System for conducting a television audience survey

Apparatus for conducting a television audience survey comprising:

• means operatively coupled to the channel selector switch of each television receiver in a sampled household for detecting the position thereof and for generating a pulse code signal including a plurality of data bits indicative of said position;
• means for generating a characteristic train of identification pulses;
• means for adding and transmitting over a transmission means said train of identification pulses followed by said pulse code signal;
• means operatively coupled to the on/off switch of each said television receiver for detecting the operation thereof and for automatically activating said channel selector switch position detecting means, said identification pulses generating means, and said adding and transmitting means when a said television receiver is turned on so as to automatically and continuously transmit over said transmission means said train of identification pulses and said pulse code signal for each television receiver which is on;
• means at a survey center connected to said transmission means for receiving information thereon and responsive to the occurrence of said characteristic train of identification pulses for demodulating received pulse code signals;
• and
• computer means coupled to said receiving and demodulating means for processing said demodulated pulse code signals.