Broadcast program identification method and apparatus

A system for identifying a plurality of defined braodcast programs in a broadcast signal comprising:

• means for detecting the occurence of a predetermined event in the broadcast signal;
• means for detecting a stability condition in the broadcast signal after the occurrence of said predetermined event;
• said stability condition detecting means including means for processing the broadcast signal at the occurrence of the predetermined event provide a first series of signal samples;
• means for processing the broadcast signal a predefined time interval after the occurrence of the predetermined event to provide a second series of signal samples;
• and means for comparing the first and second series of signal samples to detect a stability condition in the broadcast signal responsive to an identified predetermined threshold value;
• means for extracting a signature from the broadcast signal after the occurrence of said stability condition;
• means for storing the extracted signature and a time of extraction thereof;
• and
• means for comparing the stored extracted signature with a plurality of reference signatures to identify a broadcast program.

A method of monitoring a signal comprising the steps of;

• detecting the occurrence of a predetermined event in the signal;
• processing the signal at the occurrence if the predetermined event to provide a first series of signal samples;
• processing the signal a predefined time interval after the occurrence of the predetermined event to provide a second series of signal samples;
• comparing the first and second series of signal samples to detect a stability condition in the signal responsive to an identified predetermined threshold value;
• extracting a signature from the signal after the occurrence of said stability condition;
• and
• storing the extracted signature and a time of extraction thereof.

A system for monitoring a signal for use in a system for identifying a plurality of defined broadcast programs in the monitored signal, the monitoring system comprising:

• means for detecting the occurrence of a predetermined event in the signal;
• means for detecting the occurrence of a stability condition in the signal after the occurrence of said predetermined events;
• said stability condition detecting means including means for processing the signal at the occurrence of the predetermined event to provide a first series of signal samples;
• means for processing the signal a predefined time interval after the occurrence of the predetermined event to provide a second series of signal samples;
• and means for comparing the first and second series of signal samples to detect a stability condition in the signal responsive to an identified predetermined threshold value;
• means for extracting a signature from the signal after the occurrence of said stability condition;
• and
• means for storing the extracted signature and a time of extraction thereof.