KR19990054184A - Slave Logic Circuit for Group Synchronization and Analog-to-Digital Conversion of Sound Detectors - Google Patents

Abstract

The present invention relates to a mux circuit of a sound detector of a sound detector, and more particularly, a logic circuit for synchronizing with each group in the sub-mux in the sound module constituting the sound detector, controlling automatic gain control, and performing a digital conversion. It is about.

The present invention provides signal conversion means for converting and outputting an automatic gain control (AGC) signal input as serial data from a master logic circuit into respective gain level codes; The data frame is composed and output according to the synchronization signal input from the master logic circuit, and the synchronization signal SYNC and the clock signal SCLK from the master logic circuit are input, and the timing signal of each group is synchronized with this signal. Logic means for generating them; And encoder means for coding and transmitting a signal inputted from the main mux in the Manchester manner, thereby transmitting the signal transmission from the sub mux of the signal transmission module of the sound detector to the ship by grouping the frequency bands of the sound signal. And it has the effect of providing a channel selection signal required for multiplexing the pre-mux and the master mux.

Description

Slave Logic Circuit for Group Synchronization and Analog-to-Digital Conversion of Sound Detectors

The present invention relates to a mux circuit of a sound detector of a sound detector, and more particularly, a logic circuit for synchronizing with each group in the sub-mux in the sound module constituting the sound detector, controlling automatic gain control, and performing a digital conversion. It is about.

In general, in the sound detector for detecting an acoustic signal in the water to detect the exact position of the sound source, the method of detecting the sound wave in the water is an active sonar that emits sound energy and receives the reflected sound energy from the object. There is a (Sonar) method and a passive sonar method that receives only acoustic energy radiated from other sound sources.

1 is a block circuit diagram schematically showing a general sound detector. The sound detector system includes: a sound detector 10 for detecting an underwater sound signal, converting the sound signal into an electrical analog signal, converting the sound signal into a digital signal, and then multiplexing and transmitting the sound signal; A towing cable 30 for connecting the sound detector 10 to the ship 40; It is configured to include a ship 40 is connected to the sound detector 10 by the towing cable 30.

In addition, the ship 40 is classified into a data receiving device 42 for processing a mux signal transmitted from the sound detector 10, and the electrical signal data received from the data receiving device 42, the sound signal by processing It is composed of a data processor 44 for restoring the control, and comprises a control signal and a power supply 46 for controlling the sound detector 10 and supplying power.

Sound generated in the water is propagated to the surroundings by the mechanical tight action of seawater particles. The acoustic vibration reaches the hydrophone 12 in a magnitude proportional to the product of the square of the frequency and the amplitude, causing the volume change, and the hydrophone 12 responds to the volume change in response to an electric wave that is homogeneous with the sound wave. Generates the corresponding electrical signal. The electrical signal is input to the mux unit 16 via a differential amplifier 14 for noise reduction.

The signal input to the mux unit 16 is sequentially multiplexed, and then digitally signaled through a sampling and quantization process, and then transmitted to the ship 40 through a towing cable 30 through a vibration isolation module (not shown). . In this case, the transmission signal may be expressed in the form of a change in current or a change in voltage. However, since the towing cable 30 is a long distance of several kilometers, it is generally converted into a current form and transmitted.

However, the signal sensed by the hydrophone and applied to the mux of the signal transmission module via the preamplifier is not only low in output level, but also a long distance from the preamplifier to the mux is 120 m. The incoming noise is directly input to the mux, and the gain controller at the rear end of the mux has a problem that the gain is not properly processed because the gain is controlled while the noise level is raised.

In order to solve the above problems, the present invention is a logic for performing the digital signal processing required for transmitting the sound multiplexed signal grouped by the frequency band of the sound signal in the sub-mux of the sound module constituting the sound detector to ship It is an object to provide a circuit.

1 is a block circuit diagram schematically showing a circuit configuration of a general sound detector;

2 is a block diagram showing the configuration of a sound detector submux unit to which the present invention is applied;

Figure 3 is a block diagram showing the configuration of the sound detector pre-mux portion to which the present invention is applied,

Figure 4 is a block diagram showing the configuration of the master mux part to which the present invention is applied,

5 is a block diagram of a slave logic circuit constructed in accordance with the present invention.

※ Explanation of code about main part of drawing ※

10; Sonar 30, 32; Towing cable

35; Winches 36, 105; Slip ring

40; Shipboard 42; Data receiver

100; Broadband amplifier 110; Data reception amplifier

120; Decoding unit 130; Demuxing department

In order to achieve the above object, the present invention provides a plurality of hydrophones for sensing acoustic signals from underwater sound sources with electrical changes, a submux unit for multiplexing the signals of the hydrophones, and a signal of the submux unit. In the sound detector comprising a pre-mux unit for multiplexing by each group according to the acoustic frequency band and a main mux for multiplexing the signals of the pre-mux unit, the automatic gain control inputted as serial data from the master logic circuit ( Signal conversion means for converting and outputting the AGC) signal into respective gain level codes; The data frame is composed and output according to the synchronization signal input from the master logic circuit, and the synchronization signal SYNC and the clock signal SCLK from the master logic circuit are input, and the timing signal of each group is synchronized with this signal. Logic means for generating them; In addition, the present invention provides a slave logic circuit structure comprising an encoder means for coding and transmitting a signal input from the main mux in a Manchester manner.

Referring to the accompanying drawings, a preferred embodiment of the present invention will be described.

Figure 2 is a block diagram showing the configuration of the sound detector sub-mux portion to which the present invention is applied.

The sub-mux unit receives a signal from the hydrophone for each channel from channel 1 to channel 12, sample and hold circuit unit 120, mux unit 130, differential automatic gain control amplifier 140, current conversion The circuit 150 and the differential receiver 160 are configured.

At this time, for the operation of each circuit portion, a power input of + 5V for operation of the logic circuit is supplied to each portion as a power input supplied from the ship.

The filter 110 is to remove high frequency noise induced in the input cable, and includes a terminating resistor for receiving a signal transmitted in the form of a current change. This filter functions as a simple RC lowpass filter, with a cutoff frequency of preferably about 1.6 Hz.

The sample and hold circuit unit 120 is for sampling signals of all channels simultaneously. This sample and hold circuit is for holding the signal voltage after the signal is completely settled every time the channel is changed and performing mux processing in the next section. For example, with a sample signal of 4.88 마다 every 4.096 주기 period, Sample and hold the input signal.

The mux unit 130 is for multiplexing and transmitting 12 channel signals input to the sub mux unit. Twelve signals are divided into three and four small groups are applied to the mux unit 130 via the sample and hold circuit unit 120. At this time, the channel selection signal is decoded by a decoder (not shown) and applied to an enable terminal of each multiplexer to form respective small groups. At this time, the offset detection signal of the sample and hold circuit is also selected.

The differential auto gain control amplifier 140 is a differential amplifier for correcting the auto gain control of 0 to 24 dB and the offset of the sample and hold circuit.

The differential receiver 160 is a receiver of the RS-422 method. The receiver receives the RS-422 digital differential signal and converts it to a logic level. At this time, the terminal resistor is installed at the end of the line for impedance matching of the cable. In addition, the differential receiver 160 preferably uses an integrated circuit of a CMOS type to reduce current consumption.

Reference numeral 150 is a current conversion circuit. The current conversion circuit 150 converts the signal of the voltage change form into the form of the current change signal in order to transmit the sound signal through the differential receiver 160 to the pre-mux unit at a long distance.

3 is a block circuit diagram of the premux unit.

The signal converted into the current form is applied to the pre-mux part. The pre-mux part is a mux part for multiplexing the signal multiplexed 12: 1 in the sub-mux again for each group and transmitting it to the master mux part.

The premux unit includes an input filter 210, a 4: 1 mux 220, a 2: 1 mux 240, and a compensation amplifier 230.

The signal input to the pre-mux is a signal multiplexed at 12: 1 in the sub-mux, one period of which is T = 1 / (4.096 ms x 12) = 1 / 49.152 ms = 20.34 ms.

Therefore, after the channel select signal is output, the time for which the multiplexed signal of the sub-mux reaches the final stage of the receiving circuit of the master master of the rear stage and is settled with sufficient precision should be less than the period calculated before, 20.34 ms.

At this time, when the signal delay is predicted, first, the channel selection signal transmission delay is 2 ms, the sub mux circuit delay is 1 ms, the pre mux filter delay is 1 ms, the delay by multiplexing at the pre mux, and other amplifier circuits. The delay at 1 ms is about 6 ms. Therefore, the delay caused by the sub mux output cable should be less than 20.34-6 = 14.34 kHz. On the other hand, in the current output method, the smaller the terminating resistor, the smaller the settling time. It is preferable that the terminating resistor is adopted to 50 mW.

Here, the total transfer loss is calculated by multiplying the sub-mux voltage-> current conversion ratio and the current-> voltage ratio by the terminating resistor, and the transfer loss = (20 = / 5V) × 50 = 0.2 -14㏈. to be. This transmission loss is compensated by being amplified by the amplifier 230 at the later stage.

At this time, the filter 210 is for removing high-frequency noise such as a digital signal, a spike applied through a power source. When F is the main frequency component of the multiplexed input signal, F = (4.096 × 12) / 2 = 24.576 kHz, which is low frequency, but the main noise source is spike-like digital noise, which is a very high frequency component. Therefore, the cutoff frequency is preferably selected to 1MHz.

The muxes 220 and 240 are used to make a submux signal multiplexed into three or six channels into a twelve-channel multiplexed signal. At this time, it is desirable to minimize crosstalk between channels.

The compensation amplifier 230 is to compensate for the loss in the current transmission process. The signals multiplexed at mux 220,240 are applied to the input of the compensation amplifier via an RC lowpass filter. The cutoff frequency of the low pass filter is 1.6 MHz. This signal is amplified by 14 kHz to restore the input voltage level of the original submux.

Figure 4 is a block diagram showing the configuration of the sound detector master mux unit to which the present invention is applied.

The master mux multiplexes the input signals multiplexed at 12: 1 and finally outputs the multiplexed at 48: 1.

5 is a block circuit diagram of a slave logic circuit constructed in accordance with the present invention.

The slave logic performs the digital signal processing required for each of the A, B, and C groups grouping signals from 144 acoustic channels into 48 channels for each frequency band.

The slave logic, together with the master logic circuitry, functions as the digital signal control logic of the sound detector. The detailed operation of the master logic circuit is described in detail in the applicant's patent application "Master logic circuit for automatic gain control (AGC) transmission and reception and signal transmission".

Since the slave logic circuit contains a very large amount of logic circuit, it can be preferably configured using an electronically programmable logic device.

The main functions of this slave logic circuit will be described.

First, group synchronization will be described.

Various control signals of the mux of the sound detector are generated by being divided between the slave logic circuit and the master logic circuit according to the present invention. At this time, the synchronization signal SYNC and the clock signal SCLK of the master logic are inputted to the slave logic circuit so as to make the timing of the two logic circuits the same, and the timing signals for each group are generated in synchronization with the signal.

This synchronization signal is generated every frame, for example, every 4.096 ms, and the clock signal SCLK is 3.4816 MHz, which is the same as the bit rate of data transmission as a system clock.

The reception of the automatic gain control (AGC) signal will be described.

The automatic gain control (AGC) receiving circuit receives three bits of automatic gain control (AGC) data serially transmitted as a serial data signal of the master logic. The AGC signal data received in this manner is transmitted in a ship in a communication frame, while AGC1 and AGC0 are output and applied to the AGC amplifier of the master mux.

Next, the slave logic circuit controls the channel selection signal for multiplexing the premux and the master mux, the sample signal for the sample and hold circuit of the master mux, the conversion start and the high / low byte selection signal of the analog / digital converter. Generate the signal in time. In addition, the upper byte and the lower byte of the analog / digital data are sequentially read and converted into 16 bits for output.

The slave logic also constitutes a bit stream of communication data to be transmitted to the ship 40. The synchronization 1 (SYNC1), synchronization 2 frame (SYNC2 FRAME), channel data (CH DATA), automatic gain control data (AGC DATA), group identification signal (GROUP ID), and the like are inserted at the designated positions.

The slave logic circuit also includes a data coding function. In such a coding method, a signal is encoded in a Manchester method so as to recover a clock from received communication data, and then transmitted. On the other hand, in order to reduce noise at the time of transmission, it is preferable to take a scheme of differentially transmitting such data.

As described above, the present invention enables the transmission of the signal transmission from the submux of the signal transmission module of the sound detector to the ship by grouping the frequency bands of the acoustic signals, and provides a channel selection signal for multiplexing the premux and the master mux. Has the effect.

While the invention has been shown and described with respect to certain preferred embodiments, it will be appreciated that the invention can be modified and modified in various ways without departing from the spirit or scope of the invention as set forth in the claims below. Those skilled in the art will readily know.

Claims (2)

A plurality of hydrophones for detecting acoustic signals from underwater sound sources with electrical changes, a sub-mux unit for multiplexing the signals of the hydrophones, and a pre-multiplexing signal for the sub-mux units for each group according to an acoustic frequency band. In the sound detector comprising a mux unit and a main mux for multiplexing the signals of the pre-mux unit and transmitted to the ship, Signal conversion means (510) for converting and outputting an automatic gain control (AGC) signal input from the master logic circuit as serial data into respective gain level codes; The data frame is composed and output according to the synchronization signal input from the master logic circuit, and the synchronization signal SYNC and the clock signal SCLK from the master logic circuit are input, and the timing signal of each group is synchronized with this signal. Logic means 520 for generating them; And, Slave logic circuit structure, characterized in that it comprises an encoder means (530) for coding and transmitting a signal input from the main mux in Manchester. The method of claim 1, The encoder means (530) is a slave logic circuit structure, characterized in that for multiplexing 2: 2 the signal input from the main mux.