Patent Publication Number: US-6215979-B1

Title: Apparatus and method for generating alert in radio paging receiver

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to radio paging receivers and, more particularly, to an apparatus and method for generating an alert in a radio paging receiver. 
     2. Description of the Related Art 
     A radio paging receiver receives and analyzes a radio paging signal in a specific form. Upon the detection of self information from the received paging signal, the radio paging receiver displays the paging information (or message) and generates an alert. The self information is information which identifies the received paging signal as being associated with the radio paging receiver. Typically, the paging information is displayed on a liquid crystal display (LCD) and the alert is provided to the user through a speaker to notify the user that he or she has been paged. 
     Conventionally, in order to generate the alert for informing the user that paging information has been received, a decoder or an additional alert signal generator has been used. An example of such a decoder is disclosed in U.S. Pat. No. 5,287,099, entitled “Multi-Alert Radio Paging System”. Referring to FIG. 1 herein, a block diagram of a conventional decoder is shown. The conventional decoder includes an alert mode controller  404  and an alert pattern generator  405  to generate the alert. 
     Referring to FIG. 2, a conventional paging receiver which includes an alert signal generator  192  is shown. If a determination has been made by a decoder  120  indicating that self information has been received, a microcontroller  150  generates the alert by controlling alert signal generator  192 . The alert is output to the exterior through an alert unit  190 . 
     On the other hand, in order to generate the alert using decoder  120 , the elements for generating the alert must be included in the decoder. The frequency required to generate the alert is typically 2.7 or 3.2 KHz. If an incorrect frequency is used, the alert may not be generated normally. In the worst case, the decoder may need to be replaced with a new one. 
     Thus, in order for the conventional radio receiver to generate the alert using alert signal generator  192 , the conventional radio receiver must employ alert generator  192  operatively connected between microcontroller  150  and alert unit  190 . However, the use of alert signal generator  192  increases the complexity, cost, and size of the radio paging receiver in which it is employed. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an apparatus and method for generating an alert in a radio paging receiver which reduces the cost and the size of the radio paging receiver. 
     To achieve the above and other objects, an alert generating method for a radio paging receiver is provided. The method includes the steps of: generating an alert signal having a predetermined frequency using a timer circuit disposed in a microcontroller of the radio paging receiver, when self information of the radio paging receiver is detected from a received radio paging signal; and generating an alert in response to the alert signal. 
     According to another aspect of the invention, an alert generating apparatus in a radio paging receiver is provided. The apparatus includes: an antenna for receiving a radio paging signal; a radio circuit for frequency-converting, demodulating, and waveform-shaping the received radio paging signal to generate digital data; a decoder for decoding the digital data; a microcontroller having a timer circuit, said microcontroller analyzing the decoded data to determine if the decoded data includes self information of the radio paging receiver, and generating an alert signal of a predetermined frequency using the timer circuit, when the decoded data includes the self information; and an alert unit connected to an output terminal of said timer circuit, for generating an alert corresponding to said alert signal. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which: 
     FIG. 1 is a block diagram illustrating a conventional decoder; 
     FIG. 2 is a block diagram illustrating a conventional radio paging receiver having an alert signal generator; 
     FIG. 3 is a block diagram illustrating a radio paging receiver according to an embodiment of the present invention; and 
     FIG. 4 is a block diagram illustrating a timer circuit disposed in a microcontroller shown in FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The descriptions of various configurations and components of the present invention known to one skilled in the art are omitted for the sake of clarity and brevity. Also, in the figures, similar reference numerals designate similar elements. 
     FIG. 3 is a block diagram illustrating a radio paging receiver according to an embodiment of the present invention. The receiver includes a radio circuit  110  operatively connected to an antenna AT, a decoder  120 , and a switch  140 . The switch  140  is operatively connected to a battery  130 . A microcontroller is operatively coupled to decoder  120 , a memory  160 , a key input unit  170 , a display signal generator  182 , and an alert unit  190 . The display signal generator  182  is operatively coupled to a display unit  180 . 
     If a radio paging signal is received, the radio paging receiver judges whether or not the received signal includes the self information of the radio paging receiver. If so, the radio paging receiver generates an alert to the exterior. 
     The radio circuit  110  receives a radio paging signal through antenna AT and performs various functions with respect to the received signal, such as frequency conversion, demodulation and waveform shaping. Thereafter, the radio circuit  110  outputs digital radio paging data to decoder  120 . The decoder  120  decodes the received data and sets the operating mode of the radio paging receiver. In order to detect preamble data during an idle mode, decoder  120  controls the power supplied from battery  130  by periodically controlling switch  140 . During a batch mode, decoder  120  detects word synchronizing data and frame data (address codeword+message codeword). The decoder  120  decodes the detected frame data in order to convert the frame data into its original form. 
     The memory  160  stores a unique (self) address allocated to the radio paging receiver and the frame data, and also stores a paging message from a caller (or paging party) which has been processed by microcontroller  150 . The key input unit  170  interfaces the radio paging receiver with the user. The key input unit  170  has two or three switches, such as a function switch for indicating various operating modes of the radio paging receiver, a switch for confirming (or reading) the message from the caller, and a switch for selecting a desired operating mode. 
     The microcontroller  150  controls the overall operation of the radio paging receiver. For example, microcontroller  150  generates an alert signal and a display control signal upon processing the decoded data generated from decoder  120 . More specifically, microcontroller  150  compares the data generated from decoder  120  with the self address stored in memory  160 , and generates the alert signal if the radio paging signal includes the self information of the radio paging receiver. The microcontroller  150  generates the display control signal so that the paging message from the caller can be displayed on display unit  180 . Additionally, microcontroller  150  stores the paging message in memory  160 . 
     The display unit  180  displays the message from the caller and the status of the radio paging receiver. The display unit  180  is typically comprised of a liquid crystal display (LCD). The display signal generator  182  converts the paging message from the caller and the status information of the radio paging receiver into signals which can be displayed on display unit  180  according to the display control signal generated from microcontroller  150 . For example, the message from the caller may be a telephone number of the caller. 
     The alert unit  190  is comprised of a speaker and a motor. Upon receiving the alert control signal generated from microcontroller  150 , alert unit  190  generates an alert tone or vibrates the paging receiver to inform the user of the reception of a paging message. The alert unit  190  will generate the alert tone in a sound mode, and vibrate the paging receiver in a silent mode. 
     It should be noted that the radio paging receiver of the invention does not include the alert signal generator  192  shown in FIG. 2 disposed between microcontroller  150  and alert unit  190 . As will be described below with reference to FIG. 4, an alert is generated by the radio paging receiver according to the invention without the use of alert signal generator  192 . 
     FIG. 4 is a block diagram illustrating a timer circuit disposed in the microcontroller  150  of FIG.  3 . The timer circuit includes a comparator  153  operatively coupled to a scaler  151  and a frequency setter  152 . The comparator  153  is also connected to a speaker SPK, such as the speaker of alert unit  190 . 
     The timer circuit represents a timer F contained in a commercially available single-chip microcomputer which is employed as microcontroller  150 . An example of such a microcomputer is HD6473837, manufactured by Hitachi, Japan. As described in page 205 of the H8/3834 Series Hardware Manual published by Hitachi in 1994, timer F includes a PSS (Prescaler S), a TCRF (Timer Control Register F), a TCFL (8-bit Timer Counter FL), an OCRFL (Output Compare Register FL), and a compare circuit. In FIG. 4, scaler  151 , frequency setter  152 , and comparator  153  correspond to the PSS, the OCRFL, and the compare circuit, respectively. 
     The scaler  151  scales (or converts) a 4 MHz frequency of an input signal into a predetermined frequency. The frequency setter  152  sets another predetermined frequency according to data provided through an internal data bus of microcontroller  150 . For example, frequency setter  152  can set the frequency to 2.7 or 3.2 KHz, which correspond to the frequencies at which the commercially available radio paging receiver WITHME 3400 manufactured by Samsung Electronics generates an alert signal. The comparator  153  compares the frequency of the signal generated from scaler  151  with the frequency set by frequency setter  152  and, if they match, generates a signal with the frequency set by frequency setter  152 . The signal generated from comparator  153  with the set frequency is an alert signal. As such, the frequency of the signal generated from comparator  153  corresponds to the frequency at which speaker SPK of alert unit  190  can generate the alert tone. In this way, speaker SPK, which is connected to an output terminal of the timer circuit, can generate the alert in response to the signal outputted from comparator  153 . 
     Thus, the alert signal can be generated by using the timer circuit contained in microcontroller  150 . This timer circuit is driven as a typical timer and further drives the speaker as the alert signal generator. 
     In sum, the timer circuit contained in the microcontroller is used to generate the alert signal. Therefore, an additional alert signal generating circuit is not required, either separately or as part of the decoder. As a result, a radio paging receiver according to the invention requires less components than a conventional radio paging receiver. Therefore, as compared to conventional radio paging receivers, a radio paging receiver according to the invention is more easily and economically constructed and requires less space. Moreover, the inconvenience in replacing the decoder when an improper decoder is used to generate the alert signal is eliminated. 
     While the present invention has been shown and described with reference to a certain preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.