CN116015352A - Frequency hopping signal generating device and method based on Delta-sigma modulation - Google Patents
Frequency hopping signal generating device and method based on Delta-sigma modulation Download PDFInfo
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Abstract
The invention discloses a frequency hopping signal generating device and method based on Delta-sigma modulation, and belongs to the field of communication. The device comprises a digital control oscillator, a baseband signal up-sampler, a digital up-converter, a Delta-sigma modulator, a high-speed serial interface and a band-pass filter. The invention converts the input frequency hopping pattern into frequency hopping carrier frequency signals, and modulates the input digital baseband signals onto the frequency hopping carrier frequency signals to generate frequency hopping signals; and carrying out noise shaping and 1bit digital quantization on the modulated frequency hopping signal through Delta-sigma modulation to finally obtain the modulated frequency hopping signal output. The invention realizes digital up-conversion and Delta-sigma modulation in the digital domain, greatly improves the frequency hopping rate, simultaneously cancels a digital-to-analog converter for outputting a modulation waveform, achieves the aim of processing in the whole digital domain, improves the safety of a communication system, reduces the complexity of the system, and reduces the cost, the volume and the power consumption.
Description
Technical Field
The invention belongs to the field of communication, and particularly relates to a frequency hopping signal generating device and method based on Delta-sigma modulation.
Background
The frequency hopping spread spectrum communication technology has been widely paid attention to the communication field due to the advantages of good anti-interference capability, anti-interception capability, anti-fading capability and the like. Because of strong security, frequency hopping communication is widely applied in the national defense and military fields.
The united states and united kingdom began to develop frequency hopping radio equipment in 1970 s, and low-speed frequency hopping radio stations operating in the VHF band were developed at the end of 1970 s, and medium-speed frequency hopping VHF radio stations of various models were developed successively from the middle of 1980 s.
With the development of up to four fifty years, the frequency hopping communication technology and equipment are all advanced and upgraded across the ages. For the attack of the frequency hopping communication security, the communication industry synchronously researches, for example, provides a novel investigation analysis method such as tracking type interference, blocking type interference and the like, and a novel investigation analysis method such as time frequency analysis, deep learning and the like. With further research, it is found that the improvement of the frequency hopping speed is an effective defense method in terms of anti-interference and anti-interception.
In the traditional communication modulation method, a controlled frequency hopping frequency source is used as a local oscillator to generate a frequency hopping carrier signal, the frequency hopping carrier signal is sent to a mixer to carry out signal modulation, the whole modulation process is processed in an analog domain, the frequency hopping carrier signal is limited by the performance limitation of analog components, and the frequency hopping rate is generally within 10 KHop/s.
After the digital up-conversion technology is applied, the digital modulation signal output by the digital logic circuit still needs a digital-to-analog converter (DAC) to convert the modulated signal in the digital domain into an analog signal, and then the analog signal is amplified by a linear amplifier and then transmitted. Since the linear amplifier is generally a class AB amplifier, the energy utilization efficiency thereof has yet to be improved.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a frequency hopping signal generating device and method based on Delta-sigma modulation, which aims to solve the problems of insufficient frequency hopping speed, higher cost and lower power efficiency in the prior art.
In order to achieve the above purpose, the invention provides a frequency hopping signal generating device based on Delta-sigma modulation, which comprises a digital control oscillator, a baseband signal up-sampler, a digital up-converter, a Delta-sigma modulator, a high-speed serial interface and a band-pass filter.
The input end of the digital control oscillator receives the frequency hopping pattern, is controlled by the frequency hopping pattern, generates a frequency hopping carrier frequency signal, and outputs and is connected to the first input end of the digital up-converter.
The baseband signal up-sampler up-samples the digital baseband signal to the same sampling rate as the digital carrier frequency.
The second input end of the digital up-converter receives the up-sampled digital baseband signal input, the first input end receives the frequency hopping carrier frequency signal from the digital control oscillator, modulates the digital baseband signal onto the frequency hopping carrier frequency signal, generates a modulated frequency hopping signal, and sends the modulated frequency hopping signal to the output end.
The input end of the Delta-sigma modulator is connected to the digital up-converter, noise shaping and 1bit digital quantization are carried out on the modulated frequency hopping signal, and a parallelized 1bit quantized frequency hopping signal is obtained and sent to the output end.
The Delta-sigma modulator selects a set of Delta-sigma parameters for the appropriate current carrier frequency according to the hopping pattern.
The input end of the high-speed serial interface is connected to the Delta-sigma modulator, and the 1bit quantized frequency hopping signal in a parallel form is converted into a serial data stream and is sent to the output end.
The band-pass filter is an analog band-pass filter, the input end of the band-pass filter is connected to the high-speed serial interface, out-of-band noise contained in the serial data stream is filtered, and a modulated frequency hopping signal output in the communication frequency band range is obtained.
The digital control oscillator, the baseband signal up-sampler, the digital up-converter and the Delta-sigma modulator all perform digital signal processing in the digital domain.
The digital control oscillator, the baseband signal up-sampler, the digital up-converter and the Delta-sigma modulator all adopt a parallelization processing method.
The digital control oscillator adopts a direct frequency synthesis method to generate carrier frequency signals.
According to the parameters of the communication system, the Delta-sigma modulator is designed into a Delta-sigma modulation structure with different orders and different parameters and with multistage noise shaping.
Preferably, the Delta-sigma modulator employs a fourth order Delta-sigma modulator based on a cascaded resonator feedforward structure (CRFF) structure.
The passband of the bandpass filter includes the frequency hopping communications band but does not exceed the guard interval band.
The invention also provides a frequency hopping signal generation method based on Delta-sigma modulation, which comprises the following steps:
the input frequency hopping pattern is input and converted into a frequency hopping carrier frequency signal, the input digital baseband signal is up-sampled to the same sampling rate as the frequency hopping carrier frequency signal, and the frequency hopping carrier frequency signal is modulated to generate a modulated frequency hopping signal;
noise shaping and 1bit digital quantization are carried out on the modulated frequency hopping signal, and a parallelized 1bit quantized frequency hopping signal is obtained;
and converting the parallelized 1bit quantized frequency hopping signal into a serial data stream, filtering out-of-band noise contained in the serial data stream, and obtaining a modulated frequency hopping signal output in a communication frequency band range.
Compared with the prior art, the invention realizes digital up-conversion and Delta-sigma modulation in the digital domain, is not limited by an analog frequency hopping frequency synthesizer, can greatly improve the frequency hopping rate, and meanwhile, cancels a digital-to-analog converter (DAC) for outputting a modulation waveform, thereby achieving the purpose of all-digital domain processing, improving the safety of a communication system, reducing the complexity of the system and reducing the cost, volume and power consumption.
Drawings
Fig. 1 is a block diagram of a frequency hopping signal generating device based on Delta-sigma modulation according to an exemplary embodiment of the present invention.
Fig. 2 is a block diagram of a fourth order delta-sigma modulator based on a cascade resonator feedforward structure (CRFF) structure according to an exemplary embodiment of the present invention.
FIG. 3 is a graph of the parameter values and noise transfer function of a Delta-sigma modulator according to an exemplary embodiment of the present invention.
Fig. 4 is a diagram of a frequency hopping pattern and a frequency hopping signal spectrum according to an exemplary embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not interfere with each other.
Fig. 1 is a block diagram of a frequency hopping signal generating device based on Delta-sigma modulation, the frequency hopping signal generating device includes: a digitally controlled oscillator 101, a digital up-converter 102, a Delta-sigma modulator 103, a high-speed serial interface 104, a band-pass filter 105 and a baseband signal up-sampler 106.
The input of the digitally controlled oscillator 101 receives the frequency hopping pattern, is controlled by the frequency hopping pattern, generates a frequency hopping carrier signal, and is output connected to a first input of the digital up-converter 102.
The baseband signal up-sampler 106 up-samples the digital baseband signal to the same sampling rate as the digital carrier frequency.
A second input of the digital up-converter 102 receives the digital baseband signal input, and a first input receives the frequency hopped carrier signal from the digitally controlled oscillator 101, modulates the digital baseband signal onto the frequency hopped carrier signal, generates a modulated frequency hopped signal, and sends it to the output.
The input of Delta-sigma modulator 103 is connected to digital up-converter 102, which performs noise shaping and 1bit digital quantization on the modulated frequency hopping signal to obtain a parallelized 1bit quantized frequency hopping signal, which is sent to the output.
The input of the high-speed serial interface 104 is connected to the Delta-sigma modulator 103, which converts the 1bit quantized frequency hopping signal in parallel form into a serial data stream, and sends it to the output.
The band-pass filter 105 is an analog band-pass filter, and an input terminal is connected to the high-speed serial interface, and filters out-of-band noise included in the serial data stream, so as to obtain a modulated frequency hopping signal output within the communication frequency band range.
The digitally controlled oscillator 101, the digital up-converter 102, and the Delta-sigma modulator 103 all perform digital signal processing in the digital domain.
The digital controlled oscillator 101, the digital up-converter 102 and the Delta-sigma modulator 103 all adopt a parallelization processing method.
The digitally controlled oscillator 101 generates a carrier frequency signal using a direct frequency synthesis method.
Depending on the communication system parameters, the Delta-sigma modulator 103 is designed as a multistage noise-shaping Delta-sigma modulation structure with different orders and different parameters.
Preferably, the Delta-sigma modulator 103 adopts a band-pass Delta-sigma modulation structure, so that the sampling rate of a 1bit quantized signal can be reduced.
Preferably, the Delta-sigma modulator 103 employs a fourth order Delta-sigma modulator based on a cascaded resonator feedforward structure (CRFF) structure. The passband of the bandpass filter 105 encompasses the frequency-hopped communications band but does not exceed the guard interval band.
Preferably, the passband parameters of the passband range of the bandpass filter 105 are dynamically changed according to the frequency hopping frequency points, so that the signal-to-noise ratio of the output frequency hopping signal can be improved.
Fig. 2 shows a fourth order delta-sigma modulator based on a cascade resonator feed forward structure (CRFF) structure according to an exemplary embodiment of the present invention. The modulator of the embodiment comprises a quantizer and four integrators, and has good performance and stability. The noise transfer function of this embodiment is as follows.
FIG. 3 shows the parameter values and values of a Delta-sigma modulator according to an exemplary embodiment of the present inventionA noise transfer function graph. The parameter table of the modulator of this embodiment is: g 1 ＝-0.6588、g 2 ＝-0.3638、a 1 ＝0.6789、a 2 ＝0.1327、a 3 ＝0.0874、a 4 = -0.1548. The noise transfer function of this embodiment is shown in the right-hand diagram of fig. 3.
Fig. 4 is a diagram of a frequency hopping pattern and a frequency hopping signal spectrum according to an exemplary embodiment of the present invention. The hopping frequencies are 3.5GHz, 2.4GHz, 3.51GHz and 5.5GHz.
Those skilled in the art will understand that the units included in the above embodiments are only divided according to functional logic, but not limited to the above division, so long as the corresponding functions can be implemented; in addition, the specific names of the functional units are only for convenience of distinguishing from each other, and are not used to limit the protection scope of the present invention.
It will be further understood by those skilled in the art that all or part of the steps in implementing the methods of the above embodiments may be implemented by a program to instruct related hardware, where the program may be stored in a readable storage medium such as a computer, FPGA, ASIC, or embedded controller, and the storage medium includes ROM/RAM, magnetic disk, optical disk, and the like.
It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (9)
1. The frequency hopping signal generating device based on Delta-sigma modulation is characterized by comprising a digital control oscillator, a baseband signal up-sampler, a digital up-converter, a Delta-sigma modulator, a high-speed serial interface and a band-pass filter; the digital control oscillator converts the frequency hopping pattern input into a frequency hopping carrier frequency signal, the frequency hopping carrier frequency signal is transmitted to a first input end of the digital up-converter, the baseband signal up-sampler up-samples the digital baseband signal to the same sampling rate as the frequency hopping carrier frequency signal, the up-sampled digital baseband signal is transmitted to a second input end of the digital up-converter, the digital up-converter modulates the digital baseband signal onto the frequency hopping carrier frequency signal, generates a modulated frequency hopping signal, and transmits the modulated frequency hopping signal to the Delta-sigma modulator; the Delta-sigma modulator carries out noise shaping and 1bit digital quantization on the modulated frequency hopping signal according to the current carrier frequency to obtain a parallelized 1bit quantized frequency hopping signal, and the parallelized 1bit quantized frequency hopping signal is transmitted to a high-speed serial interface; the high-speed serial interface converts the parallelized 1-bit quantized frequency hopping signal into a serial data stream and transmits the serial data stream to the band-pass filter, and the band-pass filter filters out-of-band noise contained in the serial data stream to obtain a modulated frequency hopping signal output in a communication frequency band range.
2. The Delta-sigma modulation based frequency hopping signal generating device as claimed in claim 1, wherein the digitally controlled oscillator, the baseband signal up-sampler, the digital up-converter, and the Delta-sigma modulator all perform digital signal processing in a digital domain.
3. The Delta-sigma modulation-based frequency hopping signal generating device according to claim 1, wherein the digitally controlled oscillator, the baseband signal up-sampler, the digital up-converter and the Delta-sigma modulator all adopt parallelization processing methods.
4. The Delta-sigma modulation based frequency hopping signal generating device as claimed in claim 1, wherein the digitally controlled oscillator generates the carrier frequency signal using a direct frequency synthesis method.
5. The Delta-sigma modulation based frequency hopping signal generating device as claimed in claim 1, wherein the Delta-sigma modulator is a Delta-sigma modulation structure of multistage noise shaping with different orders and different parameters.
6. The Delta-sigma modulation based frequency hopping signal generating device as claimed in claim 1, wherein the pass band range of the band pass filter includes a frequency hopping communication band but does not exceed a guard interval band.
7. The frequency hopping signal generation method based on Delta-sigma modulation is characterized by comprising the following steps of:
the input frequency hopping pattern is input and converted into a frequency hopping carrier frequency signal, the input digital baseband signal is up-sampled to the same sampling rate as the frequency hopping carrier frequency signal, and the frequency hopping carrier frequency signal is modulated to generate a modulated frequency hopping signal;
noise shaping and 1bit digital quantization are carried out on the modulated frequency hopping signal, and a parallelized 1bit quantized frequency hopping signal is obtained;
and converting the parallelized 1bit quantized frequency hopping signal into a serial data stream, filtering out-of-band noise contained in the serial data stream, and obtaining a modulated frequency hopping signal output in a communication frequency band range.
8. The Delta-sigma modulation based frequency hopping signal generation method as set forth in claim 7, wherein the noise shaping and 1bit digital quantization of the modulated frequency hopping signal are Delta-sigma modulated, and the order and parameters are adjusted according to the current carrier frequency.
9. The Delta-sigma modulation based frequency hopping signal generation method as claimed in claim 7, wherein the generation of the frequency hopping signal is digital signal processing in a digital domain.
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