Co-channel transmission of program signals and ancillary signals
First Claim
1. A system for transmitting data in the same communication channel as a composite video signal, wherein the composite video signal is transmitted in a frequency band and the composite video signal has a horizontal sync period, the system comprising:
- selecting means for selecting a carrier having a carrier frequency within the frequency band at the beginning of each of a plurality of frequency stepping periods, each frequency stepping period having a duration equal to, or an integer multiple of, the horizontal sync period;
modulating means for modulating the data onto the selected carrier to produce a modulated data signal; and
,combining means for combining the modulated data signal with the composite video signal.
2 Assignments
0 Petitions
Accused Products
Abstract
In the present invention, an ancillary code is added to a composite video signal in its active video portion. The ancillary code may be spread over several frequencies and summed at the output of a decoder to enhance the legibility of the ancillary code at the output of the decoder. Frequency-stepping may be used to add the ancillary code at ones of a plurality of selected frequencies within the bandwidth of the composite video signal. The ancillary code may be hierarchically apportioned between respective uniquely specified sequential segments corresponding to many distribution points of the composite television signal. This hierarchical ancillary code may be frequency-interleaved between harmonics of the horizontal sync frequency of the composite video signal. The ancillary code may be redundantly added above and below the roll-off frequency of a VCR.
263 Citations
34 Claims
-
1. A system for transmitting data in the same communication channel as a composite video signal, wherein the composite video signal is transmitted in a frequency band and the composite video signal has a horizontal sync period, the system comprising:
-
selecting means for selecting a carrier having a carrier frequency within the frequency band at the beginning of each of a plurality of frequency stepping periods, each frequency stepping period having a duration equal to, or an integer multiple of, the horizontal sync period; modulating means for modulating the data onto the selected carrier to produce a modulated data signal; and
,combining means for combining the modulated data signal with the composite video signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A method of adding ones of a plurality of hierarchical ancillary codes to a television signal having a frequency band associated therewith, wherein each hierarchical ancillary code comprises a time datum and a location datum, wherein each location datum is uniquely associated with one of a plurality of encoders, wherein each encoder has uniquely associated therewith a corresponding one of a plurality of carrier frequencies, wherein each carrier frequency of the plurality of carrier frequencies is in the frequency band, the method comprising the steps of:
-
a) modulating each hierarchical ancillary code onto a carrier having a corresponding one of the plurality of carrier frequencies; and
,b) combining each modulated carrier frequency with the television signal. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
-
-
19. A system for transmitting data and a composite video signal in a common communication channel, wherein the composite video signal is transmitted in a frequency band, the system comprising:
-
selecting means for selecting a plurality of carriers, wherein each carrier has a correspondingly unique carrier frequency within the frequency band; modulating means for redundantly modulating the data onto each of the selected carriers; combining means for combining the redundantly modulated carriers with the composite video signal; and
,demodulating means for demodulating the data from the redundantly modulated carriers. - View Dependent Claims (20, 21, 22)
-
-
23. A system for metering tuning of television programs in a sampled household and for monitoring broadcasts of television programs, wherein the television programs are transmitted by way of a television signal, and wherein the television signal has a bandwidth, the system comprising:
-
adding means for adding first data to the television signal at a first frequency and for adding second data to the television signal at a second frequency, wherein the first and second frequencies are within the bandwidth of the television signal; metering means for metering television tuning by detecting the first data; and
,monitoring means for monitoring broadcasts of television programs by detecting the second data. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30)
-
-
31. An apparatus for non-intrusive measurement of tuning to a broadcast television signal within a sampled household, the apparatus comprising:
-
modulating means within the sampled household for modulating a time-varying ancillary code onto a carrier having a carrier frequency within a video bandwidth of the broadcast television signal; non-intrusive acquiring means adjacent a display of the television signal for non-intrusively acquiring the modulated carrier; and
,demodulating means for demodulating the time-varying ancillary data from the modulated carrier and for storing the time-varying ancillary data for subsequent transmission to a central office. - View Dependent Claims (32)
-
-
33. An apparatus for non-intrusive measurement of tuning to a broadcast television signal within a sampled household, the apparatus comprising:
-
modulating means within the sampled household for modulating a time-varying ancillary code onto a carrier having a carrier frequency within a video bandwidth of the broadcast television signal; non-intrusive acquiring means adjacent a display of the television signal for non-intrusively acquiring the modulated carrier, wherein the non-intrusive acquiring means comprises a video probe; and
,demodulating means for demodulating the time-varying ancillary data from the modulated carrier and for storing the time-varying ancillary data for subsequent transmission to a central office.
-
-
34. An apparatus for non-intrusive measurement of tuning to a broadcast television signal within a sampled household, the apparatus comprising:
-
modulating means within the sampled household for modulating a time-varying ancillary code onto a carrier having a carrier frequency within a video bandwidth of the broadcast television signal; non-intrusive acquiring means adjacent a display of the television signal for non-intrusively acquiring the modulated carrier, wherein the non-intrusive acquiring means comprises an intermediate frequency probe; and
,demodulating means for demodulating the time-varying ancillary data from the modulated carrier and for storing the time-varying ancillary data for subsequent transmission to a central office.
-
Specification