Abstract: Systems and methods are provided for gathering audience measurement data relating to exposure of an audience member to audio data. Audio data is received in a user system and is then encoded with audience measurement data. The encoded audio data is reproduced by the user system, picked up by a monitor and decoded to recover the audience measurement data.

Abstract: An encoding system for encoding a first ancillary code in media data and monitoring for reception of a second ancillary code that has a higher priority than the first ancillary code, such that upon detection of the higher priority ancillary code the encoding system modifies a characteristic and/or characteristics of the first ancillary code.

Abstract: Apparatus and methods for including a code having at least one code frequency component in an audio signal are provided. The abilities of various frequency components in the audio signal to mask the code frequency component to human hearing are evaluated and based on these evaluations an amplitude is assigned to the code frequency component. Methods and apparatus for detecting a code in an encoded audio signal are also provided. A code frequency component in the encoded audio signal is detected based on an expected code amplitude or on a noise amplitude within a range of audio frequencies including the frequency of the code component.

Abstract: Systems and methods are provided for decoding a message symbol in an audio signal. This message symbol is represented by first and second code symbols displaced in time. Values representing the code signals are accumulated and the accumulated values are examined to detect the message symbol.

Abstract: An encoding system for encoding a first ancillary code in media data and monitoring for reception of a second ancillary code that has a higher priority than the first ancillary code, such that upon detection of the higher priority ancillary code the encoding system modifies a characteristic and/or characteristics of the first ancillary code.

Abstract: Systems and methods are provided for gathering audience measurement data relating to exposure of an audience member to audio data. Audio data is received in a user system and is then encoded with audience measurement data. The encoded audio data is reproduced by the user system, picked up by a monitor and decoded to recover the audience measurement data.

Abstract: Apparatus and methods for including a code having at least one code frequency component in an audio signal are provided. The abilities of various frequency components in the audio signal to mask the code frequency component to human hearing are evaluated and based on these evaluations an amplitude is assigned to the code frequency component. Methods and apparatus for detecting a code in an encoded audio signal are also provided. A code frequency component in the encoded audio signal is detected based on an expected code amplitude or on a noise amplitude within a range of audio frequencies including the frequency of the code component.

Abstract: Apparatus and methods for including a code having at least one code frequency component in an audio signal are provided. The abilities of various frequency components in the audio signal to mask the code frequency component to human hearing are evaluated and based on these evaluations an amplitude is assigned to the code frequency component. Methods and apparatus for detecting a code in an encoded audio signal are also provided. A code frequency component in the encoded audio signal is detected based on an expected code amplitude or on a noise amplitude within a range of audio frequencies including the frequency of the code component.

Abstract: Apparatus and methods for including a code having at least one code frequency component in an audio signal are provided. The abilities of various frequency components in the audio signal to mask the code frequency component to human hearing are evaluated and based on these evaluations an amplitude is assigned to the code frequency component. Methods and apparatus for detecting a code in an encoded audio signal are also provided. A code frequency component in the encoded audio signal is detected based on an expected code amplitude or on a noise amplitude within a range of audio frequencies including the frequency of the code component.

Abstract: Methods and apparatus for encoding and decoding information in broadcast or recorded segment signals are described. In certain embodiments, an audience monitoring system encodes identification information in the audio signal portion of a broadcast or recorded segment using spread spectrum encoding. A personal monitoring device receives an acoustically reproduced version of the broadcast or recorded signal via a microphone, decodes the identification information from the audio signal portion despite significant ambient noise, and stores this information, automatically providing a diary for the audience member which is later uploaded to a centralized facility. A separate monitoring device decodes additional information from the broadcast signal, which is matched with the audience diary information at the central facility.

Abstract: In a system for monitoring use of a video monitoring system, RF signals are injected into a cable converter and a VCR in order to detect channels selected by the cable converter and VCR. Installation of probes is not required for channel detection. Channel identification signals are also injected into the VCR and cable converter for recording by the VCR on videotape. Respective channel identification signals are provided to the cable converter and VCR with time multiplexing. The state of the "TV/VCR" switch of the VCR is determined by injecting a code signal into the VCR and determining whether that signal is present in an RF video signal output by the VCR. The system includes a switch for interconnecting the cable converter, VCR and TV and also for coupling injection signals to respective inputs of the cable converter and VCR. The system also includes an injection signal receiver that detects signals injected into and passed through the VCR and cable converter for the purpose of channel detection.

Abstract: Apparatus and methods for including a code having at least one code frequency component in an audio signal are provided. The abilities of various frequency components in the audio signal to mask the code frequency component to human hearing are evaluated and based on these evaluations an amplitude is assigned to the code frequency component. Methods and apparatus for detecting a code in an encoded audio signal are also provided. A code frequency component in the encoded audio signal is detected based on an expected code amplitude or on a noise amplitude within a range of audio frequencies including the frequency of the code component.