Patent ID: 7505823

Claim:
A toy system comprising an encoder for encoding a data signal within an audio track to form a modified audio track, an electro-acoustic transducer for converting the modified audio track into a corresponding acoustic signal, and a toy responsive to the acoustic signal, wherein: the encoder comprises: (i) a first receiver operable to receive the data signal, the data signal defining a sequence of data symbols, the data signal having a data signal bandwidth, defined by a symbol duration of the data symbols, that is centered around a first frequency; (ii) a spreader operable to spread the received data signal or a carrier signal modulated with the received data signal to form a spread signal having a signal bandwidth greater than the data signal bandwidth; (iii) a modulator operable either: a) to use the data signal, before being spread by said spreader, to modulate at least one separate periodic carrier signal, whose period is smaller than the symbol duration of the data symbols, to form a modulated carrier signal such that, after spreading by the spreader, a main band of a power spectrum of the spread and modulated signal is centered around a second frequency that is different from the first frequency and that lies within an audible frequency band of 20 Hz and 20 kHz; or b) to use the spread signal to modulate at least one separate periodic carrier signal, whose period is smaller than the symbol duration of the data symbols, such that a main band of a power spectrum of the spread and modulated signal is centered around a second frequency that is different from the first frequency and that lies within an audible frequency band of 20 Hz and 20 kHz; (iv) a second receiver operable to receive an audio track; (v) a combiner operable to combine the spread and modulated signal with the audio track to generate a modified audio track; and (vi) an output operable to output the modified audio track, and wherein the toy comprises: (i) an acousto-electric transducer operable to receive and convert the acoustic signal into a corresponding electrical signal; (ii) a decoder operable to de-spread and demodulate the electrical signal obtained from said acousto-electric transducer, in order to regenerate the data signal; and (iii) a responder responsive to the data signal.