CN112290941A - Modulation signal generation method, modulation signal generator and signal transmitter for civil aviation navigation equipment - Google Patents
Modulation signal generation method, modulation signal generator and signal transmitter for civil aviation navigation equipment Download PDFInfo
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- H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION, OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
- H03L7/00—Automatic control of frequency or phase; Synchronisation
- H03L7/24—Automatic control of frequency or phase; Synchronisation using a reference signal directly applied to the generator
Abstract
The invention provides a modulation signal generation method, a modulation signal generator and a signal transmitter for civil aviation navigation equipment, which comprise the following steps: generating a carrier signal, an upper sideband signal, a lower sideband signal and a 30Hz frequency modulation signal, and synthesizing the upper sideband signal and the lower sideband signal to generate a spatial synthesis signal of an upper sideband and a lower sideband; receiving a negative feedback adjustment signal to adjust a phase difference between the spatially combined signal and the carrier signal; reading a preset identification code signal of 1020 Hz; generating a spatial modulation signal through a carrier signal, an upper sideband signal, a lower sideband signal, a spatial synthesis signal of an upper sideband and a lower sideband, a 30Hz frequency modulation signal and a 1020Hz identification code signal, and performing high-frequency carrier modulation on a low-frequency local signal through the spatial modulation signal to generate and transmit five paths of radio frequency signals; the five paths of radio frequency signals comprise carrier signals and four paths of sideband signals; the method has the beneficial effects of higher phase control precision and higher equipment stability, and is suitable for the field of civil aviation navigation equipment.
Description
Technical Field
The invention relates to the technical field of civil aviation navigation equipment, in particular to a modulation signal generation method, a modulation signal generator and a signal transmitter for the civil aviation navigation equipment.
Background
Over the years, the implementation means of international civil aviation navigation equipment mainly adopts analog technology, particularly beacon and instrument landing equipment, so that the signal synthesis and modulation process is very complex, and in addition, the adjustment of the signal phase usually needs a large number of analog circuits to form, so that the function usually needs at least more than 5 plates, and the equipment is huge in size and complex in heat energy management.
In recent years, with the development of DDS (direct digital frequency synthesizer) technology, it has become possible to synthesize signals using digital technology and implement modulation and phase adjustment of signals inside a chip; the technology can greatly reduce the research and development cost and research and development period of equipment.
However, in the prior art, the digital signal synthesis is adopted, and due to quantization errors, digital-to-analog conversion errors and the like, the problems of low phase control precision and poor equipment stability exist.
Disclosure of Invention
Aiming at the defects in the related technology, the technical problem to be solved by the invention is as follows: a modulation signal generation method, a modulation signal generator and a signal transmitter for civil aviation navigation equipment are provided, which can effectively provide phase control precision and improve equipment stability.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a method for generating a modulated signal for civil aviation navigation equipment, comprising the steps of:
generating a carrier signal, an upper sideband signal, a lower sideband signal and a 30Hz frequency modulation signal, and synthesizing the upper sideband signal and the lower sideband signal to generate a spatial synthesis signal of an upper sideband and a lower sideband;
receiving a negative feedback adjustment signal to adjust a phase difference between the spatially combined signal and the carrier signal;
reading a preset identification code signal of 1020 Hz;
generating a spatial modulation signal through the carrier signal, the upper sideband signal, the lower sideband signal, the spatial synthesis signal of the upper sideband and the lower sideband, the 30Hz frequency modulation signal and the 1020Hz identification code signal, and performing high-frequency carrier modulation on a low-frequency local signal through the spatial modulation signal to generate and transmit five paths of radio frequency signals; wherein: the five radio frequency signals comprise: a carrier signal and four sideband signals.
Preferably, the receiving negative feedback adjusting signal is used for adjusting the phase difference between the space synthesis signal and the carrier signal, and the amplitude adjusting signal and the phase adjusting signal are calculated through the following process;
sampling a carrier signal and upper and lower sideband signals in N carrier periods;
normalizing the sampled data, delaying and comparing the phases, and calculating the phase difference between the space synthesis signal and the carrier signal;
a negative feedback adjustment signal including an amplitude adjustment signal and a phase adjustment signal is output according to the phase difference data.
Accordingly, a modulated signal generator for a civil aviation navigation device, comprising:
the signal generating unit is used for generating a carrier signal, an upper sideband signal, a lower sideband signal and a 30Hz frequency modulation signal, and synthesizing the upper sideband signal and the lower sideband signal to generate a spatial synthesis signal of an upper sideband and a lower sideband;
the signal adjusting unit is used for receiving a negative feedback adjusting signal sent by the external feedback function module so as to adjust the phase difference between the space synthesis signal and the carrier signal;
the signal modulation unit is used for generating a spatial modulation signal through the carrier signal, the upper sideband signal, the lower sideband signal, the spatial synthesis signal of the upper sideband and the lower sideband, the 30Hz frequency modulation signal and the 1020Hz identification code signal stored in the ROM storage unit; carrying out high-frequency carrier modulation on a low-frequency local signal through a spatial modulation signal;
the signal transmitting unit is used for generating and transmitting five paths of radio frequency signals from the modulated high-frequency carrier signals; wherein: the five radio frequency signals comprise: a carrier signal and a four-way sideband signal;
a ROM storage unit for storing 2020Hz identification code signal, 2020Hz identification code signal and sampling clock signal;
the external feedback function module is used for sending working state parameters of the spatial modulation signals to the system control module; receiving a negative feedback adjusting signal output by the system control module, and sending the negative feedback adjusting signal to the signal adjusting unit; wherein: the negative feedback adjustment signal comprises: amplitude adjustment and phase adjustment signals;
the system control module is used for spatially modulating the working state parameters of the signals, comparing the working state parameters with user configuration list data of the transmitter and outputting negative feedback adjustment signals for maintaining the working state parameters stable.
Preferably, the negative feedback adjustment signal output by the system control module is calculated through the following process;
the sampling unit is used for sampling the carrier signal and the upper and lower sideband signals in N carrier periods;
the computing unit is used for normalizing the sampling data, delaying and comparing the phase and computing the phase difference between the space synthesis signal and the carrier signal;
and the output unit is used for outputting a negative feedback adjusting signal containing an amplitude adjusting signal and a phase adjusting signal according to the phase difference data.
Accordingly, a signal transmitter for a civil aviation navigation device, comprising:
the signal input module is used for being connected with external signal input equipment, receiving the ground-air voice signals, performing analog-to-digital conversion on the ground-air voice signals and then sending the ground-air voice signals to the FPGA module;
FPGA module, its input is connected with signal input module's output electricity for carry out high frequency carrier modulation to ground air voice signal, include: a modulation signal generator and a ROM storage unit;
the modulation signal generator includes:
the signal generating unit is used for generating a carrier signal, an upper sideband signal, a lower sideband signal and a 30Hz frequency modulation signal, and synthesizing the upper sideband signal and the lower sideband signal to generate a spatial synthesis signal of an upper sideband and a lower sideband;
the signal adjusting unit is used for receiving a negative feedback adjusting signal sent by the external feedback function module so as to adjust the phase difference between the space synthesis signal and the carrier signal;
the signal modulation unit is used for generating a spatial modulation signal through the carrier signal, the upper sideband signal, the lower sideband signal, the spatial synthesis signal of the upper sideband and the lower sideband, the 30Hz frequency modulation signal and the 1020Hz identification code signal stored in the ROM storage unit; carrying out high-frequency carrier modulation on a low-frequency local signal through a spatial modulation signal;
the signal transmitting unit is used for generating and transmitting five paths of radio frequency signals from the modulated high-frequency carrier signals; wherein: the five radio frequency signals comprise: a carrier signal and a four-way sideband signal;
a ROM storage unit for storing 1020Hz identification code signal and for storing sampling clock signal;
the power amplification module is used for amplifying the signals of the five paths of radio frequency signals and loading the signals into the antenna module;
the antenna module is used for transmitting five paths of radio frequency signals;
the power supply module is used for supplying power to the whole signal generator;
the external feedback function module is used for sending working state parameters of the spatial modulation signals to the system control module; receiving a negative feedback adjusting signal output by the system control module, and sending the negative feedback adjusting signal to the signal adjusting unit; wherein: the negative feedback adjustment signal comprises: amplitude adjustment and phase adjustment signals;
the system control module is used for spatially modulating the working state parameters of the signals, comparing the working state parameters with user configuration list data of the transmitter and outputting negative feedback adjustment signals for maintaining the working state parameters stable.
Preferably, the negative feedback adjustment signal output by the system control module is calculated through the following process;
the sampling unit is used for sampling the carrier signal and the upper and lower sideband signals in N carrier periods;
the computing unit is used for normalizing the sampling data, delaying and comparing the phase and computing the phase difference between the space synthesis signal and the carrier signal;
and the output unit is used for outputting a negative feedback adjusting signal containing an amplitude adjusting signal and a phase adjusting signal according to the phase difference data.
Preferably, the method further comprises the following steps: the updating module is used for sending phase difference data updated by a user to the system control module through the external feedback function module;
the system control module is further configured to: and updating the user configuration list according to the phase difference data updated by the user.
Preferably, the power supply module includes: the output of relay, its power end and external power supply circuit links to each other, and its control end is connected with external system control signal's output electricity, external system control signal includes: a switch control signal for controlling the relay to close;
the input end of the first power supply chip is connected with the first power supply output end of the relay and used for receiving and outputting a first power supply signal to provide power supply for the FPGA module;
and the input end of the second power supply chip is connected with the second power supply output end of the relay and is used for receiving and outputting a second power supply signal to provide power supply for the power amplification module.
The invention has the beneficial technical effects that:
1. the modulation signal generation method, the modulation signal generator and the signal transmitter for the civil aviation navigation equipment adjust the phase difference between the space synthesis signal and the carrier signal by receiving the negative feedback adjustment signal, greatly improve the accuracy of phase control and improve the stability of the equipment.
2. In the invention, in order to ensure the stability of the phase difference between the carrier signal and the upper and lower sidebands, four paths of signals of the upper and lower sidebands are added to form a composite signal of the upper and lower sidebands in space; meanwhile, in a system control module, the phase difference between the synthesized signal and the carrier signal is calculated by sampling the carrier and the upper and lower sideband signals in N carrier cycles, normalizing the sampled data and then delaying and comparing the phases; and negative feedback is performed on the transmitter, so that the transmitter adjusts the phase difference between the carrier signal and the synthesized signal by adjusting the phase adjusting word, and the practicability is strong.
3. In the invention, the phase of a reference phase signal is locked to a 30Hz synchronous signal, and when the rising edge of the 30Hz synchronous signal appears, the No. 1 antenna starts to transmit a cosine signal of a transmitter, and the No. 2 antenna starts to transmit a sine signal; this ensures that the 30Hz FM is locked in phase with respect to the reference signal, thereby ensuring the stability of the orientation of the outfield signal seen by the monitoring antenna
4. In the invention, the focus of attention is placed on the working state parameters of five paths of output radio frequency signals, and the important working state parameters comprise the frequency and the forward amplitude of the signals (because of the change of load impedance, the power cannot be detected, only the load impedance can be assumed to be ideal 50ohm, meanwhile, the reflected signals pass through a circulator to give a dummy load), the phase advance of carrier signals relative to sideband synthetic signals, the modulation degree of 30HzAM of the carrier, the modulation degree of 1020Hz, identification codes, the amplitude (peak value) of the sideband and the like; the values are returned to the system control module through the external feedback function module, and the system control module sends a negative feedback adjustment instruction to the transmitter according to the values and data in a user configuration list, so that the stability of the important parameters can be maintained, and the working consistency of the transmitter is ensured.
Drawings
FIG. 1 is a schematic flow chart of a modulation signal generation method for civil aviation navigation equipment according to an embodiment of the invention;
FIG. 2 is a schematic structural diagram of a modulated signal generator for civil aviation navigation equipment according to an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of a signal transmitter for civil aviation navigation equipment according to an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of a signal transmitter for civil aviation navigation equipment according to a second embodiment of the present invention;
FIG. 5 is a schematic structural diagram of a signal transmitter for civil aviation navigation equipment according to a third embodiment of the present invention;
in the figure: 10 is a signal input module, 20 is an FPGA module, 30 is a power amplifier module, 40 is an antenna module, 50 is a power supply module, 60 is an external feedback function module, and 70 is a system control module;
201 is a modulation signal generator, 202 is a ROM storage unit, and 203 is an updating module;
2011 is a signal generating unit, 2012 is a signal adjusting unit, 2013 is a signal modulating unit, 2014 is a signal emitting unit;
501 is a relay, 502 is a first power supply chip, 503 is a second power supply chip;
701 is a sampling unit, 702 is a calculation unit, and 703 is an output unit.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments, but not all embodiments, of the present invention; all other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Next, the present invention will be described in detail with reference to the drawings, wherein the cross-sectional views illustrating the structure of the device are not enlarged partially according to the general scale for convenience of illustration when describing the embodiments of the present invention, and the drawings are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in the actual fabrication.
An embodiment of the modulated signal generating method, the modulated signal generator and the signal transmitter for civil aviation navigation equipment according to the invention is described in detail below with reference to the accompanying drawings.
FIG. 1 is a schematic flow chart of a modulation signal generation method for civil aviation navigation equipment according to an embodiment of the invention; as shown in fig. 1, the method for generating a modulated signal for civil aviation navigation equipment comprises the following steps:
generating a carrier signal, an upper sideband signal, a lower sideband signal and a 30Hz frequency modulation signal, and synthesizing the upper sideband signal and the lower sideband signal to generate a spatial synthesis signal of an upper sideband and a lower sideband;
receiving a negative feedback adjustment signal to adjust a phase difference between the spatially combined signal and the carrier signal;
reading a preset identification code signal of 1020 Hz;
generating a spatial modulation signal through the carrier signal, the upper sideband signal, the lower sideband signal, the spatial synthesis signal of the upper sideband and the lower sideband, the 30Hz frequency modulation signal and the 1020Hz identification code signal, and performing high-frequency carrier modulation on a low-frequency local signal through the spatial modulation signal to generate and transmit five paths of radio frequency signals;
wherein: the five radio frequency signals comprise: a carrier signal and four sideband signals.
Specifically, the receiving negative feedback adjusting signal is used for adjusting the phase difference between the space synthesis signal and the carrier signal, and the amplitude adjusting signal and the phase adjusting signal are calculated through the following processes;
sampling a carrier signal and upper and lower sideband signals in N carrier periods;
normalizing the sampled data, delaying and comparing the phases, and calculating the phase difference between the space synthesis signal and the carrier signal;
a negative feedback adjustment signal including an amplitude adjustment signal and a phase adjustment signal is output according to the phase difference data.
FIG. 2 is a schematic structural diagram of a modulated signal generator for civil aviation navigation equipment according to an embodiment of the present invention; as shown in fig. 2, the modulated signal generator for civil aviation navigation equipment comprises:
a signal generating unit 2011, configured to generate a carrier signal, an upper sideband signal, a lower sideband signal, and a 30Hz frequency modulation signal, and synthesize the upper sideband signal and the lower sideband signal to generate a spatial synthesis signal of an upper sideband and a lower sideband;
a signal adjusting unit 2012, configured to receive a negative feedback adjusting signal sent by the external feedback function module 60, so as to adjust a phase difference between the spatial synthesis signal and the carrier signal;
a signal modulation unit 2013, configured to generate a spatial modulation signal from the carrier signal, the upper sideband signal, the lower sideband signal, the spatial synthesis signal of the upper and lower sidebands, the 30Hz frequency modulation signal, and the 1020Hz identification code signal stored in the ROM storage unit 202; carrying out high-frequency carrier modulation on a low-frequency local signal through a spatial modulation signal;
the signal transmitting unit 2014 is used for generating and transmitting five paths of radio frequency signals from the modulated high-frequency carrier signal; wherein: the five radio frequency signals comprise: a carrier signal and a four-way sideband signal;
a ROM storage unit 202 for storing the 2020Hz identification code signal, and storing the sampling clock signal;
an external feedback function module 60, configured to send an operating state parameter of the spatial modulation signal to the system control module 70; receiving a negative feedback adjustment signal output by the system control module 70, and sending the negative feedback adjustment signal to the signal adjustment unit 2012; wherein: the negative feedback adjustment signal comprises: amplitude adjustment and phase adjustment signals;
the system control module 70 is configured to spatially modulate the operating state parameter of the signal, compare the operating state parameter with the user configuration list data of the transmitter, and output a negative feedback adjustment signal for maintaining the operating state parameter stable.
Specifically, the negative feedback adjustment signal output from the system control module 70 is calculated through the following process;
a sampling unit 701, configured to sample a carrier signal and upper and lower sideband signals in N carrier periods;
a calculating unit 702, configured to normalize the sampled data, compare the phases in a delayed manner, and calculate a phase difference between the spatial composite signal and the carrier signal;
an output unit 703 is configured to output a negative feedback adjustment signal including an amplitude adjustment signal and a phase adjustment signal according to the phase difference data.
FIG. 3 is a schematic structural diagram of a signal transmitter for civil aviation navigation equipment according to an embodiment of the present invention; as shown in fig. 3, the signal transmitter for civil aviation navigation equipment comprises:
the signal input module 10 is used for being connected with external signal input equipment, receiving the ground-air voice signals, performing analog-to-digital conversion on the ground-air voice signals, and then sending the ground-air voice signals to the FPGA module 20;
the FPGA module 20, whose input end is electrically connected with the output end of the signal input module 10, is used for performing high-frequency carrier modulation on the ground-air voice signal, and includes: a modulation signal generator 201 and a ROM storage unit 202;
the modulation signal generator 201 includes:
a signal generating unit 2011, configured to generate a carrier signal, an upper sideband signal, a lower sideband signal, and a 30Hz frequency modulation signal, and synthesize the upper sideband signal and the lower sideband signal to generate a spatial synthesis signal of an upper sideband and a lower sideband;
a signal adjusting unit 2012, configured to receive a negative feedback adjusting signal sent by the external feedback function module 60, so as to adjust a phase difference between the spatial synthesis signal and the carrier signal;
a signal modulation unit 2013, configured to generate a spatial modulation signal from the carrier signal, the upper sideband signal, the lower sideband signal, the spatial synthesis signal of the upper and lower sidebands, the 30Hz frequency modulation signal, and the 1020Hz identification code signal stored in the ROM storage unit 202; carrying out high-frequency carrier modulation on a low-frequency local signal through a spatial modulation signal;
the signal transmitting unit 2014 is used for generating and transmitting five paths of radio frequency signals from the modulated high-frequency carrier signal; wherein: the five radio frequency signals comprise: a carrier signal and a four-way sideband signal;
a ROM storage unit 202 for storing the 1020Hz identification code signal and for storing the sampling clock signal;
the power amplifier module 30 is used for amplifying the five radio frequency signals and loading the signals into the antenna module 40;
the antenna module 40 is used for transmitting five radio frequency signals;
a power supply module 50 for supplying power to the entire signal generator;
the external feedback function module 60 is bidirectionally connected with the system control module 70 and is used for sending the working state parameters of the spatial modulation signals to the system control module 70; receiving a negative feedback adjustment signal output by the system control module 70, and sending the negative feedback adjustment signal to the signal adjustment unit 2012; wherein: the negative feedback adjustment signal comprises: amplitude adjustment and phase adjustment signals;
the system control module 70 is configured to spatially modulate the operating state parameter of the signal, compare the operating state parameter with the user configuration list data of the transmitter, and output a negative feedback adjustment signal for maintaining the operating state parameter stable.
Specifically, the negative feedback adjustment signal output from the system control module 70 is calculated through the following process; a sampling unit 701, configured to sample a carrier signal and upper and lower sideband signals in N carrier periods; a calculating unit 702, configured to normalize the sampled data, compare the phases in a delayed manner, and calculate a phase difference between the spatial composite signal and the carrier signal; an output unit 703 is configured to output a negative feedback adjustment signal including an amplitude adjustment signal and a phase adjustment signal according to the phase difference data.
Specifically, the ROM storage unit 202 is used for storing an identification code signal of 1020Hz and storing a sampling clock signal; the setting mode ensures that the identification code in the transmitter cannot be changed by a user at will, and can be set only when the transmitter is out of the factory or is returned to the factory; the identification code data comprises: 1 represents a point, and 0 represents a bar; the transmitter can define the time sequence of the identification code transmission according to the 12-bit identification code data, and after the time sequence is determined, the transmitter can read 1020Hz sampling data to transmit.
In this embodiment, a DDS technique is used to generate signals of three frequencies, namely: a carrier signal, an upper sideband signal, and a lower sideband signal, wherein: the frequency range of the carrier signal is: 108MHz to 117.975MHz, and in the present embodiment, the carrier frequency is 113MHz as the center frequency; can be provided with: carrier frequency of, upper sideband frequency of
With a lower sideband frequency of
Frequency advance of the upper sideband relative to the spatially combined upper and lower sidebands
。
According to the principle of the DDS technique, the design flow of the upper and lower sidebands and the carrier signal is as follows (for convenience of explanation, the phase values of the carrier are omitted from the above formulas in this embodiment):
(1) using matlab to generate a frequency of
The sampling points of the sine signal and the cosine signal are the same, so that the phase truncation is ensured to be the same, namely the sine signal and the cosine signal are still in phase synchronization after a period of time;
(2) using matlab to generate a frequency of
The Hz sine and cosine signals ensure the same number of sampling points, thus ensuring that the phases of the two signals are still synchronous after a period of time;
(3) according to the sum-difference product formula:
and
because the sine signal and the cosine signal of the 9960Hz frequency have the same error and
hz generates the same truncation phase error, so that the phase of the leading carrier of the upper edge band is equal to the phase of the leading lower edge of the carrier;
the spatial composite signal of the upper and lower sidebands is:
；
the transmission signals of the carrier channel are:
；
(4) the error caused by phase truncation is only that the phase of the 9960Hz modulation signal of the spatial composite signal of the upper and lower sidebands is changed, and the phase of 30Hz FM can be changed; by locking the phase of the reference phase signal to the 30Hz sync signal, antenna No. 1 starts transmitting the cosine signal and antenna No. 2 starts transmitting the sine signal whenever the rising edge of the 30Hz sync signal occurs; thus, the locking of the 30Hz FM relative to the phase of the reference signal is ensured, and the stability of the azimuth of the external field signal seen by the monitoring antenna is ensured; therefore, the external feedback functional module only needs to stably adjust the relative phase of the reference signal relative to the synchronous signal through negative feedback.
According to the design process of the upper and lower sidebands and the carrier signal, in order to ensure the stability of the phase difference between the carrier signal and the upper and lower sidebands, the four paths of signals of the upper and lower sidebands are added to form a composite signal of the upper and lower sidebands in space; in a system control module, sampling carrier and upper and lower sideband signals in N carrier cycles, normalizing sampling data, and then delaying and comparing phases to calculate the phase difference between a synthesized signal and the carrier signal; and the transmitter can carry out negative feedback to the transmitter according to the phase difference data updated by the user last time, and the transmitter adjusts the phase difference between the carrier signal and the synthesized signal by adjusting the phase adjusting word.
According to the modulation signal generation method, the modulation signal generator and the signal transmitter for the civil aviation navigation equipment, the phase difference between the space synthesis signal and the carrier signal is adjusted by receiving the negative feedback adjustment signal, so that the phase control precision is greatly improved, and the stability of the equipment is improved.
Further, the signal transmitter provided by the present invention will provide improvements in many respects compared with the conventional navigation device, and the user of the conventional navigation device provides a lot of parameter setting opportunities, and the user determines the important parameter settings of the device, such as various modulation degrees, phases, powers, etc., but these device parameters will cause unstable phenomena such as drift of the transmitter parameters after the device is operated for a long time or some board of the transmitter is replaced, especially after the important components of the transmitter are replaced, and the problem is that the device still needs not to be calibrated, that is, the device has to confirm the working state and the important parameters of the device by calibration to a large extent.
In order to ensure the consistency of the operation of the transmitter, the invention puts the focus of attention on the operating state parameters of the five paths of output radio frequency signals, and the important operating state parameters comprise the frequency of the signals, the forward amplitude (because of the change of load impedance, it is impossible to detect the power, only the load impedance can be assumed to be ideal 50ohm, meanwhile, the reflected signals pass through a circulator to give a dummy load), the phase advance of the carrier signals relative to the sideband synthetic signals, the modulation degree of 30HzAM of the carrier, the modulation degree of 1020Hz, the identification codes, the amplitude (peak-to-peak value) of the sideband, and the like; the values are returned to the system control module through the external feedback function module, and the system control module sends a negative feedback adjustment instruction to the transmitter according to the values and data in a user configuration list to maintain the stability of the important parameters; in addition, the above parameters may be displayed at the transmitter.
Example two
FIG. 4 is a schematic structural diagram of a signal transmitter for civil aviation navigation equipment according to a second embodiment of the present invention; as shown in fig. 4, on the basis of the first embodiment, the signal transmitter for civil aviation navigation equipment further includes: an update module 203 for sending user update data to the system control module 70 through the external feedback function module 60; the system control module 70 is further configured to: and updating the user configuration list according to the user updating data.
In this embodiment, a user may click "execute" in a user terminal, and some data (phase difference data) updated by the user is sent to the system control module through the update module, and the system control module updates the user configuration list according to the data updated by the user; the invention puts the concerned gravity center behind the emission parameter of the device, so that the emission signal of the emitter is always kept stable, after the user replaces the system, the user configuration list is downloaded again, and the emitter can automatically adjust to make the new system emitter signal and the emission signal of the device keep completely consistent.
In this embodiment: when the user adjusts the transmitter parameters before the user terminal is calibrated, the following operations can be carried out:
firstly, inputting increased or decreased phase degrees, transmitting the phase degrees to a system control module through a user terminal (an updating module), and modifying a numerical value of 'phase difference between carrier and sideband synthetic signals' in a user configuration list by the system control module;
secondly, after calculating the value of the phase adjustment, the system control module periodically sends the value to the user terminal, and continuously sends a phase adjustment instruction to the transmitter according to a user configuration list (the phase is adjusted by one step length every time, and the adjustment is carried out according to the step length of 0.1 degree);
and finally, the transmitter is connected with an external feedback function module, so that the phase can be automatically adjusted in a negative feedback manner, and the stable phase difference between the carrier and the sideband sum signal is finally realized.
EXAMPLE III
FIG. 5 is a schematic structural diagram of a signal transmitter for civil aviation navigation equipment according to a third embodiment of the present invention; as shown in fig. 5, on the basis of the first embodiment, the signal transmitter for civil aviation navigation equipment includes:
relay 501, its power end links to each other with external power supply circuit's output, and its control end is connected with external system control signal's output electricity, external system control signal includes: a switch control signal for controlling the relay to close;
the input end of the first power supply chip 502 is connected to the first power supply output end of the relay 501, and is used for receiving and outputting a first power supply signal to provide power supply for the FPGA module 20;
and an input end of the second power supply chip 503 is connected to a second power output end of the relay 501, and is configured to receive and output a second power signal to provide power supply for the power amplifier module 30.
In this embodiment, the transmitter normally supplies power through 28V of an external power supply circuit, and in the process of supplying power to the whole transmitter by the power supply module, as long as a power switch is closed, the transmitter normally supplies power, and the input 28V voltage enters the first power supply chip and the second power supply chip after passing through the relay, and the first power supply chip and the second power supply chip can respectively provide 5V or 3.3V power supply voltage for the FPGA module and the power amplifier module; when the transmitter is required to be started, the system control module inputs a control signal to the 28V relay to close the relay so as to supply power to all parts of the transmitter; subsequently, the system control module sends an instruction to the FPGA module, the FPGA module starts to generate five paths of radio frequency signals, for the DDS, a reset signal is generated in a delayed manner, and when the rising edge of the 30Hz synchronous signal and the reset signal are simultaneously satisfied, the whole DDS program starts to transmit at the rising edge of the 30Hz as follows:
at the rising edge time of 30Hz, the antenna No. 1 starts to transmit an SB1 signal, the antenna No. 2 starts to transmit an SB2 signal, the antenna No. 25 starts to transmit an SB3 signal, and the sideband antenna No. 26 starts to transmit an SB4 signal; the switching of the sideband antennas is shown in the following table (the sideband antennas are arranged in a counterclockwise direction when viewed from above);
the user configuration list in this embodiment is shown in the following table:
in the invention, the system control module uses a simple, stable and reliable operating system to manage all tasks, thus being convenient for programming; the FPGA module has the function of parallel operation, has high calculation speed, can process a plurality of tasks in parallel, and ensures that the program compiling is simpler and the operation is more reliable; meanwhile, in order to avoid accumulation of instructions, the instructions are overstocked, the instructions are covered, some instructions are lost, and finally the system is abnormal in operation, each instruction sending cycle should be fixed, a chain is formed in the sending queue, all the instructions are guaranteed to be sent out, and the instructions are executed immediately after receiving one instruction at the receiving end.
In addition, most of the instructions sent by the system control module dynamically adjust the equipment parameters, and if the instructions are not received by the transmitter, the transmitter continues to send the instructions next time to adjust the equipment state. For the user configuration list part, if the transmitter cannot receive the information, the trouble occurs, especially in the process of flight correction, the equipment is adjusted and does not respond, and the work is interrupted; in order to avoid the situation, after the transmitter receives a command sent by the system control module, the transmitter may forward the same command, and after the system control module receives the command, the command may be cancelled in the transmission chain, and every 1 second (the period may be adjusted), the system control module checks that the command which is not sent one second before in the sequence is deleted, and then the command is re-arranged into the sequence and sent again; when the reserved instructions in the sequence are excessive (the threshold can be arranged according to the actual test result), the instruction for restarting can be sent to the transmitter; the transmitter pulls the enable signal low and after a delay (the delay value is arranged according to the actual test result) the transmitter is re-enabled and starts transmitting (in this case the system control module does not have to re-transmit the transmitter part of the user configuration list, while the new transmission command is not in the chain of transmission commands).
In addition, the transmitter in the invention can be set for double systems, thereby ensuring the stability and reliability of the system.
The invention relates to a modulation signal generating method, a modulation signal generator and a signal transmitter for civil aviation navigation equipment, which are used for establishing a set of design scheme of a new navigation equipment transmitter from the perspective of a user by combining the development experience of the prior navigation equipment, wherein a new algorithm (a modulation signal generating method) is designed to generate radio frequency signals, a new generation transmitter provides a detailed scheme in the aspects of complete signal generation, synthesis, modulation, phase control and system structure (the scheme creatively uses a user configuration list to record the detailed parameters and equipment working state of a transmitter part, and explains the working flow of managing the working state of the transmitter by using the user configuration list in detail, and the scheme also provides a communication protocol between the transmitter part and a system control module (system controller).
By using the DDS technology, the precision of amplitude control and phase control of the carrier signal, the upper sideband signal and the lower sideband signal by the equipment can be further improved, the power consumption of the equipment can be greatly reduced, the volume and the weight of the equipment are reduced, and richer equipment state parameters are provided for users.
In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
In the embodiments provided in the present application, it should be understood that the disclosed system and method may be implemented in other ways. The above-described system embodiments are merely illustrative, and for example, the division of the modules is merely a logical division, and other divisions may be realized in practice, and for example, a plurality of modules or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection of devices or units through some communication interfaces, and may be in an electrical, mechanical or other form.
The modules described as separate parts may or may not be physically separate, and parts displayed as modules may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (8)
1. A method for generating a modulated signal for a civil aviation navigation device, characterized in that: the method comprises the following steps:
generating a carrier signal, an upper sideband signal, a lower sideband signal and a 30Hz frequency modulation signal, and synthesizing the upper sideband signal and the lower sideband signal to generate a spatial synthesis signal of an upper sideband and a lower sideband;
receiving a negative feedback adjustment signal to adjust a phase difference between the spatially combined signal and the carrier signal;
reading a preset identification code signal of 1020 Hz;
generating a spatial modulation signal through the carrier signal, the upper sideband signal, the lower sideband signal, the spatial synthesis signal of the upper sideband and the lower sideband, the 30Hz frequency modulation signal and the 1020Hz identification code signal, and performing high-frequency carrier modulation on a low-frequency local signal through the spatial modulation signal to generate and transmit five paths of radio frequency signals;
wherein: the five radio frequency signals comprise: a carrier signal and four sideband signals.
2. The modulated signal generating method for civil aviation navigation equipment according to claim 1, wherein: receiving a negative feedback adjustment signal to adjust the phase difference between the space synthesis signal and the carrier signal, wherein the amplitude adjustment signal and the phase adjustment signal are obtained by calculation through the following processes;
sampling a carrier signal and upper and lower sideband signals in N carrier periods;
normalizing the sampled data, delaying and comparing the phases, and calculating the phase difference between the space synthesis signal and the carrier signal;
a negative feedback adjustment signal including an amplitude adjustment signal and a phase adjustment signal is output according to the phase difference data.
3. Modulated signal generator for civil aviation navigation devices, characterized in that: the method comprises the following steps:
a signal generating unit (2011) for generating a carrier signal, an upper sideband signal, a lower sideband signal and a 30Hz frequency modulation signal, and synthesizing the upper sideband signal and the lower sideband signal to generate a spatial synthesis signal of an upper sideband and a lower sideband;
the signal adjusting unit (2012) is used for receiving a negative feedback adjusting signal sent by the external feedback function module (60) so as to adjust the phase difference between the space synthesis signal and the carrier signal;
a signal modulation unit (2013) for generating a spatial modulation signal from the carrier signal, the upper sideband signal, the lower sideband signal, the spatial synthesis signal of the upper and lower sidebands, the 30Hz FM signal, and the 1020Hz identification code signal stored in the ROM storage unit (202); carrying out high-frequency carrier modulation on a low-frequency local signal through a spatial modulation signal;
the signal transmitting unit (2014) is used for generating and transmitting five paths of radio frequency signals from the modulated high-frequency carrier signal; wherein: the five radio frequency signals comprise: a carrier signal and a four-way sideband signal;
a ROM storage unit (202) for storing the 2020Hz identification code signal, and storing the sampling clock signal;
the external feedback function module (60) is used for sending the working state parameters of the spatial modulation signals to the system control module (70); receiving a negative feedback adjustment signal output by the system control module (70), and sending the negative feedback adjustment signal to the signal adjustment unit (2012); wherein: the negative feedback adjustment signal comprises: amplitude adjustment and phase adjustment signals;
the system control module (70) is used for spatially modulating the working state parameters of the signals, comparing the working state parameters with user configuration list data of the transmitter, and outputting negative feedback adjustment signals for maintaining the working state parameters stable.
4. The modulated signal generator for civil aviation navigation devices of claim 3, wherein: the negative feedback adjusting signal output by the system control module (70) is obtained by the following process calculation;
a sampling unit (701) for sampling the carrier signal and the upper and lower sideband signals in N carrier periods;
a calculating unit (702) for normalizing the sampling data, delaying and comparing the phase, and calculating the phase difference between the spatial composite signal and the carrier signal;
and an output unit (703) for outputting a negative feedback adjustment signal including an amplitude adjustment signal and a phase adjustment signal according to the phase difference data.
5. Signal transmitter for civil aviation navigation devices, characterized in that: the method comprises the following steps:
the signal input module (10) is connected with external signal input equipment, receives the ground-air voice signals, performs analog-to-digital conversion on the ground-air voice signals, and then sends the ground-air voice signals to the FPGA module (20);
the FPGA module (20), its input is connected with the output of signal input module (10) electrically, is used for carrying out high frequency carrier modulation to the air-ground voice signal, includes: a modulation signal generator (201) and a ROM storage unit (202);
the modulation signal generator (201) comprises:
a signal generating unit (2011) for generating a carrier signal, an upper sideband signal, a lower sideband signal and a 30Hz frequency modulation signal, and synthesizing the upper sideband signal and the lower sideband signal to generate a spatial synthesis signal of an upper sideband and a lower sideband;
the signal adjusting unit (2012) is used for receiving a negative feedback adjusting signal sent by the external feedback function module (60) so as to adjust the phase difference between the space synthesis signal and the carrier signal;
a signal modulation unit (2013) for generating a spatial modulation signal from the carrier signal, the upper sideband signal, the lower sideband signal, the spatial synthesis signal of the upper and lower sidebands, the 30Hz FM signal, and the 1020Hz identification code signal stored in the ROM storage unit (202); carrying out high-frequency carrier modulation on a low-frequency local signal through a spatial modulation signal;
the signal transmitting unit (2014) is used for generating and transmitting five paths of radio frequency signals from the modulated high-frequency carrier signal; wherein: the five radio frequency signals comprise: a carrier signal and a four-way sideband signal;
the ROM storage unit (202) is used for storing an identification code signal of 1020Hz and storing a sampling clock signal;
the power amplification module (30) is used for amplifying the signals of the five paths of radio frequency signals and loading the signals into the antenna module (40);
the antenna module (40) is used for transmitting five radio frequency signals;
a power supply module (50) for providing power supply for the whole signal generator;
the external feedback function module (60) is used for sending the working state parameters of the spatial modulation signals to the system control module (70); receiving a negative feedback adjustment signal output by the system control module (70) and sending the negative feedback adjustment signal to the signal transmitting unit (2014); wherein: the negative feedback adjustment signal comprises: amplitude adjustment and phase adjustment signals;
the system control module (70) is used for spatially modulating the working state parameters of the signals, comparing the working state parameters with user configuration list data of the transmitter, and outputting negative feedback adjustment signals for maintaining the working state parameters stable.
6. Signal transmitter for civil aviation navigation devices according to claim 5, characterized in that: the negative feedback adjusting signal output by the system control module (70) is obtained by the following process calculation;
a sampling unit (701) for sampling the carrier signal and the upper and lower sideband signals in N carrier periods;
a calculating unit (702) for normalizing the sampling data, delaying and comparing the phase, and calculating the phase difference between the spatial composite signal and the carrier signal;
and an output unit (703) for outputting a negative feedback adjustment signal including an amplitude adjustment signal and a phase adjustment signal according to the phase difference data.
7. Signal transmitter for civil aviation navigation devices according to claim 5, characterized in that: further comprising:
an updating module (203) for sending the phase difference data updated by the user to the system control module (70) through the external feedback function module (60);
the system control module (70) is further configured to: and updating the user configuration list according to the phase difference data updated by the user.
8. Signal transmitter for civil aviation navigation devices according to claim 5, characterized in that: the power supply module (50) comprises:
relay (501), its power end links to each other with external power supply circuit's output, and its control end is connected with external system control signal's output electricity, external system control signal includes: a switch control signal for controlling the relay (501) to close;
the input end of the first power supply chip (502) is connected with the first power supply output end of the relay (501) and is used for receiving and outputting a first power supply signal to provide power supply for the FPGA module (20);
and the input end of the second power supply chip (503) is connected with the second power supply output end of the relay (501) and is used for receiving and outputting a second power supply signal to provide power supply for the power amplification module (30).
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