Apparatus for correlating the operation of sound reproducing and picture projecting devices

Claim 1

A CONTROL UNIT FOR CORRELATING THE OPERATION OF A PICTURE PROJECTOR OF THE TYPE HAVING REMOTELY CONTROLLABLE PICTURE-CHANGING MECHANISM INCLUDING REMOTE CONTROL TERMINALS THEREFOR AND A SEPARATE SOUND-RECORDINGAND-REPRODUCING UNIT OF THE TYPE HAVING AN AUDIO AMPLIFIER AND INCLUDING AUDIO INPUT TERMINALS AND SPEAKER THEREPUT TERMINALS FOR CONNECTING AN EXTERNAL SPEAKER THERETO; SAID CONTROL UNIT COMPRISING: A RELAY HAVING SWITCH CONTACTS, CONNECTION MEANS FOR ELECTRICALLY CONNECTING SAID SWITCH CONTACTS TO THE REMOTE CONTROL TERMINALS OF A PROJECTOR TO BE CONTROLLED THEREBY, A TUNED PARALLEL-RESONANT ELECTRICAL CIRCUIT; MEANS FOR COUPLING ENERGY BETWEEN SAID RESONANT CIRCUIT AND THE AUDIO INPUT AND SPEAKER OUTPUT TERMNALS OF A RECORDING-AND-REPRODUCING UNIT TO BE OPERATED WITH SAID PROJECTOR, SAID RESONANT CIRCUIT BEING RESONANT AT A PREDETERMINED AUTIO FREQUENCY LYING WELL WITHIN THE NORMAL AUDIO PASS BAND OF SAID RECORDINGAND-REPRODUCING UNIT, A TRIODE HAVING A CATHODE, AN ANODE, AND A CONTROL GRID, A SOURCE OF D.C. OPERATING POTENTIALS FOR SAID TRIODE, THE NEGATIVE SIDE OF WHICH CONSTITUTES A COMMON CIRCUIT GROUND, AND MEANS INTERCONNECTING SAID RESONANT CIRCUIT, SAID TRIODE AND SAID POTENTIAL SOURCE AND INCLUDING MEANS CONNECTING SAID RESONANT CIRCUIT BETWEEN SAID GRID AND SAID CIRCUIT GROUND, A CATHODE RESISTOR, FIRST AND SECOND LOAD RESISTORS, A NORMALLY OPEN SWITCH IN SERIES WITH SAID FIRST LOAD RESISTOR, AND A SELECTOR SWITCH OPERATIVE IN A FIRST CONDITION TO CONNECT SAID CATHODE TO AN INTERMEDIATE POINT ON SAID RESONANT CIRCUIT AND TO CONNECT SAID ANODE TO THE POSITIVE SIDE OF SAID POTENTIAL SOURCE THROUGH SAID FIRST LOAD RESISTOR AND SAID NORMALLY OPEN SWITCH WHEREBY, WHEN SAID LAST MENTIONED SWITCHIS CLOSED SAID TRIODE WILL OPERATE IN CONJUCTION WITH SAID RESONANT CIRCUIT AS AN OSCILLATOR PRODUCING CONTROL SIGNALS OF SAID PREDETERMINED FREQUENCY IN SAID COUPLING MEANS, AND SAID SELECTOR SWITCH BEING OPERATIVE IN A SECOND CONDITION TO CONNECT SAID CATHODE TO SAID CIRCUIT GROUND THROUGH SAID CATHODE RESISTOR AND TO CONNECT SAID ANODE TO THE POSITIVE SIDE OF SAID POTENTIAL SOURCE THROUGH SAID SECOND ANODE RESISTOR WHEREBY SAID TRIODE WILL OPERATE IN CONJUNCTION WITH SAID RESONANT CIRCUIT AS A FREQUENCY-SELECTIVE AMPLIFIER RESPONSIVE TO CONTROL SIGNALS OF SAID PREDETERMINED FREQUENCY APPLIED THERETO BY SAID COUPLING MEANS AND MEANS RENDERING SAID RELAY RESPONSIVE TO CONTROL SIGNAL OUTPUT OF AT LEAST A PREDETERMINED MINIMUM DURATION FROM SAID TRIODE DURING EITHER MODE OF OPERATION.