JPH0659043B2 - Ultrasonic data transmission system - Google Patents

Description

The present invention relates to a method of converting digital data into ultrasonic signals and transmitting the data.

(B) Conventional technology and its problems Generally, in measuring instruments such as inclinometers that measure the inclination of the seabed, it is difficult to collect the measuring instrument because it is necessary to install and fix it below the seabed. May be temporarily stored in a measuring device, and the data stored by a command from the sea may be converted into an ultrasonic signal and transmitted to a ship anchored at sea. At that time, if the collected digital data string is directly converted into an ultrasonic signal in bit units and transmitted to a receiver on the sea, for example, 640 × 10 at an ultrasonic carrier frequency of 10 KHz.
^When transmitting ^3- bit data, it takes more than one hour, which causes problems such as the maneuverability of a ship berthed at sea and inconvenience that the measuring equipment consumes a lot of power. Moreover, the receiver side easily causes a reading error in the data to be transmitted, and accurate data transmission cannot be performed.

(C) Purpose The present invention solves the above-mentioned conventional problems, and converts collected data into an ultrasonic signal so that the data can be efficiently transmitted in a short time and accurately without causing confusion. The purpose is to do.

(D) Configuration In order to achieve the above-mentioned object, the present invention divides each unit data included in the digital data into a plurality of pieces when converting the digital data into ultrasonic signals and transmitting the data.
The transmission time interval between these respective divided data is time-distributed so as to be different from the transmission time interval set for each unit data, and the respective divided data is converted into the excitation duration of the ultrasonic signal according to the data content. Moreover, a constant ultrasonic wave excitation rise time is added to this excitation duration time.

(E) Example Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

FIG. 1 is an explanatory diagram including a seabed measuring apparatus to which the method of the present invention is applied and a repeater that receives an ultrasonic signal transmitted from the seabed measuring apparatus. In the figure, reference numeral 1 is a ship that is anchored at sea, and 2 is a peter suspended from the ship 1 via a cable 4. The repeater 2 includes a piezoelectric element 6 for performing mutual conversion between an ultrasonic signal and an electric signal, a transceiver 8 for transmitting / receiving data, and a data memory for temporarily storing data transmitted / received by the transceiver 8. It includes an electronic circuit 12 including and a battery 14.

Further, 16 is a seabed measuring device for measuring depth, temperature, vibration, inclination, etc. of the seabed. This seabed measuring device 16 is a detector for detecting changes in the depth, temperature, vibration, inclination, etc. in a pressure resistant container 18. 20, an electronic circuit 22 including a data memory for temporarily storing the data obtained by the detector 20, a transceiver 24 for transmitting and receiving data, and a piezoelectric element 26 for performing mutual conversion between ultrasonic signals and electric signals. And a battery 28. Reference numeral 30 is a pedestal for the seabed measuring device 16. When performing data transmission between the repeater 2 and the submarine measuring device 16, a command signal is generated from the transmitter / receiver 8 of the repeater 2, and the command signal is converted into an ultrasonic signal by the piezoelectric element 6 to the submarine measuring device 16. Send. Since the data obtained by the detector 20 is stored in the data memory of the electronic circuit 22 in the submarine measuring device 16 in advance, the submarine measuring device 16 responds to the command signal from the repeater 2 with the measured data. At the same time as reading from the data memory, this read data is converted into a digital data string and sent to the piezoelectric element 26 via the transceiver 24. Thereby, the piezoelectric element 2
6 is driven to be excited, an ultrasonic wave signal is radiated from the piezoelectric element 26, and the radiated ultrasonic wave signal is received by the repeater 2. Then, the repeater 2 stores the data transmitted from the seabed measuring device 16 in the data memory of the electronic circuit 12.

FIG. 2 is a time chart of an ultrasonic signal when converting the digital data into an ultrasonic signal and transmitting it from the seabed measuring device 16 to the repeater 2. In converting the digital data read from the data memory of the seabed measuring device 16 into an ultrasonic signal by the piezoelectric element 26 and transmitting the data,
When each unit data included in the digital data is composed of 8 bits, first, the unit data of 8 bits is divided into two parts, that is, 4 bits before and after. Then, a constant transmission time interval T ₁ is set between each 4-bit divided data, and a constant transmission time interval T ₂ is also set between sequentially transmitted unit data. Moreover, the transmission time interval T ₁ between the respective divided data is the transmission time interval T between the unit data.
Allocate the time differently from ₂ . For example, when the transmission time interval T ₁ between each divided data is set to ₁ ms, the transmission time interval T ₂ between each unit data is set to ₂ ms. This is to clarify the distinction between the transmitted unit data and prevent confusion between the unit data. In addition, regarding each divided data, the divided data is converted into an excitation duration T ₃ according to the data content, and the rise time until the piezoelectric element 26 is excited and the ultrasonic signal is emitted is considered. Set time T
Add ₄ . For example, in the case of an ultrasonic carrier frequency of 50 KHz, the ultrasonic excitation rise time T ₄ is 500 μs.
(For 25 pulses of ultrasonic waves), set to 500 μs,
20 for every 1 bit increase depending on the content of transmitted data
0 μs (10 ultrasonic pulses) is added. Therefore, as a result, each divided data is at least 0.5ms to maximum 0.5ms +
The time width is modulated within 15 × 0.2 ms = 3.5 ms. As a result, a maximum of 3.5 ms + 1 ms + 3.5 ms + 2 ms = 10 ms is required to transmit 8-bit unit data, and the data transmission rate per unit time is 800 bits / second. Now, if performing data transmission ^{640 × 10 3 bit, 640 ×} 10 3/800 = 800 seconds = 13.3
This is a minute (maximum), and the data transmission time can be greatly shortened compared to the conventional case.

In this embodiment, the case where 8-bit data is transmitted as the unit data has been described, but the unit data is 16 bi.
It goes without saying that the present invention can be applied to the case of t or the case of transmitting data in units of more bits.

(C) Effect As described above, according to the present invention, it is possible to convert the collected data into an ultrasonic signal and efficiently transmit it in a short time. Moreover, there is an excellent effect that data can be accurately transmitted without causing data confusion.

[Brief description of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is an explanatory view including a seabed measuring instrument to which the method of the present invention is applied and a repeat for receiving an ultrasonic signal transmitted from the seabed measuring instrument, FIG. FIG. 3 is a time chart of ultrasonic signals when digital data is converted into ultrasonic signals and transmitted. T ₁ ...... Transmission time interval between divided data, T ₂ ...... Transmission time interval between unit data, T ₃ ...... Excitation duration, T ₄ ...... Ultrasonic excitation rise time.

Claims (1)

[Claims] 1. When converting digital data into ultrasonic signals and transmitting the data, each unit data included in the digital data is divided into a plurality of units, and a transmission time interval between the respective divided data is unit data. In addition to allocating time so as to be different from the transmission time interval set in, the divided data is converted into the excitation duration of the ultrasonic signal according to the data content, and a constant ultrasonic excitation rise time is added to this excitation duration. A data transmission method using ultrasonic waves.