WO1994008421A1

WO1994008421A1 - Voice pager

Info

Publication number: WO1994008421A1
Application number: PCT/US1993/009507
Authority: WO
Inventors: Xing Gao
Original assignee: Gensonic Inc
Current assignee: Gensonic Inc
Priority date: 1992-10-07
Filing date: 1993-10-05
Publication date: 1994-04-14
Anticipated expiration: 1995-04-07
Also published as: CN1086644A

Abstract

A telephone pager (10) for alerting a user of the pager to call a specified telephone number and having the capability of receiving nonvoice FSK encoded signals, generating a voice announcement of the telephone number to be called and generating a plurality of audible tones corresponding to the digits of the telephone number that can be used to automatically dial the telephone number. The pager includes a radio frequency receiver (18), a microprocessor (30) having serial and parallel ports, a logic array voice synthesizer (82), a DTMF tone generator (78), and a plurality of peripheral devices for alerting the user to incoming messages, such as an LED (62), a vibrator (54) and a speaker (58). The pager is controlled by a software operating system stored in ROM in the microprocessor.

Description

VOICE PAGER

TECHNICAL FIELD The present invention relates to electronic pager receivers and more particularly to a pager receiver that utilizes a voice synthesizer to announce the telephone number to be called and a DTMF generator to permit one- touch call-back dialing of the announced telephone number.

BACKGROUND ART

Telephone pager receivers ("pager") of the type that alert a pager user to call a specified telephone number are well-known in the art. Typically, when a caller dials the telephone number assigned to the pager, the call is received at a central location. A transmitter at the central location then transmits a radio frequency (RF) signal to the pager that includes an identification code corresponding to the pager for which the message is intended, as well as the telephone number to be called. Typically the transmitted signal is in the 130 MHz to 950 MHz frequency range, depending on the carrier frequency assigned to the paging company, and the pager is preset to receive the specific frequency transmitted by the paging company. Most pagers include a user alert function that alerts the pager user that a message has been received. Common alert functions include audible tones, flashing lights and/or vibrations. Most commercially available pagers also include a display that shows the telephone number to be called in numeric or alphanumeric form. The pager user then locates a telephone, views the display, and manually dials the indicated telephone number.

In a related technological area, pagers are known that can receive and play back short voice messages. For example, U.S. Pat. No. 4,419,668, issued to C. Ganucheau on Dec. 6, 1983, discloses a pager in which a tone only or a combined tone and voice message can be received by the pager. Similarly, U.S. Pat. No. 4,769,642, issued to W. Davis et al. on Sept. 6, 1988, discloses a pager which receives voice messages that have been transmitted using linear predictive coding (LPC) encoding. U.S. Pat. No. 4,965,569, issued to P. Bennett et al. on Oct. 23, 1990, discloses a pager and method for receiving analog voice messages, digitizing and storing the received message and alerting the pager user of the received message through an audible signal or through a vibrating signal. Additionally, U.S. Pat. No. 3,729,680, issued to R. McDonald on April 24, 1973, illustrates a pager that utilizes a type of tone generator. U.S. Pat. No. 4,873,520, issued to K. Fisch et al. on Oct. 10, 1989 illustrates a pager that utilizes an audio producing module. U.S. Pat. No. 4,868,560, issued to G. Oliwa et al. on Sept. 19, 1989 illustrates flow diagrams for various types of pager software.

None of the prior art listed above discloses a pager that receives a nonvoice message and converts the nonvoice message to a voice message that is played back to announce the telephone number to be called in response to the nonvoice message. Nor does any of the prior art listed above disclose a pager that allows the pager user to automatically dial the received telephone number.

SUMMARY OF THE PRESENT INVENTION Briefly, the preferred embodiment of the present invention comprises a telephone pager that receives nonvoice FSK encoded signals that are processed in the pager and used to generate a voice announcement of the telephone number to be called. The pager also has the capability of displaying the telephone number in numeric form on an LCD display and of generating a plurality of audible tones corresponding to the digits of the telephone number that can be used to automatically dial the telephone number.

The pager includes a radio frequency receiver, a microprocessor having serial and parallel ports, an EEPROM memory unit, a logic array voice synthesizer, a DTMF tone generator, an LCD display, selection means for selecting pager functions and a plurality of peripheral devices for alerting the user to incoming messages, such as an LED, a vibrator and a speaker.

A software system is stored in ROM memory included in the microprocessor for controlling functions such as the decoding and error correction (Chien search technique) of incoming signals, preamble detection and validation of incoming signals, message processing, alert interface activation, voice message announcement and dialing tone generation.

Voice announcements of the telephone number to be called are controlled by using the microprocessor to decode and process the incoming nonvoice FSK encoded signal to yield a digital representation of the telephone number to be called. The digital representation is stored in RAM in the microprocessor and is displayed on the LCD display. If the pager user selects the voice announcement output option, the microprocessor communicates with the voice synthesizer attached to the parallel port of the microprocessor. A voice announcement is generated by a speaker which is driven by the output of the voice synthesizer.

If the pager user desires to automatically dial the telephone displayed on the LCD display, the user selects the dial function on the user interface. The microprocessor then accesses the DTMF generator through the serial port that generates a tone representation of the displayed telephone number that is sent out through the speaker.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram of a voice pager according to the present invention; Fig. 2 is a flowchart of the call alert program sequence according to the present invention; and

Fig. 3 is a flowchart of the message review program sequence according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Fig. 1 is a block diagram that illustrates the electrical components of a voice pager 10. An antenna 14 is connected to a receiving unit 18 which is connected to a direct current to direct current (DC-DC) convertor 22 and a decoder 30.

In some cases, where the transmitted signal has a frequency that cannot be processed by the receiving unit

18, a frequency convertor unit 32 is positioned between the antenna 14 and the receiving unit 18 to convert the received signal to a usable frequency range.

The antenna 14 is a standard antenna selected for receiving RF signals in the specific frequency range being used by the pager 10. For example, if the pager 10 is being used to receive signals in the 150 to 450 MHz range, a loop antenna is used. If the pager 10 is being used to receive signals in the 900 MHz range, then a metal strip antenna is used.

The receiving unit 18 is a radio frequency (RF) pager receiver capable of receiving and demodulating frequency shift keying (FSK) signals and of converting them to a digital form that can be processed by the decoder 30. In the preferred embodiment, the receiving unit 18 is a pager receiver capabable of processing signals in the 25 to 512 MHz range.

The frequency convertor 32 is a standard electrical circuit capable of converting high frequency signals (e.g. 931 MHz signals) received by the antenna 14 down to a lower frequency range (e.g. approximately 200 MHz) before the received signal is processed by the receiving unit 18. If the transmitted signal is already in a frequency range that can be processed by the receiving unit 18 (i.e. below 500 MHz), then the frequency convertor 32 is not needed and the antenna 14 is connected directly to the receiving unit 18 shown in Fig. 1.

In the preferred embodiment, the frequency convertor 32 has a common circuit design that comprises an antenna matching network, an RF low noise amplifier, a saw filter and a first mixer to convert the high frequency signal down to an appropriate frequency, like 233 MHz, that can be handled by the receiving unit 18. The DC-DC convertor 22 boosts the output of a battery 24 (1.5 V) to an approximately 3.0 V level to allow the receiving unit 18 and the decoder unit 30 to function properly.

The decoder 30 is a general purpose microcontroller having a microprocessor, built-in read only memory (ROM), built-in random access memory (RAM), a built-in liquid crystal display (LCD) driver, a serial communication interface (port) and several parallel communication interfaces (ports). In the preferred embodiment, the decoder 30 is a 4-Bit CMOS single-chip microcomputer.

The decoder 30 operates under the control of software ("system software") stored in the ROM of the decoder 30, to process incoming messages, activate an alert interface unit 38 and display at least part of the incoming message on a visible display unit 42. In the preferred embodiment, the display unit 42 is a one line LCD display supporting twelve digits, with seven segments per digit, that is capable of displaying two screens sequentially.

The alert interface 38 includes a plurality of circuit elements (e.g. transistors, resistors and capacitors) required to connect the speaker 58, vibrator 54, LED 62 and lamp 66 to other circuit elements such as the decoder 30.

An electrically erasable programmable read only memory (EEPROM) unit 44 is connected to the decoder 30 for storing data about the address of the pager 10.

The built-in RAM in the decoder 30 has the capacity to store eight incoming messages comprised of up to twenty-four characters in each message. In the preferred embodiment, each message comprises a ten digit telephone number. Typically, before the message is displayed it is preceded by a call source identifier which is typically a letter (A, B, C or D).

The decoder 30 has the capacity of handling four call source identifiers (i.e. four telephone numbers can be assigned to the voice pager 10). The call source identifier indicates which pager telephone number the caller dialed, thereby giving the user the possibility of evaluating the source of the call (e.g. one pager telephone number can be given out to clients, while another pager telephone number can be given to personal acquaintances).

A user interface unit 46 is also connected to the decoder 30 for allowing a user of the voice pager 10 to select various options relating to the functioning of voice pager 10. A switch 50 allows the user to select either a mute alert mode, a normal alert mode or a voice alert mode. In the mute alert mode, a vibrator 54 is activated by the alert interface 38 when an incoming message is received.

The user interface 46 also includes a plurality of common circuit elements (e.g. transistors, resistors and capacitors) required to connect the switch 50 and the pushbuttons 70 and 74 to the decoder 30.

In the normal mode, an audible signal, such as a beep, is emitted from a speaker 58 when an incoming message is received. In the voice mode, the incoming message is announced from the speaker 58 by an artificial voice message that approximates the sound of a normal human voice. In each of the mute, normal and voice modes, the incoming message is also indicated by a blinking light emitting diode (LED) 62 and the incoming message is displayed on the LCD display 42. The alert interface 38 also includes a lamp 66 used to illuminate the display 42. A pushbutton 70 allows the user to review messages stored in the decoder 30. For example, depressing the pushbutton 70 once displays the first message stored in the RAM of the decoder 30. Depressing the pushbutton 70 a second time displays the second stored message, etc. If the switch 50 is in the mute or normal position, the stored messages are displayed on the display 42. The voice mode is selected by placing the switch 50 in the normal position and depressing the pushbutton 70 while a "voice-mode symbol" is displayed on the display 42. When the voice mode is selected, the stored messages are announced in voice form as well as being displayed on the display 42.

A pushbutton 74 allows the user to automatically dial the telephone number indicated by the displayed message. To use this feature, the user depresses pushbutton 70 until the desired message is displayed on the display 42. The user then positions the voice pager 10 near the microphone/transmitter part of a telephone and depresses pushbutton 74. A series of DTMF tones corresponding to the displayed message are then emitted from the speaker 58, thereby effectively dialing the telephone number indicated by the displayed message.

The DTMF tones are generated by a dual-tone multi- frequency (DTMF) generator 78. The DTMF generator 78 is connected to a serial interface port of the decoder 30.

The voice announcements of incoming messages are generated by a voice synthesizer 82 which is connected to the parallel interface port of the decoder 30. In the preferred embodiment, the voice synthesizer 82 is a CMOS sound/speech synthesis chip. In ordering a voice chip, the specific partial voice message elements are specified before the voice chip is manufactured.

The voice synthesizer 82 includes a logic array which allows pieces of voice messages to be assembled according to their assigned voice message addresses. For example, the voice synthesizer 82 includes a plurality of partial voice messages, with each partial voice message including a human voice saying one of the numbers from zero to nine (0-9) and being assigned a voice message address. A complete telephone number voice message is then constructed by sending commands from the decoder 30 to the voice synthesizer 82. The logic array in the synthesizer 82 then uses the specified voice message addresses to assemble the individual partial voice messages, thereby generating the complete telephone number voice message in a form that approximates the sound of a normal human voice.

Fig. 2 is a flowchart of the system software that controls the call alert functions and hardware of the pager 10. Block 100 indicates that an initial check of the pager 10 is automatically conducted whenever the pager 10 is turned on. During the initial check, the system software queries the various hardware components of the pager 10 such as the serial and parallel ports of the decoder 30, the peripheral devices attached to the ports, and the power level of the battery 24. A failure of any tested component causes an error message to be displayed on the display 42.

Block 104 indicates that after a successful initial check, the pager 10 scans for a preamble code that identifies the beginning of a new transmission. The code format of most pager transmissions conforms to the CCIR Radio Paging Code No. 1 protocol (POCSAG).

In order to insure that the transmitted data is correctly received, an error correction process must be performed at various times on the received message. In the preferred embodiment, the Chien search error correction technique is employed to detect errors such as missing bits and error bits. The Chien search error correction technique is explained in the paper by R.T. Chien, entitled "Cyclic Decoding Procedures for Bose- Chaudhuri-Hocquenghem Codes," published in IEEE Transactions On Information Theory, pp. 357-363 (October 1964). Typically, error correction is performed in conjunction with blocks 108, 112 and 116, discussed below. Block 108 indicates that when a preamble code is detected, the pager 10 scans for a synchronization code. The synchronization code word indicates the point in a batch transmission in which a message for the pager 10 is contained. A batch transmission consists of eight frames and the information transmitted to a particular pager is in one of the eight frames. Error correction is performed when checking for the synchronization code.

Block 112 indicates that after the synchronization code has been detected, the pager 10 scans for an address code. The address code in the message must match one of the address codes for the pager 10 in order to establish that the message is intended for a specific pager 10 and not for some other pager. The address codes for the pager 10 are stored in the EEPROM 44, and in the preferred embodiment, the pager 10 can have up to four address codes. Error correction is performed when checking for the address code.

Block 116 indicates that once an address code match has been established, the decoder 30 scans the 32 bit word for the part of the received message that contains the telephone number to be called by the pager user. Error correction is performed when scanning for the telephone number.

Block 120 indicates that after the decoder 30 has decoded the telephone number, the telephone number is stored in the RAM of the decoder 30. Block 124 indicates that after the telephone number has been stored in memory, the alert interface 38 is activated by sending a signal to the parallel port to which the alert interface 38 is connected. At approximately the same time, the display 42 is activated. Blocks 128 and 132 indicate that the telephone number is then loaded from memory and displayed on the display 42. Blocks 136, 140, 144, 148 and 152 indicate that after the telephone number is displayed on the display 42, either the vibrator 54, the voice synthesizer 82 or beeping from the speaker 58 is enabled to alert the pager user to the displayed telephone number. The decoder activates the appropriate alert mode (i.e. either the normal, mute or voice modes) by checking for a signal from the user interface 46 that indicates which alert mode has been selected by the user with the switch 50.

Block 156 indicates that the telephone number remains on the display 42 and the alert interface remains activated until a preset alert time has expired. In the preferred embodiment, an alert time of about eight seconds is used.

Fig. 3 is a flowchart of the system software that controls the replaying of messages stored in the pager 10. When the pager user desires to review a stored message, the user depresses pushbutton 70 (Fig. 1) one time.

Block 170 indicates that after the pushbutton 70 has been depressed, the decoder 30 checks for incoming calls. If there is an incoming call, the message playback sequence is stopped until the incoming call has been stored in memory. If or when there are no incoming calls, blocks 174 and 178 indicate that the desired message will be retrieved from the RAM of decoder 30 for viewing on the display 42.

Because the pager 10 can store a total of eight messages for the four telephone numbers assigned to the pager 10, the first item to appear on the display 42 is an address code that identifies which message is about to be displayed. For example, the code B-l may appear, indicating that for the pager telephone number identified as "B," the first telephone number message is about to be displayed. A second screen then appears that shows the telephone number stored in the B-l address. If the pager user depresses the pushbutton 70 a second time, another address code will appear (e.g. B-3). This process can be repeated until all of the stored messages have been reviewed .

Blocks 182, 186 and 190 indicate that while the telephone number is being displayed, the decoder 30 checks the setting in the user interface 46 for the alert interface 38. If the mute or normal modes were selected, no further display action is required. However, if the voice mode was selected, the decoder 30 enables the voice synthesizer 82 through the serial port. Digital information which identifies the displayed telephone number is sent to the voice synthesizer 82 where the voice element corresponding to each digit of the displayed telephone number is retrieved in order. The voice elements are then assembled in order and a complete voice message of the telephone number is announced through the speaker 58.

While a telephone number is displayed on the display 42, the pager user also has the option of activating the automatic dial feature of the pager 10 by depressing the pushbutton 74. Blocks 194 and 198 indicate that when the automatic dial feature (dial back) is activated, the decoder 30 verifies that the voice message is finished. The dial back function cannot continue until the voice message is finished because both functions utilize the speaker 58. When the voice message is finished, block 200 indicates that the DTMF generator 78 is activated by sending digital information which identifies the displayed telephone number to the DTMF generator 78 through the serial port of the decoder 30. The DTMF generator 78 generates a tone sequence corresponding to each digit of the displayed telephone number and a complete DTMF tone replication of the displayed telephone number is played through the speaker 58. When this tone replication is played into the microphone of a standard telephone, it has the effect of automatically dialing the number.

Block 204 indicates that when the dial back feature is not selected, the alert message will continue to be displayed (and/or announced) until a preset alert time limit has expired. In the preferred embodiment the alert time limit is about eight seconds.

Although the present invention has been described in terms of the presently preferred embodiment, it is to be understood that such disclosure is not to be interpreted as limiting. Various alterations and modifications will no doubt become apparent to those skilled in the art after having read the above disclosure. Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention.

Claims

CLAIMS I claim:

1. An electronic pager for alerting a pager user to call a specified telephone number comprising: a receiving means for receiving a digital signal that includes information about a telephone number to be called by a user of the electronic pager; a processor means for processing the signal to yield a message that includes said telephone number; and a voice synthesizer means for generating an audible announcement of said telephone number, said audible announcement approximating the sound of a human voice.

2. The electronic pager of claim 1 wherein: the voice synthesizer includes a logic array.

3. The electronic pager of claim 1 wherein: the voice synthesizer includes a plurality of prerecorded elements corresponding to the digits 0-9, said prerecorded elements being capable of electronic arrangement to yield said audible announcement.

4. The electronic pager of claim 1 further comprising: a generator means for generating a plurality of audible tones corresponding to the digits of said telephone number that can be used to automatically dial said telephone number.

5. The electronic pager of claim 1 further comprising: a memory means for storing at least part of said message for future use; a display means for visibly displaying at least part of said message; a user interface means for allowing a user of the electronic pager to choose at least one alert option selected from the group consisting of an audible signal alert, a visible indicator alert or a vibration alert; and an alert interface means for conveying an output signal from the decoder means to at least one device selected from the group consisting of a audio speaker, an LED or a vibrator to alert the user that the message has been received.

6. An electronic pager for alerting a pager user to call a specified telephone number comprising: a receiving means for receiving and demodulating a digitally encoded RF signal that includes information about a telephone number to be called by a user of the electronic pager to yield a received signal; a decoder means for processing the received signal to yield a message that includes said telephone number; a memory means for storing at least part of said message for future use; a display means for visibly displaying at least part of said message; a user interface means for allowing a user of the electronic pager to choose at least one alert option for notifying the user that the message has been received and for allowing the user to cause the message to be retrieved from the memory means and displayed on the display means; an alert interface means for conveying an output signal from the decoder means to at least one device for notifying the user that the message has been received; and a voice synthesizer means for generating an audible announcement of said telephone number, said audible announcement approximating the sound of a human voice.

7. The electronic pager of claim 6 wherein, the decoder means comprises a microprocessor having a serial port and a parallel port.

8. The electronic pager of claim 6 wherein, the voice synthesizer means comprises a semiconductor device having a logic array.

9. The electronic pager of claim 6 wherein, the receiving means comprises a radio frequency pager receiver.

10. The electronic pager of claim 6 further including: a convertor means for boosting the output of a DC battery to a voltage suitable for use with the decoder means.

11. The electronic pager of claim 6 further including: a tone generating means for generating a plurality of tones corresponding to the digits of said telephone number that can be used to automatically dial said telephone number.

12. The electronic pager of claim 6 wherein, the alert device is selected from the group consisting of an audio speaker, an LED or a vibrator.

13. A method for alerting a user of a telephone pager that a message has been received comprising the steps of: a. receiving a digital message with a telephone pager, the message including information specifying a telephone number to be called by a pager user; b. processing the message with said telephone pager to yield said telephone number in a form that can be used by a microprocessor included in said telephone pager; and c. sending a plurality of signals from said microprocessor to a voice synthesizer included in said telephone pager that cause said voice synthesizer to generate an audible announcement of said telephone number.