Iq phase imbalance broadband compensation method and device and computer equipment

Abstract

The application relates to an IQ phase imbalance wideband compensation method, device and computer equipment. The method comprises the following steps: determining the phase response of each channel; obtaining the phase equalization all-pass filter of the corresponding channel based on the phase response; cascading the all-pass filter and the corresponding channel; and compensating each frequency point of the channel after each cascaded all-pass filter. The method can compensate the IQ phase imbalance wideband compensation accurately by equalizing each channel and then compensating the frequency point of the cascaded channel.

Description

TECHNICAL FIELD

[0001] The present application relates to the chip technical field, in particular to an IQ phase imbalance wideband compensation method, device and computer equipment. BACKGROUND

[0002] The digital tester is provided with an arbitrary waveform generator (AWG) and a digitizer (DGT), which can be used for testing various types of chips. With the rapid development of the electronic information field, the electronic information system structure becomes more and more complex, especially the higher bandwidth requirement. This means that the AWG and the DGT have higher sampling rate and bandwidth to adapt to more complex chip test scenarios. For AC circuit test scenarios, the AWG and the DGT both contain IQ functions, and two channels realize a set of IQ signals. The IQ keeps orthogonal, which is the premise of correct demodulation of the signal, so the phase-frequency characteristics between the hardware channels should be consistent. However, due to the imperfection of the device, even if the layout and wiring of the IQ channels are completely the same, the respective phase-frequency characteristics will still be different, and this difference will affect the chip test results, so the different phase differences between the IQ channels at different frequencies must be calibrated.

[0003] The existing IQ phase imbalance compensation technology is based on the calibration of a single tone signal. After establishing a single tone signal IQ imbalance mathematical model, estimating the IQ amplitude and phase imbalance factors, and calculating the correction matrix to compensate for the IQ, the IQ phase imbalance wideband compensation method, device and computer equipment are provided.

[0004] However, the current calibration based on a single tone signal can only estimate the phase imbalance factor of a single frequency point for compensation. Due to the imperfection of the analog-digital hybrid board card channel hardware, the phase imbalance factors of the corresponding frequency points between the IQ channels in the entire bandwidth are not equal. For AC testing, if the imbalance factors of each frequency point in the frequency band are too different, even if the average value is taken, the imbalance will be worsened after compensation. SUMMARY

[0005] Therefore, it is necessary to provide an IQ phase imbalance wideband compensation method, device and computer equipment capable of accurately compensating for IQ phase imbalance in a wideband.

[0006] In a first aspect, the present application provides an IQ phase imbalance wideband compensation method, which comprises:

[0007] determining the phase response of each channel;

[0008] obtaining a phase equalization all-pass filter for the corresponding channel based on the phase response, respectively;

[0009] concatenate the all-pass filter with the corresponding channel;

[0010] compensate each frequency point of the channel after each concatenated all-pass filter.

[0011] In one of the embodiments, the determining the phase response of each channel comprises:

[0012] collecting discrete time domain data of each channel, and converting each of the discrete time domain data into frequency domain data;

[0013] obtaining each initial phase response based on each of the frequency domain data, and unwrapping the phase of each of the initial phase responses to obtain the phase response of each channel.

[0014] In one of the embodiments, the obtaining the phase equalization all-pass filter of the corresponding channel based on the phase response comprises:

[0015] interpolating the phase response to obtain an interpolated phase response;

[0016] determining the group delay corresponding to each frequency point of the channel based on the interpolated phase response;

[0017] obtaining the phase equalization all-pass filter of the channel based on the group delay corresponding to each frequency point of the channel.

[0018] In one of the embodiments, the obtaining the phase equalization all-pass filter of the channel based on the group delay corresponding to each frequency point of the channel comprises:

[0019] obtaining an expected group delay under a sampling point based on the group delay corresponding to each frequency point of the channel;

[0020] obtaining a complex cepstrum sequence based on the expected group delay under the sampling point;

[0021] obtaining an unwrapped phase and a complex cepstrum even sequence based on the complex cepstrum sequence;

[0022] obtaining an amplitude of a minimum phase signal Fourier transform based on the complex cepstrum even sequence;

[0023] determining the phase equalization all-pass filter of the channel based on the amplitude of the minimum phase signal Fourier transform and the unwrapped phase.

[0024] In one of the embodiments, the compensating each frequency point of the channel after each concatenated all-pass filter comprises:

[0025] determining a first group delay corresponding to each frequency point of the I channel and a second group delay corresponding to each frequency point of the Q channel after each concatenated all-pass filter, and obtaining a group delay difference between the channels based on the first group delay and the second group delay.

[0026] performing a time-domain data point coordinate shift operation on all data points of the lagging channel based on the group delay difference to compensate for each frequency point of the lagging channel.

[0027] In one of the embodiments, the performing a time-domain data point coordinate shift operation on all data points of the lagging channel based on the group delay difference to compensate for each frequency point of the lagging channel comprises:

[0028] obtaining an average delay difference based on the group delay difference;

[0029] shifting time-domain coordinates of all data points of the lagging channel left by the average delay difference sample points to compensate for each frequency point of the lagging channel.

[0030] In one of the embodiments, the shifting time-domain coordinates of all data points of the lagging channel left by the average delay difference sample points to compensate for each frequency point of the lagging channel comprises:

[0031] performing interpolation on time-domain data point coordinates of the lagging channel;

[0032] shifting interpolated data point coordinates left by the average delay difference sample points to compensate for each frequency point of the lagging channel.

[0033] In one of the embodiments, the determining the first group delay corresponding to each frequency point of the I channel and the second group delay corresponding to each frequency point of the Q channel after the cascaded all-pass filters comprises:

[0034] determining a first target phase response of the I channel and a second target phase response of the Q channel after the cascaded all-pass filters;

[0035] performing interpolation on the first target phase response to obtain a first target interpolated phase response of the I channel and performing interpolation on the second target phase response to obtain a second target interpolated phase response of the Q channel;

[0036] determining the first group delay corresponding to each frequency point of the I channel after the cascaded all-pass filters based on the first target interpolated phase response and determining the second group delay corresponding to each frequency point of the Q channel after the cascaded all-pass filters based on the second target interpolated phase response.

[0037] In a second aspect, the application further provides an IQ phase imbalance wideband compensation device, which comprises:

[0038] a phase response determination module configured to determine phase responses of channels;

[0039] The all-pass filter determination module is configured to determine a phase equalization all-pass filter for a corresponding channel based on the phase response of the channel;

[0040] The cascading module is configured to cascade the all-pass filter with the corresponding channel;

[0041] The compensation module is configured to compensate each frequency point of the channel after each cascaded all-pass filter.

[0042] In a third aspect, the present application provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method described above when executing the computer program.

[0043] The IQ phase imbalance wideband compensation method, device and computer device described above first determine the phase responses of the channels, then determine a phase equalization all-pass filter for a corresponding channel based on the phase response of the channel, cascade the all-pass filter with the corresponding channel, and compensate each frequency point of the channel after each cascaded all-pass filter. In this way, the channels are equalized first, and then the frequency points of the cascaded channels are compensated, so as to achieve the purpose of IQ wideband calibration and compensation, and the IQ phase imbalance wideband compensation can be accurately performed. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings needed to be used in the description of the embodiments of the present application or the related art will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other related drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0045] Figure 1 A flowchart of the IQ phase imbalance wideband compensation method in an embodiment;

[0046] Figure 2 A principle framework diagram of the IQ phase imbalance wideband compensation method in the present application;

[0047] Figure 3 A flowchart of the determination step of the all-pass filter in an embodiment;

[0048] Figure 4 A comparison effect of the group delay calculated by using the difference method after the channel phase response is interpolated by a cubic polynomial and the group delay calculated by directly using the difference method in an embodiment;

[0049] Figure 5 A schematic diagram of a comparison between the single frequency point phase imbalance calibration compensation and the wideband calibration in an embodiment;

[0050] Figure 6Effect of wideband calibration compensation before and after interpolation in one embodiment;

[0051] Figure 7 Flow chart of IQ channel phase imbalance bandwidth compensation method in one embodiment;

[0052] Figure 8 Structural block diagram of IQ phase imbalance wideband compensation device in one embodiment;

[0053] Figure 9 Internal structural diagram of computer device in one embodiment. DETAILED DESCRIPTION

[0054] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0055] In one embodiment, as shown in Figure 1 , an IQ phase imbalance wideband compensation method is provided. The present embodiment takes the method applied to an analog-digital hybrid board card as an example for illustration. It should be understood that the method can also be applied to an upper computer, an industrial computer or a communication intelligent device, and can also be applied to a calibration hardware. In the present embodiment, the method includes the following steps:

[0056] S102: Determine the phase response of each channel.

[0057] The phase response of the channel is obtained by converting the discrete time domain data obtained by sampling the channel into frequency domain data.

[0058] The channel in the application includes an I channel and a Q channel in an analog-digital hybrid board card, each I channel and each Q channel in the analog-digital hybrid board card is a group, and at least one group of the above channels can be included in one analog-digital hybrid board card. In the case of compensating for the IQ phase imbalance in each group of the analog-digital hybrid board card, each group of the above channels can be compensated for in series or in parallel, and the compensation method of each group of the above channels can adopt the method in the application. In addition, the calculation of the phase equalization all-pass filter of the I channel and the Q channel in each group can be parallel calculation or serial calculation, which will not be repeated here. In actual application, since the analog-digital hybrid board card includes a plurality of groups of the above channels, in the case of compensation, each group of the above channels is compensated for in parallel, and in the process of compensation calculation of each group of the above channels, the calculation of the phase equalization all-pass filter of the I channel and the Q channel adopts parallel calculation, the corresponding phase equalization all-pass filter is cascaded to the I channel and the Q channel respectively, and the group delay of the I channel and the Q channel is calculated in parallel, and then the group delay difference of each group is calculated, and finally the group delay difference is used to compensate for each frequency point of the lag channel.

[0059] S104: obtaining a phase equalization all-pass filter of the corresponding channel based on the phase response.

[0060] The group delay of the channel can be obtained based on the phase response of the channel, the group delay corresponding to the all-pass filter can be obtained based on the group delay of the channel, then the phase response corresponding to the all-pass filter can be obtained based on the group delay corresponding to the all-pass filter, and the phase equalization all-pass filter of the corresponding channel can be obtained based on the phase response corresponding to the all-pass filter.

[0061] The group delay is used to describe the degree of change of phase with frequency.

[0062] In some optional embodiments, the group delay of the channel can be obtained based on the phase response of the channel, which can be approximated by using the derivative of the phase response by the difference method, and the negative of the derivative is the group delay. However, because the frequency point interval of the current sampling is large, the accuracy of the group delay calculated by directly using the finite difference method is too low, which leads to inaccurate calculation, so the phase response of the channel is first interpolated, for example, the interpolated phase response is obtained by cubic polynomial interpolation, and then the group delay of the channel is obtained based on the interpolated phase response.

[0063] The group delay corresponding to the all-pass filter can be obtained based on the group delay of the channel, that is, the group delay in the form of 0-2π all-pass is obtained, which can reduce the influence of the sudden change of the group delay on the sudden point.

[0064] The design of the digital all-pass filter in this application is based on the discrete Hilbert transform. Its basic principle is to determine the phase of the desired pole portion of the all-pass filter based on a given group delay; then, the amplitude spectrum of the pole portion is obtained from the phase using the discrete Hilbert transform. In other embodiments, the all-pass filter can be designed in other ways, which are not specifically limited here. In this embodiment, a complex cepstrum sequence can be obtained first based on the group delay corresponding to the all-pass filter, and then the phase response corresponding to the all-pass filter can be obtained based on the complex cepstrum sequence.

[0065] Finally, based on the phase response of the all-pass filter, the denominator polynomial coefficients and numerator coefficients of the all-pass filter are obtained, thus yielding the expression for the all-pass filter, which is the all-pass filter itself.

[0066] S106: Cascade the all-pass filter with the corresponding channel.

[0067] Among them, combined Figure 2 As shown, Figure 2 This is a schematic diagram illustrating the principle framework of the IQ phase imbalance broadband compensation method in this application. Figure 2 The diagram only shows the principle framework of one set of channels; those skilled in the art can understand the principle framework of other sets of channels. Figure 2 The underlying principle is the same as in the previous example, and will not be repeated here. In this embodiment, each channel is cascaded with at least one all-pass filter to first equalize each channel, and then the frequency points of the cascaded channels are compensated for the time delay difference of each channel by data position shifting.

[0068] For ease of understanding, the following is... Figure 2 The underlying principles within the framework will be explained:

[0069] Let the transfer function of the all-pass filter be... The transfer function of the channel system is The cascaded system for:

[0070]

[0071] The frequency response of the cascaded system is:

[0072]

[0073] The parameters carrying 'ap' represent the parameters corresponding to the all-pass filter, while the parameters carrying 'd' represent the parameters of the channel.

[0074] The phase relationship of the cascaded system is as follows:

[0075]

[0076] Group delay of the system after cascading Therefore, the group delay of the system after cascading is:

[0077]

[0078] Wherein is the group delay of the all-pass system, is the group delay of the channel system. Therefore, the all-pass filter can be designed according to the group delay of the channel, so that the passband of the system after cascading satisfies:

[0079]

[0080] is a constant.

[0081] In this application, the IQ channel of the analog-digital hybrid board card is involved, therefore, the I channel and the Q channel are designed in this application, wherein the group delay of the I channel after cascading the all-pass filter APF1 is , and the group delay of the Q channel after cascading the all-pass filter APF2 is At this time, the group delay is irrelevant to the frequency, and is a constant, and the phase difference of the IQ channel is

[0082] According to the time shift characteristic of Fourier transform, the delay in the time domain is represented as the phase shift in the frequency domain, that is, the time domain signal is delayed by , and the signal in the frequency domain produces phase shift. Therefore, after passing through the all-pass filter, only the time domain signal of the leading channel is delayed by , so that the phase of the two channels is aligned, that is, the channel equalization is realized.

[0083] Based on this, the principle of determining the all-pass filter in step S104 can include:

[0084] For the M-order all-pass filter, the transfer function is:

[0085]

[0086] Wherein . The frequency response of the M-order all-pass filter is:

[0087]

[0088] From the above formula, the group delay response of is related to the denominator polynomial group delay of as follows:

[0089]

[0090] The same relationship applies to the average group delay:

[0091]

[0092] and

[0093]

[0094] The Discrete Hilbert Transform relation correlates the logarithmic magnitude of the Fourier transform of a minimum-phase signal with its phase. That is:

[0095]

[0096] in and Corresponding to Fourier transform and unconvert phase, yes The complex cepstral coefficients, To obtain a stable system, the coefficients of the denominator polynomial must be minimum-phase signals. Therefore, the design algorithm for an all-pass filter based on the discrete Hilbert transform first uses equations and to obtain the coefficients of the denominator polynomial. Then, from equation , it can be seen that the numerator coefficients are the inverted sequence of the denominator coefficients, and finally, the coefficients of the desired all-pass filter are obtained.

[0097] S108: Compensates for each frequency point of the channel after each stage of the all-pass filter.

[0098] The determined all-pass filters are cascaded into the corresponding channels to align the phases of each channel, thus achieving channel equalization. However, there are still differences in group delay between I and Q. These differences result in equal delay differences at each frequency point between I and Q. Compensation should be performed for these delay differences. Therefore, the frequency points of each channel after each cascaded all-pass filter are determined, and then compensation is performed.

[0099] The aforementioned broadband compensation method for IQ phase imbalance first determines the phase response of each channel; then, based on the phase response, a phase-equalized full-pass filter is obtained for each corresponding channel; the full-pass filter is cascaded with the corresponding channel; and compensation is performed on each frequency point of the channel after each cascaded full-pass filter. By first equalizing each channel and then compensating the frequency points of the cascaded channel, the broadband calibration and compensation between I and Q phase imbalances can be achieved, thus enabling accurate broadband compensation for IQ phase imbalance.

[0100] In one of the optional embodiments, the phase response of each channel is determined by collecting discrete time domain data of each channel, and converting each discrete time domain data into frequency domain data respectively; obtaining an initial phase response based on each frequency domain data respectively, and unwrapping each initial phase response to obtain the phase response of each channel.

[0101] wherein the multi-tone signal is sent to the channel and the time domain data is obtained by collection . The multi-tone frequency vector is set according to the channel allowed bandwidth and the sampling rate , and is a frequency vector with uniform interval, i.e. , the frequency point interval can be divided by , i.e. the point number of subsequent FFT operation, wherein in the present embodiment, .

[0102] The determination method of the phase response of each channel includes: firstly, ADC sampling to obtain discrete time domain data , performing FFT (Fourier Transform) operation on the discrete time domain data to obtain frequency domain data ; then using the four quadrant inverse tangent function to obtain the phase response, i.e. ; in order to eliminate the jump in the phase signal, finally using the unwrap algorithm to unwrap the phase, to obtain . It should be noted that the method of obtaining the frequency domain data based on the discrete time domain data can also use other methods, and the method of unwrapping the phase can also use other methods, which are not limited here.

[0103] In one of the optional embodiments, the phase equalization all-pass filter of the corresponding channel is obtained based on the phase response, including: interpolating the phase response to obtain an interpolated phase response; determining the group delay corresponding to each frequency point of the channel based on the interpolated phase response; obtaining the phase equalization all-pass filter of the channel based on the group delay corresponding to each frequency point of the channel.

[0104] wherein, as shown in Figure 3 , the flow chart of the determination steps of the all-pass filter in one embodiment is shown in Figure 3 , in which embodiment, the group delay corresponding to each frequency point of the channel is calculated first.

[0105] wherein, in the present application, the derivative on the phase response is calculated by using the difference method, and the negative number is the group delay. However, because the frequency point interval of the current sampling is large, the accuracy of the group delay calculated by using the finite difference method is too low, which leads to inaccurate calculation, so the phase response Interpolation can be performed, for example, using cubic polynomial interpolation to obtain... That is, fitting the phase frequency curve through interpolation, where the interpolation step size is... Generally, a smaller step size leads to higher approximation accuracy. However, an excessively small step size may result in inaccurate calculations due to rounding errors. Therefore, a suitable step size needs to be chosen that balances computational accuracy and stability. After interpolation, the derivative of the phase response is calculated using the finite difference method. :

[0106]

[0107] Group delay is the negative of the derivative, i.e., the group delay of the channel. :

[0108]

[0109] In this application, the group delay is first calculated by interpolation and then by differential calculation, which can improve the smoothness of the group delay curve and ensure that the first derivative of the phase response after interpolation is continuous at the original frequency. In this way, the instantaneous slope can be obtained to approximate the group delay response of the IQ channel. The calculation accuracy is high, so the imbalance between IQ channels is compensated after broadband calibration.

[0110] Specifically, in combination Figures 4 to 6 As shown, Figure 4 This example compares the group delay calculation using the finite difference method after cubic polynomial interpolation of the channel phase response with the group delay calculation using the finite difference method directly, in one embodiment. Figure 5 This is a schematic diagram comparing single-frequency point and broadband calibration for phase imbalance calibration compensation in one embodiment. Figure 6 This illustrates the broadband calibration compensation effect before and after interpolation in one embodiment.

[0111] In summary, the algorithm presented in this application has the following advantages: If differential calculation is performed directly without interpolation, the calculation accuracy is very low due to the large frequency interval, and the result is worse after calibration. The curve of group delay calculation after phase interpolation is smoother and the calculation accuracy is high, so the IQ imbalance is compensated after broadband calibration. Secondly, for scenarios where the phase imbalance at different frequencies between IQ channels is different, the traditional single-frequency calibration method for IQ imbalance cannot be effective. However, by using the broadband filtering calibration method, which uses an all-pass filter to perform phase equalization within a single channel and then compensates for the time delay difference between channels, the phase imbalance of different IQ channels can be compensated.

[0112] In one of the optional embodiments, the phase equalization all-pass filter of a channel is obtained based on the group delay of each frequency point of the channel, comprising: obtaining the expected group delay under the sampling point unit based on the group delay of each frequency point of the channel; obtaining the complex cepstrum sequence based on the expected group delay under the sampling point unit; obtaining the unwrapping phase and the complex cepstrum even sequence based on the complex cepstrum sequence; obtaining the amplitude of the minimum phase signal Fourier transform based on the complex cepstrum even sequence; determining the phase equalization all-pass filter of the channel based on the amplitude of the minimum phase signal Fourier transform and the unwrapping phase.

[0113] In the present application, the ways of determining the phase equalization all-pass filter of each channel are the same, and only the general principle is described in the present application. For the way of determining the phase equalization all-pass filter of each channel, the corresponding parameters are replaced with the channel parameters, and details are not described here.

[0114] Based on the group delay of each frequency point of the channel, the expected group delay under the sampling point unit is obtained, comprising: calculating the expected group delay of the all-pass filter to be designed . The characteristic function is used to derive the all-pass filter. In order to reduce the influence of the sudden change of the group delay on the sudden change point, the group delay of the all-pass filter is in the form of . Then The group delay on is symmetrical.

[0115]

[0116] The expected group delay of the all-pass filter to be designed , wherein .

[0117] The expected group delay under the sampling point unit is obtained by converting from time unit to sampling point unit, and is , which is the expected group delay under the sampling point unit.

[0118] Based on the expected group delay under the sampling point unit, the complex cepstrum sequence is obtained, comprising: performing N-point IFFT on to obtain the sequence , and then calculating the complex cepstrum sequence using the following formula:

[0119]

[0120] Based on the complex cepstrum sequence, the unwrapping phase and the complex cepstrum even sequence are obtained, comprising:

[0121] The unwrapping phase is calculated by performing Fourier transform on the complex cepstrum sequence and then taking the imaginary part: .

[0122] where Imag denotes imaginary part, and FFT denotes Fourier transform.

[0123] Computing complex cepstrum sequence . where

[0124]

[0125] IFFT operation is performed on to obtain the magnitude of minimum phase signal Fourier transform , i.e. the real number of denotes modulo operation.

[0126] Based on the magnitude of minimum phase signal Fourier transform and unwrapped phase, the all-pass filter of the channel is determined, including:

[0127] The denominator polynomial coefficient of the all-pass filter is calculated . It is worth noting that as increases , the magnitude of decreases, and when , , because is the minimum phase sequence.

[0128] According to the order of the required all-pass filter , the denominator coefficient of the all-pass filter is obtained:

[0129]

[0130] Based on the denominator coefficient of the all-pass filter , the numerator coefficient of the all-pass filter transfer function is obtained, .

[0131] Thus, based on the denominator coefficient and the numerator coefficient of the all-pass filter, the all-pass filter corresponding to the channel can be obtained. Wherein the coefficients of the numerator and denominator of the transfer function of the phase equalization all-pass filter of the I channel are respectively; the coefficients of the numerator and denominator of the transfer function of the phase equalization all-pass filter of the Q channel are .

[0132] In the above embodiment, after the phase of the sampled IQ multitone signal is obtained, the phase response is first interpolated, and then the group delay is calculated by using the difference method. This method ensures that the first derivative of the interpolated phase response at the original frequency point is continuous, so as to obtain the instantaneous slope to approximate the group delay response of the IQ channel.

[0133] In one of the optional embodiments, the compensation of each frequency point of each channel after the cascaded all-pass filter includes: determining the first group delay corresponding to each frequency point of the I channel after the cascaded all-pass filter and the second group delay corresponding to each frequency point of the Q channel, and obtaining the group delay difference between the channels based on the first group delay and the second group delay; and performing a time-domain data point coordinate drift operation on all data points of the lagging channel to compensate for each frequency point of the lagging channel based on the group delay difference.

[0134] The first group delay and the second group delay are determined based on the channels after the corresponding cascaded all-pass filter. In this embodiment, the group delay corresponding to each channel can be determined respectively. It should be noted that the determination method of the first group delay and the second group delay in this embodiment can be a differential method. In order to ensure accuracy, the phase response of the channel after the corresponding cascaded all-pass filter is first interpolated, and then the corresponding group delay is calculated based on the interpolated phase response.

[0135] In one of the optional embodiments, the determination of the first group delay corresponding to each frequency point of the I channel after the cascaded all-pass filter and the second group delay corresponding to each frequency point of the Q channel includes: determining a first target phase response of the I channel and a second target phase response of the Q channel after the cascaded all-pass filter; interpolating the first target phase response to obtain a first target interpolation phase response of the I channel, and interpolating the second target phase response to obtain a second target interpolation phase response of the Q channel; determining the first group delay corresponding to each frequency point of the I channel after the cascaded all-pass filter based on the first target interpolation phase response, and determining the second group delay corresponding to each frequency point of the Q channel after the cascaded all-pass filter based on the second target interpolation phase response.

[0136] For convenience, the determination method of the first group delay of the I channel is taken as an example for description, and the determination method of the second group delay of the Q channel is similar and will not be described here.

[0137] After the I channel is cascaded with the corresponding all-pass filter, the discrete time-domain data of the I channel is sampled, and then the discrete time-domain data of the I channel after the corresponding all-pass filter is processed, for example, Fourier transform is performed to obtain frequency domain data. Subsequently, the phase response of the I channel after the corresponding all-pass filter is obtained by using the four-quadrant arctangent function. Finally, in order to eliminate the jump in the phase signal, the phase unwrapping is performed to obtain the first target phase response of the I channel after the corresponding all-pass filter.

[0138] Then the first target interpolation phase response of the I channel is obtained by interpolating the first target phase response, for example, by using a cubic polynomial interpolation method, and the determination of the interpolation step can refer to the above, and will not be repeated here.

[0139] Finally, the first group delay corresponding to each frequency point of the I channel after the cascaded all-pass filter is determined based on the first target interpolation phase response. Specifically, the first group delay corresponding to each frequency point of the I channel after the cascaded all-pass filter is determined based on the first target interpolation phase response by a difference method.

[0140] Wherein, the group delay difference between the two channels Since the phase difference between the channels is compensated, In the entire frequency band is relatively flat, and the method of time domain data point coordinate shift is used to achieve the purpose of wideband calibration compensation between IQ, and at this time the channel itself also has a linear phase.

[0141] In one of the optional embodiments, based on the group delay difference, the time domain data point coordinate of all data points of the lagging channel is shifted to compensate for each frequency point of the lagging channel, including: obtaining an average delay difference based on the group delay difference; shifting the time domain coordinates of all data points of the lagging channel to the left by the average delay difference to compensate for each frequency point of the lagging channel.

[0142] Wherein, the calculation method of the average delay difference is:

[0143] Wherein, n is the number of frequency points.

[0144] After the average delay difference is determined, the time domain coordinates of all data points of the lagging channel are shifted to the left by sampling points, wherein the lagging channel is the phase lagging channel.

[0145] In one of the optional embodiments, the time domain coordinates of all data points of the lagging channel are shifted to the left by the average delay difference to compensate for each frequency point of the lagging channel, including: interpolating the time domain data point coordinates of the lagging channel; shifting the coordinates of each data point after interpolation to the left by the average delay difference to compensate for each frequency point of the lagging channel.

[0146] Wherein, in some embodiments, is not an integer sampling point and cannot be directly shifted, and in this application, the method of sinc interpolation (in other embodiments, other methods can be used) is used to shift all time domain data coordinates of the channel. The interpolation formula is:

[0147] The original coordinate position m of the time domain data to be shifted is The value of its corresponding integer sampling point , The kernel represents the convolution kernel, and t represents the interpolation coordinates. The interpolated values ​​are delayed over all time-domain data points of the channel. The coordinates of each sampling point are Specifically, at a new coordinate point Its interpolation formula is:

[0148]

[0149] This represents the length of the sinc convolution kernel, which theoretically has an infinite number of points. However, in actual calculations, the convolution kernel cannot be infinitely long and will be truncated. Therefore, an appropriate kernel needs to be selected based on the required accuracy. .

[0150] In this embodiment, by shifting the data position, the group delay difference of each frequency point of the IQ channel is compensated. After the delay, the phase imbalance between the I channel and the Q channel will be compensated, and there will be no IQ mismatch effect from the channel itself on the broadband signal.

[0151] Specifically, for ease of understanding, combined with Figure 7 As shown, Figure 7 This is a flowchart of a phase imbalance bandwidth compensation method for IQ channels in one embodiment. In this embodiment, the parameters corresponding to the I channel carry i, and the parameters corresponding to the Q channel carry q, so as to distinguish the parameters of the I channel and the Q channel.

[0152] Multi-tone data is acquired from the I and Q channels and then processed. Figure 7 Taking the I-channel as an example, the phase corresponding to each frequency point of the I-channel is calculated. The group delay between I-channels is calculated using cubic polynomial interpolation and the finite difference method. Finally, the expected group delay of the all-pass filter to be designed in the I-channel is calculated. The group delay is converted from a time unit to a sampling point unit, and then the complex cepstral sequence is calculated. For complex cepstral sequences Perform a Fourier transform and calculate the unwound phase. Calculate complex cepstral even sequences For complex cepstral even sequences Perform an FFT transform and take the argument to obtain the amplitude of the minimum phase signal Fourier transform, then calculate the denominator polynomial. Based on the required filter order, obtain the denominator coefficients of the all-pass filter. Calculate the numerator coefficients of the all-pass filter. The first group delay of the I channel after the cascading is calculated. Similarly, the second group delay of the Q channel is calculated by using the above method, and then the group delay difference between the I channel and the Q channel is calculated, and the average of the group delay difference between the I channel and the Q channel is calculated and converted into a sampling point unit, and all data point time domain coordinates of the channel are shifted by using a sinc interpolation algorithm, and the IQ channel wideband phase imbalance calibration and compensation is completed.

[0153] In the above embodiment, after the phase of the sampled IQ multitone signal is obtained, the phase response is first interpolated by using a cubic polynomial, and then the group delay is calculated by using a difference method, which ensures that the first derivative of the interpolated phase response at the original frequency point is continuous, so that the instantaneous slope is calculated to approximate the group delay response of the IQ channel. The method of equalizing the phase of a single channel by using an all-pass filter and then shifting the time domain data point coordinates is used to achieve the purpose of IQ wideband calibration and compensation, and at this time the channel itself also has a linear phase.

[0154] It should be understood that, although each step in the flowchart involved in each of the above embodiments is displayed in sequence according to the arrow, these steps are not necessarily executed in the order indicated by the arrow. Unless otherwise specified herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other orders. Moreover, at least part of the steps in the flowchart involved in each of the above embodiments can include multiple steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily sequential, but can be executed in rotation or alternation with at least part of other steps or steps or stages in other steps.

[0155] Based on the same inventive concept, the embodiments of the present application also provide an IQ phase imbalance wideband compensation device for implementing the above-mentioned IQ phase imbalance wideband compensation method. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme described in the above method, and therefore the specific limitations in one or more IQ phase imbalance wideband compensation device embodiments provided below can refer to the limitations of the IQ phase imbalance wideband compensation method described above, which will not be repeated here.

[0156] In one exemplary embodiment, as shown in Figure 8 An IQ phase imbalance wideband compensation device is provided, comprising: a phase response determination module 801, an all-pass filter determination module 802, a cascading module 803, and a compensation module 804, wherein:

[0157] The phase response determination module 801 is configured to determine the phase response of each channel.

[0158] The all-pass filter determination module 802 is configured to determine a phase equalization all-pass filter of a corresponding channel based on a phase response.

[0159] The cascading module 803 is configured to cascade the all-pass filter with the corresponding channel.

[0160] The compensation module 804 is configured to compensate each frequency point of the channel after each cascaded all-pass filter.

[0161] In one of the optional embodiments, the phase response determination module 801 is specifically configured to collect discrete time domain data of each channel, and convert each discrete time domain data into frequency domain data respectively; determine each initial phase response based on each frequency domain data respectively, and perform phase unwrapping on each initial phase response to obtain the phase response of each channel.

[0162] In one of the optional embodiments, the all-pass filter determination module 802 is specifically configured to perform interpolation on the phase response to obtain an interpolated phase response; determine the group delay corresponding to each frequency point of the channel based on the interpolated phase response; and determine the phase equalization all-pass filter of the channel based on the group delay corresponding to each frequency point of the channel.

[0163] In one of the optional embodiments, the all-pass filter determination module 802 is specifically configured to determine the expected group delay under the sampling point unit based on the group delay corresponding to each frequency point of the channel; determine a complex cepstrum sequence based on the expected group delay under the sampling point unit; determine an unwrapped phase and a complex cepstrum even sequence based on the complex cepstrum sequence; determine the amplitude of the minimum phase signal Fourier transform based on the complex cepstrum even sequence; and determine the phase equalization all-pass filter of the channel based on the amplitude of the minimum phase signal Fourier transform and the unwrapped phase.

[0164] In one of the optional embodiments, the compensation module 804 is specifically configured to determine the first group delay corresponding to each frequency point of the I channel and the second group delay corresponding to each frequency point of the Q channel after each cascaded all-pass filter, and determine the group delay difference between the channels based on the first group delay and the second group delay; and perform a time domain data point coordinate drift operation on all data points of the lagging channel to compensate each frequency point of the lagging channel based on the group delay difference.

[0165] In one of the optional embodiments, the compensation module 804 is specifically configured to determine the average delay difference based on the group delay difference; and shift the time domain coordinates of all data points of the lagging channel to the left by the average delay difference sampling points to compensate each frequency point of the lagging channel.

[0166] In one of the optional embodiments, the compensation module 804 is specifically configured to interpolate the time-domain data point coordinates of the lag channels; and shift the interpolated data point coordinates to the left by the average delay difference to compensate for each frequency point of the lag channels.

[0167] In one of the optional embodiments, the compensation module 804 is specifically configured to determine a first target phase response of the I channel and a second target phase response of the Q channel after the cascaded all-pass filters; interpolate the first target phase response to obtain a first target interpolated phase response of the I channel, and interpolate the second target phase response to obtain a second target interpolated phase response of the Q channel; determine the first group delay corresponding to each frequency point of the I channel after the cascaded all-pass filters based on the first target interpolated phase response, and determine the second group delay corresponding to each frequency point of the Q channel after the cascaded all-pass filters based on the second target interpolated phase response.

[0168] The modules in the IQ phase imbalance wideband compensation device can be implemented by software, hardware, or a combination thereof. The modules can be embedded in or independent of a processor in a computer device in hardware form, or stored in a memory in the computer device in software form, so as to be called and executed by the processor to perform the operations corresponding to the modules.

[0169] In one of the exemplary embodiments, a computer device is provided, which can be a terminal, and the internal structure diagram of the computer device can be as shown in Figure 9As shown in the figure. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. Among them, the processor, the memory and the input / output interface are connected through the system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capability. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operating system and the computer program in the non-volatile storage medium to run. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals in a wired or wireless manner. The wireless manner can be realized through WIFI, mobile cellular network, near field communication (Near Field Communication, NFC) or other technologies. The computer program is executed by the processor to realize an IQ phase imbalance wideband compensation method. The display unit of the computer device is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen. The input device of the computer device can be a touch layer overlaid on the display screen, or a key, trackball or touchpad arranged on the shell of the computer device, or an external keyboard, touchpad or mouse, etc.

[0170] Those skilled in the art can understand that, Figure 9 The structure shown in the figure is only a block diagram of part of the structure related to the scheme of the present application, and does not constitute a limitation on the computer device to which the scheme of the present application is applied. The specific computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different component arrangement.

[0171] In one embodiment, a computer device is also provided, including a memory and a processor, the memory storing a computer program, and the processor executing the computer program to realize the steps in each of the above method embodiments.

[0172] In one embodiment, a computer readable storage medium is provided, which stores a computer program, and the computer program is executed by a processor to realize the steps in each of the above method embodiments.

[0173] In one embodiment, a computer program product is provided, including a computer program, and the computer program is executed by a processor to realize the steps in each of the above method embodiments.

[0174] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when executed, can include the processes of the above-mentioned embodiment methods. Any reference to memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. The non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. The volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration but not limitation, the RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., without being limited thereto.

[0175] The technical features of the above embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present application.

[0176] The above-described embodiments are merely illustrative of several embodiments of the present application, which are described in more detail and in a specific manner, but should not be construed as limiting the scope of the patent of the present application. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A broadband compensation method for IQ phase imbalance, characterized in that, The method includes: Determine the phase response of each channel, which includes I-channel and Q-channel; Phase-equalized all-pass filters for the corresponding channels are obtained based on the phase responses. The all-pass filter is cascaded with the corresponding channel to equalize each channel so that each channel itself has a basically linear phase. Compensation is performed on each frequency point of the channel after each stage of the all-pass filter, including: determining the first group delay corresponding to each frequency point of the I channel and the second group delay corresponding to each frequency point of the Q channel after each stage of the all-pass filter, and obtaining the group delay time difference between the channels based on the first group delay and the second group delay. Based on the group delay difference, time-domain data point coordinate drift operation is performed on all data points of the lag channel to compensate for each frequency point of the lag channel.

2. The method according to claim 1, characterized in that, Determining the phase response of each channel includes: Collect discrete time-domain data from each channel, and convert each discrete time-domain data into frequency-domain data respectively; Each initial phase response is obtained based on the frequency domain data, and the initial phase response is de-wound to obtain the phase response of each channel.

3. The method according to claim 1, characterized in that, The step of obtaining phase-equalized all-pass filters for corresponding channels based on the phase response includes: Interpolating the phase response yields the interpolated phase response; The group delay corresponding to each frequency point of the channel is determined based on the interpolated phase response; The phase-equalized all-pass filter for the channel is obtained based on the group delay corresponding to each frequency point of the channel.

4. The method according to claim 3, characterized in that, The phase-equalized all-pass filter for the channel, obtained based on the group delay corresponding to each frequency point of the channel, includes: Based on the group delay corresponding to each frequency point of the channel, the expected group delay per sampling point unit is obtained; The complex cepstral sequence is obtained based on the expected group delay under the sampling point unit; Based on the complex cepstral sequence, the unwound phase and the complex cepstral even sequence are obtained; The amplitude of the minimum phase signal Fourier transform is obtained based on the complex cepstral even sequence; Based on the amplitude of the Fourier transform of the minimum phase signal and the unwound phase, the phase-equalized all-pass filter of the channel is determined.

5. The method according to claim 1, characterized in that, The step of performing time-domain data point coordinate shifting operation on all data points of the lagging channel based on the group delay difference to compensate for each frequency point of the lagging channel includes: The average delay difference is obtained based on the group delay difference; The time-domain coordinates of all data points in the lag channel are shifted to the left by the average delay difference by a number of sampling points to compensate for each frequency point of the lag channel.

6. The method according to claim 5, characterized in that, The step of shifting the time-domain coordinates of all data points in the lag channel to the left by the average delay difference by a number of sampling points to compensate for each frequency point of the lag channel includes: Interpolate the coordinates of the time-domain data points in the hysteresis channel; The coordinates of each interpolated data point are shifted to the left by the average delay difference by a number of sampling points to compensate for each frequency point of the lag channel.

7. The method according to claim 1, characterized in that, The determination of the first group delay corresponding to each frequency point of the I channel and the second group delay corresponding to each frequency point of the Q channel after the cascaded all-pass filters includes: Determine the first target phase response of the I channel and the second target phase response of the Q channel after each stage of the all-pass filter; Interpolating the first target phase response yields the first target interpolated phase response for the I channel, and interpolating the second target phase response yields the second target interpolated phase response for the Q channel. The first group delay corresponding to each frequency point of the I channel after the first target interpolation phase response is determined, and the second group delay corresponding to each frequency point of the Q channel after the second target interpolation phase response is determined.

8. A broadband compensation device for IQ phase imbalance, characterized in that, The device includes: A phase response determination module is used to determine the phase response of each channel, including I-channel and Q-channel; The all-pass filter determination module is used to obtain the phase-equalized all-pass filters for the corresponding channels based on the phase response. A cascade module is used to cascade the all-pass filter with the corresponding channel to first equalize each of the channels so that each of the channels has a basically linear phase. The compensation module is used to compensate for each frequency point of the channel after each stage of the all-pass filter, including: determining the first group delay corresponding to each frequency point of the I channel and the second group delay corresponding to each frequency point of the Q channel after each stage of the all-pass filter, and obtaining the group delay time difference between the channels based on the first group delay and the second group delay. Based on the group delay difference, time-domain data point coordinate drift operation is performed on all data points of the lag channel to compensate for each frequency point of the lag channel.

9. The apparatus according to claim 8, characterized in that, The phase response determination module is specifically used to collect discrete time-domain data of each channel and convert each discrete time-domain data into frequency-domain data; obtain each initial phase response based on each frequency-domain data, and perform phase dewinding on each initial phase response to obtain the phase response of each channel.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

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