Abstract: A portable pulsed signal generator which generates a low-frequency, high-ered signal from a constant direct current, low power source is disclosed as including an inverter for driving a plurality of motors which, in turn, actuate control switches by means of cams and cam followers associated therewith. A potentiometer driven by one of said motors, in turn, effectively controls the output of a direct current amplifier, with the varying direct current output signal therefrom having the alternate half-waves thereof polarity reversed by switch controlled relays, the switch of which is timely actuated by one of the aforesaid cams, cam followers, and other switches, respectively, so as to produce a low-frequency, high-power, substantially alternating current signal. After appropriate transduction said low-frequency, high-power, substantially alternating current signal may be employed for sweeping mines.

Abstract: A voice operated relay system is disclosed which includes signal processing ircuitry for receiving and discriminating with respect to human speech signals and for actuating a relay in response thereto. A power supply test is also included, as well as circuitry for preventing relay drop out due to input speech hesitations. The preferred embodiment of the subject system is disclosed as a means of enabling a cassette recorder and for causing it to record said human speech signals at either near or remote locations.

Abstract: Apparatus is described for remote VOR (voice operated relay) control of a pe recorder having a single control element, e.g., a push-button, for effecting both pause and run functions on alternate actuations. A function feedback signal conditions a logic network so that solenoid actuation of the push-button occurs only in response to appropriate VOR logic command signals.