Circuit for echo and noise suppression of acoustic signals transmitted through a drillstring

摘要

In an electronic circuit for digitally processing analog electrical signals produced by at least one acoustic transducer, a digital time delay circuit is utilized which employs an array of First-in-First-out (FiFo) microchips. Also, a bandpass filter is used at the input to this circuit for isolating drillstring noise and eliminating high frequency output. Spaced sensors 52, 54 provide a delayed signal to summer 46 which is combined with a signal from source 28 and applied to sensors 42, 44 to transmit an uphole measurement signal without any downward travelling noise. Similar arrangement of transducers 62, 64 provide an adaptive amplitude control to balance 75 the signals from the transducer pairs. IMAGE