Metal oil storage tank temperature detection method based on pi/4-QPSK spread spectrum ultrasonic communication

Abstract

The invention discloses a metal oil storage tank temperature detection method based on pi / 4-QPSK spread spectrum ultrasonic communication, and the method comprises the steps: obtaining temperature data in a closed metal oil storage tank at a current moment through a temperature measurement circuit, carrying out the modulation processing of the temperature data, and converting a modulated signal into an ultrasonic signal, wherein the closed metal oil storage tank wall is used as a transmission medium to be transmitted out of the closed metal tank; converting the received ultrasonic signal into an electric signal, demodulating the electric signal to obtain temperature data in the closed metal oil storage tank, and displaying the temperature data through a display device; after the temperature data is obtained, the temperature data needs to be adjusted, for example, the temperature is increased, decreased or kept unchanged. Temperature adjusting information serves as input information to be modulated and converted into ultrasonic signals, then the wall of the closed metal oil storage tank serves as a transmission medium to be transmitted into the closed metal tank to be converted into electric signals, the electric signals are demodulated, temperature control information can be obtained, and temperature adjusting is carried out.

Description

technical field [0001] The invention relates to an ultrasonic communication method, in particular to a method for detecting the temperature of a metal oil storage tank based on π / 4-QPSK spread spectrum ultrasonic communication. Background technique [0002] The temperature of the oil storage tank is an important parameter for oil preservation. Too high temperature will cause the edible oil to become sour and deteriorate. At present, the temperature measurement of oil storage tanks mostly adopts the method of temperature measurement optical fiber. This method needs to reserve a cable position on the closed storage tank, which will affect the sealing of the storage tank. Using ultrasonic waves as a communication carrier to transmit temperature information can There is no need to reserve a cable position on the oil storage tank, and the phenomenon of electrostatic shielding of electromagnetic waves generated by the metal oil storage tank can also be avoided. [0003] In additi...

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Problems solved by technology

[0003] In addition, the traditional π / 4-QPSK modulation method is that the phase differences corresponding to the baseband signal I and Q are π / 4, 3π / 4, 5π / 4 respectively and 7π / 4, the initial phase is 0, so there are 8 phases of the differentially encoded π / 4-QPSK signal, which are 0, π / 4, π / 2, 3π / 4, π, 5π / 4, 3π / 2 and 7π / 4, corresponding to the two differential signals, five amplitudes of '±1', '±0.707' and '0' will be generated. When performing correlation calculations with different amplitudes, it is impossible to judge the synchronization and correlation property, causing the spread spectrum communication receiving end to generate error synchronization results when despreading and performing correlation operations, and at the same time cause errors in demodulation results

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