Electronic alarm apparatus

In apparatus for monitoring the presence or absence of a common coded radio frequency signal within a given area, monitoring means including electronic circuit means for receiving said coded radio frequency signal, and a plurality of transmitting means associated with said monitoring means including electronic circuit means for producing and transmitting said coded radio frequency signal periodically in predetermined spaced apart time intervals to one another;

• said monitoring means including:
• electronic circuit means for programming said plurality of transmitting means to produce and transmit said coded radio frequency signal in said predetermined spaced apart time intervals to one another;
• electronic circuit means, including a logic timing circuit, for identifying said coded radio frequency signal received with one of said plurality of transmitting means;
• and electronic circuit means and alarm means for indicating failure of reception of said common coded radio frequency signal.

In apparatus for monitoring the presence or absence of at least one object within a given area, monitoring means including electronic circuit means, including antenna and receiver, for receiving a common transmitted coded radio frequency signal, and at least one transmitting means associated with said monitoring means including means for attachment to said object and including electronic circuit means for producing said coded radio frequency signal periodically in predetermined spaced apart time intervals, and electronic circuit means for transmitting said signal produced;

• said monitoring means including:
• electronic circuit means for programming said transmitting means to produce and transmit said coded radio frequency signal in said predetermined spaced apart time intervals;
• electronic circuit means, including a logic timing circuit, for identifying said coded radio frequency signal received with said associated transmitting means, storing means containing a coded signal;
• verifying electronic circuit means including a check circuit for comparing said coded radio frequency signal received with said coded signal stored, and electronic circuit means and alarm means for indicating failure of reception of said common coded radio frequency signal.

In apparatus for monitoring the presence or absence of a plurality of objects within a given area, monitoring means including electronic circuit means, including antenna and receiver, for receiving a common transmitted coded radio frequency signal, and a plurality of transmitting means associated with said monitoring means including means for attachment to said objects and including electronic circuit means for producing said coded radio frequency signal periodically in predetermined spaced apart time intervals to one another, and electronic circuit means for transmitting said signal produced;

• said monitoring means including:
• electronic circuit means for programming said plurality of transmitting means to produce and transmit said coded radio frequency signal in said predetermined spaced apart time intervals to one another;
• electronic circuit means, including a logic timing circuit, for identifying said coded radio frequency signal received with one of said plurality of transmitting means;
• storing means containing a coded signal;
• verifying electronic circuit means including a check circuit for comparing said coded radio frequency signal received with said coded signal stored;
• and electronic circuit means and alarm means for indicating failure of reception of said common coded radio frequency signal.

In electronic alarm apparatus for monitoring the presence or absence of at least one object within a given area, monitoring means including an antenna and receiver for receiving, demodulating and decoding a common transmitted radio frequency signal including a digital identification code, and at least one transmitting means associated with said monitoring means for producing and transmitting said radio frequency signal periodically in predetermined spaced apart time intervals;

• said transmitting means including means for attachment to said object and including a shift register for storing said digital identification code and outputting same to a transmitting electronic circuit and a logic circuit for recirculating said digital identification code outputted from said shift register back into said shift register, said transmitting electronic circuit including means for modulating and encoding said digital identification code;
• said monitoring means including:
• electronic circuit means for programming said transmitting means to produce and transmit said coded radio frequency signal in said predetermined spaced apart time intervals;
• electronic circuit means, including a logic timing circuit, for identifying said radio frequency signal received with said associated transmitting means;
• storing means containing a coded signal comprised of a digital code substantially identical to said digital identification code stored in said shift register of said transmitting means;
• verifying electronic circuit means including a check circuit for comparing said radio frequency signal received, including the digital identification code, with said coded signal stored;
• and electronic circuit and alarm means including audio logic circuit and liquid crystal display for indicating failure of reception of said common radio frequency signal.

In electronic alarm apparatus for monitoring the presence or absence of a plurality of objects within a given area, monitoring means including an antenna and receiver for receiving, demodulating, and decoding a common transmitted radio frequency signal including a digital identification code, and a plurality of transmitting means associated with said monitoring means for producing and transmitting said radio frequency signal periodically in predetermined spaced apart time intervals;

• said transmitting means including means for attachment to said object and including a shift register for storing said digital identification code and outputting same to a transmitting electronic circuit and a logic circuit for recirculating said digital identification code outputted from said shift register back into said shift register, said transmitting electronic circuit including means for modulating and encoding said digital identification code;
• said monitoring means including:
• electronic circuit for programming said plurality of transmitting means to produce and transmit said coded radio frequency signal in said predetermined spaced apart time intervals to one another;
• electronic circuit means, including a logic timing circuit, for identifying said radio frequency signal received with one of said plurality of transmitting means;
• storing mean containing a coded signal comprised of a digital code substantially identical to said digital identification code stored in said shift register of said transmitting means;
• verifying electronic circuit means including a check circuit for comparing said radio frequency signal received, including the digital identification code, with said code signal stored;
• and electronic circuit and alarm means including audio logic circuit and liquid crystal display for indicating failure of reception of said common radio frequency signal.