CN112491766A - Digital modulation method and device, and storage medium - Google Patents
Digital modulation method and device, and storage medium Download PDFInfo
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Abstract
The application relates to a digital modulation method, a digital modulation device and a storage medium, wherein the digital modulation method comprises the following steps: acquiring a digital signal; performing forming filtering processing and IQ calculation processing on the digital signal according to a preset modulation type to obtain modulation data; and converting the modulation data to obtain a modulation signal. On one hand, because the acquired digital signal comprises the amplitude and the phase corresponding to the plurality of constellation points, the amplitude and the phase are easy to be processed separately in the subsequent modulation process, so that a modulation signal with a fixed phase or a constantly changing phase is generated; on the other hand, the technical scheme realizes the modulation modes of multiple modulation types including QAM, PSK, ASK, FSK and MSK by reasonably configuring the processes of forming filtering processing and IQ calculation processing, and can avoid the use situation of single modulation mode in the existing vector signal source.
Description
Technical Field
The invention relates to the technical field of signal digital modulation, in particular to a digital modulation method and device and a storage medium.
Background
With the development of communication technology, vector signal sources are more and more popular, functions are more and more abundant, various basic modulations and generation of various communication protocol signals can be realized, the basic modulations are standard matching functions of various vector sources, and how to realize a strong basic modulation function is still pursued by each manufacturer.
In the field of test measurement, two very common instruments are a signal generator (including an arbitrary waveform generator, a radio frequency signal source, a vector signal generator, etc.) for generating signals of various frequencies and various waveform shapes and a spectrum analyzer for receiving and measuring various signals, such as power (amplitude), frequency, phase, bandwidth, etc., of the signals, and even performing various modulation-demodulation analyses on the signals.
The signal modulation technique is a process of converting a signal generated by a signal source into a form suitable for wireless transmission, and can be divided into an analog modulation process and a digital modulation process. At present, digital modulation is mostly realized by adopting a lookup table, and the method can only generate some modulation signals with fixed phases based on a constellation diagram and cannot generate modulation signals with continuously changing phases, for example, the method is not used in modulation modes such as FSK and MSK. In the prior art, the I-path numerical value and the Q-path numerical value corresponding to the constellation diagram are directly stored in the lookup table, and then the I-path data and the Q-path data are directly indexed out by using the information source bit stream as the address of the lookup table.
Disclosure of Invention
The invention mainly solves the technical problems that: how to overcome the limitation of the existing look-up table mode to realize digital modulation. In order to solve the above problems, the present invention provides a digital modulation method and apparatus, and a storage medium.
According to a first aspect, the present invention provides a digital modulation method comprising: acquiring a digital signal; the digital signal comprises amplitudes and phases corresponding to a plurality of constellation points respectively; performing forming filtering processing and IQ calculation processing on the digital signal according to a preset modulation type to obtain modulation data; and converting the modulation data to obtain a modulation signal.
The acquiring of the digital signal comprises: obtaining a bit stream from a modulation source; and inquiring a pre-configured amplitude phase table according to the bit stream, and respectively indexing a plurality of constellation points to obtain corresponding amplitude and phase, thereby forming the digital signal.
The configuration process of the amplitude phase table comprises the following steps: the coordinates of each constellation point are distributed and set in the constellation diagram, the corresponding amplitude and phase are calculated by utilizing the coordinates of each constellation point, and the corresponding amplitude and phase are stored in the amplitude and phase table; for the constellation points with coordinates (x (i), y (i)), if the modulation type is QAM, PSK or ASK, the formulas for calculating the corresponding amplitude and phase are respectively expressed as
amp(i) = sqrt(x(i)^2 + y(i)^2)；
phase(i) = atan(y(i)/ x(i))；
If the modulation type is FSK or MSK, the formulas for calculating the corresponding amplitude and phase are respectively expressed as
amp(i)=1；
phase(i)=((i-(N-1)/2)/((N-1)/2))* (Fsk_dev/N)*(pi/Sym_rate)；
Wherein i is a serial number of the constellation point, N is a number of the constellation points, sqrt () is a square root calculation function, atan () is an arc tangent calculation function, pi is a circumferential rate (i.e., pi), Fsk _ dev is a preset frequency offset parameter, and Sym _ rate is a preset symbol rate parameter.
The performing a shaping filtering process and an IQ calculation process on the digital signal according to a preset modulation type to obtain modulation data includes: determining a modulation type for the digital signal; if the modulation type is QAM, PSK or ASK, IQ calculation processing is carried out on the digital signal to obtain an I-path modulation result and a Q-path modulation result, and the I-path modulation result and the Q-path modulation result are subjected to forming filtering processing to obtain modulation data; if the modulation type is FSK or MSK, IQ calculation processing is carried out on the amplitude of each constellation point in the digital signal, forming filtering processing, accumulation processing and IQ calculation processing are carried out on the phase of each constellation point in the digital signal in sequence, and modulation data are formed according to an I-path modulation result and a Q-path modulation result obtained through calculation; the mode of the shaping filtering processing comprises any one of Gaussian filtering, raised cosine filtering and root raised cosine filtering.
The converting the modulation data to obtain a modulation signal includes: calculating an interpolation multiple required by digital-to-analog conversion according to the sampling rate of the digital-to-analog conversion and the sampling rate of the modulation data, and performing interpolation processing on the modulation data according to the interpolation multiple so as to interpolate to the sampling rate of the digital-to-analog conversion to obtain interpolation data; and D/A conversion is carried out on the interpolation data to obtain a modulation signal corresponding to the digital signal.
According to a second aspect, the present invention provides a digital modulation apparatus comprising: a signal generation unit for acquiring a digital signal; the digital signal comprises the amplitude and the phase corresponding to each constellation point; the signal processing unit is used for carrying out forming filtering processing and IQ calculation processing on the digital signal according to a preset modulation type to obtain modulation data; and the signal conversion unit is used for converting the modulation data to obtain a modulation signal.
The device also comprises a modulation information source and a storage unit which are connected with the signal generating unit; the modulation source is used for generating a bit stream; the storage unit is used for storing a pre-configured amplitude phase table; the signal generating unit queries a pre-configured amplitude phase table according to the bit stream, and indexes the pre-configured amplitude phase table to obtain the amplitude and the phase corresponding to the plurality of constellation points, so as to form the digital signal.
The signal processing unit comprises a configuration module, an IQ calculation module, a forming filter and an accumulator; the configuration module is used for configuring the modulation type of the digital signal; the IQ calculation module is used for executing IQ calculation processing and outputting an I-path modulation result and a Q-path modulation result; the shaping filter is used for executing shaping filtering processing, and the shaping filtering processing mode comprises any one of Gaussian filtering, raised cosine filtering and root raised cosine filtering; the accumulator is used for executing accumulation processing; if the modulation type is QAM, PSK or ASK, IQ calculation processing is carried out on the digital signal, and then shaping filtering processing is carried out on the obtained I-path modulation result and Q-path modulation result to obtain modulation data; and if the modulation type is FSK or MSK, performing IQ calculation processing on the amplitude of each constellation point in the digital signal, sequentially performing forming filtering processing, accumulation processing and IQ calculation processing on the phase of each constellation point in the digital signal, and forming modulation data according to an I-path modulation result and a Q-path modulation result obtained by calculation.
The signal conversion unit includes: the rate matching module is used for interpolating the modulation data to the sampling rate of digital-to-analog conversion to obtain interpolated data; and the digital-to-analog converter is used for performing digital-to-analog conversion on the interpolation data to obtain a modulation signal corresponding to the digital signal.
According to a third aspect, the invention provides a computer readable storage medium comprising a program executable by a processor to implement the method described in the first aspect above.
The beneficial effect of this application is:
the above embodiments provide a digital modulation method, a digital modulation apparatus, and a storage medium, where the digital modulation method includes: acquiring a digital signal; performing forming filtering processing and IQ calculation processing on the digital signal according to a preset modulation type to obtain modulation data; and converting the modulation data to obtain a modulation signal. On one hand, because the acquired digital signals comprise the amplitude and the phase corresponding to each constellation point, the amplitude and the phase are easy to be processed separately in the subsequent modulation process, thereby generating modulation signals with fixed phases or continuously changed phases; on the other hand, the technical scheme realizes the modulation modes of multiple modulation types including QAM, PSK, ASK, FSK and MSK by reasonably configuring the processes of forming filtering processing and IQ calculation processing, and can avoid the use situation of single modulation mode in the existing vector signal source.
Drawings
Fig. 1 is a schematic structural diagram of a digital modulation apparatus according to an embodiment of the present application;
FIG. 2 is a schematic diagram of the operation of the digital modulation apparatus;
FIG. 3 is a flow chart of a digital modulation method according to a second embodiment of the present disclosure;
FIG. 4 is a flow chart of acquiring a digital signal;
FIG. 5 is a flow chart of processing resulting modulated data;
FIG. 6 is a flow chart of processing a resulting modulated signal;
fig. 7 is a schematic structural diagram of a digital modulation apparatus according to a third embodiment of the present application.
Detailed Description
The present invention will be described in further detail with reference to the following detailed description and accompanying drawings. Wherein like elements in different embodiments are numbered with like associated elements. In the following description, numerous details are set forth in order to provide a better understanding of the present application. However, those skilled in the art will readily recognize that some of the features may be omitted or replaced with other elements, materials, methods in different instances. In some instances, certain operations related to the present application have not been shown or described in detail in order to avoid obscuring the core of the present application from excessive description, and it is not necessary for those skilled in the art to describe these operations in detail, so that they may be fully understood from the description in the specification and the general knowledge in the art.
Furthermore, the features, operations, or characteristics described in the specification may be combined in any suitable manner to form various embodiments. Also, the various steps or actions in the method descriptions may be transposed or transposed in order, as will be apparent to one of ordinary skill in the art. Thus, the various sequences in the specification and drawings are for the purpose of describing certain embodiments only and are not intended to imply a required sequence unless otherwise indicated where such sequence must be followed.
The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings).
The first embodiment,
Referring to fig. 1, the present embodiment discloses a digital modulation apparatus, the digital modulation apparatus 1 mainly includes a signal generating unit 11, a signal processing unit 12 and a signal converting unit 13, which are respectively described below.
The signal generating unit 11 obtains a digital signal by performing amplitude and phase indexing on the plurality of constellation points, respectively, and the digital signal here includes the amplitude and phase corresponding to each of the plurality of constellation points.
The signal processing unit 12 has a capability of processing each constellation point in the digital signal, and is mainly used for performing a shaping filtering process and an IQ calculation process on the digital signal according to a preset modulation type, so as to process and obtain modulation data.
The signal conversion unit 13 has a function of digital-to-analog conversion (DAC), and is capable of converting modulation data to obtain a modulation signal in an analog form.
Further, referring to fig. 1, the digital modulation apparatus 1 further includes a modulation source 14 and a storage unit 15 connected to the signal generation unit 11, which are respectively described below.
The modulation source 14 is used to generate a binary data stream, such as a bit stream, which can then be used as the signal needed to index the amplitude phase table. The modulation source 14 can generate a bit stream by using a pseudo-random sequence, or can generate a bit stream according to a sequence mode defined by a user.
It should be noted that the pseudo-random sequence has the characteristics of predetermined and repeated production and reproduction, and also has the random characteristics (i.e., statistical characteristics) of a certain random sequence, so that it is a certain sequence of a certain random characteristic. The series of pseudo-random sequences has good randomness and correlation function close to white noise and has advanced determinability and repeatability, and the characteristics enable the pseudo-random sequences to be widely applied.
The storage unit 15 may be some kind of storage medium with a storage function, such as a read-only memory, a random access memory, a magnetic disk, an optical disk, a hard disk, etc., and is mainly used for storing a pre-configured amplitude phase table.
Under the coordination of the modulation information source 14 and the storage unit 15, the signal generating unit 11 queries an amplitude phase table configured in advance in the storage unit 15 according to the bit stream generated by the modulation information source 14, and obtains the amplitude and the phase corresponding to a plurality of constellation points by indexing, thereby forming a digital signal.
In one embodiment, the signal generating unit 11 may be configured to form a magnitude phase table, and store the configured magnitude phase table in the storage unit 15. The process of the signal generating unit 11 configuring the amplitude phase table is described below.
(1) The coordinates of a plurality of constellation points are distributed in the constellation diagram, such as (x (i), y (i)), the corresponding amplitude and phase are calculated by using the coordinates of each constellation point, and the corresponding amplitude and phase are stored in an amplitude and phase table.
(2) If the modulation type is QAM, PSK or ASK, the formulas for calculating the corresponding amplitude and phase are respectively expressed as
amp(i) = sqrt(x(i)^2 + y(i)^2)；
phase(i) = atan(y(i)/ x(i))。
(3) If the modulation type is FSK or MSK, the formulas for calculating the corresponding amplitude and phase are respectively expressed as
amp(i)=1；
phase(i)=((i-(N-1)/2)/((N-1)/2))* (Fsk_dev/N)*(pi/Sym_rate)。
Wherein i is the serial number of the constellation point and satisfies i =0,1,2 …, N-1; n is the number of constellation points; amp () is amplitude calculation function, phase () is phase calculation function, sqrt () is square root calculation function, atan () is arctan calculation function, Fsk _ dev is preset frequency offset parameter, Sym _ rate is preset symbol rate parameter.
It should be noted that the frequency offset parameter can be regarded as the amplitude of the frequency modulation signal deviating from the carrier frequency; the symbol rate parameter may be referred to as symbol rate, baud rate, and refers to the rate of data transmission, and is related to the bit rate of the signal and the channel parameter, and has a unit of MB/S.
It should be noted that, since the number of the plurality of constellation points in the amplitude phase table is N, the address length of the amplitude phase table is considered to be N, and log2(N) bits are required to represent the address length. Then each log2(N) bit stream is indexed both amplitude and phase as a set of addresses to an index table, each set being the result of one amplitude data and one phase data.
In a particular embodiment, referring to fig. 1, the signal processing unit 12 may include a configuration module 121, an IQ calculation module 122, a shaping filter 123, and an accumulator 124, each described below.
The configuration module 121 is mainly used for configuring a modulation type of the digital signal, such as any one modulation type of QAM, PSK, ASK, FSK, and MSK.
Of course, the configuration module 121 may also configure parameters such as a symbol rate parameter, a frequency offset parameter, a filter coefficient, and an oversampling multiple, which may be set by user input, may be set by default of the system, and is not particularly limited. Wherein, the symbol rate parameter and the frequency offset parameter are used for configuring in the signal generating unit 11 to form an amplitude phase table; the filter coefficient and the oversampling multiple are used to set parameters of the shaping filter 123.
The IQ calculation module 122 has a digital operation function, and is mainly configured to perform IQ calculation processing, thereby outputting an I-path modulation result and a Q-path modulation result. In general, the IQ computation module 122 may divide the input data into two paths for carrier modulation, where the two paths are orthogonal to each other, I (in-phase) is in-phase, q (quadrature) is orthogonal, and the phase difference between the two paths is 90 degrees.
For example, the process of the IQ calculation module 122 calculating the I-path modulation result and the Q-path modulation result according to the amplitude and the phase is represented as:
I = amp * cos(phase)；
Q= amp * sin(phase)。
and amp and phase are numerical values output when the amplitude phase table is indexed. If the modulation type is FSK, phase is the phase value obtained by the phase lookup table output after shaping filtering and then accumulating.
The shaping filter 123 is used to perform shaping filtering processing. Here, the mode of the shaping filter processing includes any one of gaussian filtering, raised cosine filtering, and root raised cosine filtering.
It should be noted that the shaping filter 123 may adopt a gaussian filter, a raised cosine filter and a root raised cosine filter, and its function is to eliminate interference between symbols. Generally, interpolation is required to be performed on data when performing the shaping filtering processing, and the interpolation multiple is at least 2 times or more; for example, the gaussian filter uses a hold interpolation method, and the other filters use a zero insertion method. In addition, in the case where the modulation type is FSK or MSK, shaping filtering is enabled before the accumulator, and in the case where the modulation type is QAM, PSK, or ASK, shaping filtering is enabled after the IQ modulation result is calculated.
The accumulator 124 is used to perform accumulation processing. In the case of FSK and MSK modulation types, the angular frequency is stored in the amplitude phase table, so the phase data output by indexing needs to pass through the accumulator 124, so as to directly output the phase value.
Here, if the modulation type is QAM, PSK, or ASK, the digital signal is first IQ-calculated by the IQ calculation module 122, and then the I-path modulation result and the Q-path modulation result obtained are shaped and filtered by the shaping filter 123, so as to obtain modulation data.
Here, if the modulation type is FSK or MSK, the IQ calculation module 122 performs IQ calculation processing on the amplitude of each constellation point in the digital signal, and sequentially performs shaping filtering processing (performed by the shaping filter 123), accumulation processing (performed by the accumulator 124), and IQ calculation processing (performed by the IQ calculation module 122) on the phase of each constellation point in the digital signal, thereby forming modulation data according to the I-path modulation result and the Q-path modulation result obtained by the calculation.
It should be noted that, since the amplitude in the digital signal is constant in the case where the modulation types are FSK and MSK, the amplitude data does not need to perform the shaping filtering process.
In one embodiment, referring to fig. 1, the signal conversion unit 13 includes a rate matching module 131 and a digital-to-analog converter 132, which are described below, respectively.
The rate matching module 131 obtains the modulation data from the signal processing unit 12, and then interpolates the modulation data to a sampling rate of digital-to-analog conversion to obtain interpolated data; that is, the rate matching module 131 implements an interpolation function capable of interpolating modulation data to the sampling rate of the digital-to-analog converter 132.
The digital-to-analog converter 132 obtains the interpolation data from the rate matching module 131, and performs digital-to-analog conversion on the interpolation data to obtain a modulation signal corresponding to the digital signal.
To assist the skilled person to understand the working process of the digital modulation apparatus 1 in the present embodiment, the working principle diagram of fig. 2 will be specifically described.
Referring to fig. 1 and 2, the configuration module 121 in the signal processing unit 12 functions as a configuration parameter, and configures a modulation type, a symbol rate parameter, a frequency offset parameter, a filter coefficient, and an oversampling multiple of a digital signal. Wherein, the modulation type is sent to the signal processing unit 11 to participate in setting the data processing path; the symbol rate parameter and the frequency offset parameter are sent to the signal generating unit 11 to participate in configuration to form an amplitude phase table; the filter coefficients, the oversampling multiples, are sent to the shaping filter 123 to assist in setting the parameters of the filter itself.
The signal generating unit 11 obtains a bit stream from the modulation source 14, looks up an amplitude phase table configured in advance in the storage unit 15 according to the bit stream, and obtains the amplitude and the phase corresponding to a plurality of constellation points through indexing, thereby forming a digital signal.
The signal processing unit 12 determines the modulation type, and if the modulation type is QAM, PSK, or ASK, the IQ computation module 122 performs IQ computation on the digital signal, and then the shaping filter 123 performs shaping filtering on the I-path modulation result and the Q-path modulation result, so as to obtain modulation data, and at this time, the modulation data is transmitted from the shaping filter 123 to the rate matching module 131 for rate matching processing. The signal processing unit 12 determines that the modulation type is FSK or MSK, and then the IQ calculation module 122 performs IQ calculation processing on the amplitude of each constellation point in the digital signal, and at the same time, the shaping filter performs shaping filtering processing on the phase of each constellation point in the digital signal, the data after filtering processing is accumulated by the accumulator 124, the accumulated data is further subjected to IQ calculation processing by the IQ calculation module 122, and then modulation data formed by the I-path modulation result and the Q-path modulation result is obtained, and at this time, the modulation data is transmitted from the IQ calculation module 122 to the rate matching module 131 for rate matching processing.
The rate matching module 131 in the signal conversion unit 13 obtains the modulation data from the signal processing unit 12, and then interpolates the modulation data to a sampling rate of digital-to-analog conversion to obtain interpolated data, thereby implementing rate matching processing of the modulation data. The digital-to-analog converter 132 in the signal conversion unit 13 obtains the interpolation data from the rate matching module 131, so as to perform digital-to-analog conversion on the interpolation data, and obtain a modulation signal corresponding to the digital signal. The digital-to-analog converter 132 may output the modulated signal.
It should be noted that qam (quadrature Amplitude modulation) refers to quadrature Amplitude modulation, whose Amplitude and phase change simultaneously, and belongs to non-constant envelope two-dimensional modulation; QAM can be considered a combination of quadrature carrier modulation techniques and multi-level amplitude keying. The QAM uses two independent baseband signals to carry out carrier-restraining double-sideband amplitude modulation on two mutually orthogonal same-frequency carriers, and realizes the transmission of two paths of parallel digital information by utilizing the orthogonality of the frequency spectrum of the modulated signals in the same bandwidth.
Psk (phase shift keying) is phase shift keying modulation, which is a modulation technique for representing input signal information by carrier phase. Phase shift keying is divided into absolute phase shift and relative phase shift, where phase modulation with the phase of an unmodulated carrier as a reference is called absolute phase shift. Taking binary phase modulation as an example, when a code element is taken as '1', a modulated carrier wave is in phase with an unmodulated carrier wave; when the code element is taken as '0', the modulated carrier wave and the unmodulated carrier wave are reversed; the "1" and "0" are the modulated carrier phase difference of 180 degrees.
Ask (amplitude Shift keying) is amplitude Shift keying modulation, which is a relatively simple modulation scheme. ASK corresponds to amplitude modulation in an analog signal, but is simply a binary number multiplied by a carrier frequency signal. The amplitude shift is a constant in frequency and phase, and a variable in amplitude, and the information bits are transmitted by the amplitude of the carrier wave.
It should be noted that fsk (frequency Shift keying) is a modulation method used earlier in information transmission, and has some advantages: the method is easy to realize, has good noise and attenuation resistance, and is widely applied to medium and low speed data transmission.
It should be noted that msk (minimum Shift keying) is minimum Shift keying modulation, which is a modulation technique for transmitting information by changing carrier frequency, i.e. a special continuous phase Shift keying method. The MSK maximum frequency shift is 1/4 at bit rate, i.e. MSK is a continuous phase FSK with a modulation factor of 0.5. The MSK also delays the quadrature baseband signal by half the symbol interval relative to the in-phase baseband signal, thereby eliminating 180 DEG phase jump in the modulated signal.
Example II,
The present embodiment discloses a digital modulation method, which is mainly applied in cooperation with the signal generating unit, the signal processing unit 12 and the signal converting unit 13 in fig. 1.
Referring to fig. 3, the claimed digital modulation method includes steps S210-S230, which are described below.
In step S210, a digital signal is acquired. The digital signal here includes amplitudes and phases corresponding to a plurality of constellation points.
Step S220, performing a shaping filtering process and an IQ calculation process on the digital signal according to a preset modulation type to obtain modulation data.
Step S230, converting the modulation data to obtain a modulation signal.
In this embodiment, referring to fig. 4, the step S210 mainly relates to a process of acquiring a digital signal, and may specifically include steps S211 to S212, which are respectively described as follows.
In step S211, the signal generating unit 11 obtains a bit stream from a modulation source. Since the bit stream is used as a signal required for indexing the amplitude phase table, the modulation information source 14 may generate the bit stream by using a pseudo-random sequence, or may generate the bit stream according to a sequence manner defined by a user, which is not specifically limited herein.
In step S212, the signal generating unit 11 queries the amplitude phase table pre-configured in the storage unit 15 according to the bit stream, and indexes the amplitude phase table to obtain the amplitude and the phase corresponding to each of the plurality of constellation points, thereby forming a digital signal.
In a specific embodiment, the signal generating unit 11 arranges coordinates of a plurality of constellation points in a constellation diagram, calculates corresponding amplitude and phase by using the coordinates of each constellation point, and stores the amplitude and phase into an amplitude and phase table, thereby configuring the amplitude and phase table.
For the constellation points with coordinates (x (i), y (i)), if the modulation type is QAM, PSK or ASK, the formula for the signal generating unit 11 to calculate the corresponding amplitude and phase is expressed as
amp(i) = sqrt(x(i)^2 + y(i)^2)；
phase(i) = atan(y(i)/ x(i))。
If the modulation type is FSK or MSK, the formula for calculating the corresponding amplitude and phase by the signal generating unit 11 is expressed as FSK or MSK, respectively
amp(i)=1；
phase(i)=((i-(N-1)/2)/((N-1)/2))* (Fsk_dev/N)*(pi/Sym_rate)。
Wherein i is the serial number of the constellation point, and N is the number of the constellation point; amp () is the amplitude calculation function, phase () is the phase calculation function, pi is the circumference (i.e., pi), sqrt () is the square root calculation function, atan () is the arctangent calculation function, Fsk _ dev is the predetermined frequency offset parameter, and Sym _ rate is the predetermined symbol rate parameter.
It should be noted that the frequency offset parameter can be regarded as the amplitude of the frequency modulation signal deviating from the carrier frequency; the symbol rate parameter may be referred to as symbol rate, baud rate, and refers to the rate of data transmission, and is related to the bit rate of the signal and the channel parameter, and has a unit of MB/S.
In this embodiment, referring to fig. 5, the step S220 mainly relates to a process of acquiring a digital signal, and may specifically include steps S221 to S223, which are respectively described as follows.
In step S221, the signal processing unit 12 determines the modulation type for the digital signal, where the modulation type is any one of QAM, PSK, ASK, FSK, and MSK.
Step S222, when the signal processing unit 12 determines that the modulation type is QAM, PSK, or ASK, IQ computation is performed on the digital signal to obtain an I-path modulation result and a Q-path modulation result, and the I-path modulation result and the Q-path modulation result are further subjected to shaping filtering to obtain modulation data.
In a specific embodiment, referring to fig. 1, the IQ calculation module 122 in the signal processing unit 12 performs IQ calculation on the digital signal, and then the shaping filter 123 performs shaping filtering on the I-path modulation result and the Q-path modulation result to obtain modulation data, at this time, the modulation data is transmitted from the shaping filter 123 to the rate matching module 131 for rate matching processing.
Step S223, if the signal processing unit 12 determines that the modulation type is FSK or MSK, then perform IQ calculation processing on the amplitude of each constellation point in the digital signal, and sequentially perform shaping filtering processing, accumulation processing, and IQ calculation processing on the phase of each constellation point in the digital signal, and form modulation data according to the I-path modulation result and the Q-path modulation result obtained by the calculation.
In an embodiment, the IQ calculation module 122 in the signal processing unit 12 performs IQ calculation on the amplitude of each constellation point in the digital signal, and at the same time, the shaping filter performs shaping filtering on the phase of each constellation point in the digital signal, the filtered data is accumulated by the accumulator 124, the accumulated data is further subjected to IQ calculation by the IQ calculation module 122, and then modulation data formed by the I-path modulation result and the Q-path modulation result is obtained, at this time, the modulation data is transmitted from the IQ calculation module 122 to the rate matching module 131 for rate matching processing.
In this embodiment, referring to fig. 6, the step S230 mainly relates to a process of acquiring a digital signal, and may specifically include steps S231-S232, which are respectively described as follows.
In step S231, the signal conversion unit 13 calculates an interpolation multiple required for digital-to-analog conversion according to the sampling rate of digital-to-analog conversion and the sampling rate of the modulation data, and performs interpolation processing on the modulation data according to the interpolation multiple, thereby interpolating to the sampling rate of digital-to-analog conversion to obtain interpolation data.
In a specific embodiment, referring to fig. 1, the signal conversion unit 13 calculates an interpolation multiple required by the operation of the digital-to-analog converter 132 according to the sampling rate of the digital-to-analog converter 132 and the sampling rate of the modulation data, and then the rate matching module 131 interpolates the modulation data obtained from the signal processing unit 12, so as to interpolate to the sampling rate of the digital-to-analog conversion, obtain interpolated data, and further implement the rate matching processing of the modulation data.
In step S232, the signal conversion unit 13 performs digital-to-analog conversion on the interpolated data to obtain a modulated signal corresponding to the digital signal.
In a specific embodiment, referring to fig. 1, the digital-to-analog converter 132 in the signal conversion unit 13 obtains the interpolation data from the rate matching module 131, so as to perform digital-to-analog conversion on the interpolation data, and obtain a modulation signal corresponding to the digital signal. The digital-to-analog converter 132 may output the modulated signal.
Example III,
On the basis of the full memory depth measurement method disclosed in the second embodiment, a digital modulation apparatus is disclosed in the present embodiment.
Referring to fig. 7, the digital oscilloscope 3 includes a memory 31 and a processor 32. Among them, the memory 31 may be considered as a computer-readable storage medium for storing a program, which may be a program code corresponding to the digital modulation method in the second embodiment.
The processor 32 is connected to the memory 31 for implementing the digital modulation method by executing the program stored in the memory 31. Then, the functions implemented by the processor 32 can refer to steps S210-S230 in the second embodiment, and refer to the steps disclosed in fig. 4 to fig. 6, and will not be described in detail here.
Those skilled in the art will appreciate that all or part of the functions of the various methods in the above embodiments may be implemented by hardware, or may be implemented by computer programs. When all or part of the functions of the above embodiments are implemented by a computer program, the program may be stored in a computer-readable storage medium, and the storage medium may include: a read only memory, a random access memory, a magnetic disk, an optical disk, a hard disk, etc., and the program is executed by a computer to realize the above functions. For example, the program may be stored in a memory of the device, and when the program in the memory is executed by the processor, all or part of the functions described above may be implemented. In addition, when all or part of the functions in the above embodiments are implemented by a computer program, the program may be stored in a storage medium such as a server, another computer, a magnetic disk, an optical disk, a flash disk, or a removable hard disk, and may be downloaded or copied to a memory of a local device, or may be version-updated in a system of the local device, and when the program in the memory is executed by a processor, all or part of the functions in the above embodiments may be implemented.
The present invention has been described in terms of specific examples, which are provided to aid understanding of the invention and are not intended to be limiting. For a person skilled in the art to which the invention pertains, several simple deductions, modifications or substitutions may be made according to the idea of the invention.
Claims (10)
1. A digital modulation method, comprising:
acquiring a digital signal; the digital signal comprises amplitudes and phases corresponding to a plurality of constellation points respectively;
performing forming filtering processing and IQ calculation processing on the digital signal according to a preset modulation type to obtain modulation data; the method specifically comprises the following steps: determining a modulation type for the digital signal; if the modulation type is QAM, PSK or ASK, IQ calculation processing is carried out on the digital signal to obtain an I-path modulation result and a Q-path modulation result, and the I-path modulation result and the Q-path modulation result are subjected to forming filtering processing to obtain modulation data; if the modulation type is FSK or MSK, IQ calculation processing is carried out on the amplitude of each constellation point in the digital signal, forming filtering processing, accumulation processing and IQ calculation processing are carried out on the phase of each constellation point in the digital signal in sequence, and modulation data are formed according to an I-path modulation result and a Q-path modulation result obtained through calculation;
and converting the modulation data to obtain a modulation signal.
2. The method of claim 1, wherein said obtaining a digital signal comprises:
obtaining a bit stream from a modulation source;
and inquiring a pre-configured amplitude phase table according to the bit stream, and respectively indexing a plurality of constellation points to obtain corresponding amplitude and phase, thereby forming the digital signal.
3. The method of claim 2, wherein the configuring of the amplitude phase table comprises:
the coordinates of each constellation point are distributed and set in the constellation diagram, the corresponding amplitude and phase are calculated by utilizing the coordinates of each constellation point, and the corresponding amplitude and phase are stored in the amplitude and phase table;
for the constellation points with coordinates (x (i), y (i)), if the modulation type is QAM, PSK or ASK, the formulas for calculating the corresponding amplitude and phase are respectively expressed as
amp(i) = sqrt(x(i)^2 + y(i)^2)；
phase(i) = atan(y(i)/ x(i))；
If the modulation type is FSK or MSK, the formulas for calculating the corresponding amplitude and phase are respectively expressed as
amp(i)=1；
phase(i)=((i-(N-1)/2)/((N-1)/2))* (Fsk_dev/N)*(pi/Sym_rate)；
Wherein i is a serial number of the constellation point, N is a number of the constellation points, sqrt () is a square root calculation function, atan () is an arc tangent calculation function, pi is a circumferential rate, Fsk _ dev is a preset frequency offset parameter, and Sym _ rate is a preset symbol rate parameter.
4. The method of claim 1, wherein the shaping filter process comprises any one of gaussian filtering, raised cosine filtering, and root raised cosine filtering.
5. The method of claim 1, wherein said converting said modulated data to obtain a modulated signal comprises:
calculating an interpolation multiple required by digital-to-analog conversion according to the sampling rate of the digital-to-analog conversion and the sampling rate of the modulation data, and performing interpolation processing on the modulation data according to the interpolation multiple so as to interpolate to the sampling rate of the digital-to-analog conversion to obtain interpolation data;
and D/A conversion is carried out on the interpolation data to obtain a modulation signal corresponding to the digital signal.
6. A digital modulation apparatus, comprising:
a signal generation unit for acquiring a digital signal; the digital signal comprises amplitudes and phases corresponding to a plurality of constellation points respectively;
the signal processing unit is used for carrying out forming filtering processing and IQ calculation processing on the digital signal according to a preset modulation type to obtain modulation data;
and the signal conversion unit is used for converting the modulation data to obtain a modulation signal.
7. The apparatus of claim 6, further comprising a modulation source and storage unit connected to the signal generation unit;
the modulation source is used for generating a bit stream;
the storage unit is used for storing a pre-configured amplitude phase table;
the signal generating unit queries a pre-configured amplitude phase table according to the bit stream, and indexes the plurality of constellation points respectively to obtain corresponding amplitudes and phases, so as to form the digital signal.
8. The apparatus of claim 6, wherein the signal processing unit comprises a configuration module, an IQ computation module, a shaping filter, and an accumulator;
the configuration module is used for configuring the modulation type of the digital signal;
the IQ calculation module is used for executing IQ calculation processing and outputting an I-path modulation result and a Q-path modulation result;
the shaping filter is used for executing shaping filtering processing, and the shaping filtering processing mode comprises any one of Gaussian filtering, raised cosine filtering and root raised cosine filtering;
the accumulator is used for executing accumulation processing;
if the modulation type is QAM, PSK or ASK, IQ calculation processing is carried out on the digital signal, and then shaping filtering processing is carried out on the obtained I-path modulation result and Q-path modulation result to obtain modulation data;
and if the modulation type is FSK or MSK, performing IQ calculation processing on the amplitude of each constellation point in the digital signal, sequentially performing forming filtering processing, accumulation processing and IQ calculation processing on the phase of each constellation point in the digital signal, and forming modulation data according to an I-path modulation result and a Q-path modulation result obtained by calculation.
9. The apparatus of claim 6, wherein the signal conversion unit comprises:
the rate matching module is used for interpolating the modulation data to the sampling rate of digital-to-analog conversion to obtain interpolated data;
and the digital-to-analog converter is used for performing digital-to-analog conversion on the interpolation data to obtain a modulation signal corresponding to the digital signal.
10. A computer-readable storage medium, characterized by comprising a program executable by a processor to implement the method of any one of claims 1-5.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5945885A (en) * | 1998-03-05 | 1999-08-31 | Hewlett-Packard Company | Digital baseband modulator adaptable to different modulation types |
| US20050220218A1 (en) * | 2004-04-02 | 2005-10-06 | Jensen Henrik T | RF transmitter architecture for continuous switching between modulations modes |
| US20110188604A1 (en) * | 2010-02-03 | 2011-08-04 | Infineon Technologies Ag | Digital Modulator and Digital-to-Analog Conversion Techniques Associated Therewith |
| US20120163831A1 (en) * | 2010-12-22 | 2012-06-28 | Michael Eiselt | Digital modulation method and device, especially an optical digital modulation method and device |
| CN105530215A (en) * | 2015-12-08 | 2016-04-27 | 重庆金美通信有限责任公司 | 8PSK soft differential decoding method based on CORDIC |
| CN105991508A (en) * | 2016-05-13 | 2016-10-05 | 深圳市统先科技股份有限公司 | 8QAM modulation method and system thereof |
| CN111800368A (en) * | 2020-06-29 | 2020-10-20 | 中国工程物理研究院电子工程研究所 | Digital communication method based on 16-system 8-8 constellation map mapping |
| CN111970087A (en) * | 2020-07-30 | 2020-11-20 | 西南电子技术研究所（中国电子科技集团公司第十研究所） | GMSK modulation hardware implementation method |
-
2020
- 2020-12-24 CN CN202011546833.XA patent/CN112491766B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5945885A (en) * | 1998-03-05 | 1999-08-31 | Hewlett-Packard Company | Digital baseband modulator adaptable to different modulation types |
| US20050220218A1 (en) * | 2004-04-02 | 2005-10-06 | Jensen Henrik T | RF transmitter architecture for continuous switching between modulations modes |
| US20110188604A1 (en) * | 2010-02-03 | 2011-08-04 | Infineon Technologies Ag | Digital Modulator and Digital-to-Analog Conversion Techniques Associated Therewith |
| US20120163831A1 (en) * | 2010-12-22 | 2012-06-28 | Michael Eiselt | Digital modulation method and device, especially an optical digital modulation method and device |
| CN105530215A (en) * | 2015-12-08 | 2016-04-27 | 重庆金美通信有限责任公司 | 8PSK soft differential decoding method based on CORDIC |
| CN105991508A (en) * | 2016-05-13 | 2016-10-05 | 深圳市统先科技股份有限公司 | 8QAM modulation method and system thereof |
| CN111800368A (en) * | 2020-06-29 | 2020-10-20 | 中国工程物理研究院电子工程研究所 | Digital communication method based on 16-system 8-8 constellation map mapping |
| CN111970087A (en) * | 2020-07-30 | 2020-11-20 | 西南电子技术研究所（中国电子科技集团公司第十研究所） | GMSK modulation hardware implementation method |
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