Patent No. 3886314 No hands voice instruction for EEG telemetering system
Patent No. 3886314 No hands voice instruction for EEG telemetering system (Pori, May 27, 1975) Abstract A no hands voice instruction system for specific use in an EEG telemetering system in which the EEG signal is FM modulated on several carrier frequencies and where a voice instruction signal is transmitted from the receiving end to a loudspeaker at the transmitting end of the system. The frequency modulated data information is prevented from being reproduced by the loudspeaker by means of a nulling arrangement in which the FM data channel signal is applied to both inverting and noninverting inputs of an operational amplifier one side of which is coupled to a telephone line pair over which the voice instructions are transmitted from the receiving end of the system. The loudspeaker is connected to the output of the operational amplifier. Notes : No hands voice instruction for EEG telemetering system. Filed September 1973