Interactive video distribution systems – Use surveying or monitoring – By passively monitoring receiver operation
Reexamination Certificate
1999-08-02
2003-02-18
Mehta, Bhavesh (Department: 2611)
Interactive video distribution systems
Use surveying or monitoring
By passively monitoring receiver operation
C725S009000, C725S010000, C725S014000, C725S019000, C455S002010
Reexamination Certificate
active
06523175
ABSTRACT:
FIELD OF THE INVENTION
The invention relates generally to broadcast audience measurement, and, more particularly, to methods and apparatus for identifying the source of a signal selected by an audience member in a statistically selected dwelling unit via an intermediate frequency probe.
BACKGROUND OF THE INVENTION
It is well known that broadcast ratings (e.g., television and radio program ratings) are developed by companies such as Nielsen Media Research by monitoring the usage patterns of audience members in statistically selected homes. By developing accurate readings of the programs received by the members of theses homes, it is possible to develop similarly accurate indications of the size and demographic composition of the audience in general. To ensure the ratings developed are as accurate as possible, it is important to ensure accuracy in identifying the programs received by the monitored audience members. To ensure that the monitoring process does not inconvenience the monitored audience by requiring members to monitor their own usage, electronic monitoring of the signals received by the receivers of the audience members has long been preferred.
The use of a super-heterodyne tuner in which a user-selected local oscillator frequency is heterodyned with a received RF signal to generate a fixed-frequency band of tuned signals that is input to an intermediate frequency (hereinafter I.F.) amplifier has long been known in the radio signaling arts.
Watanabe, U.S. Pat. No. 3,803,349, discloses a television audience measurement system wherein successive sound I.F. signals taken from a monitored television receiver are compared with respective sound I.F. signals taken from a slaved television tuner of the measurement apparatus. Watanabe does not teach the use of video I.F. signals for making this comparison, nor does it disclose the use of a non-invasive probe or pick-up for acquiring an I.F. signal from the monitored receiver. Watanabe also fails to disclose a method or apparatus for injecting an I.F. recognition signal into the monitored receiver.
Azuma, U.S. Pat. No. 5,678,214, and Eum, U.S. Pat. No. 5,633,690, disclose arrangements for adjusting the levels of I.F. signals in a receiver.
Those in the field of broadcast audience measurement have long realized the advantages of making tuning measurements on a sampled receiver in a minimally invasive manner (i.e., in a manner that seeks to avoid opening the enclosure of a monitored receiver and that seeks to avoid making a direct metallic connection to the circuitry of the receiver). Such minimally invasive approaches are advantageous because they minimize the chance of damaging a panelist's receiver, and they decrease the time required for installation of equipment within a statistically selected dwelling. A well-known approach to achieving this goal has been the use of local oscillator measurements. For example, Freeman, U.S. Pat. No. 2,892,885, discloses a local oscillator measurement approach in which a signal which is representative of the local oscillator frequency generated by a measured receiver is acquired by a probe or antenna that does not make direct electrical contact with the receiver. Another known non-invasive approach is that of acquiring a video signal by placing an appropriate antenna or pick-up adjacent a cathode ray tube (CRT) associated with the monitored television receiver. This latter approach is taught by Chan et al., U.S. Pat. No. 5,889,548, which is assigned to the same assignee as is the present invention, and which is incorporated herein in its entirety by reference.
A tuner measurement approach that is also relevant to the present invention, but that heretofore has not been available as a non-invasive measurement of a sampled television, is that of signal injection. Porter, U.S. Pat. No. 4,044,376, discloses a tuning measurement approach in which a characteristic RF signal is injected at the antenna terminals of a measured receiver during the vertical blanking period of the television signal that is being displayed. After sequentially injecting the RF signal at each of the channels to which the receiver could be tuned, the channel that is actually tuned on the television set is identified by making an electrical connection to a video test point and observing when the injected signal appears at the output of the tuner. To avoid interference with the television signal being viewed, Porter injects the signal during the vertical blanking interval. A shortcoming of the Porter approach is that, in a common measurement situation in which two receivers in a sampled dwelling are served by the same cable, a recognition signal injected at the antenna terminals of one of the receivers could also be received at the other receiver where it would generate visible interference if that other receiver was tuned to a different signal source. This problem has been solved by using a directional coupler to isolate the monitored receiver from any other receiver serviced by the same antenna cable.
Another signal injection arrangement, which involves replacing a sampled tuner with one modified by the addition of measurement apparatus, is taught by Mostafa et al., U.S. Pat. No. 5,495,282. In the Mostafa et al. arrangement the characteristic signal is injected, detected, and stripped in a separate apparatus interposed between the external tuner and a television set.
SUMMARY OF THE INVENTION
In accordance with an aspect of the invention, a method is provided for determining whether a signal of a program tuned by a tuner of a receiver is being output by an output device of the receiver. The method comprises the steps of: radiating an intermediate frequency recognition signal from an intermediate frequency probe disposed adjacent the tuner of the receiver; developing a representation of a signal output by the output device of the receiver with an output probe and examining a representation of a signal output by the output device of the receiver to determine if the recognition signal is present in the signal.
In some embodiments, the method also includes the steps of: detecting a second signal output by the output device of the receiver; and determining a time interval corresponding to a non-viewable portion of the second signal by examining a representation of the second signal. In such embodiments, the step of radiating an intermediate frequency recognition signal is performed during the time interval determined from the second signal. In some such embodiments, the time interval corresponds to an overscan region of a viewable picture on the output device, and/or the representation of the second signal comprises the second signal.
In some embodiments, the representation of the signal comprises the signal.
In some embodiments, the intermediate frequency recognition signal is radiated at a predetermined frequency offset from a tuned frequency by less than a width of a broadcast television channel.
Optionally, the output device is a display device and the representation of the signal is acquired from a video probe disposed adjacent the display device.
In some embodiments, the method also includes the steps of: developing a representation of a tuned intermediate frequency signal radiated by the tuner by parasitically detecting the tuned intermediate frequency signal with the intermediate frequency probe; obtaining a representation of a direct input signal; and comparing the direct input signal representation with the signal representation developed by the output probe, and comparing the tuned intermediate frequency signal representation with the signal representation developed by the output probe to determine whether the signal displayed on the output device is the tuned intermediate frequency signal or the direct input signal.
In accordance with another aspect of the invention, an apparatus is provided for determining if a signal output by a receiver having a plurality of local inputs was tuned by a tuner of the receiver. The apparatus includes an intermediate frequency probe disposed in proximity to the tuner of the receive
Huynh Son P.
Katten Muchin Zavis & Rosenman
Mehta Bhavesh
Nielsen Media Research, Inc.
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