CN111614589A - Triangular frequency modulation signal modulator, demodulator and wireless communication system - Google Patents
Triangular frequency modulation signal modulator, demodulator and wireless communication system Download PDFInfo
- Publication number
- CN111614589A CN111614589A CN202010301576.7A CN202010301576A CN111614589A CN 111614589 A CN111614589 A CN 111614589A CN 202010301576 A CN202010301576 A CN 202010301576A CN 111614589 A CN111614589 A CN 111614589A
- Authority
- CN
- China
- Prior art keywords
- signal
- triangular
- frequency
- target
- frequency modulation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/10—Frequency-modulated carrier systems, i.e. using frequency-shift keying
- H04L27/12—Modulator circuits; Transmitter circuits
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/10—Frequency-modulated carrier systems, i.e. using frequency-shift keying
- H04L27/14—Demodulator circuits; Receiver circuits
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
Abstract
A triangular fm modulator, a demodulator, and a wireless communication system, the wireless communication system including a triangular fm modulator and a triangular fm demodulator, the triangular fm modulator adapted to generate a target triangular fm signal, a phase of the target triangular fm signal determined by an initial frequency of the target triangular fm signal and a frequency step determined by a bandwidth of the target triangular fm signal, a spreading factor of the target triangular fm signal, and a monotonicity of the target triangular fm signal; the triangular frequency modulation signal demodulator is suitable for demodulating the target triangular frequency modulation signal. By the scheme, data loss caused by lock losing of the phase-locked loop circuit can be avoided, low-power-consumption remote transmission of signals can be realized, and the data transmission rate can be improved.
Description
Technical Field
The invention relates to the technical field of communication, in particular to a triangular frequency modulation signal modulator, a triangular frequency modulation signal demodulator and a wireless communication system.
Background
Wireless communication technology has gained rapid development worldwide and has become a popular technology of common interest in the global IT and communication fields. In recent years, with the development of the internet of things technology, the world internet of things construction is spreading out comprehensively, and the market demand for wireless communication technology is emerging continuously.
In the technical field of wireless communication, the transmission rate of a communication system is continuously improved, and a fourth generation mobile communication technology (4G) enables people to enter a mobile internet era; nowadays, the fifth generation mobile communication technology (5G) is coming up, which has the characteristics of high frequency and high speed, and the theoretical peak transmission rate can reach tens of Gb per second, which is hundreds of times faster than the prior technology (4G). In some application scenarios, however, a too high data rate may not be required, but rather a large coverage area and low power consumption may be required.
The physical layer design of the traditional low-power-consumption Bluetooth BLE technology uses Gaussian Frequency Shift Keying (GFSK) signal modulation, successfully reduces the complexity of design, realizes the low power consumption of a communication chip, but has a small transmission range limited to only a few meters to dozens of meters. Direct sequence spread spectrum techniques are known and can achieve very high coding gain levels, achieve very good noise immunity, and enable long-range signal transmission. But the power consumption of the terminal using the direct sequence spread spectrum technique is large. The linear frequency modulation technology is adopted to obtain the linear frequency modulation signal, so that low power consumption and long-distance signal transmission can be realized. However, a frequency jump point exists in the linear frequency modulation signal, and when the frequency jumps, partial data loss is caused by the loss of lock of a phase-locked loop circuit in the radio frequency circuit, so that the related energy of the signal in the synchronization process of the receiver is reduced, and the demodulation performance is influenced.
Disclosure of Invention
The embodiment of the invention aims to realize low power consumption and long-distance signal transmission and improve the data transmission rate while avoiding data loss caused by the loss of lock of a phase-locked loop circuit.
To achieve the above object, embodiments of the present invention provide a triangular fm modulator, which is adapted to generate a target triangular fm signal,the phase of the target triangular frequency modulation signal is determined by the initial frequency of the target triangular frequency modulation signal and the frequency step, the initial frequency of the target triangular frequency modulation signal is determined by the bandwidth of the target triangular frequency modulation signal, and the frequency step of the target triangular frequency modulation signal is fstep ═ BW/2SF-1) D, wherein fstep is the frequency step, BW is the bandwidth of the target triangular frequency modulation signal, SF is a spreading factor of the target triangular frequency modulation signal, and d is monotonicity of the target triangular frequency modulation signal; the target triangular frequency modulation signal consists of two or three sections of signals with continuous frequencies; the target triangular frequency modulation signal is a mapping result after encoding processing of information to be transmitted, and the maximum number of the target triangular frequency modulation signals is 2SF-1(ii) a The triangular frequency modulation signal modulator comprises a digital modulation circuit and a radio frequency analog modulation circuit, wherein: the digital modulation circuit is suitable for generating a control signal of the target triangular frequency modulation signal; the digital modulation circuit includes an encoder and a control signal generator, wherein: the encoder is suitable for encoding data to be transmitted, generating encoded data corresponding to the data to be transmitted and transmitting the encoded data to the control signal generator; the control signal generator is suitable for generating the control signal according to the coded data; the radio frequency analog modulation circuit is coupled with the digital modulation circuit; the radio frequency analog modulation circuit comprises a phase-locked loop circuit; the digital modulation circuit is suitable for outputting the control signal to the phase-locked loop circuit so as to control the phase-locked loop circuit to generate the target triangular frequency modulation signal.
Optionally, the target triangular frequency modulation signal is s (t) sin (2 pi × f (t) × t),
the digital baseband signal of the target triangular frequency modulation signal is
1≤n≤2SFSF is a spreading factor; the phase of the digital baseband signal at the point m is as follows:
wherein f iscIs the radio frequency, fstartIs the initial frequency, f, of the target triangular FM signalstepFor the frequency step of the target triangular frequency modulation signal, the control signal is determined by f (n); thetamIs the phase of the digital baseband signal at m points, BW is the bandwidth of the digital baseband signal, theta0N is a positive integer for the initial phase of the digital baseband signal.
Optionally, the initial frequency range of the target triangular frequency modulation signal is [ -BW/2, BW/2 ].
Optionally, the frequency step f of the target triangular frequency modulation signalstepCalculated using the following formula:
when the difference value of the frequency increases along with the time, d is 1; when the difference value of the frequency decreases along with the time, d is-1; the time length of the target triangular frequency modulation signal is determined by the spreading factor SF of the target triangular frequency modulation signal.
Optionally, the time-equality difference of the frequency of the first segment of the target triangular frequency modulation signal is increased from-BW/2 to BW/2, and the time-equality difference of the frequency of the second segment of the target triangular frequency modulation signal is decreased from BW/2 to-BW/2.
In order to achieve the above object, an embodiment of the present invention further provides a triangular fm signal demodulator, adapted to receive a target triangular fm signal transmitted by any one of the above triangular fm signal modulators, and demodulate the target triangular fm signal, where the triangular fm signal demodulator includes: first mixer, synchronous buffer, processor, wherein: a first mixer adapted to down-convert the received signal from a low intermediate frequency to a zero intermediate frequency; receiving the frequency offset value output by the processor, and performing frequency offset removal processing on the received signal according to the frequency offset value; the processor is suitable for generating a local triangular frequency modulation signal which is synchronous with the sampling signal and has the same length, performing complex multiplication operation on the sampling signal and the local triangular frequency modulation signal, and performing discrete Fourier transform on a complex multiplication operation result; and calculating the synchronous address and the frequency offset value according to the discrete Fourier transform result, and performing decoding operation according to the discrete Fourier transform result.
Optionally, the processor includes: local triangle FM signal generator, discrete Fourier transform unit, synchronization unit, frequency offset calculation tracking unit and decoding unit, wherein: the local triangular frequency modulation signal generator is suitable for generating the local triangular frequency modulation signal; the discrete Fourier transform unit is suitable for performing complex multiplication operation on the sampling signal and the local triangular frequency modulation signal, performing discrete Fourier transform on a complex multiplication operation result, and respectively outputting the obtained discrete Fourier transform result to the synchronization unit, the frequency offset calculation tracking unit and the decoding unit; the synchronization unit is suitable for calculating the synchronization address according to the discrete Fourier transform result; the frequency offset calculation tracking unit is suitable for calculating the frequency offset value according to the discrete Fourier transform result; and the decoding unit is suitable for performing decoding operation according to the discrete Fourier transform result.
Optionally, the discrete fourier transform unit is adapted to equally divide the sampling signal and the local triangular frequency modulation signal into two sections, and perform complex multiplication on a conjugate of a previous section of the sampling signal and a previous section of the local triangular frequency modulation signal to obtain a first product; carrying out complex multiplication operation on the later section of the sampling signal and the later section of the local triangular frequency modulation signal to obtain a second product; performing discrete Fourier transform on the first product to obtain a first energy maximum value; performing discrete Fourier transform on the second product to obtain a second energy maximum value; and selecting the larger value of the first energy maximum value and the second energy maximum value as the discrete Fourier transform result.
Optionally, the triangular fm signal demodulator further includes: and the digital low-pass filter is suitable for filtering the signal output by the first mixer and outputting the processed signal to the synchronous buffer.
The embodiment of the invention also provides a wireless communication system which comprises any one of the triangular frequency modulation signal modulator and the triangular frequency modulation signal demodulator.
Compared with the prior art, the technical scheme of the embodiment of the invention has the following beneficial effects:
a triangular frequency modulation signal modulator is adopted to generate a target triangular frequency modulation signal, the target triangular frequency modulation signal is composed of two or three sections of signals, and the frequencies of the different sections of signals are continuous. Therefore, the frequency of the target triangular frequency modulation signal is continuously changed in one code element without generating jump, and the data loss caused by the loss of the lock of a phase-locked loop circuit is avoided. And moreover, the target triangular frequency modulation signal is adopted, and the spread spectrum gain of the target triangular frequency modulation signal is utilized, so that long-distance low-power-consumption transmission can be realized. The target triangular frequency modulation signals with different initial frequencies can correspond to different data, and the data transmission rate can be effectively improved.
Drawings
Fig. 1 is a schematic structural diagram of a wireless communication terminal according to an embodiment of the present invention;
fig. 2 is a waveform diagram of a target triangular chirp signal in an embodiment of the present invention;
fig. 3 is a waveform diagram of another target triangular chirp signal in an embodiment of the present invention;
fig. 4 is a waveform diagram of a target triangular chirp signal in an embodiment of the invention;
FIG. 5 is a block diagram of a digital modulation circuit according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a digital demodulation circuit according to an embodiment of the present invention.
Detailed Description
As described above, the physical layer design of the conventional bluetooth low energy BLE technology uses Gaussian Frequency Shift Keying (GFSK) signal modulation, successfully reduces the complexity of the design, and achieves low power consumption of the communication chip, but the transmission range is small and is limited to only a few meters to a few tens of meters. Direct sequence spread spectrum techniques are known and can achieve very high coding gain levels, achieve very good noise immunity, and enable long-range signal transmission. But the power consumption of the terminal using the direct sequence spread spectrum technique is large. The linear frequency modulation technology is adopted to obtain the linear frequency modulation signal, so that low power consumption and long-distance signal transmission can be realized. However, there is a frequency jump point in the chirp signal, and when the frequency jumps, the phase-locked loop in the rf circuit loses lock, which may cause partial data loss, thereby causing energy reduction related to the signal during demodulation, and affecting the receiving sensitivity.
In the embodiment of the invention, a triangular frequency modulation signal modulator is adopted to generate a target triangular frequency modulation signal, the target triangular frequency modulation signal consists of two or three sections of signals, and the frequencies of the different sections of signals are continuous. Therefore, the frequency of the target triangular frequency modulation signal continuously changes in one code element without jumping, so that data loss caused by lock losing of a phase-locked loop circuit can be avoided, energy reduction related to the signal in the demodulation process can not be caused, and the receiving sensitivity and the demodulation performance can not be influenced. And moreover, the target triangular frequency modulation signal is adopted, and the spread spectrum gain of the target triangular frequency modulation signal is utilized, so that long-distance low-power-consumption transmission can be realized. The target triangular frequency modulation signals with different initial frequencies can correspond to different data, and the data transmission rate can be effectively improved.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
Referring to fig. 1, an embodiment of the present invention provides a wireless communication system, including a triangular fm modulator and a triangular fm demodulator. The triangular fm modulator and the triangular fm demodulator will be described in detail below.
In a specific implementation, the triangular fm modulator is adapted to generate a target triangular fm signal. In an embodiment of the present invention, the phase of the target triangular fm signal is determined by an initial frequency of the target triangular fm signal and a frequency step, the initial frequency of the target triangular fm signal may be determined by a bandwidth of the target triangular fm signal, and the frequency step of the target triangular fm signal may be determined by the bandwidth of the target triangular fm signal, a spreading factor of the target triangular fm signal, and a monotonicity of the target triangular fm signal.
For the target triangular frequency modulation signal, the frequency isodifference value of the corresponding first section signal is increased from the initial frequency to BW/2 along with time, the frequency isodifference value of the corresponding second section signal is decreased from BW/2 to-BW/2 along with time, and the frequency isodifference value of the corresponding third section signal is increased to the initial frequency along with time. When the initial frequency is-BW/2 or BW/2, the target triangular frequency modulation signal only consists of two sections of signals. BW is the bandwidth of the digital baseband signal, i.e. the bandwidth of the target triangular frequency modulation signal.
Referring to fig. 2, a waveform diagram of a target triangular chirp signal in an embodiment of the present invention is shown.
In fig. 2, the first segment 21 of the target triangular fm signal has a frequency from fstartThe difference increases with time to BW/2 and the frequency of the second segment signal 22 decreases from BW/2 to f with timestart. The first segment signal 21 and the second segment signal 22 are continuous in frequency, and the first segment signal 21 and the second segment signal 22 have the same duration.
In the examples of the present invention, fstart-BW/2. That is, the frequency of the first segment 21 of the target triangular frequency modulated signal increases from-BW/2 to BW/2 with the time equal difference, and the frequency of the second segment 22 of the target triangular frequency modulated signal decreases from BW/2 to-BW/2 with the time equal difference.
In specific implementation, the target triangular frequency modulation signal is a mapping result after encoding processing of information to be transmitted, and the maximum number of the target triangular frequency modulation signals is 2SF-1. In the embodiment of the invention, the target triangular frequency modulation signal can correspond to different information to be transmitted according to different starting frequencies.
Referring to fig. 3, a waveform diagram of another target triangular chirp signal in an embodiment of the present invention is shown.
In fig. 3, the first segment 31 of the target triangular fm signal has a frequency fstartThe time-equipotent value decreases to-BW/2, and the frequency of the second segment signal 32 increases from-BW/2 to fstart. The first segment signal 31 and the second segment signal 32 are continuous in frequency, and the first segment signal 31 and the second segment signal 32 are equal in duration.
Referring to fig. 4, a waveform diagram of a target triangular fm signal according to another embodiment of the invention is shown. Unlike fig. 2 and 3, the initial frequency of the target triangular fm signal in fig. 4 is 0, which corresponds to the target triangular fm signal in fig. 2 shifted to the left by t/4. The target triangular chirp signal in fig. 4 is divided into three segments, which are a first segment signal 41, a second segment signal 42, and a third segment signal 43 in that order.
In the embodiment of the present invention, fig. 2, fig. 3, and fig. 4 may respectively characterize data corresponding to one symbol. Because the waveforms corresponding to fig. 2, 3, and 4 are different, the data corresponding to fig. 2, 3, and 4 may be different, that is, the corresponding information to be transmitted is different.
Referring to fig. 1, in a specific implementation, a triangular fm modulator may include a digital modulation circuit 11 and a radio frequency analog modulation circuit 12. The digital modulation circuit 11 may generate a control signal corresponding to the target triangular frequency modulation signal, and output the control signal to the radio frequency analog modulation circuit 12. The radio frequency analog modulation circuit 12 may further process the control signal to generate a target triangular frequency modulated signal.
In specific implementation, referring to fig. 5, a schematic structural diagram of a digital modulation circuit 11 in an embodiment of the present invention is provided. In fig. 5, the digital modulation circuit 11 may include an encoder 111 and a control signal generator 112. In the embodiment of the present invention, the encoder 111 may encode data to be transmitted, generate encoded data corresponding to the data to be transmitted, and transmit the encoded data to the control signal generator 112. The control signal generator 112 may generate a corresponding control signal according to the encoded data after receiving the encoded data.
In a specific implementation, the initial frequency of the target triangular frequency modulation signal can be determined according to the bandwidth of the transmission signal. In the embodiment of the present invention, the range of the initial frequency of the target triangular frequency modulation signal may be [ -BW/2, BW/2 ].
In specific implementation, the spreading factor of the target triangular frequency modulation signal can be predetermined according to the actual application requirement. Through the spread spectrum factor of the target triangular frequency modulation signal, the time length of the target triangular frequency modulation signal which continuously changes in the time domain can be determined, namely: according to the spreading factor of the target triangular frequency modulation signal, a time window with the time length of delta t can be determined. At the initial moment of the time window, the frequency of the target triangular frequency modulation signal is the initial frequency of the target triangular frequency modulation signal; and at the termination time of the time window, the frequency of the target triangular frequency modulation signal is the termination frequency of the target triangular frequency modulation signal.
According to the time length delta t corresponding to the spreading factor of the target triangular frequency modulation signal and the bandwidth of the target triangular frequency modulation signal, the frequency step f can be calculatedstep＝2BW/Δt。
In an embodiment of the present invention, the frequency step of the target triangular frequency modulated signal is further related to the monotonicity of the target triangular frequency modulated signal. When the monotonicity of the target triangular frequency modulation signal is increased by the equal difference value along with the time, the monotonicity value is 1, and at the moment, the frequency stepping is still fstep(ii) a When the monotonicity of the target triangular frequency modulation signal is decreased with the time equal difference value, the monotonicity value is-1, and at the moment, the frequency step is-fstep。
The target triangular frequency modulation signal has a monotonicity turning point, namely corresponding monotonicity before and after a certain frequency is opposite. For the target triangular frequency modulation signal, the corresponding monotonicity turning points are BW/2 and-BW/2.
In fig. 2, the monotonicity of the first segment 21 of the target triangular fm signal is increased with time by an equal difference, and the monotonicity takes a value of 1, so that the frequency of the first segment 21 is stepped by fstep(ii) a The monotonicity of the second signal 22 is decreasing with time and the difference value is-1, so the frequency of the second signal 22 is stepped by-fstep。
In an embodiment of the present invention, the generated target triangular chirp signal is s (t) sin (2 pi × f (t) × t), wherein:
fcis the radio frequency, that is, the transmission frequency of the antenna in the radio frequency circuit; the digital baseband signal corresponding to the target triangular frequency modulation signal can be expressed as:
SF is a spreading factor; the control signal is determined by f (n).
In one embodiment, the antenna may transmit at 433MHz, i.e., fcIs 433 MHz. It will be appreciated that the transmission frequency of the antenna may be different in different application scenarios.
In a specific implementation, n is a discrete time point and t is a continuous time. Thus, f (n) substantially corresponds to f (t) at discrete times.
In an embodiment of the present invention, for a discrete data signal system, t is n/BW. Thus, the phase of the digital baseband signal at point m is
Wherein, thetamFor the phase of the digital baseband signal at m points, fstartIs the initial frequency of the target triangular FM signal, BW is the bandwidth of the digital baseband signal, theta0Is the initial phase of the digital baseband signal; m is more than or equal to 1 and less than or equal to M, M is the total point number of the target triangular frequency modulation signal, and M is 2SFAnd SF is the value of the spreading factor. For example, if SF is 6, then M is 64.
In an embodiment of the invention, the sampling frequency of the discrete data signal system is equal to the bandwidth of the digital baseband signal.
That is, in the embodiment of the present invention, the phase of the generated target triangular fm signal is related to the frequency, and the phase corresponding to a certain sampling point is related to the following data: an accumulated value of the frequencies of points before it and an initial frequency of the target triangular chirp signal.
In a specific implementation, the radio frequency analog modulation circuit 12 may be coupled with the digital modulation circuit 11. The radio frequency analog modulation circuit 12 may include a phase locked loop circuit including a frequency Divider (DIV). Digital modulation circuit 11 may be coupled to a phase-locked loop circuit. After generating the control signal, the digital modulation circuit 11 may output the control signal to the phase-locked loop circuit, and control a Voltage Controlled Oscillator (VCO) in the phase-locked loop circuit by the control signal to generate a target triangular frequency modulation signal with a frequency varying with time; the frequency Divider (DIV) is controlled by a control signal to generate a frequency division value corresponding to a target triangular frequency modulation signal output by a Voltage Controlled Oscillator (VCO).
In the embodiment of the present invention, the control signal generated by the digital modulation circuit 11 may be a digital signal, the control signal in the digital signal format may be converted into a control signal in a corresponding analog signal format through a digital-to-analog converter (DAC), and the Voltage Controlled Oscillator (VCO) is controlled by the control signal in the analog signal format.
With continued reference to fig. 1, in an embodiment of the present invention, the triangular fm demodulator may include a digital demodulation circuit 14 and an analog demodulation circuit 15. The analog demodulation circuit 15 may include an antenna circuit (LNA), a second mixer 132, a filter & analog-to-digital converter (ADC), and the like. The received signal is amplified and the like by an antenna circuit (LNA), down-converted by a second mixer 132, and filtered by a filter & analog-to-digital converter (ADC). Since the received signal is an analog signal, the received signal needs to be analog-to-digital converted by an analog-to-digital converter (ADC) to obtain a digital signal and output the digital signal to the digital demodulation circuit 14.
In specific implementation, the specific function and structure of the analog demodulation circuit 15 may refer to the analog demodulation circuit portion in the existing radio frequency circuit.
In a specific implementation, the digital demodulation circuit may include a first mixer, a synchronization buffer, and a processor, wherein:
a first mixer adapted to down-convert the received signal from a low intermediate frequency to a zero intermediate frequency; receiving the frequency offset value output by the processor, and performing frequency offset removal processing on the received signal according to the frequency offset value;
the synchronous buffer is suitable for storing a sampling signal with a preset length, and the preset length is determined by the spread spectrum factor of the target triangular frequency modulation signal; receiving a synchronous address output by the processor, and synchronizing the stored sampling signals; the sampling signal with the preset length is a signal obtained by equally dividing the output signal of the first mixer;
the processor is suitable for generating a local triangular frequency modulation signal which is synchronous with the sampling signal and has the same length, performing complex multiplication operation on the sampling signal and the local triangular frequency modulation signal, and performing discrete Fourier transform on a complex multiplication operation result; and calculating a synchronous address and a frequency offset value according to the discrete Fourier transform result, and performing decoding operation according to the discrete Fourier transform result.
In an embodiment of the present invention, the processor may include: local triangle FM signal generator, discrete Fourier transform unit, synchronization unit, frequency offset calculation tracking unit and decoding unit, wherein: a local triangular frequency modulation signal generator adapted to generate a local triangular frequency modulation signal; the discrete Fourier transform unit is suitable for performing complex multiplication operation on the sampling signal and the local triangular frequency modulation signal, performing discrete Fourier transform on a complex multiplication operation result, and respectively outputting the obtained discrete Fourier transform result to the synchronization unit, the frequency offset calculation tracking unit and the decoding unit; a synchronization unit adapted to calculate a synchronization address from a discrete fourier transform result; the frequency offset calculation tracking unit is suitable for calculating a frequency offset value according to a discrete Fourier transform result; and the decoding unit is suitable for performing decoding operation according to the discrete Fourier transform result.
Referring to fig. 6, a schematic diagram of a digital demodulation circuit 14 according to an embodiment of the present invention is shown. Referring to fig. 1, the structure of the digital demodulation circuit 14 is described, and in the embodiment of the present invention, the digital demodulation circuit 14 may include a first mixer 51, a synchronization buffer 52, a local triangular chirp generator 53, a discrete fourier transform unit 54, a synchronization unit 55, a frequency offset tracking calculation unit, and a decoding unit 57.
In a specific implementation, a first input terminal of the first mixer 51 may be coupled to an output terminal of the analog demodulation circuit 15, a second input terminal of the first mixer 51 may be coupled to an output terminal of the frequency offset calculation tracking unit 56, and an output terminal of the first mixer 51 may be coupled to an input terminal of the synchronization buffer 52.
The first mixer 51 may receive the frequency offset value output by the frequency offset tracking unit 56, and perform frequency mixing processing on the signal output by the analog demodulation circuit 15, so as to down-convert the signal output by the analog demodulation circuit 15 from a low intermediate frequency to a zero intermediate frequency, and eliminate the frequency offset in the signal output by the analog demodulation circuit 15.
Those skilled in the art will appreciate that the signal output by the analog demodulation circuit 15 and the signal output by the first mixer 51 are both substantially target triangular frequency modulated signals. The signal output by the analog demodulation circuit comprises a target triangular frequency modulation signal and noise, and the carrier frequency corresponding to the target triangular frequency modulation signal is medium-low frequency. The signal output by the first mixer 51 is a target triangular frequency modulation signal corresponding to a zero intermediate frequency.
In an embodiment of the present invention, a first input terminal of the synchronization buffer 52 may be coupled to an output terminal of the first mixer 51, and a second input terminal of the synchronization buffer 52 may be coupled to the synchronization unit 55.
The synchronization buffer 52 may store a preset length of the sampling signal. The preset length can be determined according to the number of sampling points corresponding to the spreading factor. The sampling signal is substantially a part of the target triangular frequency modulated signal, that is, the target triangular frequency modulated signal is equally divided into N segments, and the N segmented sampling signals are sequentially input to the synchronization buffer 52. Only one segmented sample signal may be stored in the synchronization buffer 52 at a time.
The synchronization buffer 52 may output the stored sample signal to the discrete fourier transform unit 54 after buffering the sample signal of a preset length. Alternatively, the discrete fourier transform unit 54 may retrieve the stored sample signal from the synchronization buffer 52.
In particular implementations, local triangular chirp generator 53 may generate a local triangular chirp that is synchronized to the sampled signal and of the same length. The local triangular chirp generated by local triangular chirp generator 53 may be related to the target triangular chirp. The local triangular chirp generated by the local triangular chirp generator 53 may be different corresponding to different segmented sampled signals, which correspond to the local triangular chirp one-to-one.
That is, if the sampled signal is the first segment of the target triangular chirp signal and the length of the sampled signal is X, the length of the local triangular chirp signal generated by the local triangular chirp signal generator 53 is X and the generated local triangular chirp signal corresponds to the first segment of the target triangular chirp signal. When the sampling signal is the second segment of the target triangular chirp, the local triangular chirp generated by the local triangular chirp generator 53 corresponds to the sampling signal of the second segment.
In a specific implementation, the discrete fourier transform unit 54 may be coupled to the synchronization buffer 52 and the local triangular chirp generator 53, and may respectively read the stored sampled signal from the synchronization buffer 52 and receive the local triangular chirp generated by the local triangular chirp generator 53. The discrete fourier transform unit 54 may perform a complex multiplication operation on the local triangular frequency modulation signal and the sampling signal to obtain a complex multiplication result.
Discrete fourier transform section 54 performs discrete fourier transform on the complex multiplication result, and outputs the obtained discrete fourier transform result to synchronization section 55, decoding section 57, and frequency offset calculation tracking section 56.
The synchronization unit 55 may obtain the synchronization address from the discrete fourier transform result after receiving the discrete fourier transform result output from the discrete fourier transform unit 54. After calculating the synchronization address, the synchronization unit 55 may send the synchronization address to the synchronization buffer 52. The synchronization buffer 52 may synchronize the sampling signals stored therein upon receiving the synchronization address.
In the embodiment of the present invention, after receiving the synchronization address, the synchronization buffer 52 synchronizes the sampling signal stored therein, which may be updating the sampling signal stored therein to the next segment of the target triangular chirp signal.
For example, the sampled signal stored in the synchronization buffer 52 is a first segment of the target triangular chirp signal. The sync buffer 52 updates the stored sampled signal to the second segment of the target triangular chirp signal after receiving the sync address.
In a specific implementation, the frequency offset calculation tracking unit 56 may calculate the frequency offset value according to the discrete fourier transform result after receiving the discrete fourier transform result. The frequency offset calculation tracking unit 56 may output the obtained frequency offset value to the first mixer 51.
In a specific implementation, after receiving the discrete fourier transform result, the decoding unit 57 may perform a corresponding decoding operation according to the discrete fourier transform result.
In the embodiment of the present invention, when performing complex multiplication on the sampling signal and the local triangular frequency modulation signal, the discrete fourier transform unit 54 may first equally divide the sampling signal and the local triangular frequency modulation signal into two sections. The discrete fourier transform unit 54 performs complex multiplication on the previous segment of the sampling signal and the conjugate of the previous segment of the local triangular frequency modulation signal to obtain a first product; and carrying out complex multiplication operation on the later section of the sampling signal and the later section of the local triangular frequency modulation signal to obtain a second product. The discrete fourier transform unit 54 performs discrete fourier transform on the first product to obtain a first energy maximum; the second product is subjected to discrete fourier transform to obtain a second energy maximum. And selecting a larger value from the first energy maximum value and the second energy maximum value, and taking the selected larger value as a discrete Fourier transform result.
In a particular implementation, the digital demodulation circuit may also include a digital low pass filter 58. The digital low pass filter 58 may be disposed between the first mixer 51 and the synchronization buffer 52, and may perform digital filtering processing on the output of the first mixer 51 and output the signal after the digital filtering processing to the synchronization buffer 52.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (10)
1. A triangular fm modulator adapted to generate a target triangular fm signal having a phase determined by an initial frequency of the target triangular fm signal and a frequency step determined by a bandwidth of the target triangular fm signal, the frequency step of the target triangular fm signal being fstep (BW/2)SF-1) D, wherein fstep is the frequency step, BW is the bandwidth of the target triangular frequency modulation signal, SF is a spreading factor of the target triangular frequency modulation signal, and d is monotonicity of the target triangular frequency modulation signal; the target triangular frequency modulation signal is a mapping result after encoding processing of information to be transmitted, and the maximum number of the target triangular frequency modulation signals is 2SF-1(ii) a The target triangular frequency modulation signal consists of two or three sections of signals with continuous frequencies;
the triangular frequency modulation signal modulator comprises a digital modulation circuit and a radio frequency analog modulation circuit, wherein: the digital modulation circuit is suitable for generating a control signal of the target triangular frequency modulation signal; the digital modulation circuit includes an encoder and a control signal generator, wherein: the encoder is suitable for encoding data to be transmitted, generating encoded data corresponding to the data to be transmitted and transmitting the encoded data to the control signal generator; the control signal generator is suitable for generating the control signal according to the coded data; the radio frequency analog modulation circuit is coupled with the digital modulation circuit; the radio frequency analog modulation circuit comprises a phase-locked loop circuit; the digital modulation circuit is suitable for outputting the control signal to the phase-locked loop circuit so as to control the phase-locked loop circuit to generate the target triangular frequency modulation signal.
2. Triangular FM signal modulation as claimed in claim 1The device is characterized in that the target triangular frequency modulation signal is s (t) sin (2 pi × f (t) × t),
the digital baseband signal of the target triangular frequency modulation signal is
1≤n≤2SF(ii) a The phase of the digital baseband signal at the point m is as follows:
wherein f iscIs the radio frequency, fstartIs the initial frequency, f, of the target triangular FM signalstepFor the frequency step of the target triangular frequency modulation signal, the control signal is determined by f (n); thetamIs the phase of the digital baseband signal at m points, BW is the bandwidth of the digital baseband signal, theta0N is a positive integer for the initial phase of the digital baseband signal.
3. The triangular frequency modulated signal modulator of claim 2, wherein the initial frequency of the target triangular frequency modulated signal has a range of [ -BW/2, BW/2 ].
4. A triangular fm signal modulator as claimed in claim 2 wherein the frequency step f of the target triangular fm signalstepCalculated using the following formula:
when the difference value of the frequency increases along with the time, d is 1; when the difference value of the frequency decreases along with the time, d is-1;
the time length of the target triangular frequency modulation signal is determined by the spreading factor SF of the target triangular frequency modulation signal.
5. A triangular fm signal modulator as claimed in claim 2, wherein the first segment of the target triangular fm signal has a frequency that varies with time by an amount that increases from-BW/2 to BW/2, and the second segment of the target triangular fm signal has a frequency that varies with time by an amount that decreases from BW/2 to-BW/2.
6. A triangular FM demodulator, adapted to receive a target triangular FM signal transmitted through the triangular FM modulator of any one of claims 1 to 5 and demodulate the target triangular FM signal; the triangular frequency modulation signal demodulator comprises: first mixer, synchronous buffer, processor, wherein:
the first mixer is suitable for down-converting the received signal from a low intermediate frequency to a zero intermediate frequency; receiving the frequency offset value output by the processor, and performing frequency offset removal processing on the received signal according to the frequency offset value;
the synchronous buffer is suitable for storing a sampling signal with a preset length, and the preset length is determined by the spread spectrum factor of the target triangular frequency modulation signal; receiving a synchronous address output by the processor, and synchronizing the stored sampling signals; the sampling signal with the preset length is a signal obtained by equally dividing the output signal of the first mixer;
the processor is suitable for generating a local triangular frequency modulation signal which is synchronous with the sampling signal and has the same length, performing complex multiplication operation on the sampling signal and the local triangular frequency modulation signal, and performing discrete Fourier transform on a complex multiplication operation result; and calculating the synchronous address and the frequency offset value according to the discrete Fourier transform result, and performing decoding operation according to the discrete Fourier transform result.
7. A triangular FM signal demodulator as claimed in claim 6, wherein said processor comprises: local triangle FM signal generator, discrete Fourier transform unit, synchronization unit, frequency offset calculation tracking unit and decoding unit, wherein:
the local triangular frequency modulation signal generator is suitable for generating the local triangular frequency modulation signal;
the discrete Fourier transform unit is suitable for performing complex multiplication operation on the sampling signal and the local triangular frequency modulation signal, performing discrete Fourier transform on a complex multiplication operation result, and respectively outputting the obtained discrete Fourier transform result to the synchronization unit, the frequency offset calculation tracking unit and the decoding unit;
the synchronization unit is suitable for calculating the synchronization address according to the discrete Fourier transform result;
the frequency offset calculation tracking unit is suitable for calculating the frequency offset value according to the discrete Fourier transform result;
and the decoding unit is suitable for performing decoding operation according to the discrete Fourier transform result.
8. A triangular FM demodulator as claimed in claim 7, wherein said discrete Fourier transform unit is adapted to equally divide said sampled signal and said local triangular FM signal into two sections, and perform a complex multiplication operation on a previous section of said sampled signal and a conjugate of a previous section of said local triangular FM signal to obtain a first product; carrying out complex multiplication operation on the later section of the sampling signal and the later section of the local triangular frequency modulation signal to obtain a second product; performing discrete Fourier transform on the first product to obtain a first energy maximum value; performing discrete Fourier transform on the second product to obtain a second energy maximum value; and selecting the larger value of the first energy maximum value and the second energy maximum value as the discrete Fourier transform result.
9. A triangular fm signal demodulator as claimed in claim 6, further comprising: and the digital low-pass filter is suitable for filtering the signal output by the first mixer and outputting the processed signal to the synchronous buffer.
10. A wireless communication system comprising a triangular FM modulator according to any one of claims 1 to 5 and a triangular FM demodulator according to any one of claims 6 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010301576.7A CN111614589B (en) | 2020-04-16 | 2020-04-16 | Tri-angle FM signal modulator, demodulator and wireless communication system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010301576.7A CN111614589B (en) | 2020-04-16 | 2020-04-16 | Tri-angle FM signal modulator, demodulator and wireless communication system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111614589A true CN111614589A (en) | 2020-09-01 |
| CN111614589B CN111614589B (en) | 2023-07-18 |
Family
ID=72199593
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010301576.7A Active CN111614589B (en) | 2020-04-16 | 2020-04-16 | Tri-angle FM signal modulator, demodulator and wireless communication system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111614589B (en) |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0555089A2 (en) * | 1992-02-07 | 1993-08-11 | Victor Company Of Japan, Limited | Spread spectrum communication system |
| JP2009156582A (en) * | 2007-12-25 | 2009-07-16 | Honda Elesys Co Ltd | Electronic scanning type radar system, and method, and program for estimating direction of received wave |
| CN102474297A (en) * | 2009-07-02 | 2012-05-23 | 纳米实验室 | Communications system |
| EP2469783A1 (en) * | 2010-12-23 | 2012-06-27 | The Swatch Group Research and Development Ltd. | FSK radio signal receiver with high-sensitivity demodulator and method for operating said receiver |
| IT201700090111A1 (en) * | 2017-08-03 | 2019-02-03 | Vodafone Automotive S P A | CODING METHOD OF A SIGNAL, RECEIVER DEVICE AND ASSOCIATED TRANSMISSION SYSTEM |
| JP2019021963A (en) * | 2017-07-11 | 2019-02-07 | 日本無線株式会社 | Demodulator and demodulation method |
| US20190086531A1 (en) * | 2017-09-21 | 2019-03-21 | Hach Company | Frequency profiles for non-contact range measurement with multi-scale analysis |
| CN110493154A (en) * | 2019-10-14 | 2019-11-22 | 上海磐启微电子有限公司 | Modulator, demodulator and wireless communication system |
| CN110831118A (en) * | 2018-08-08 | 2020-02-21 | 深圳市力合微电子股份有限公司 | Chirp signal generation method and communication method for realizing low-power consumption wake-up code |
-
2020
- 2020-04-16 CN CN202010301576.7A patent/CN111614589B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0555089A2 (en) * | 1992-02-07 | 1993-08-11 | Victor Company Of Japan, Limited | Spread spectrum communication system |
| JP2009156582A (en) * | 2007-12-25 | 2009-07-16 | Honda Elesys Co Ltd | Electronic scanning type radar system, and method, and program for estimating direction of received wave |
| CN102474297A (en) * | 2009-07-02 | 2012-05-23 | 纳米实验室 | Communications system |
| EP2469783A1 (en) * | 2010-12-23 | 2012-06-27 | The Swatch Group Research and Development Ltd. | FSK radio signal receiver with high-sensitivity demodulator and method for operating said receiver |
| JP2019021963A (en) * | 2017-07-11 | 2019-02-07 | 日本無線株式会社 | Demodulator and demodulation method |
| IT201700090111A1 (en) * | 2017-08-03 | 2019-02-03 | Vodafone Automotive S P A | CODING METHOD OF A SIGNAL, RECEIVER DEVICE AND ASSOCIATED TRANSMISSION SYSTEM |
| US20190086531A1 (en) * | 2017-09-21 | 2019-03-21 | Hach Company | Frequency profiles for non-contact range measurement with multi-scale analysis |
| CN110831118A (en) * | 2018-08-08 | 2020-02-21 | 深圳市力合微电子股份有限公司 | Chirp signal generation method and communication method for realizing low-power consumption wake-up code |
| CN110493154A (en) * | 2019-10-14 | 2019-11-22 | 上海磐启微电子有限公司 | Modulator, demodulator and wireless communication system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111614589B (en) | 2023-07-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110493154B (en) | Modulator, demodulator, and wireless communication system | |
| CN102739590B (en) | CP-EBPSK communication system for pseudorandom sequence phase modulation and communication method thereof | |
| WO2009049468A1 (en) | A transmitting and receiving system and method of ultra-wideband pulse or pulse sequence | |
| JP2010071899A (en) | Fmcw signal generator and radar apparatus using the fmcw signal generator | |
| CN101395880A (en) | Method and apparatus for generating clock signals for quadrature sampling | |
| US8125258B2 (en) | Phase synchronization device and phase synchronization method | |
| CN101207406B (en) | Wireless communication apparatus and wireless communication method | |
| CN111614589B (en) | Tri-angle FM signal modulator, demodulator and wireless communication system | |
| KR20170125738A (en) | Communication process and system for high-sensitivity and synchronous demodulation signals | |
| CN116137539B (en) | Signal generation method and device based on LoRa modulation and LoRa equipment | |
| CN113965435B (en) | High dynamic frequency tracking method suitable for low-speed signals | |
| CN1314211C (en) | Improvements in or relating to frequency-hopping modulators and demodulators | |
| JP3818526B2 (en) | Orthogonal frequency division multiplex signal receiving apparatus and orthogonal frequency division multiplex signal receiving method | |
| CN101036363A (en) | Differential phase coding in wireless communications system | |
| JP4521600B2 (en) | Receiving device for receiving code-spread pulse signal and communication device using the same | |
| JP3818535B2 (en) | Orthogonal frequency division multiplex signal transmission / reception system and orthogonal frequency division multiplex signal transmission / reception method | |
| JP3818531B2 (en) | Orthogonal frequency division multiplex signal receiving apparatus and orthogonal frequency division multiplex signal receiving method | |
| JP3818538B2 (en) | Orthogonal frequency division multiplex signal transmission / reception system and orthogonal frequency division multiplex signal transmission / reception method | |
| JP4228353B2 (en) | Orthogonal frequency division multiplex signal transmission / reception system and orthogonal frequency division multiplex signal transmission / reception method | |
| JP3818528B2 (en) | Orthogonal frequency division multiplex signal receiving apparatus and orthogonal frequency division multiplex signal receiving method | |
| JP3818530B2 (en) | Orthogonal frequency division multiplex signal receiving apparatus and orthogonal frequency division multiplex signal receiving method | |
| JP3818536B2 (en) | Orthogonal frequency division multiplex signal transmission / reception system and orthogonal frequency division multiplex signal transmission / reception method | |
| JP3818533B2 (en) | Orthogonal frequency division multiplex signal transmission / reception system and orthogonal frequency division multiplex signal transmission / reception method | |
| WO2023163792A1 (en) | Systems and methods for synthesis of modulated rf signals | |
| JP3818529B2 (en) | Orthogonal frequency division multiplex signal receiving apparatus and orthogonal frequency division multiplex signal receiving method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |