Engineering topics
Publications and source records attributed to Kojima, G. K..
Microprocessor-based system analyzes amplitudes and rise times of neural waveforms. Displaying histograms of measured parameters helps researchers determine how many nerves contribute to signal and specify waveform characteristics of each. Results are improved noise rejection, full or partial separation of overlapping peaks, and isolation and identification of related peaks in different histograms. 2
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A miniature echosonometer adapted for implantation in the interior of an animal for imaging the internal structure of a organ, tissue or vessel is presented. The echosonometer includes a receiver/transmitter circuit which is coupled to an ultrasonic transducer. Power is coupled to the echosonometer by electromagnetic induction through the animal's skin. Imaging signals from the echosonometer are electromagnetically transmitted through the animal's skin to an external readout apparatus.
Miniature ultrasonic echosonometer implanted within laboratory animals obtains energy from RF power oscillator that is electronically transduced via induction loop to power receiving loop located just under animal's skin. Method of powering device offers significant advantages over those in which battery is part of implanted package.
A correlation microphone arrangement was used in the test section of the Ames 7- by 10-Foot and 40- by 80-Foot Wind Tunnels in an attempt to reject the reverberant and wind noise. The tests in the 7- by 10-foot wind tunnel covered a frequency range from 400 Hz to 8 kHz while the tests in the 40- by 80-foot tunnel covered the range from 31.5 to 800 Hz. Examination of the experimental data plus calculations of cross-correlations due to reflective noise indicate that the correlation microphone is effective in rejecting microphone wind noise and reverberant noise even at low frequencies, and that the low-frequency background noise monitored by the correlation microphone is reflected noise with a preferred direction from the tunnel drive system. Design studies indicate that this tunnel drive noise can be reduced substantially through suitable modification of the drive fans and acoustical treatment of the nacelles that house these fans.