at the collector of the associated transistor and the memory cell having a non-destroyed Zener diode develops a logical "1" output, and when a logical "0" input is applied, the memory cell having a destroyed Zener diode develops a logical "1" output and the cell having a non-destroyed Zener diode develops a logical "0" output. Since the transistors 820 of all cells of each memory are connected in parallel, they establish an AND gate to produce a logical "1" output at the output line 82 when there is a one-to-one coincidence between the address code and identification code. The coincidence output from each memory is coupled by an OR gate 85 to oscillator 9 to activate the speaker 10 and to a control terminal of the display unit 7 to provide a display of a message signal following the address signal.
From the transmitting station, two paging signals respectively having BCH (31,16) and BCH (31,21) formatted address signals are respectively transmitted on the local-area channel and wide-area channel. When the user is in his own local service area, switches 12 and 13 are positioned so that quartz crystal 414 and memory 84 are enabled. Oscillator 4 is tuned to the local-area channel to NE-71 ~ 7~
check the BCH ( 31,16) address signal transmitted on the local-area channel against the BCH (31,16) identification code stored in memory 84. When the user enters the wide service area, switches 12 and 13 are moved to wide-area service positions so that quartz crystal 412 and memory 83 are enabled. Oscillator 4 is tuned to receive the wide-area channel to decode the BCH ( 31,21) address signal transmitted on the wide-area channel by comparing it with the BCH
(31,21) identification code stored in memory 83.
It is preferred that error correction circuits be provided respectively for correcting errors in the address signals of the BCH ( 31, 21) and BCH ( 31,16) code formats.
In Fig. 3, a l-bit error correction circuit 86 and a 2-bit error correction circuit 87 are provided to receive the output of waveshaper 6. Each error correction circuit includes a buffer, or shift register into which the received address signal is sequentially loaded in a manner as it is loaded into the shift register of Fig. 2. The address bits stored in the shift register undergo an error correction process known in the art. The l-bit error correction circuit 86 is connected to the contact 101 so that it is enabled simultaneously with memory 83 during wide-area reception mode and the 2-bit error correction circuit 87 is connected to the contact 103 to be enabled with memory 84 during local-area reception mode. During local-area (008A/M3) 1~7~
reception mode, 2-bit error correction is performed by circuit 87 on the address signal of the BCH (31, 16) code format and during wide-area reception mode, l-bit error correction is performed by circuit 86 on the address signal of the BCH (31, 21) code format. The error-corrected 31-bit address signals are applied from error correction circuits 86 and 87 are respectively applied to memories 83 and 84 on input lines 81.
Claims (6)
1. A radio pager comprising:
manually controlled selecting means for selecting a first channel to operate the pager in a local area reception mode and selecting a second channel to operate the pager in a wide area reception mode;
receiving means responsive to said selecting means for receiving a first paging signal transmitted on the first channel and receiving a second paging signal transmitted on the second channel, said first paging signal containing an address signal in a first code format and said second paging signal containing an address signal in a second code format;
and decoding means responsive to said selecting means for comparing the address signal of said first paging signal with an identification signal representing a user's first identification number in said first code format when said first channel is selected and comparing the address signal of said second paging signal with an identification code representing a user's second identification number in said second code format, said decoding means generating a coincidence signal when the address signal of each of said code formats coincides with the identification signal of the corresponding code formats.
(008A/M3)
manually controlled selecting means for selecting a first channel to operate the pager in a local area reception mode and selecting a second channel to operate the pager in a wide area reception mode;
receiving means responsive to said selecting means for receiving a first paging signal transmitted on the first channel and receiving a second paging signal transmitted on the second channel, said first paging signal containing an address signal in a first code format and said second paging signal containing an address signal in a second code format;
and decoding means responsive to said selecting means for comparing the address signal of said first paging signal with an identification signal representing a user's first identification number in said first code format when said first channel is selected and comparing the address signal of said second paging signal with an identification code representing a user's second identification number in said second code format, said decoding means generating a coincidence signal when the address signal of each of said code formats coincides with the identification signal of the corresponding code formats.
(008A/M3)
2. A radio pager as claimed in claim 1, wherein said user's first identifcation number is the same as said user's second identification number.
3. A radio pager as claimed in claim 1, wherein said second code format has a greater number of code bits than the number of code bits of said first code format.
4. A radio pager as claimed in claim 1, wherein the address signal of said first paging signal and said first identification code are in the Bose-Chaudhuri-Hocquenghem (L, M) code format and the address signal of said second paging signal and said second identification code are in the BCH (L, N) code format, where L > N > M.
5. A radio pager as claimed in claim 4, further comprising a first error correction circuit operable during said local-area reception mode and a second error correction circuit operable during the wide-area reception mode, said first error correction circuit providing two-bit error correction on the address signal of the BCH (L, M) code format and said second error correction circuit providing 1-bit error correction on the address signal of the BCH (L, N) code format.
(008A/M3)
(008A/M3)
6. A radio pager as claimed in claim 5, wherein L, M and N are 31, 16 and 21, respectively.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60-73239 | 1985-04-06 | ||
| JP60073239A JPS61232731A (en) | 1985-04-06 | 1985-04-06 | Selecting call receiver |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1283708C true CA1283708C (en) | 1991-04-30 |
Family
ID=13512431
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000505830A Expired - Lifetime CA1283708C (en) | 1985-04-06 | 1986-04-04 | Radio pager having local- and wide-area reception modes |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4910511A (en) |
| EP (1) | EP0197534B1 (en) |
| JP (1) | JPS61232731A (en) |
| AU (1) | AU592783B2 (en) |
| CA (1) | CA1283708C (en) |
| DE (1) | DE3675801D1 (en) |
Families Citing this family (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1988003350A1 (en) * | 1986-10-21 | 1988-05-05 | Motorola, Inc. | Apparatus and method for altering the ratio of information to parity in a digital communications system |
| JPH0671227B2 (en) * | 1987-09-08 | 1994-09-07 | 日本電気株式会社 | Wireless individual call receiver |
| JPH0197026A (en) * | 1987-10-09 | 1989-04-14 | Nippon Telegr & Teleph Corp <Ntt> | Radio calling system |
| JP2647130B2 (en) * | 1988-04-26 | 1997-08-27 | 株式会社東芝 | Selective call receiver |
| US5051999A (en) * | 1989-03-13 | 1991-09-24 | Motorola, Inc. | Programmable error correcting apparatus within a paging receiver |
| CA2065274C (en) * | 1989-10-23 | 1995-11-28 | Michael Joseph Deluca | Nation-wide paging with local modes |
| US5254986A (en) * | 1989-10-23 | 1993-10-19 | Motorola, Inc. | Nation-wide paging with local modes of operation |
| US5047763A (en) * | 1989-11-30 | 1991-09-10 | Motorola, Inc. | Selective call system with message rebroadcasting over another selective call system |
| US5666107A (en) * | 1995-09-20 | 1997-09-09 | Motorola, Inc. | Method and apparatus for efficient roaming among communication system |
| US5732357A (en) * | 1996-02-21 | 1998-03-24 | Glenayre Electronics, Inc. | Selective simulcast paging system |
| KR100263661B1 (en) * | 1997-05-12 | 2000-08-01 | 김동연 | Call receiving control method for preventing receiving error |
| US7062281B2 (en) * | 1999-11-27 | 2006-06-13 | Long Range Systems, Inc. | Multi-mode paging system |
| US7349691B2 (en) * | 2001-07-03 | 2008-03-25 | Microsoft Corporation | System and apparatus for performing broadcast and localcast communications |
| US6950642B2 (en) * | 2001-07-03 | 2005-09-27 | Microsoft Corporation | System and method for reducing noise in a recording receiver |
| US6999545B2 (en) * | 2001-10-26 | 2006-02-14 | Microsoft Corporation | Method and system for undersampled symbol synchronization |
| US6907234B2 (en) * | 2001-10-26 | 2005-06-14 | Microsoft Corporation | System and method for automatically tuning an antenna |
| US6970465B2 (en) * | 2001-10-26 | 2005-11-29 | Microsoft Corporation | System and method for locating a data frame within a transmitted data stream |
| US7043214B2 (en) * | 2002-12-11 | 2006-05-09 | Microsoft Corporation | Tower discovery and failover |
| JP4846384B2 (en) * | 2006-02-20 | 2011-12-28 | 株式会社東芝 | Semiconductor memory device |
| JP2007305267A (en) * | 2006-05-15 | 2007-11-22 | Toshiba Corp | Semiconductor storage device |
Family Cites Families (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3078443A (en) * | 1959-01-22 | 1963-02-19 | Alan C Rose | Compound error correction system |
| US3648236A (en) * | 1970-04-20 | 1972-03-07 | Bell Telephone Labor Inc | Decoding method and apparatus for bose-chaudhuri-hocquenghem codes |
| US3851251A (en) * | 1971-10-25 | 1974-11-26 | Martin Marietta Corp | Receiver method and apparatus |
| US3836974A (en) * | 1971-10-25 | 1974-09-17 | Martin Marietta Corp | Transmitter sequencing method and apparatus |
| US3808367A (en) * | 1971-10-25 | 1974-04-30 | Martin Marietta Corp | Method and circuit for timing signal derivation from received data |
| GB1500232A (en) * | 1974-07-04 | 1978-02-08 | Marconi Co Ltd | Digital data signal transmission arrangements |
| JPS584289Y2 (en) * | 1978-04-18 | 1983-01-25 | 日本電気株式会社 | Radio selective calling receiver with display device |
| JPS5654133A (en) * | 1979-10-09 | 1981-05-14 | Nec Corp | Selective callout receiver |
| JPS56136050A (en) * | 1980-03-28 | 1981-10-23 | Nec Corp | Individual selective call reception system |
| US4518961A (en) * | 1980-10-01 | 1985-05-21 | Motorola, Inc. | Universal paging device with power conservation |
| KR900007702B1 (en) * | 1980-10-01 | 1990-10-18 | 모토로라 인코포레이티드 | Paging device with modifiable operational characteristics |
| US4471352A (en) * | 1981-04-01 | 1984-09-11 | Midian Electronics, Inc. | Programmable paging encoder |
| US4644347A (en) * | 1983-08-10 | 1987-02-17 | Motorola, Inc. | Multiple frequency message system |
| JPS6152038A (en) * | 1984-08-22 | 1986-03-14 | Nec Corp | Radio selective calling receiver |
| GB2173660B (en) * | 1985-03-28 | 1989-01-25 | Multitone Electronics Plc | Paging receivers |
| GB2177244B (en) * | 1985-06-26 | 1988-08-17 | Multitone Electronics Plc | Paging system |
-
1985
- 1985-04-06 JP JP60073239A patent/JPS61232731A/en active Granted
-
1986
- 1986-04-04 CA CA000505830A patent/CA1283708C/en not_active Expired - Lifetime
- 1986-04-04 US US06/848,320 patent/US4910511A/en not_active Expired - Lifetime
- 1986-04-07 EP EP86104715A patent/EP0197534B1/en not_active Expired - Lifetime
- 1986-04-07 DE DE8686104715T patent/DE3675801D1/en not_active Expired - Lifetime
- 1986-04-07 AU AU55698/86A patent/AU592783B2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| US4910511A (en) | 1990-03-20 |
| JPH0449817B2 (en) | 1992-08-12 |
| EP0197534B1 (en) | 1990-11-28 |
| AU592783B2 (en) | 1990-01-25 |
| JPS61232731A (en) | 1986-10-17 |
| EP0197534A1 (en) | 1986-10-15 |
| DE3675801D1 (en) | 1991-01-10 |
| AU5569886A (en) | 1986-10-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed | ||
| MKLA | Lapsed |
Effective date: 19990430 |