Selective call apparatus having display

Abstract

 A selection call signal transmitted from a transmitter is received and compared with a preset selective call signal. When the compared signals coincide with each other, an alert tone is produced and a received message signal is displayed on a display device. An error detection circuit is provided for detecting an error of the message signal to produce an error signal. According to the presence or absence of the error signal the message signal is converted into display signals of opposite signs so as to display messages containing and not containing the error with opposite contrasts.

Description

[0001] This invention relates to a selective call receiving apparatus or paging receiver having a display- which receives a paging signal including a selective calling signal or address signal and a message signal sent from a radio transmitter.

[0002] The selective call receiving apparatus having a di-splay is generally constituted by a receiving section, a signal processing section, a display section, an error processing section, and an alert signal generating section. The signal processing section contains a number setting circuit which presets its own call number. A carrier wave modulated with a selective calling signal and a message signal is transmitted from the transmitter. The transmitted wave is received by the receiving section and its waveform is then shaped. Then the signal processing section compares a received selective calling signal with a call number preset in the number setting circuit. When the compared signals coincide with each other, a loudspeaker provided for the alert signal generating section generates an alert for informing to one who carries with the receiver that there is a call and for displaying the received message on the display of the display section. The message signal is sent to the error processing section which detect that the message signal contains an error, and it produces an error detection signal which drives the display section so as to cause it to display the error.

[0003] In the prior art selective call receiving apparatus, an area for displaying a message and an area for displaying the error of the message are provided for the display surface of the display so that, when an error is detected in the message, a special symbol such as dot, cursor or the like is displayed on the error display area, in addition to the message to be displayed on the message display area.

[0004] Typical examples of the prior art display system will be described with reference to Figs. 1A-1C. Fig. lA shows a case when there is now error, and Figs. 1B and lC show examples of displaying an error with dot and a cursor, respectively.

[0005] However, the prior art selective call receiving apparatus having display has the following defects. First, it is necessary to provide a circuit for displaying a special error symbol on the error display area and hence the processing of the display signal is complicated. Second, since the error display area is used only for displaying the error, the efficient utilization of the display area is precluded. Third, identification of erroneous message is not always easy.

[0006] Accordingly, it is an object of this invention to provide a selective call receiving apparatus having display which does not require the error display area and hence a circuit for displaying the special error symbol on the error display area, and can readily identify an error message.

[0007] According to this invention, there is provided a selective call receiving apparatus having display comprising receiving means for receiving a signal representing a selective call number and a signal representing a message; a signal processing means including means for presetting a selective call number of the selective call receiving apparatus and comparing the received selective call number with the preset selective call number to output an alert signal and a message signal when the compared signals coincide with each other; an error detecting means supplied with the message signal for producing an error signal when there is an error in the message signal; display means including a display supplied with the message signal and the output signal of the error detecting means for converting message signals containing and not containing the error into opposite signals, thereby displaying the message signals containing and not containing the error with opposite contrasts on the display.

[0008] In the accompanying drawings:

Fig. lA, 1B and 1C show examples of error display system in prior art;

Fig. 2 is a block diagram showing the selective call receiving apparatus having display according to this invention;

Fig. 3A is a diagram for explaining the construction of a received signal;

Fig. 3B is a diagram showing the bit configuration of a selective call number word;

Fig. 3C is a diagram showing the bit configuration of a message word;

Fig. 4 is diagrams showing bit positions of respective character codes in consecutive words;

Fig. 5 is a flow chart useful to explain the operation of the signal processing circuit 4 shown in Fig. 2;

Fig. 6 is a flow chart useful to explain the operation of the display control circuit 8 shown in Fig. 2;

Fig. 7 is a flow chart useful to explain the operation of the error detection circuit 9 shown in Fig. 2;

Fig. 8 is a flow chart useful to explain the operation of the display data processing circuit 10 shown in Fig. 2; and

Figs. 9A and 9B are diagrams useful to explain an error character display.

[0009] In Fig. 2 showing one embodiment of the selective call receiving apparatus having display according to the present invention, the output terminal of a receiving section 2 including an antenna 1 for receiving signals is connected to the input terminal of a waveform shaper 3. The output terminal of the waveform shaper 3 is connected to the input terminal of a signal processing circuit 4 which is also supplied with the output of a call number setting circuit 5. The receiving section 2 and the waveform shaper 3 operate intermittently or continuously in accordance with control signals supplied from the processing circuit 4 through respective control lines, not shown. The output terminal 4a of the signal processing circuit 4 is connected to the input terminal of an alert signal generator 6 with an output terminal connected to a loudspeaker 7. The other output terminal 4b of the signal processing circuit 4 is connected to the input terminals of a display controller 8 and an error detector 9. The output terminals of the display controller 8 and of the error detector 9 are respectively connected to the input terminals 10a and 10b of a display data processor 10. The output terminal of the display,data processor 10 is connected to the input of a display driver 11 with an output terminal connected to a display 12.

[0010] The operation of the circuit shown in Fig. 2 will be described as follows.

[0011] A carrier wave modulated with a selective calling signal and with a message signal which is sent from a transmitter, not shown, is received by antenna 1 and both of the selective calling signal and the message signal are demodulated by the receiving section 2 and unwanted noise components are eliminated by a low pass filter, not shown, of the waveform shaper 3, and the waveforms of the demodulated signals are shaped into rectangular waves by a comparator, not shown, the rectangular waves being sent to the signal processor 4.

[0012] Fig. 3A shows the construction of the received signal in which N designates a selective call number word comprising 32 bits,'and I₁, I₂, I3 ... designate message words each comprising 32 bits. P represents a preamble signal and F a frame synchronizing signal. Figs. 3B and 3C respectively show bit configurations of the selective call number word and the message word. The first bit D of each word is a designator for identifying that whether the word is the selective call number word or the message word. In the case of the selective call number word, it is shown by a logic "0" whereas in the case of the message word it is shown by a logic "1". 20 bits from the second to the 21th bits contain a selective call number or a message. Succeeding 10 bits are check bits for any word and the last one bit is an even parity bit EP. Since the display device displays one character with 7 bits code, the bit positions of the character codes in respective message words I₁, I₂ ... vary as shown in Fig. 4 which shows a case when alphabets A-W are sequentially received as the message. As can be noted. from Fig. 4, the bit positions in one wo.rd are repeated with 7 words as one period.

[0013] Turning back to the description of the operation of the circuit shown in Fig. 2, the signals shown by Figs. 3A, 3B and 3C and inputted to the signal processing circuit 4 are processed as shown in the flow chart of Fig. 5. In Fig. 5, at step S51, the receiver 2 and the waveform shaper 3 are operating intermittently, and a judgment is made as to whether a signal received is a .. preamble signal P or not. When the preamble signal P is detected, the reception of the signal is continued, and the flow is advanced to step S52. When the result of the judgment at step S51 is No, the step S51 repeated. At step S52, signal reception is made for a definite interval during which a judgment is made as to whether a frame synchronizing signal F has been received or not. When the frame synchronizing signal F is detected, the flow is advanced to step S53. If signal F is not detected the flow is returned to step S51 for executing the intermittent operation.

[0014] At step S53, the input words are synchronized with the output of the call number setting circuit 5 using the detected frame synchronizing signal F, and the content of the received selective call number word is compared with the number preset in the number setting circuit 5 in order to detect the message addressing to own selective call receiving apparatus. If a result of the comparison indicates that the both numbers are coincident with each other, the flow is advanced to step S54, but when the coincidence is not detected, the flow is returned to step S51. At step S54, the alert generating circuit 6 is driven to generate an alert and the display circuit 8 and the error detector 9 are started. Then, at step S55, the message signal sent after the selective call number signal is processed for sending message data to the display control circuit 8 and the error detector 9. Next, the flow is advanced to step S56 for checking whether or not the message is completed. This may be done by checking message end bits contained in the message signal. When the message end bits are not detected, the flow is returned to step S55 for continueing the message data reception, whereas when the message end bits are detected, the flow is returned to step S51 after the signal terminates and the intermittent operation is performed.

[0015] Fig. 6 is a flow chart for describing the operation of the display controller 8 shown in Fig. 2. In response to a starting instruction of the display controller 8 issued at step S54 shown in Fig. 5, the flow is advanced to step S61 at which a message buffer memory, not shown, for storing 32 bits data is cleared. At step S62, the 32 bits data received from the signal processor 4 is stored in the-message buffer memory. Then at step S63, the most significant bit (MSB) of the stored data is checked for judging whether the data corresponds to a message or not. In other words, when the MSB is "1", the signal is judged as the message signal and the flow is advanced to step S64, whereas when the signal is not the message signal, the flow is transferred to step S65. In step S64, the character data each including 7 bits are derived out from the information bits (20 bits) and the derived out character codes are supplied to the display data processor 10. If the extracted character code data does not include 7 bits, the data is temporarily stored in a dummy buffer memory for waiting the reception of the next word. At step S65, a termination signal of the message data is sent to the signal processor 4, thus terminating the operation.

[0016] Fig. 7 is a flow chart for describing the operation of the error detector 9. When the error detector 9 is started at step S54 shown in Fig. 5, the flow enters into step S71 at which the 32 bits data is received from the signal processor 4 and a syndrome is calculated. At step S72, a judgment is made as to whether the value of the syndrome is zero or not for judging whether there is an error or not. Thus, where there is an error, it is judged by utilizing the fact that the value of its syndrom does not become zero. At steps S73 and S74, the error detection signal is made operative or inoperative according to the value of the syndrome.

[0017] Fig. 8 is a flow chart for describing the operation of the display data processor 10. At step S80, a character generator, not shown, in the display data processor 10 converts the 7 bits character code signal supplied from the display controller 8 into a 5x7 or 5x8 bits code and supplies the converted code to the display driver 11 as a display data. At step 581, a judgment is made as to whether there is an error detection signal from the error detector 9. The flow is branched to steps S82 and S83 in accordance with the result of the judgment. Step S83 shows a processing when an error is not detected, and the display data is stored in a display random access memory (RAM), not shown, in the display driver 11 as it is. Step S82 shows a processing when an error is detected. At this time, the logic of the display data is inverted and then stored in the display RAM. In accordance with the content of the display RAM, the display driver 11 generates signals for driving LCD display elements.

[0018] Figs. 9A and 9B show examples of the displayed character according to the present invention. Thus Fig. 9A shows a display of a letter E under a normal condition that is with no error. Fig. 9B shows a reverse display of the letter E which is judged as an erroneous letter. More particularly, the display 12 displays one letter or character with 5x7 dots. In the normal condition the dots representing the letter are bright (black portions in Fig. 9A) and other dots are dark (white portions in Fig. 9A). In Figs. 9A and 9B, bright and dark portions are shown opposite. With this mode of display, whether there is an error or not can be readily judged so that it is not necessary to provide dots or cursor at the lower portion.

[0019] As can be clearly noted, according to the selective call receiving apparatus embodying the invention, not only the display area of the display device can be efficiently utilized but also the construction of the display circuit can be simplified. Moreover, the error character can readily be identified.

Claims

1. A selective call receiving apparatus having display having receiving means (2) for receiving a signal representing a selective call number and a signal representing a message, signal processing means (3, 4, 5) including means (5) for presetting a selective call number of said selective call receiving apparatus and comparing. said received selective call number with said preset selective call number to output an alert signal and a message signal when said compared signals coincide with each other, an error detecting (9) means supplied with said message signal for producing an error signal when there is an error in said message signal, display means (8, 9, 10, 11) including a display (12), characterized in that said display means is supplied with said message signal and an output signal of said error detecting means for converting message signals containing and not containing said error into opposite signals, thereby displaying said message signals containing and not containing said error with opposite contrasts on said display.

2. The apparatus according to claim 1 wherein said display means (8, 9, 10, 11, 12) comprises a display control circuit (8) supplied with the message signal from said signal processing means (4) for outputting character codes constituting respective characters, a display data processing circuit (10) including a display buffer memory, and supplied with an output signal of said display control circuit (8) and an output signal of said error detecting circuit (9) for converting said character code into display data and storing said display data into said display buffer memory, said display data being displayed on said display (12) by changing a signal conversion logic in accordance with presence or absence of said error signal, and a display driving circuit reading out a content of said display buffer memory for driving said display.

Drawing