Patent ID: 9455791
Filing Date: 2016-09-27
CPC Classification: H04B,H04L,Y02D

Claim Text:
1. A method for simultaneous bi-directional communication through a metallic wall using a single pair of piezoelectric transducers, the method comprising the steps of: providing a metallic wall having an inner side and an outer side; providing coaxially aligned inside and outside piezoelectric traducers mounted on respective opposite sides of the metallic wall; communicating a differentially encoded binary command word from the outer side of the metallic wall to the inner side of the metallic wall by a first sub-process comprising the steps of: selecting a command word; translating the command word to binary bits; configuring the binary bits of the command word as part of a binary outside packet, the outside packet also comprising an incoming Barker sequence, translating the binary bits of the outside binary packet into differentially encoded bits using an algorithm comprising modulo-2 addition of each binary bit with the most recently transmitted differentially encoded bit; applying a carrier signal ( receiving the carrier signal at the inner side of the wall with the inside transducer; determining an envelope of the carrier signal received by the inside transducer, called a carrier signal envelope, using an inside envelope detector circuit; periodically sampling the carrier signal envelope using an analog-to-digital converter (ADC), the periodic sampling being timed to coincide with a periodic transmission of a selected bit from the inner side to the outer side of the wall, wherein the selected bit falls within an outgoing Barker sequence, and wherein the periodic transmission of the selected bit have a consistent amplitude; translating a plurality of consecutive envelope samples into a plurality of translated binary bits using a complex programmable logic device (CPLD); wherein the translating step comprises determining whether an absolute value of the difference between each envelope sample and an immediately preceding envelope sample is above a threshold value, interpreting the envelope sample as a translated binary bit having the same binary value as an immediately preceding translated binary bit when said absolute value is below the threshold value, and interpreting the envelope sample as a translated binary bit having a different binary value than the immediately preceding translated binary bit when said absolute value is above the threshold value; determining the command word using the plurality of translated binary bits; and using the command word to control electronics; wherein an initial frequency and a minimum power level for the carrier signal ( applying a carrier signal having a power level and a frequency at the outer side ( terminating the initial frequency selection algorithm if a Barker sequence is detected, the detected Barker signal indicating that the power level and frequency used most recently used were adequate to send power and communications through the wall; and increasing the carrier signal power level and stepping through the range of carrier signal frequencies again if no Barker sequence is detected, and repeating the steps of increasing the carrier signal power level and then stepping through the range of carrier signal frequencies until an initial frequency and minimum power level are found which result in detection of a Barker sequence sent from the inner side ( wherein after the initial frequency and minimum power level are determined, the frequency of the carrier signal ( applying a carrier signal having said initial frequency and said minimum power level to the outer wall; sampling and quantifying a voltage level of a power harvesting capacitor ( stepping the carrier signal ( stepping the carrier signal ( stepping the carrier signal ( repeating the process of stepping the carrier signal frequency in the same direction when the previous step resulted in a higher voltage reading, and stepping the carrier signal in the opposite direction when the previous step resulted in a lower voltage reading; the method for simultaneous bi-directional communication further comprising communicating binary inside data from the inside ( providing a metal oxide semiconductor field-effect transistor which is linked to the inside transducer, the metal oxide semiconductor field-effect transistor having an on position corresponding to a binary value 1 and an off position corresponding to a binary value 0; applying a continuous wave carrier to the outer side ( altering an electrical load on the inside transducer by turning the metal oxide semiconductor field-effect transistor on and off, thereby modulating the acoustic impedance of the inside transducer and changing the strength of the reflected wave; wherein the reflected wave interacts with the outside transducer, and thereby modifies the electrical input impedance of the outside transducer, so that the electrical input impedance of the outside transducer varies in response to the varying strength of the reflected wave; monitoring variations in the amplitude of a voltage applied across the outside transducer, said variations corresponding to variations in the electrical input impedance of the outside transducer, and thereby also corresponding to the binary inside data from the inner side of the wall; determining the envelope of the voltage applied across the outside transducer, termed a reflected signal envelope, using an outside envelope detector circuit; sampling the reflected signal envelope using an analog to digital converter; adjusting at least one of the reflected signal envelope and samples of the reflected signal envelope to correct for overlay between the reflected wave and the carrier signal from the first sub process; and processing reflected signal envelope samples with a digital signal processor to recover the binary inside data.