An improved system for locating concealed underground objects

摘要: An improved locator system is provided which transmits digital and analog information over an electromagnetic field (32) that radiating from underground source (20). The includes a transmitter (100) modulates its output signal by turning on off in response to sequence of words. also onto the transmitted signal. modulated can include audio frequency or voice receiver (200) senses detects impressed radiated field. demodulates provides operator.