JPH04311116A - Method for transmitting data and the like in water - Google Patents

Abstract

PURPOSE:To transmit many kinds of data with high accuracy by simultaneously using plural ultrasonic frequencies and repeating non-modulation and two-wave modulation to transmit necessary data. CONSTITUTION:While always transmitting plural ultrasonic frequencies a modulation ON/OFF synchronizing circuit 8 sends the 1st modulation wave f1 or the 2nd modulation wave f2 from an ultrasonic oscillation antenna 5 at the same timing and allows respective corresponding receiving parts 11a to 11n to receive the sent frequency bands. Thereby a pair of signal data consisting of plural modulation waves modulated by the 1st modulation wave f1 or the 2nd modulation wave f2 are formed following non-modulated carrier frequency in the same common time band. In this case, a difference between the modulation frequency bands of the 1st and 2nd modulation waves f1, f2 expresses ON/OFF and the non-modulation frequency is functioned as the division of signals. Thus the required number of signals can be transmitted by repeating non-modulation and two-wave modulation in all transmitting parts 1a to 1n in each fixed time.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for transmitting data underwater.

0002

[Prior art and its technical issues] Remote control of equipment installed underwater, unmanned research boats, etc., and data collected by equipment and unmanned research boats, including numerical values such as water temperature, salinity, depth, and position. As a method for transmitting and receiving data, a transmission method using ultrasonic waves has been implemented. However, in the past, ultrasonic waves were transmitted by setting a certain ultrasonic frequency and modulating it. Specifically, it was common to apply modulation to a single carrier wave in series.

However, unlike in the atmosphere, differences in ultrasonic transmission speed occur in water due to differences in ultrasonic frequency, water temperature, salt concentration, water flow direction, flow velocity, etc. Therefore, in conventional methods, arrival time delays and distortions due to transmission speed differences are unavoidable and cannot be corrected. For this reason, there have been problems such as poor accuracy of transmitted data, malfunction of remote control, and limited types of signals that can be transmitted.

0004

[Means for Solving the Problems] The present invention was devised to solve the above-mentioned problems, and its purpose is to transmit and receive various types of data with high accuracy underwater. The object of the present invention is to provide a method for transmitting data underwater. In order to achieve the above object, the present invention provides a method for transmitting signals underwater using ultrasonic waves, in which a plurality of ultrasonic frequencies are simultaneously used, and the plurality of waves are constantly transmitted as carrier frequencies, and each The purpose is to create a set of modulated signal data by changing the wave to one of two high and low modulation frequencies at the same timing, and to transmit the necessary data by repeating non-modulation and two-wave modulation.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an example of a circuit used in the underwater data transmission method of the present invention.
8, 12, 16, etc.) and a plurality of corresponding receiving sections 11a to 11n. Each of the transmitting units 1a to 1n has a carrier wave oscillator 2 and two modulation frequency oscillators 3a and 3b, and the carrier wave oscillator 2 is connected to an ultrasonic vibration antenna 5 via a transmission output amplifier 4. There is. In addition, the modulation frequency oscillator 3
a is connected to the modulation on/off circuit 7 via the on modulator 6a, and the modulation frequency oscillator 3b is connected to the modulation on/off circuit 7 via the off modulator 6b, the output section of which is connected to the transmission output amplifier 4. The modulation on/off circuit 7 of each transmitting section 1a to 1n is connected to a modulation on/off synchronizing circuit 8, and two types of modulated waves by the on modulator 6a and the off modulator 6b are transmitted to each transmitting section 1a to 1n.
so that they are sent at the same timing. Receiving section 1
Each of 1a to 11n has an ultrasonic vibration antenna 9, a receiving circuit 20, and a signal amplifier 21. Signal amplifier 21
The output of is connected to a decoder (not shown), which stores patterns and corresponding signals in advance, and determines a specific signal from a combination of multiple modulated waves received simultaneously.
It is set to be sent.

[0006] The plurality of transmitting units 1a to 1n use different ultrasonic carrier frequencies. For example, for 5 waves, 25KHz, 27KHz, 30KHz, 33K
Hz and 37KHz, 8 waves, 8KHz, 8.
5KHz, 9KHz, 10KHz, 10.5KHz, 1
Such as 1KHz and 11.5KHz. These ultrasonic carrier frequencies are always transmitted simultaneously from each transmitter 1a to 1n. The present invention does not simply turn on/off or modulate/unmodulate a plurality of waves, but also
Two modulated waves are used for each ultrasonic carrier frequency of ~1n. This is the first modulated wave f1 in the on modulator 6a.
(for example, 1 KHz), and the second
This is done by creating a modulated wave f2 (for example, 300 Hz). In other words, in terms of the 8 waves mentioned above, 8KHz, 8.5K
Hz, 9KHz, 10KHz, 10.5KHz, 11K
Hz and 11.5KHz are the first modulated wave f1 and the second modulated wave f1, respectively.
This is a combination having a modulated wave f2.

[0007] In the present invention, as described above, while constantly transmitting a plurality of ultrasonic carrier frequencies, the modulation on/off synchronization circuit 8 converts the first modulated wave f1 or the second modulated wave f2 into ultrasonic waves at the same timing. The signals are transmitted from the vibrating antenna 5 and received by the corresponding receiving sections 11a to 11n, respectively. As a result, a set of signal data consisting of a plurality of modulated waves modulated to the first modulated wave f1 or the second modulated wave f2 after the non-modulated carrier frequency is created in the same shared time zone. In this case, the difference between the modulation frequencies of the first modulated wave f1 and the second modulated wave f2 represents on and off, and the non-modulated carrier frequency functions as a signal delimiter. The first modulated wave f1 and the second modulated wave f2 of the respective ultrasonic carrier frequencies are the respective first modulated waves f1
Since it is possible to use a parity check code such as setting code 1 to code 1 and setting each second modulated wave f2 to code 0, accuracy can be further increased.

[0008] The present invention transmits the required number of signals by repeating the above-mentioned two unmodulated and modulated waves at fixed time intervals in all the transmitting units 1a to 1n. For example, eight ultrasonic carrier frequencies are used. When using 256 types by repeating non-modulation and 2-wave modulation, 4096 types with 12 waves, 1
With 6 waves, 65536 types of signal transmission are possible. FIG. 2 shows an example applied to an 8-bit EB/SDIC code. In this example, the two-wave modulation time T1 is 0.1 seconds, the non-modulation time T2 is 0.3 seconds, each first modulated wave f1 is 1 KHz and code 1, and each second modulated wave f2 is 300 Hz and code 0. shows the waveform of repeated transmission waves. The combination of modulated waves in the first shared time zone is 1, 1, 0, 0, 1, 1,
0, 1, and in the katakana mode of the 8-bit code table, a "f" signal is represented. The second combination is 0,1
,0,0,0,1,0,1, so it is "E" and 3
The th combination is 0, 0, 1, 1, 0, 1, 0, 1, so it is "5", and the 4th combination is 1, 0, 0, 1,
Since it is 0, 0, 1, 1, it is "g". If the repetition frequency per second is increased, that is, the modulation frequency per time is increased to the equivalent of 20 KHz, it is possible to transmit an extremely large number of types, such as 432,537,600 types per second, with 16 carrier waves and a repetition frequency of 6600.

[0009]

[Effects of the Invention] According to the present invention as described above, in a method of transmitting signals underwater using ultrasonic waves, multiple ultrasonic frequencies are simultaneously used and these multiple waves are constantly transmitted as carrier frequencies. At the same time, each wave is changed to one of two high and low modulation frequencies at the same timing to create a set of modulated signal data, and the necessary data is transmitted by repeating non-modulation and two-wave modulation. In addition to being able to transmit a very wide variety of signals, it is possible to check each signal because the carrier wave and two modulation waves are repeated, and therefore, it is possible to check each signal individually. Transmission speed difference due to flow direction, flow velocity, etc.
It is easy to correct the arrival time delay (arrival time delay) and distortion, and the excellent effect of transmitting highly accurate data can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of a circuit used to implement the present invention;

FIG. 2 is a waveform diagram showing an example of transmission according to the present invention.

[Explanation of symbols]

1a to 1n... transmitter, 6a... on modulator, 6b... off modulator, 11a to 11n... receiver, f1... first modulated wave, f
2...Second modulation wave

Claims (1)

[Claims] Claim 1: A method of transmitting signals underwater using ultrasonic waves, in which multiple ultrasonic frequencies are used at the same time, the multiple waves are constantly transmitted as carrier frequencies, and each wave is transmitted at the same timing. An underwater data transmission method characterized by creating a set of modulated signal data by changing the modulation frequency to one of two types, high and low, and transmitting the necessary data by repeating non-modulation and two-wave modulation. .