Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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AUDIENCE MEASUREMENT SYSTEM AND METHOD FOR
DIGITAL BROADCASTS
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to program identification and audience
measurement,
and more specifically, to identification of digital broadcasts of television
and radio programs.
2. Description of the Prior Art
Systems for the quantification of audiences of analog television and radio
broadcasts,
including the identification of channels and programs being received, are well
known.
However, with the increase in digital broadcasts in addition to or replacement
of analog
broadcasts, the known systems either fail to function or function
inefficiently.
A typical audience measurement system determines both the channels to which
the
receivers in the statistically selected households are tuned and the times
that the receivers are
tuned to those channels. The tuned channels, and the times during which those
channels are
tuned, are periodically transmitted to a central facility where the tuned
channels, and the
times during which those channels are tuned, are compared to a program record
which is
compiled from information supplied by the sources of programs, and is intended
to reflect the
identity of the programs which are supposed to be aired at the times indicated
in the program
record. Systems which read codes imbedded in the program material by
broadcasters or
syndicators are used to verify the accuracy of the program records, i.e. that
the programs
were actually aired at the intended times as indicated in the program records.
An example of such a system is disclosed in U.S. Pat. No. 4,025,851. The
system
disclosed therein monitors those programs which have codes written on video
lines of one or
more of the video programs' vertical blanking intervals. The system described
in this patent,
referred to therein as the Automated Monitoring of Line-up (AMOL) system, has
been in
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general use in the United States for over a decade, and is used to determine
(i) the identities
of aired programs, (ii) the local stations which air these programs, and (iii)
the times during
which these programs are aired. A system of this type significantly reduces
the complexity,
and improves the accuracy, of the resulting program records that are an
essential element of
current television audience measurements. The AMOL system is not used within a
sample
household due to code loss problems that can be more successfully remedied at
a broadcast
monitoring site, but that may be intractable in the sample household.
A system for radio audience monitoring is disclosed by Weinblatt in U.S. Pat.
No. 4,718,106. Weinblatt teaches an audience measurement system in which each
participant
l0 wears a metering device that includes a microphone and a detection circuit
which responds to
in-band codes in the programming. Weinblatt discusses background noise as a
problem in
this method, and teaches that such noise is avoidable by using a microphone
having a low
sensitivity. The system disclosed in U.S. Pat. No. 4,807,031 utilizes a robust
video
luminance coding method with a low data rate. The system disclosed in U.S.
Pat. No.
~ 5 4,945,412 utilizes a subaudible 40 Hz tone to encode the audio portion of
a broadcast.
The foregoing systems, which rely upon encoded broadcasts, require that all
programs
be encoded by at least one of the sources (e.g., broadcasters) in the
distribution system. Even
in the unlikely event that all broadcasters were to agree to cooperate,
occasional encoding
equipment failures would likely cause gaps in the data provided by systems
that rely solely
'.0 on codes. These gaps would cause losses of rating data and would render
all of the audience
share measurements meaningless whenever any significant number of programs
were not
encoded. Thus, there is a need to collect program identifying data even when
there is no
code present in the programs to be identified.
Several broadcast measurement systems have been suggested which do not detect
.5 embedded codes in order to identify programs, but which instead monitor
program content.
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These systems generally receive programs to be monitored at a measurement site
(e.g. sample
household), extract broadcast signatures from the programs, and compare these
broadcast
signatures with corresponding reference signatures extracted from reference
copies of these
programs (e.g., distribution tapes) or from previous broadcasts of the
programs being
monitored. For example, in U.S. Pat. No. 4,697,209, a program monitoring
system is
disclosed in which broadcast signatures are collected in sampled households
relative to
certain program content (e.g., a scene change in the video portion of a
monitored program).
These broadcast signatures are subsequently compared to reference signatures
collected by
reference equipment tuned to broadcast sources available in the selected
market. A
l0 coincidence between the broadcast signature and the corresponding reference
signature
identifies the programs, not just the channel, being viewed.
A program monitoring system disclosed in U.S. Pat. No. 4,677,466, logs the
broadcasts of selected programs (e.g., commercial advertisements). This
monitoring system
makes video tape recordings of unrecognized, suspected commercials (e.g.,
programs
l5 existing for short intervals which typically begin and end with a blank
frame interval and
which have lengths generally commensurate with the typical lengths of
commercials) for
subsequent viewing so that manual identification of the unrecognized,
suspected commercials
may be made by a human operator. In order to manually identify those
unrecognized,
suspected commercials on the video tape recordings, such recordings must be
transmitted to
;0 the human operator. As the unrecognized, suspected commercials are manually
identified,
they are given program ID's as appropriate.
Systems which rely upon the extraction of signatures in order to identify
programs,
however, also have well-known shortcomings. Such systems are computationally
expensive,
and their use has been restricted by the cost of computer hardware.
Additionally, such
5 systems rely on reference measurement sites that collect reference
signatures from known
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program sources. When one set of reference equipment fails, all reference
signature data for
those program sources may be lost. If the lost data accounts for a significant
fraction of
tuning activity, the widely used statistic normally referred to as "share"
becomes
correspondingly unreliable. It might be noted in the interest of fairness that
a functioning
backup site can prevent the loss of this data.
Another known method is to transmit (e.g., over a telephone connection)
digitally
compressed video and/or audio replicas of programs. For example, in U.S. Pat.
No. 4,888,638, programs are compressed and are sent over telephone lines to
households.
The compressed programs are stored in equipment in the households, and are
subsequently
L O displayed on television receivers as substitutes for regularly scheduled
programs when
certain preselected conditions are met (such as in response to program ID's
contained in the
compressed programs). A more recent teaching relating to the use of compressed
video
and/or audio replicas is disclosed by Strubbe in U.S. Pat. No. 5,223,924.
Strubbe's system
permits a television viewer to select programs for future viewing or recording
based on the
l5 viewer's exposure to facsimiles of the program material generated from the
compressed
replicas stored in a database in the viewer's home.
U.5. Pat. No. 4,547,804 disclosed a method and apparatus for the automatic
identification and verification of commercial broadcast programs. A digital
encoded
identifying number is embedded in the programs, by which they can be
automatically
;0 monitored, to verify that they have been broadcast as and when intended.
However, the
digital number is embedded in what is otherwise an analog program. This method
is usable
only during the transition period from analog to digital broadcasting
technology, when some
digital equipment or connection is in use together with older analog equipment
or
connections. It will not work when the broadcasting stations have fully
digital operations,
5 e.g., recording a program in digital form, storing it digitally on tape or
disk, performing
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nonlinear digital edits and digital commercial insertions, and transmitting
digitally over the
air, or delivering a digital stream to a cable or satellite operator to
multiplex with other digital
streams.
In U.S. Patent No. 3,919,479 a process is disclosed for automatic electronic
, recognition and identification of programs and commercial advertisements
broadcast on
television and radio wherein a digitally sampled reference signal segment
derived from either
the audio or the video portion of the original program content to be
identified is compared
with successive digitally sampled segments of the corresponding audio or video
portion of a
broadcast signal in a correlation process to produce a correlation function
signal. The
sampling rates and the time duration of the reference signal segment and the
broadcast signal
segments are the same. When the signal segments that are compared are the
same, the
correlation function signal is relatively large and a recognition of the
broadcast signal is
achieved when such correlation function signal exceeds a selected threshold
level. The
compared signal segments may also be obtained as low frequency signals derived
from the
l S original reference and broadcast signals by non-linear and envelope
formation processing
techniques.
U.S. Pat. No. 4,647,974 discloses a system for the automatic insertion of
auxiliary
video information into an analog television signal. The system may be used by
a local station
to insert its call letters or logo into network programming.
'0 U.S. Pat. No. 4,697,209 discloses a method and apparatus for identifying
television
programs, by detecting the occurrence of events such as scene changes in a
video signal, and
extracting a signature from the signal. Signatures and their times of
occurrence are stored
and compared with reference signatures to identify the program. As the system
is
independent of the format used to transmit the signal, it will work with both
analog and
!5 digital television. It has the disadvantage of requiring that a large
volume of reference data
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be collected for every possible station transmitting and program being
transmitted, and for
every site monitored, which will require a large computing capacity and a long
computing
time to correlate the two sets of data to determine which station or program
is being received
at each monitored site at each instant that each receiver is turned on.
U.S. Patent No. 4,230,990 teaches an automated method and system for
identifying
broadcast programs wherein a pattern recognition process is combined with a
signaling event
which acts as a trigger signal. At least one such trigger, or "cue" signal,
occurs with each
broadcast of every program which is to be identified; and these signals are
used to activate
the pattern recognition process which results in program identification. These
cue signals
can either be artificially inserted into the program signal or they can be
events that occur
naturally as part of normal broadcast procedures. A segment of each program at
a
predetermined location with respect to one of these cue signals is sampled and
processed
according to a feature extraction algorithm to form the program's reference
signature, which
is stored in computer memory. In the field, the monitoring equipment detects
cue signals
L 5 broadcast by a monitored station and, upon detection, samples the
broadcast program signal
at the same predetermined location with respect to the detected cue and uses
the same feature
extraction process to create a broadcast signature of unknown program
identity. By
comparing broadcast signatures to reference signatures, a computer identifies
the broadcasts
of programs whose reference signatures have been stored in memory.
!0 U.S. Pat. No. 4,972,503 discloses a method and apparatus for determining
the channel
to which a remotely controlled television receiver is tuned. While it is
independent of the
format (analog or digital) used to transmit the signal, its implementation on
a mass scale for
audience ratings will not be practical, as it requires an individual hardware
or software
adaptation to each remote control used in the monitored sites to determine
what function is
:5 activated when a key pressing is detected.
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U.S. Patent No. 4,425,578 teaches a system and method for determining the
channel
to which a video wave receiver is tuned. The system includes an RF signal
source connected
to the antenna input of the video wave receiver, a frequency control stage
that determines the
signal frequencies generated by the RF signal source and a system and advance
control stage
S to appropriately program operation of the frequency control stage. The RF
signal source is
conditioned by the system and advance control stage and the frequency control
stage to
output signals such that the fundamental or one of the harmonics when combined
with the
video carrier of a corresponding channel results in a signal having a
predetermined
frequency. The RF signal source is successively advanced to output a set of
predetermined
frequencies, corresponding to each of the receivable channels to which the
video receiver is
tunable. The system includes a detector/receiver arranged to monitor the video
signal of the
video receiver to detect the predetermined frequency resulting from the
combined signal from
the RF signal source and a video carrier to which the video receiver is tuned.
The RF signal
source is stepped through a predetermined set of frequencies corresponding to
each
l5 receivable channel and the system outputs a signal denoting the received
channel to which
the video receiver is tuned when the predetermined frequency is detected by
the
detector/receiver.
U.S. Pat. No. 5,019,899 discloses an electronic data encoding and recognition
system
for creating digital signatures from frames of selected video segments such as
television
>.0 commercials by a digitalizing, compression and selection process which
produces a multi-
digit signature from each frame.
U.S. Pat. No. 5,278,988 discloses a method and apparatus for determining the
transmitting station from which analog program signals are received and
translated by a
monitored receiver within a test area.
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U.S. Pat. No. 5,425,100 discloses a multilevel encoded signal monitoring
system and
a universal broadcast code for identifying programs, commercial, networks,
stations, etc.
U.5. Patent No. 4,723,302 teaches a method and apparatus for identifying a
channel to
which a receiver is tuned by sequentially detecting a signal of the receiver
and storing a
characteristic value of the detected signal for a predefined sequence of
frequencies. The
stored values corresponding to the predetermined channels of the receiver are
identified and
assigned predetermined values. The stored values corresponding to each of a
plurality of
harmonic frequencies of the predetermined channels are identified and assigned
one of a
plurality of different predetermined values. A total assigned value is then
calculated for each
of the predetermined channels with the corresponding values for the identified
harmonic
frequencies thereof. The calculated total values are then compared to identify
a maximum
value corresponding to the channel to which the receiver is tuned.
U.5. Pat. No. 5,450,122 discloses an in-station method and apparatus for
encoding
analog television programs, including commercials, with a digital
identification code
recorded on a selected video scan line which is not normally visible to the
television viewer,
and for verifying the proper airing of such programs by television broadcast
stations.
U.5. Pat. No. 5,450,490 discloses apparatus and methods for including an
inaudible
code in an analog audio signal, and for decoding it.
In U.S. Patent No. 4,739,398 a method, apparatus and system are provided for
?0 recognizing broadcast segments, such as commercials, in real time by
continuous pattern
recognition without resorting to cues or codes in the broadcast signal. Each
broadcast frame
is parametized to yield a digital word and a signature is constructed for
segments to be
recognized by selecting, in accordance with a set of predetermined rules, a
number of words
from among random locations throughout the segment and storing them along with
offset
?S information indicating their relative locations. As a broadcast signal is
monitored, it is
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parametized in the same way and the library of signatures is compared against
each digital
word and words offset therefrom by the stored offset amounts. A data reduction
technique
minimizes the number of comparisons required which still require maintaining a
large
database.
U.S. Pat. No. 5,512,933 discloses a system for identifying a program stream
being
displayed at a receiver location, by measuring the relative luminance of a
plurality of
predetermined areas in each frame of a television transmission, at both the
transmitting
station and the receiver. As the system is independent of the format used to
transmit the
signal, it will work for both analog and digital television. But it has the
disadvantage of
requiring that a large volume of reference data be collected for every
possible station
transmitting and program being transmitted, and for every site monitored, as
well as requiring
a large computing capacity and a long computing time to correlate the two sets
of data to
determine which station or program has been received at each monitored site at
each instant
that the receiver was turned on.
U.S. Pat. No. 5,574,962 discloses a method and apparatus for automatically
identifying a program, by adding an inaudible encoded message to the audio
signal.
U.5. Patent No. 5,243,423 discloses a co-channel communication system that
allows
transmission of one or more data signals in an active or visible portion of
video raster in a
manner that is imperceptible to a viewer. More particularly, the data signal
is transmitted
ZO over preselected active video lines of a video raster. In order to reduce
the perceptibility of
the data signal, the video lines over which the data signal is transmitted are
varied according
to a random sequence. In an alternate embodiment, the data is also modulated
at relatively
low modulation levels, for example, by converting the data signal to a spread
spectrum
signal.
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U.S. Pat. No. 5,646,675 discloses a system and method for monitoring the
reception
of video program material, using codes inserted on scan lines.
U.S. Patent No. 5,594,934 discloses a correlation meter for determining tuning
status
of a tunable receiver. The correlation meter receives an output of the tunable
receiver, such
as an acoustic audio output of the tunable receiver. An analog to digital
converter converts
the output of the tunable receiver to a digital sample side representation. An
antenna or other
signal collector receives reference side representations corresponding to
channels to which
the tunable receiver may be tuned. The correlation meter correlates the
digital sample side
representation and the reference side representations as the reference side
representations are
received by the correlation meter in order to determine the tuning status of
the tunable
receiver.
U.S. Patent No. 4,885,632 discloses a system and methods for monitoring a home
TV
viewing system which may include a TV, a VCR and one or more cable converters.
The
system obtains information for identifying the source of video displayed or
being recorded,
i.e., off air antenna, satellite antenna, cable converter tuner, VCR, personal
computer, video
game, etc. The system also obtains information identifying the video path of
the video being
displayed and/or recorded. The system "fingerprints" video recorded by the VCR
so that the
played back video may be identified as having been previously recorded. The
system may
record the date and time of recording and the video source of the video being
recorded. The
system includes probe/detector devices which obtain signals related to the
frequency to which
the TV, VCR, and cable converter are tuned, and a higher level processor which
receives and
processes those signals to identify channel tuning of the TV, VCR, and cable
converter. The
probe/detector monitoring the VCR includes a lower level processor and
circuitry that
fingerprint a video signal being recorded by the VCR. The system generates
timing signals
ZS to record and detect fingerprints in the vertical blanking interval of the
TV signal. The
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system has multilevel processing, and may be programmed to include a number of
downloadable and uploading parameters. The system also includes an
alphanumeric display
and data entry unit for each TV being monitored, and provides for interactive
information
entry by TV viewers including guests and by an installer.
U.S. Patent No. 5,481,294 teaches an audience measurement system that collects
data
representative of tuned programs rather than of tuned channels, and includes
(i) a household
metering apparatus which records ancillary codes or extracts program
signatures from the
programs if no ancillary codes are found therein, (ii) a reference apparatus
which monitors
broadcast programs to be monitored, which extracts reference signatures
therefrom, which
records whatever ancillary codes may be associated with these broadcast
programs and, if no
ancillary codes are present, which compresses and stores digital replicas
representative of the
broadcast programs to be monitored, (iii) a data collection apparatus which
compares the
household and reference data to determine (a) which of the broadcast programs
to be
monitored were selected for viewing and/or listening, (b) which of the metered
households
selected the broadcast programs to be monitored for viewing and/or listening,
and (c) at
which times the broadcast programs to be monitored were selected for viewing
and/or
listening.
U.S. Patent No. 5,974,299 describes an audience rating system for digital
television
and radio, using identification codes in control streams of time-multiplexed
digital
?0 transmissions. When a television set or radio, that is being monitored
pursuant to the system,
is turned on and tuned into a channel, and each time that the channel is
changed, an
identification code for each audio, video or auxiliary digital stream of the
channel tuned to is
extracted from the control stream, and recorded along with the time. The time
is also
recorded when the television set or radio is turned off. This data makes it
possible to
?5 determine what stations, channels, and programs members of the audience
being monitored
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are watching or listening to at any particular time. In the first preferred
embodiment, the
multiplexed digital transmission is received separately by the television set
or radio (or an
attached IRD) and a meter connected to it. The meter compares digital streams
of the
channel being received by the television set or radio with digital streams of
each of the
channels in the multiplexed digital transmission, until it finds a match. In
the second
preferred embodiment, the meter does not receive the multiplexed digital
transmission
separately, but has access to elementary streams extracted from the
transmission by an IRD,
and extracts identification codes for the channels being received from their
elementary
streams. The elementary stream may be accessed through an auxiliary connector
in a digital
decoder, through an access control card connector, or through soldering
electrical
connections to internal points in the IRD.
SUMMARY OF THE INVENTION
A method and system for identification of channels for purposes of measurement
of
audiences for digital broadcasts is provided. In digitally transmitted
television, a digital
stream of data is time multiplexed so that video, audio and data (including
without limitation
program identification data) for several channels can be sent on a single
frequency to a
decoder or other reception device. When the user in the home selects a channel
to view, the
decoder begins taking video, audio and data that are assigned to that channel
in the
multiplexing scheme employed by the system. There may also be general data
such as an
electronic program guide that is captured irrespective of the channel that is
selected. The
video and audio are processed for either analog or digital output as
appropriate once the
decoder validates that the home meets all the requirements set for viewing the
channel or
program.
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In the present invention, the data structure is configured so that not only
can the
program identification data (also known as "banner" information) for each
program be
accessed for viewer use, but also the program identification data or a subset
of it such as the
channel identification data is output to a data communication port (i.e.
serial or parallel port)
on the decoder or other reception device, through which port this data is then
sent to an
audience data gathering and measurement device (meter). This structure also
allows the
broadcaster to define the data rate (the speed of the digital bits being sent
in an asynchronous
standard data format) to the data communication port.
A transfer of significant program or channel identification data thus takes
place with
the present invention. The broadcaster transmits to the decoder a unique start
byte, an
encoded data byte and a unique stop byte. This defines, for example, the
channel selected at
the home decoder. The broadcaster sends the coded channel ID information
periodically in
the service instruction stream.
A probe collects the coded channel ID or other data from the data
communication port
of the decoder, converts the data into a format readable and recordable by a
meter, and
transmits the data to the meter in each household that is part of the audience
measurement
sample. The probe sends channel ID information by a system of low frequencies
that are
measured in the meter and correlated to a channel map in the unit. Future
embodiments are
anticipated to transmit the data from the probe to the meter digitally so that
interpolation is
not necessary and so other types of data can be transferred.
In order to determine what programs are broadcast on identified channels at
particular
times, program identification data is sent to the data communication port of a
decoder or
other reception device, and from there to a computer which tracks both program
lineup and
the airing of advertisements, electronically and automatically by channel. The
program
identification data may include but is not limited to program start and end
time, program
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name, censor's classification, program genre, and a brief description of the
program. This
information only needs to be collected at significant locations for
determining or validating
program lineups and advertisement data.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the invention will become more fully apparent when
the
following detailed description is read in conjunction with the accompanying
drawings in
which:
FIG. 1 is a block diagram of the broadcaster, decoder, probe
and meter of the present invention;
FIG. 2 is a detailed block diagram of the decoder and probe of
the present invention;
FIG. 3 is a flow chart of the functioning of the decoder of the
present invention;
FIG. 4 is an electrical schematic of the probe of the present
invention;
FIG. 5 is another electrical schematic of the probe of the
present invention;
FIG. 6 is a flowchart of the functioning of the probe of the
present invention; and
FIG. 7 is another flowchart of the functioning of the probe of
the present invention.
DETAILED DESCRIPTION OF
THE PREFERRED EMBODIMENTS
Overview
Referring to FIGS. 1 and 2, in digitally transmitted television, a digital
stream of data
is time multiplexed so that video, audio and data for several channels can be
sent on a single
frequency from broadcaster 102. When the user in the home selects a channel to
view, the
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decoder 104 begins taking video, audio and data that are assigned to that
channel in the
multiplexing scheme employed by the system. There may also be general delivery
data,
which is captured irrespective of the channel that is selected. The video and
audio are
processed for either analog or digital output depending on the system once the
decoder
validates that the home meets all the requirements set for viewing this
program.
The present invention takes advantage of the ability and flexibility of a
satellite
delivery system where each of the decoders 104 is fitted with a serial port
connection. The
data structure to the decoder 104 is defined such that some data, such as
program
identification data and electronic program guide (EPG) information can be
sent, and stored
for use by the viewer to enhance his ability to make program viewing
decisions. Other data
may be available for reading of news or other text. The data structure of the
present
invention is such that program identification data and coded channel ID data
is output to the
serial port 202 of decoder 104, through which port this data is accessed by
the probe 106.
The signal is then converted by probe 106 into a meter readable format. The
signal is then
sent to an audience data gathering and measurement device (meter) 108. This
structure also
allows for the broadcaster 102 to define the data rate (the speed of the
digital bits being sent
in an asynchronous standard data format) to the serial port 202. More
specifically, the
decoder 104 is equipped with operational software in flash memory or other re-
writeable but
non-volatile memory able to be controlled by the service instruction data
packets sent by the
broadcaster 102 as digital data to permit portions of the broadcast signal to
be directed to
various ports of the decoder 104. These service instruction data packets from
the broadcaster
are used generally to control the functionality of the decoder. One of these
service
instruction data packets can instruct the decoder to output a data packet,
containing the coded
channel ID data, to the RS232 port 202 thus enabling the audience data
gathering and
measurement device (meter) 108 to access the data. To achieve the above
function, the
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broadcaster 102 adds to the broadcast signal the above service instruction
data packets
required to direct the coded channel ID data information to the RS232 port
202, from which a
probe 106 passes this coded current channel ID data to the meter 108.
Because of the flexibility that exists in the system of the present invention,
there is a
pathway open whereby a transfer of significant TV audience data can take place
as coded
channel ID data. The broadcaster 102 transmits to the decoder 104 a unique
start byte, an
encoded data byte and a unique stop byte. This defines the channel selected at
the home
decoder. Program identification data, which is similar to the banner and
information
available to the viewer, may also be sent to the serial RS232 port 202 to
enable a computer
attached to a decoder 104 to track program lineup and advertisement airing,
electronically
and automatically per channel. The program banner includes but is not limited
to:
Program start and end time
Program name
Censor's classification
Program genre and a brief description of the program
This banner information only needs to be collected at significant locations
for
validation of program lineups and advertiser data. The broadcaster 102 sends
the coded
channel ID information periodically (currently every 1-10 seconds) in the
service instruction
stream.
The probe 106 collects the data from the RS232 serial port 202 of the decoder
104,
converts the data into a format readable and recordable by an audience data
gathering and
measurement device (meter) 108, and transmits to the meter 108 in households
that are part
of the measurement sample. The probe 106 sends channel information by a system
of low
frequencies that are measured in the meter 108 and correlated to a channel map
in the unit.
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Because the decoder 104 has its own programming to which it must respond,
filtering
of the coded channel ID data takes place at the decoder level. The coded
channel ID data is
not passed on to the serial RS232 port 202 if any of these conditions exist:
1. The channel selected is not part of the service to which the home has
subscribed;
2. Service to the home has been discontinued because of non-payment, or
service has never been set up;
3. A parental personal identification number (PIN) has been entered and
the program or channel is presently locked out to home viewing;
4. The decoder 104 is in an "off' or standby condition;
5. The channel is pay-per-view, and those pay-per-view conditions have
not been met.
If any of the above conditions exist, there would normally be a "blue screen"
shown
to the viewer and a box describing the reason why the program cannot be viewed
in the
ZO home. When this condition exists, no coded channel ID data is sent to the
RS232 serial port
202. The probe 106 times into a "lock" condition after 20 seconds of not
receiving coded
',
channel ID data from the decoder 104.
There are also program selection modes, which the viewer may use on the
decoder
104. One is the Mosaic mode, where many small video screens are viewed at once
and the
ZS user can select by navigation which program he wishes to view. Another is
the electronic
program guide (EPG) where information on programs for all channels for many
days can be
looked at in a daytime - channel, chart format. The method of program
selection (Mosaic or
EPG) is significant to the broadcaster and so these modes are also reportable
by the decoder
104 to the RS232 serial port 202.
30 System Components
The system of the present invention includes the following components.
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The Broadcaster: The broadcaster 102 uses its standard digital broadcast
equipment
known in the art. The broadcaster 102 sets up each channel to be monitored
with a data
stream which, when periodically sent to the decoder 104 in the home, directs
the decoder 104
to send coded channel ID information to the RS232 port 202 at a specified data
rate as
S discussed in further detail below. The digital broadcast can be, for
example, satellite, cable
or fiber optic.
The Decoder: Presently there are multiple manufacturers of decoder 104 useable
in
the present invention; each such decoder 104 is able to carry out the commands
from the
broadcaster's service instruction stream. All exemplary decoders 104 have
RS232 ports and
SCART connector 204 for detecting an "on" condition. The decoder 104 also
carries out
overrides in the home. For the decoder 104 to function in the present
invention, the home
must be subscribed to the service, a parental lock must not be in place for
that channel, and
the decoder 104 must be in the powered "on" state, or the coded channel ID is
not transferred
to the RS232 serial port 202. Manufacturers of decoder 104 known in the art
include but are
not limited to Pace (Model No. DSR620-GM) and Zenith (Model No. DTH310-4).
The Digital Satellite Probe: The probe 106 uses two micro controllers and is
connected to the RS232 port 202 of the decoder 104. One microcontroller is
used to monitor
the RS232 port 202 of the decoder 104. It is able to automatically adjust to
changes in the
standard baud rates from 1200 to 19,200 baud. The probe 106 includes software
that tests the
ZO coded channel ID information data stream for a valid signal in the format
[STX] [ID Byte]
[ETX]. Once a valid ID Byte is isolated from the data stream, the coded
channel ID is passed
on to the second processor. If a period of 20 seconds passes during which no
valid code is
received, the probe 106 generates a "lock" code to indicate that the channel
is not subscribed
to, that it is blocked by parental pin code, or that the signal is missing,
indicating that the
?5 decoder 104 is in a standby mode. The second micro controller takes the
channel data passed
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to it and uses a look-up table to determine a matching frequency defined for
that channel to
be sent to the audience data gathering and measurement device (meter) 108.
This frequency
is similar to the prescaled UHF local oscillators normally monitored by the
meter 108. The
channel range from 21-59 is presently used with channels 60-71 being reserved
for future
expansion and special functions. Channel 70 presently designates the "lock"
condition.
Channel 60 designates that the mosaic mode is selected where multiple channels
are being
viewed at once.
THE AUDIENCE DATA GATHERING AND MEASUREMENT DEVICE
(METER): The meter 108 is connected to the probe 106 and ascertains the type
of probe
106 by the voltage level presented by the divider voltage at pin 3. It detects
that the decoder
104 is "on" by the on/off detector signal, takes the frequency inputs and
computes an
effective channel.
The meter 108 also has many parameters for audience measurement monitoring
that
have been entered or downloaded for taking samples and reporting information.
The meter
108 determines the actual channel being viewed on the television, or being
recorded onto a
VCR, and adds the viewers in the home who have logged in as watching the
program. An
exemplary meter 108 is the ACN 6000 unit used by subsidiaries of ACNielsen
Corporation.
Decoder Function
Referring to FIGS. 1 and 3, the decoder 104 is equipped with operation
software in
re-writeable, non-volatile memory able to be controlled by service instruction
data packets
sent by the broadcaster 102 as digital data such that portions of the
broadcast signal is
directed to specific ports of decoder 104, best shown in FIG. 3. At block 302
decoder 104
receives the digital transmission, including digital video, audio, electronic
program guide and
service instruction data packets from broadcaster 102. At block 304, the
decoder 104
separates the data received from broadcaster 102 into their video, audio,
electronic program
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guide and service instruction components. At block 306, the decoder 104 checks
the
electronic program guide data for booked (pre-selected) channel and service
instruction
commands. The front panel control can be employed to issue commands at block
308. Any
service instruction data from the broadcaster 102, the electronic program
guide, or the front
panel is processed by decoder 104 at block 310. From block 310, the correct
audio and video
data for the selected channel is directed by decoder 104 to the audio and
video outputs of
decoder 104 at block 314. Also from block 310, if the decoder 104 has received
from
broadcaster 102 service instruction data packets instructing decoder 104 to
output a data
packet containing the coded channel ID data and/or the program identification
data to the
RS232 port of decoder 104, the decoder 104 does so. The data from the decoder
104 is
received by probe 106 and is converted to an output emulating the appropriate
frequency
detection system at block 316: At block 318 the converted data from probe 106
is processed
by the meter 108.
Probe Com onents
The probe 106 includes the following hardware components, grouped by
functionality.
ID Extraction: Referring to FIGS. 2 and 4, the probe 106 is connected to the
decoder
104 by a standard extension 9 pin Dsub connector cable 402. The RS232C port
signal from
decoder 104 is inputted to Q1 (element 404) which translates the signal to TTL
levels for the
processor 406 at P3Ø R1 (element 408) limits the current into the base and
into the reverse
voltage limiting diode DO1 (element 410). R02 (element 411) is the pull-up
resistor to Vcc.
The processors 406 and 412 are given a proper power on reset time by the
combination C07
(element 414) and R09 (element 416). The crystal frequency of 11.0592MHz for
the
processors was chosen to allow the greatest number of baud rate options. The
micro
?5 controller processors 406 and 412 are both Amtel 89C2051, which are flash
based allowing
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reuse of the IC if a software upgrade is required. The software automatically
adjusts to
changes in the Baud Rate of the coded channel ID information data stream and
can operate
on data rates of 1200, 2400, 4800, 9600, and 19200 baud.
The coded channel ID information data stream from the decoder 104 consists of
a
start transmit byte [STX], the coded channel ID byte [IDByte] and an end
transmit byte
[ETX]. The data byte has been structured to make the start and end transmit
bytes unique,
that is never found in the ID byte, to eliminate false queuing.
Channel Generator: Referring to FIGS. 2 and 4, channel generator 208 operates
as
follows: Once a coded channel ID has been accepted by processor ICO1 (element
406), it is
decoded and passed onto second processor IC02 (element 412), through port 1 of
both
processors. Pull-up resistors RPO1 (element 418) are added at this port for
noise immunity.
Processor IC02 (element 412) takes the coded channel ID, strips out the
coding, and does a
table look up for the frequency to be sent to the meter 108. The processor 412
outputs this
frequency and continues to monitor the input port.
Detector ID: Referring to FIGS. 2 and 4, detector ID 210 functions as follows.
The
resistor divider R03 (element 420) and R04 (element 422) create a voltage for
the meter 108
called the recognition voltage for deciding which probe 106 is plugged into
the port to
control which software routines to execute for setup and run. The probe 106 is
set to
duplicate the values of the UNI-Detector 495A and is seen by the meter 108 as
a UNI-Det3/4.
The power supplx: Referring to FIGS. 2 and 5, power supply 212 includes an
external wall transformer with a primary voltage to suit the country of
implementation, a
secondary voltage of 9 to 15 VDC, and a current capacity greater than SOma.
The connector
is a standard DC power jack. The input to the probe 106 is polarity protected
by D02
(element 502) and filtered by C02 (element 504) and C03 (element 506). A
standard fixed 5
?5 volt regulator is used REGOl (element 508) with a standard high output
voltage protection
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diode D03 (element S 10) and filtering and stabilizing capacitors C04 (element
512) and CO l
(element 514). The regulator is well oversized as the nominal current draw is
only about
SOma.
The On/Off state detection: Referring to FIGS. 2 and 5, the on/off state
detection
circuit 214 connects to pin 8 of the scarf connector 204 labeled "TV." This
pin has a voltage
present when the unit is powered. The VCR Scarf connector does not have this
signal. This
signal enters the probe 106 through an RCA connector. When the decoder 104 is
on, a
voltage greater than 5 VDC is present, the optocoupler OPTO1 (element 516) is
reverse
biased and does not conduct current. When the decoder is "off ', the output is
either driven
low, or becomes a high impedance. The resistor R06 (element 518) limits the
current through
the isolator, and R07 (element 520) provides a secondary current path for the
"decoder off
state current. The optocoupler 516 is "on" when the decoder 104 is in the "off
' state. The
transistor output pulls down the pull-up resistor R08 (element 522) and
presents a low, "ofd',
signal to the meter 108. When the decoder 104 is "on", the optocoupler 516 is
"ofd' and the
pull-up resistor R08 (element 522) presents a high or "on" signal to the meter
108.
Probe Function
Probe 106 functions as follows, as best shown in FIGS. 6 and 7. As the probe
106
powers up at block 602, the first processor ICO1 (element 406) clears
registers, set up timers,
counters, and default baud rate selections for the serial communication at
block 604. At
power up the selected channel is not known, and a "lock" condition is reported
at block 604.
A "lock" condition is a timed default condition at blocks 604, 606, 608, 610,
and 612, which
show that after 20 seconds of not receiving data, that a "lock" condition is
outputted. This
indicates that the decoder 104 is not tuned to something it is allowed to
decode and output
video, for reasons of either subscription or parental lockout, or that the
decoder is not "on".
ZS (Because of these and other system configurations with other video sources,
the meter 108
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must take the coded channel ID along with the on/off detector state and other
input states into
the meter 108 and ascertain what is being viewed.) After receiving data at
block 614, the
probe 106 program software looks for a start byte (STX) at block 622. If the
byte is a good
start byte, a "start" flag is set at block 624 and the software returns to
look for the next byte
of data. As the next byte of data is received, the software ascertains that
the "started" flag is
set at blocks 614, 616, and 618, and takes that byte of data for the coded
channel ID and
saves it to a register called Tempdata, for use when a valid end of
transmission byte is
received, thus validating the string. When the next byte of data is received,
and it is
ascertained that data has been taken by the "ID taken" flag set at block 618,
then the data is
tested to see if it is an end of transmission byte (ETX) at block 620. If the
received byte is
validated, the coded channel ID stored in Tempdata is outputted to processor
IC02 (element
412) at block 626, and the reception flags are cleared, the "lock" timer is
reset, and the
Bytecount is reset at block 628. If a received byte is not validated in block
620 or block 622,
the Bytecount register is incremented at block 630, and any reception flags
that have been set
1 S are cleared. The Bytecount register is then checked to see if it has
passed a number set to
indicate that a baud rate miss-match must have occurred at block 632. When
this number is
passed, a baud rate adjustment routine is entered where the correct baud rate
is selected on
the next transmission, at block 634.
Referring next to FIG. 7, after the coded channel ID stored in temp data is
outputted
to processor IC02 (element 412) at block 626 of FIG. 6, probe 106 starts, at
block 702, a
meter frequency matching program. From block 702 the variables and frequency
look-up
tables are initialized at block 704. The coded channel ID input is read at
block 706, and the
coded channel ID is sent to the meter 108 at block 708 at the frequency
determined at block
704.
23
