Paging receiver suitable for an emergency call

• US 5,493,285 A
• Filed: 01/27/1994
• Issued: 02/20/1996
• Est. Priority Date: 01/28/1993
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Yoshizawa, Shigeo
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): MERZ, EDWARD W
• Application Number:
  US08/188,147
• Time in Patent Office: 754 Days
• Field of Search: 340/825.44, 340/311.1, 379/57
• US Class Current: 340/7.51
• CPC Class Codes: G08B 5/227 with call or message storage means

Abstract

A paging receiver of the present invention includes a decoder for processing a paging number and a message signal of a transmitted radio signal and receives the radio signal selectively by comparing the paging number with a predetermined paging number of the receiver. A timer stamps the message signal with current time when the paging number coincides with the predetermined paging number of the receiver. A memory stores message signals already received and stamped with time information. The message signal stamped with current time is compared with the message signals stamped with received time stored in the memory and, when contents of these message signals are coincident and a difference in time between these message signals is within a predetermined time, the message signal is deemed as an urgent message and an urgent report is performed.

Claims

1. A paging receiver comprising:

decoder means for decoding a paging number and message information subsequent to said paging number from an input signal received;

check means for comparing said paging number received with a paging number of said paging receiver and producing a first coincidence signal when both paging numbers coincide with each other;

timer means for determining a current time;

time stamping means responsive to said first coincidence signal for stamping the message information with the current time determined by said timer means, and for producing message information stamped with current time;

memory means for storing message information stamped with current time as message information stamped with received time;

comparing means for comparing said message information stamped with current time, with the message information stamped with received time stored in said memory means and generating a second coincidence signal when said message information being coincident and the current time and the received time being within a predetermined time period; and

emergency report means responsive to said second coincidence signal for performing an emergency report.

2. A paging receiver claimed in claim 1, wherein said timer means times with using clock pulses.

3. A paging receiver claimed in claim 1, wherein said time stamping means comprises an adder.

4. A paging receiver claimed in claim 1, wherein said memory means comprises an S-RAM.

5. A paging receiver claimed in claim 1, wherein said comparing means includes a first comparator for comparing said current time time stored in said memory means, and generating a first comparison signal, a second comparator for taking a difference between said first comparison signal and the predetermined time period, a third comparator for comparing a content of said message information stamped with current time with a content of said message information stored with received time in said memory means.

6. A paging receiver claimed in claim 5, wherein, when said comparing means generates said second coincidence signal, said message information stamped with received time stored in said memory means and compared is overwritten with said message information stamped with current time.

7. A received signal control circuit comprising:

timer means for determining a current time;

stamping means for stamping a received signal with a time determined by said timer means and producing a received signal stamped with current time;

memory means for storing a received signal stamped with current time as a received signal stamped with received time; and

comparing means for comparing said received signal stamped with current time with the received signal stamped with received time stored in said memory means, and producing a coincidence signal when a difference in time between said received signal stamped with current time and said received signal stamped with received time is within a predetermined time period and contents of these signals are coincident.

8. A received signal control circuit claimed in claim 7, wherein said comparing means includes a subtractor for differentiating said current time from said time stored in said memory means to produce a time difference, a first comparator for comparing said time difference with the predetermined time period, a second comparator for comparing a content of said received signal stamped with current time with a content of said received signal stored in said memory means and stamped with received time, and means for performing an urgent report when said time difference is within said predetermined time period and contents of these signals are coincident.