Abstract: A downhole toroidal coupled telemetry apparatus is disclosed in which the secondary winding comprises a plurality of turns wrapped around a generally annular core member.

Abstract: A system and method is described for amplifying and transmitting an information signal from a downhole drillstring location. The amplifier shifts the relatively low frequency information signal up to a high frequency level, amplifies the high frequency signal and processes it through an impedance matching transformer, and then demodulates the amplified signal back to the original low frequency for transmission through the earth to the surface, thus enabling the use of a much smaller transformer than when the information signal is processed entirely at the low frequency level. A novel transducer consisting of generally cylindrical conductive sleeves separated by an insulative gap is used to provide structural integrity and to transmit the amplified information signal. The conductive sleeves are heat shrunk onto an insulative sleeve and a central mandrel.

Abstract: This invention relates to pulse radar detection of targets in extended media, including natural phenomena such as oil, coal and ore deposits within the earth. In particular, this invention relates to a pulse radar system employing a synthetic pulse formed from a Fourier spectrum of frequencies generated and detected by a digitally controlled transmitter and receiver circuits.