DSC signaling coding signal generator

Abstract

The utility model provides a DSC signaling coding signal generator, which enables a micro control unit (MCU) to generate required DSC signals of a local machine identification code, a digital identification system ID code, a selective call ID, a group ID, ship position and time, digital output and a distress call through keying of keys. The DSC signal amplification circuit amplifies a DSC signal output by the micro control unit MCU to a level required by the modulator in an undistorted manner; functions completed by the keys and output of digits and functions generated by the MCU are displayed on the liquid crystal display screen. According to the utility model, DSC signals of level amplitude values required by output frequency offset of different modulators can be generated, and the DSC signals are modulated by combining a high-frequency signal generator and then are output to a detected decoding module / equipment. The large-scale accurate test can be carried out on the decoding module with the digital selection calling function of the VHF-band maritime mobile communication system accurately, reliably and quickly, so that the bit error rate of the decoding module is obtained.

Description

Technical Field

[0001] The utility model relates to the technical field of digital selective calling, and more specifically, to a DSC signaling coding signal generator. Background Art

[0002] Digital Selective Calling (DSC for short) is a standard for transmitting predefined digital information through medium frequency (MF), high frequency (HF) and very high frequency (VHF) maritime radio systems. It is a core part of the Global Maritime Distress and Safety System (GMDSS). DSC signals are stable signals with narrow bands, without noise during reception, and their propagation distance is about 25% longer than that of analog signals, and the speed is also faster than that of analog signals. Ships usually use two DSC devices, VHF and MF / HF. For VHF devices, DSC has an independent receiving and transmitting channel, namely CH70. When a ship sends a distress signal, the DSC device will send the ship's own MMSI code. If the device includes GPS or is connected to an external GPS system, it can also send the coordinate position in real time, and can also send reserved distress voice and text messages when necessary. On VHF devices, signals are sent in the CH70 frequency band, and the device can wait up to 4 minutes to obtain confirmation from the coastal rescue center. If no confirmation is received, the device will repeat the distress signal alarm multiple times.

[0003] Since there is currently no standard instrument available for testing the digital selective calling function, it is necessary to provide a DSC signaling coding signal generator to be used in conjunction with a narrowband integrated tester to achieve the testing of VHF maritime devices with DSC functions. Summary of the Utility Model

[0004] In order to solve the deficiencies of the above-mentioned prior art, the purpose of the present utility model is to provide a DSC signaling coding signal generator to overcome the defects in the prior art.

[0005] To achieve the above object, the utility model provides a DSC signaling encoding signal generator, which includes a micro control unit (MCU), a key, a liquid crystal display screen, and a DSC signal amplification circuit. Among them, the micro control unit (MCU) is electrically connected and signal-connected to the key, so that by typing on the key, the micro control unit (MCU) can generate the required local identification code, digital identification system ID code, selective call ID, group ID, ship position and time, digital output, and DSC signal for distress call. The micro control unit (MCU) is electrically connected and signal-connected to the DSC signal amplification circuit, so that the DSC signal amplification circuit can amplify the DSC signal output by the micro control unit (MCU) without distortion to the level required by the modulator and output the DSC signal. The micro control unit (MCU) is electrically connected and signal-connected to the liquid crystal display screen, so that the functions completed by the key and the output of the numbers and functions generated by the micro control unit (MCU) are displayed on the liquid crystal display screen.

[0006] Through the above technical solution, the micro control unit (MCU) can generate the required local identification code, digital identification system ID code, selective call ID, group ID, ship position and time, digital output, and DSC signal for distress call according to the typing on the key, and amplify, eliminate high-frequency clutter, and filter out high-frequency components outside the band through the DSC signal amplification circuit, and amplify the DSC signal output by the micro control unit (MCU) without distortion to the level required by the modulator (Vpp = 2V). This level can meet the level amplitude value required for the output frequency deviation of different modulators. The DSC signaling encoding signal generator is mainly used in combination with a high-frequency signal generator, that is, the output end of the DSC signal amplification circuit of the DSC signaling encoding signal generator is connected to the MODULATION INPUT interface of the comprehensive tester through a feeder. The comprehensive tester can modulate the DSC signal output by the DSC signal amplification circuit to a signal source with a carrier frequency of 156.525 MHz, and then output it to the decoded module / device under test, so as to accurately, reliably, and quickly conduct a large-scale accurate test on the decoding module of the digital selective call function of the maritime mobile communication system in the VHF band, and thus obtain its bit error rate.

[0007] As a further description of the DSC signaling encoding signal generator of the present utility model, preferably, the DSC signal amplification circuit includes an operational amplifier U1A. The pin 8 of the operational amplifier U1A is respectively connected to one end of a fifth capacitor C5, one end of a sixth capacitor C6, one end of a fifth resistor R5, and one end of a fourth resistor R4. The other end of the fourth resistor R4 is respectively connected to a power supply VCC and one end of a fourth capacitor C4. The other ends of the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6 are grounded. The pin 5 of the operational amplifier U1A is respectively connected to the other end of the fifth resistor R5, one end of a third resistor R3, and one end of a second resistor R2. The other end of the second resistor R2 is connected to one end of a third capacitor C3. The other end of the third capacitor C3 is respectively connected to one end of a second capacitor C2 and one end of a first resistor R1. The other end of the first resistor R1 is respectively connected to one end of a first capacitor C1 and a microcontroller unit MCU. The other ends of the first capacitor C1, the second capacitor C2, and the third resistor R3 are all grounded. The pin 1 of the operational amplifier U1A is respectively connected to one end of an eighth resistor R8 and one end of a seventh resistor R7. The other end of the seventh resistor R7 is respectively connected to the pin 6 of the operational amplifier U1A and one end of a sixth resistor R6. The other end of the sixth resistor R6 is connected to one end of a ninth capacitor C9. The other end of the ninth capacitor C9 is grounded. The other end of the eighth resistor R8 is connected to one end of a seventh capacitor C7. The other end of the seventh capacitor C7 is connected to one end of a ninth resistor R9. The other end of the ninth resistor R9 is connected to one end of an eighth capacitor C8. The other end of the eighth capacitor C8 serves as the DSC signal output terminal. The pin 4 of the operational amplifier U1A is grounded.

[0008] Through the above technical solution, the DSC signal amplification circuit is different from a conventional signal amplification circuit in that it only amplifies the DSC signal, suppresses the remaining interference signals above 11 KHz and below 16 Hz, can amplify the amplitude of the input signal by 3 times to achieve the required modulation deviation frequency, suppresses the signals above 11 KHz, and suppresses the signals near 16 Hz and below.

[0009] As a further description of the DSC signaling encoding signal generator of the present utility model, preferably, the keys include a control key, numeric keys, and a DISTRESS key. The control key is used to control the input and output of the local identification code, digital identification system ID code, selective call ID, group ID, ship position and time, digital output, and the sending of distress calls. The numeric keys are used to input the local identification code, digital identification system ID code, selective call ID, group ID, ship position and time, and digital output. The DISTRESS key is used to send distress calls.

[0010] Through the above technical solution, different types of DSC signals corresponding to the above inputs are output by the micro control unit MCU1 through key operations.

[0011] As a further description of the DSC signaling encoding signal generator of the present invention, preferably, the local identification code is a 9-digit MMSI code.

[0012] As a further description of the DSC signaling encoding signal generator of the present invention, preferably, the digital identification system ID code is an automatically transmitted 10-digit ATIS code.

[0013] As a further description of the DSC signaling encoding signal generator of the present invention, preferably, the distress call is a distress call sent by the DISTRESS button on the key.

[0014] As a further description of the DSC signaling encoding signal generator of the present invention, preferably, the micro control unit MCU includes information obtained from the NMEA-0183 port, so that the DA output of the micro control unit MCU includes DSC signals containing NMEA-0183 information.

[0015] As a further description of the DSC signaling encoding signal generator of the present invention, preferably, the digital output is information output through the NMEA-0183 port.

[0016] The beneficial effects of the present invention are as follows: For the DSC signaling encoding signal generator of the present invention, its micro control unit MCU can generate the required local identification code, digital identification system ID code, selective call ID, group ID, ship position and time, digital output, and DSC signal of the distress call according to the key input, and amplify the DSC signal through the DSC signal amplification circuit, eliminate high-frequency clutter, and filter out high-frequency components outside the band, and amplify the DSC signal output by the micro control unit MCU without distortion to the level required by the modulator (Vpp = 2V), and this level can meet the level amplitude value required for the output frequency deviation of different modulators. By connecting the output end of the DSC signal amplification circuit of the DSC signaling encoding signal generator to the MODULATION INPUT interface of the comprehensive tester through a feeder, the comprehensive tester can modulate the DSC signal output by the DSC signal amplification circuit to a signal source with a carrier frequency of 156.525 MHz, and then output it to the measured decoding module / device, and can accurately, reliably, and quickly conduct large-scale accurate tests on the decoding module of the digital selective call function of the maritime mobile communication system in the VHF band, so as to obtain its bit error rate. Description of the Drawings

[0017] Figure 1 It is a structural schematic diagram of the DSC signaling encoding signal generator;

[0018] Figure 2 It is the circuit diagram of the DSC signal amplification circuit. Specific implementation mode

[0019] In order to further understand the structure, features and other purposes of the present invention, the following is a detailed description with reference to the attached preferred embodiments and accompanying drawings. The embodiments described by these drawings are only used to illustrate the technical solutions of the present invention and do not limit the present invention.

[0020] In the first implementation mode of the present invention, as Figure 1 shown, a DSC signaling encoding signal generator includes a microcontroller unit MCU1, a key 2, a liquid crystal display screen 3, and a DSC signal amplification circuit 4.

[0021] The microcontroller unit MCU1 is electrically connected and signal-connected to the key 2, so that the microcontroller unit MCU1 generates the required 9-digit local identification code (MMSI code), automatically transmits the 10-digit identification system ID code (ATIS code), selective call ID, group ID, ship position and time, digital output (i.e., positioning information) output through the NMEA-0183 port, and DSC signal of distress call sent by the DISTRESS key when the key 2 is pressed. Among them, the microcontroller unit MCU1 includes the information obtained from the NMEA-0183 port, so that the DA output of the microcontroller unit MCU1 contains the DSC signal with NMEA-0183 information.

[0022] The microcontroller unit MCU1 is electrically connected and signal-connected to the DSC signal amplification circuit 4, so that the DSC signal amplification circuit 4 amplifies the DSC signal output by the microcontroller unit MCU1 without distortion to the level required by the modulator and outputs the DSC signal.

[0023] The microcontroller unit MCU1 is electrically connected and signal-connected to the liquid crystal display screen 3, so that the functions completed by the key 2 and the numbers and functions generated by the microcontroller unit MCU1 are displayed on the liquid crystal display screen 3.

[0024] In the DSC signaling encoding signal generator of this embodiment, the microcontroller unit (MCU) can generate the required 9-digit local identification code (MMSI code) according to the key input, automatically transmit the 10-digit identification system ID code (ATIS code), selective call ID, group ID, ship position and time, digital output through the NMEA0183 port, DSC signal of the distress call sent by the DISTRESS key, amplify it through the DSC signal amplification circuit, eliminate high-frequency clutter (LPF AMP) to filter out high-frequency components outside the band, and amplify the DSC signal output by the microcontroller unit (MCU) without distortion to the level required by the modulator (Vpp = 2V). This level can meet the level amplitude values required for different modulator output frequency deviations.

[0025] The DSC signaling encoding signal generator in this embodiment is mainly used in combination with a high-frequency (250KHz - 1000MHz) signal generator, that is, the output end of the DSC signal amplification circuit 4 of the DSC signaling encoding signal generator is connected to the MODULATION INPUT interface of an integrated tester (such as HP8921A) through a feeder. The integrated tester can modulate the DSC signal output by the DSC signal amplification circuit to a signal source with a carrier frequency of 156.525MHz, and then output it to the decoding module / device under test, so as to accurately, reliably and quickly conduct large-scale accurate tests on the decoding module of the digital selective call function of the maritime mobile communication system in the VHF band, and thus obtain its bit error rate.

[0026] In the second embodiment of the present utility model, as Figure 2As shown, the DSC signal amplification circuit 4 includes an operational amplifier U1A. Pin 8 of the operational amplifier U1A is respectively connected to one end of the fifth capacitor C5, one end of the sixth capacitor C6, one end of the fifth resistor R5, and one end of the fourth resistor R4. The other end of the fourth resistor R4 is respectively connected to the power supply VCC and one end of the fourth capacitor C4. The other ends of the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6 are grounded. Pin 5 of the operational amplifier U1A is respectively connected to the other end of the fifth resistor R5, one end of the third resistor R3, and one end of the second resistor R2. The other end of the second resistor R2 is connected to one end of the third capacitor C3. The other end of the third capacitor C3 is respectively connected to one end of the second capacitor C2 and one end of the first resistor R1. The other end of the first resistor R1 is respectively connected to one end of the first capacitor C1 and the microcontroller unit MCU1. The other ends of the first capacitor C1, the second capacitor C2, and the third resistor R3 are all grounded. Pin 1 of the operational amplifier U1A is respectively connected to one end of the eighth resistor R8 and one end of the seventh resistor R7. The other end of the seventh resistor R7 is respectively connected to pin 6 of the operational amplifier U1A and one end of the sixth resistor R6. The other end of the sixth resistor R6 is connected to one end of the ninth capacitor C9. The other end of the ninth capacitor C9 is grounded. The other end of the eighth resistor R8 is connected to one end of the seventh capacitor C7. The other end of the seventh capacitor C7 is connected to one end of the ninth resistor R9. The other end of the ninth resistor R9 is connected to one end of the eighth capacitor C8. The other end of the eighth capacitor C8 serves as the DSC signal output terminal. Pin 4 of the operational amplifier U1A is grounded.

[0027] In this embodiment, the DSC signal amplification circuit 4 is different from the conventional signal amplification circuit in that it only amplifies the DSC signal, suppresses the remaining interference signals above 11KHz and below 16Hz, can amplify the amplitude of the input signal by 3 times to achieve the required modulation deviation frequency, suppresses the signals above 11KHz, and suppresses the signals near below 16Hz.

[0028] In the third embodiment of the present utility model, the key 2 includes a control key, numeric keys, and a DISTRESS key, and is used to input the 9-digit ship station identification number (MMSI number), automatically transmit the 10-digit identification system ID code (ATIS code), selective call ID, group ID, ship position and time, digital output through the NMEA0183 port, and the distress call sent by the DISTRESS key. Furthermore, the micro control unit MCU1 outputs different types of DSC signals corresponding to the above inputs. For example, if only the 9-digit ship station identification number (MMSI number) is input through the key 2, the micro control unit MCU1 outputs a DSC signal containing the information of the 9-digit ship station identification number (MMSI number). The DSC signaling coding signal generator generates the DSC signal of the above information to meet the test of decoding the above information by the decoding module for the digital selective calling function.

[0029] It should be noted that the above content of the utility model and the specific implementation manners are intended to prove the practical application of the technical solution provided by the present utility model, and should not be construed as a limitation of the protection scope of the present utility model. Those skilled in the art can make various modifications, equivalent replacements, or improvements within the spirit and principle of the present utility model. The protection scope of the present utility model shall be subject to the appended claims.

Claims

1. A DSC signaling coding signal generator, characterized in that: It comprises a microcontroller unit MCU (1), a key (2), a liquid crystal display screen (3) and a DSC signal amplifying circuit (4); wherein: The microcontroller unit MCU (1) is electrically connected to the key (2) and is signal-connected so that the microcontroller unit MCU (1) generates a required local identification code, a digital identification system ID code, a selective call ID, a group ID, a ship position and time, a digital output, and a DSC signal for a distress call by pressing the key (2); The micro control unit MCU (1) is electrically and signal-connected to a DSC signal amplifying circuit (4), so that the DSC signal amplifying circuit (4) amplifies the DSC signal output by the micro control unit MCU (1) to a level required by a modulator without distortion and outputs the DSC signal; The microcontroller unit MCU (1) is electrically and signal-connected to a liquid crystal display screen (3), so that the functions completed by the keys (2) and the digital and functional outputs generated by the microcontroller unit MCU (1) are displayed on the liquid crystal display screen (3).

2. The DSC signaling coding signal generator according to claim 1, characterized in that: The DSC signal amplifying circuit (4) comprises an operational amplifier U1A, wherein a pin 8 of the operational amplifier U1A is respectively connected to one end of a fifth capacitor C5, one end of a sixth capacitor C6, one end of a fifth resistor R5, and one end of a fourth resistor R4, the other end of the fourth resistor R4 is respectively connected to a power supply VCC and one end of a fourth capacitor C4, and the other end of the fourth capacitor C4, the other end of the fifth capacitor C5, and the other end of the sixth capacitor C6 are grounded; The pin 5 of the operational amplifier U1A is respectively connected to the other end of the fifth resistor R5, one end of the third resistor R3 and one end of the second resistor R2; the other end of the second resistor R2 is connected to one end of the third capacitor C3; the other end of the third capacitor C3 is respectively connected to one end of the second capacitor C2 and one end of the first resistor R1; the other end of the first resistor R1 is respectively connected to one end of the first capacitor C1 and the microcontroller unit MCU (1); the other end of the first capacitor C1, the other end of the second capacitor C2 and the other end of the third resistor R3 are all grounded; Pin 1 of the operational amplifier U1A is respectively connected to one end of the eighth resistor R8 and one end of the seventh resistor R7, the other end of the seventh resistor R7 is respectively connected to pin 6 of the operational amplifier U1A and one end of the sixth resistor R6, the other end of the sixth resistor R6 is connected to one end of the ninth capacitor C9, and the other end of the ninth capacitor C9 is grounded; the other end of the eighth resistor R8 is connected to one end of the seventh capacitor C7, the other end of the seventh capacitor C7 is connected to one end of the ninth resistor R9, the other end of the ninth resistor R9 is connected to one end of the eighth capacitor C8, and the other end of the eighth capacitor C8 serves as a DSC signal output end; pin 4 of the operational amplifier U1A is grounded.

3. The DSC signaling coding signal generator according to claim 1, characterized in that: The keys (2) include control keys, numeric keys and a DISTRESS key; the control keys are used to control the input and output of the local identification code, the digital identification system ID code, the selective call ID, the group ID, the ship's position and time, the digital output and the sending of the distress call; the numeric keys are used to input the local identification code, the digital identification system ID code, the selective call ID, the group ID, the ship's position and time, the digital output; and the DISTRESS key is used to send the distress call.

4. The DSC signaling coding signal generator as claimed in claim 3, characterized in that: The local identification code is a 9-digit MMSI code.

5. The DSC signaling coding signal generator as claimed in claim 3, characterized in that: The digital identification system ID code is an automatically transmitted 10-digit ATIS code.

6. The DSC signaling coding signal generator as claimed in claim 3, characterized in that: The distress call is a distress call sent by the DISTRESS button in the button (2).

7. The DSC signaling coding signal generator according to claim 1, characterized in that: The micro control unit MCU (1) includes information obtained by the NMEA-0183 port, so that the DA of the micro control unit MCU (1) outputs a DSC signal containing the NMEA-0183 information.

8. The DSC signaling coding signal generator as claimed in claim 7, characterized in that: The digital output is information output via the NMEA-0183 port.

Images