Acoustric logging system utilizing first half-cycle of received signal

Claim 2

An acoustical logging system for logging formations penetrated by a borehole, said system comprising: a downhole instrument having at least a transmitting transducer and a receiving transducer; said transducers being spaced from each other; circuit means for energizing said transmitting transducer to generate a series of acoustical waves, said receiving transducer receiving said pulses and converting them to a related electrical signal; an amplifying circuit means coupled to said receiving transducer for amplifying the first half cycle of said related electrical signal and blocking the remainder of said related electrical signal, said amplifying circuit comprising first, second and third triode stages, the plate of said first stage being coupled to the grid of said second stage, the plate of said first stage also being coupled to the grid of said third stage through a diode disposed to pass only negative signals, the cathode of said second stage being coupled to the cathode of the first stage through a Zener diode, said Zener diode being biased to pass the second half cycle of said related electrical signal to the first stage to apply a positive voltage to the cathode thereof of sufficient magnitude to cause said First stage to cut off; a transmission circuit coupled to said amplifying circuit means for transmitting the amplified first half cycle signal to a surface recording means.

Claim 3

An acoustical probing system for measuring acoustic transmission properties of the wall of an elongated opening adapted to receive a probe, said system comprising: a probe having at least a transmitting transducer and at least one receiving transducer; said transducers being spaced from each other a distance of less than 1 foot; means for urging said transducers into close proximity with the wall of the opening; circuit means for energizing said transmitting transducer to generate a series of acoustical waves having a frequency exceeding 50 kilocycles per second, said receiving transducer receiving said waves and converting them to a corresponding electrical signal; an amplifying circuit means coupled to said receiving transducer for amplifying the first half cycle of said related electrical signal and blocking the remainder of said related electrical signal, said amplifying circuit comprising first, second and third triode stages, the plate of said first stage being coupled to the grid of said second stage, the plate of said first stage also being coupled to the grid of said third stage through a diode disposed to pass only negative signals, the cathode of said second stage being coupled to the cathode of the first stage through a Zener diode, said Zener diode being biased to pass the second half cycle of said related electrical signal to the first stage to apply a positive voltage to the cathode thereof of sufficient magnitude to cause said first stage to cut off; a transmission circuit coupled to the third stage of said amplifying circuit means for transmitting the amplified first half cycle signal to a remote recording means, said remote recording means recording the amplitude of said amplified signal.

Claim 4

An acoustical probing system for measuring acoustic transmission properties of the wall of an elongated opening adapted to receive a probe, said system comprising: a probe having at least a transmitting transducer and at least one receiving transducer; said transducers being spaced from each other a distance of less than 1 foot; means for urging said transducers into close proximity with the wall of the opening; circuit means for energizing said transmitting transducer to generate a series of acoustical waves having a frequency exceeding 50 kilocycles per second, said receiving transducer receiving said waves and converting them to a corresponding electrical signal; an amplifying circuit means coupled to said receiving transducer for amplifying the first half cycle of said related electrical signal and blocking the remainder of said related electrical signal, said amplifying circuit comprising first, second and third triode stages, the plate of said first stage being coupled to the grid of said second stage, the plate of said first stage also being coupled to the grid of said third stage through a diode disposed to pass only negative signals, the cathode of said second stage being coupled to the cathode of the first stage through a Zener diode, said Zener diode being biased to pass the second half cycle of said related electrical signal to the first stage to apply a positive voltage to the cathode thereof of sufficient magnitude to cause said first stage to cut off; a transmission circuit coupled to the third stage of said amplifying circuit means for transmitting the amplified first half cycle signal to a remote recording means, said remote recording means recording the amplitude of said amplified signal.