Broadcast audience surveillance using intercepted audio

1. A broadcast-signal source identification method, comprising, in combination,

(a) receiving calls from one or more telephones;

(b) digitizing all or part of the audio-frequency content of said received telephone calls;

(c) receiving broadcast signals from one or more known sources at substantially the same time as the received telephone calls;

(d) digitizing all or part of the audio-frequency content of said received broadcast signals;

(e) comparing the digitized contents of the received telephone calls to the digitized contents of the received broadcast signals to determine the degree of match between the received telephone calls and the received broadcast signals;

(f) sensing the presence of broadcast signals in said received telephone calls based on said degree of match;

(g) recognizing the source of matching broadcast signals based on the identities of the known broadcast sources.

2. The broadcast-signal identification method of claim 1 wherein at least one of the telephones is a mobile telephone.

3. The broadcast-signal identification method of claim 1 wherein a received broadcast signal is a radio broadcast.

4. The broadcast-signal identification method of claim 1 wherein a received broadcast signal is the audio portion of a television broadcast.

5. The broadcast-signal identification method of claim 1 wherein a received broadcast signal is a broadcast from a satellite.

6. The broadcast-signal identification method of claim 1 wherein the method for comparing said content of said received telephone calls to said content of said received broadcast signals is a statistical signal analysis method.

7. The statistical matching means of claim 6 wherein said signal analysis method is cross-correlation analysis.

8. The cross-correlation analysis of claim 7 wherein said cross-correlation analysis is performed at positive and negative relative time lags.

9. The statistical matching method of claim 6 wherein said signal analysis method is co-spectral analysis.

10. The broadcast-signal identification method of claim 1 wherein the content of the received broadcast signal contains an incidental encoded, injected or embedded survey signal.

11. The broadcast-signal identification method of claim 1 further including associating data related to the identity of a calling telephone.

12. An apparatus for identifying the source of a broadcast signal, comprising in combination,

(a) means for receiving one or more incoming telephone calls;

(b) means for digitizing all or part of the audio-frequency contents of said incoming telephone calls;

(c) receivers for one or more broadcast signals;

(d) means for digitizing substantially at the same time as said received telephone calls all or part of the audio-frequency output signals from said broadcast receivers;

(e) processing means for matching said digitized audio contents of one or more said incoming telephone calls with one or more said digitized audio-frequency output signals of said broadcast receivers;

(f) automated decision means for identifying the source of broadcast signal is based on the degree of said matching.

13. The apparatus of claim 12 further including automated means for reporting said identification decisions on the sources of broadcast signals.

14. The apparatus of claim 13 further including automated means for generating a listenership report.

15. The broadcast-signal source identification apparatus of claim 12 wherein the broadcast source selection decisions are associated with demographic information related to the identities of callers making the incoming telephone calls.

16. The broadcast-signal source identification apparatus of claim 15 wherein a demographics database is generated by inducing callers to provide demographic information in return for a service.

17. The broadcast-signal source identification apparatus of claim 16 wherein said service is traffic information.