Transmitter circuit, compensation value correction device, and compensation value correction method

Abstract

This invention relates to a transmitter circuit, a compensation value correction device, and a compensation value correction method. A compensation value correction method for correcting one or more compensation values ​​used by a compensation device of a transmitter includes: obtaining multiple output signals generated by the transmitter sequentially processing a set of input signals according to multiple sets of compensation values ​​as multiple feedback signals, wherein each feedback signal corresponds to one of the multiple sets of compensation values; obtaining the signal component of the feedback signal at a given frequency as a portion of the feedback signal; determining a set of unbalanced equivalent parameters based on the multiple sets of compensation values ​​and the portion of the feedback signal during the correction operation; and determining a set of corrected compensation values ​​based on the set of unbalanced equivalent parameters, and providing the set of corrected compensation values ​​to the compensation device.

Description

Technical Field

[0001] This invention relates to a compensation value correction method for transmitter circuits to reduce radio frequency impairment (RF impairment) in transmitter circuits. Background Technology

[0002] Zero-IF (Zero Intermediate Frequency) transmitters or receivers suffer from IQ imbalance performance limitations because they use only one mixer stage to convert the baseband signal to RF, or to directly convert the received RF signal to baseband. This IQ imbalance arises because a difference in the responses of the in-phase and positive-mode channels results in unequal amplitude or phase gains for the two signals passing through them.

[0003] To address the IQ imbalance problem in zero-IF transmitters or receivers, a method for effectively correcting the IQ imbalance compensation value and a corresponding transmitter circuit are needed. Summary of the Invention

[0004] The purpose of this invention is to provide a method and corresponding transmitter circuit for effectively correcting IQ imbalance compensation values, so as to solve the IQ imbalance problem in zero-IF transmitters or zero-IF receivers, and to find the optimal compensation value in the correction operation more quickly than the prior art.

[0005] According to an embodiment of the present invention, a transmitter circuit includes a compensation device, at least one transmit signal processing device, and a digital signal processor. The compensation device is configured on the transmit signal processing path to sequentially process a set of input signals according to multiple sets of compensation values ​​to generate multiple sets of compensated signals. At least one transmit signal processing device is configured on the transmit signal processing path to sequentially process multiple sets of compensated signals to generate multiple output signals. The digital signal processor is configured on a feedback signal processing path and coupled to the compensation device, wherein the feedback signal processing path is coupled to the output terminal of the transmit signal processing path, the output signals are provided to the digital signal processor as multiple feedback signals through the feedback signal processing path, and the digital signal processor performs a correction operation based on the feedback signals and the multiple sets of compensation values. In the correction operation, the digital signal processor determines a set of imbalance equivalent parameters based on the multiple sets of compensation values ​​and the feedback signals, determines a set of corrected compensation values ​​based on the set of imbalance equivalent parameters, and provides the set of corrected compensation values ​​to the compensation device.

[0006] According to another embodiment of the present invention, a compensation value correction device is provided for correcting one or more compensation values ​​used by a compensation device of a transmitter, comprising a fast Fourier transform (FFT) device and a digital signal processor (DSP). The FFT device performs a FFT on multiple feedback signals received from the transmitter to generate frequency-domain feedback signals, wherein each feedback signal corresponds to one of multiple sets of compensation values. The DSP is coupled to the FFT device and the compensation device to determine a set of corrected compensation values ​​based on the multiple sets of compensation values ​​and the frequency-domain feedback signals during the correction operation, and provides the corrected compensation values ​​to the compensation device. Specifically, the DSP obtains the signal component of the feedback signal at a given frequency as a portion of the feedback signal based on the frequency-domain feedback signal, determines a set of unbalanced equivalent parameters based on the multiple sets of compensation values ​​and the portion of the feedback signal, and determines the set of corrected compensation values ​​based on the set of unbalanced equivalent parameters.

[0007] According to another embodiment of the present invention, a compensation value correction method is provided for correcting one or more compensation values ​​used by a compensation device of a transmitter, comprising: obtaining a plurality of output signals generated by the transmitter sequentially processing a set of input signals according to a plurality of compensation values ​​as a plurality of feedback signals, wherein each feedback signal corresponds to one of the plurality of compensation values; obtaining the signal component of the feedback signal at a given frequency as a portion of the feedback signal; determining a set of unbalanced equivalent parameters based on the plurality of compensation values ​​and the portion of the feedback signal during the correction operation; and determining a set of corrected compensation values ​​based on the set of unbalanced equivalent parameters, and providing the set of corrected compensation values ​​to the compensation device. Attached Figure Description

[0008] Figure 1 A transmitter circuit according to an embodiment of the present invention is shown.

[0009] Figure 2 An example of the spectrum of a radio frequency signal is shown.

[0010] Figure 3 An example of the spectrum of the feedback signal is shown.

[0011] Figure 4 An example flowchart of the compensation value correction method according to an embodiment of the present invention is shown.

[0012] Figure 5 An equivalent baseband circuit diagram of a transmitter circuit according to an embodiment of the present invention is shown.

[0013] Figure 6 A detailed flowchart of the calibration operation according to an embodiment of the present invention is shown. Detailed Implementation

[0014] Figure 1A transmitter circuit according to an embodiment of the present invention is shown. The transmitter circuit 100 may include a transmit signal processing path 110 and a feedback signal processing path 120. The transmit signal processing path 110 may include multiple stages of transmit signal processing devices for processing the transmit signal, for example, converting a baseband signal into a radio frequency signal. According to an embodiment of the present invention, the transmit signal processing path 110 may include a compensation device 111, digital to analog converters (DACs) 112-1 and 112-2 located on the in-phase channel and the positive-mode channel, respectively, filters 113-1 and 113-2, mixers 114-1 and 114-2, and adder 115 and buffer circuit 116.

[0015] A compensation device 111 is configured on the transmission signal processing path 110. The compensation device 111 can receive a set of input signals located on the in-phase (I) channel and the quadrature (Q) channel, respectively. It performs IQ imbalance compensation on the received signals according to a set of compensation values ​​CMP_X and CMP_Y to generate a compensated signal. The compensation values ​​CMP_X and CMP_Y can be compensation values ​​used to compensate for the amplitude or phase of the in-phase channel and the quadrature (Q) channel, respectively. For example, the compensation device 111 can multiply the input signal on the in-phase (I) channel by the compensation value CMP_X, and multiply the input signal on the in-phase (I) channel by the compensation value CMP_Y and add it to the input signal on the quadrature (Q) channel to compensate for the IQ imbalance on the transmission signal processing path. In embodiments of the present invention, the compensation values ​​CMP_X and CMP_Y are real numbers.

[0016] Digital-to-analog converters 112-1 and 112-2 are used to convert multiple compensated signals from the digital domain to the analog domain on the in-phase and positive-mode channels, respectively. Filters 113-1 and 113-2 are used to perform filtering operations on the received signals. Mixers 114-1 and 114-2 are used to multiply the received signal with an oscillation signal LO_Sig, respectively, to convert the received signal from the baseband to the radio frequency (RF) signal. The oscillation signal LO_Sig provided to mixers 114-1 and 114-2 can be two signals with the same frequency and orthogonal phase. In this embodiment, the oscillation frequency of the oscillation signal LO_Sig is LO. Adder 115 is used to combine the signals on the in-phase and positive-mode channels. Buffer circuit 116 can be the driving circuit of power amplifier 117, used to buffer the received RF signal and drive the subsequent power amplifier 117. Power amplifier 117 is used to amplify the RF signal before it is transmitted through the antenna.

[0017] In embodiments of the present invention, the feedback signal processing path 120 may include multiple feedback signal processing devices, such as a mixer 124, a programmable gain amplifier (PGA) 123, an analog-to-digital converter (ADC) 122, a fast Fourier transform (FFT) device 121, and a digital signal processor 125. The feedback signal processing path 120 may be coupled to the output of at least one transmitting signal processing device, such as the output of a buffer circuit 116, to receive the output signal generated by the transmitting signal processing device as a feedback signal and process the feedback signal. The output signal is the signal obtained after signal processing by the transmitting signal processing device. This signal processing may include the aforementioned signal processing performed on the in-phase and positive-mode channels, respectively. The mixer 124 multiplies the received feedback signal by itself to down-convert the feedback signal to a baseband signal. The programmable gain amplifier 123 is used to amplify / attenuate the received feedback signal. The analog-to-digital converter 122 is used to convert the feedback signal from the analog domain to the digital domain. The fast Fourier transform device 121 can perform a fast Fourier transform on the received feedback signal to generate a frequency domain feedback signal.

[0018] Digital signal processor 125 is coupled to fast Fourier transform device 121 and compensation device 111 to perform a correction operation based on the frequency domain feedback signal to correct one or more compensation values ​​used by compensation device 111. Compared to the prior art, in embodiments of the present invention, digital signal processor 125 can more quickly find the optimal compensation values ​​CMP_X and CMP_Y that optimize the image rejection ratio (IMR) during the correction operation.

[0019] Figure 2 An example of the spectrum of a radio frequency (RF) signal is shown, where this RF signal is the output signal from the buffer circuit 116, for example, the RF signal obtained at node S. Assume the input signal Sig is a set of angular frequencies... Single-frequency signals, such as Figure 1 The angular frequency shown is A pair of input signals, which may include sinusoidal signals With cosine signal Because of the IQ imbalance in the transmission signal processing path, the frequency spectrum of the RF signal generated on the transmission signal processing path 110 is not only in the frequency range... The energy contained in the input signal Sig is at a frequency of The location also contains the energy of the unwanted mirror signal Img.

[0020] Figure 3 An example of the spectrum of the feedback signal is shown, for example, the spectrum of the feedback signal obtained after conversion by the Fast Fourier Transform device 121. Due to the presence of the mirror signal Img, the signal generated after the feedback signal is processed by the mixer 124 has a different frequency. It still possesses considerable energy, as shown in the figure at frequency. The signal Sig*Img at that point has an energy proportional to the amplitude of Sig*LO_Sig.

[0021] Therefore, according to an embodiment of the present invention, the compensation device 111 is used to perform IQ imbalance compensation on the received signal according to a set of compensation values ​​CMP_X and CMP_Y, so as to reduce or minimize the energy of the image signal generated on the transmit signal processing path, thereby solving the IQ imbalance problem. When dealing with the RF damage problem caused by IQ imbalance, an attempt can be made to find the optimal compensation value that optimizes the image rejection ratio on the transmit signal processing path 110 during the correction operation. For example, the image rejection ratio on the signal processing path 110 can be increased or maximized. This optimal compensation value also ensures that the processed signal on the feedback signal processing path 120, such as the feedback signal generated after processing by the mixer 124, programmable gain amplifier 123, or analog-to-digital converter 122, has minimum energy at a given frequency. In other words, the optimal compensation value minimizes the energy of the signal component containing the image signal in the feedback signal.

[0022] In embodiments of the present invention, the absolute value of the given frequency is twice the input frequency of the input signal. For example, when the angular frequency of the test signal is... When the absolute value of a given frequency is twice the angular frequency, the given frequency can be _____. It should be noted that the given frequency can be changed depending on the design of the mixer 124. For example, when the mixer 124 is designed to multiply the feedback signal with a signal having another frequency, the given frequency can be adjusted to another value resulting from the addition or subtraction of the input frequency and that frequency.

[0023] When the radio frequency signal is at frequency Energy at a given frequency The larger the energy difference at each point, the better the image rejection capability of the transmitter circuit 100. Therefore, the corresponding feedback signal at the frequency... The lower the energy at the point of origin, the better. In embodiments of the present invention, the digital signal processor 125 can be used to find the optimal compensation values ​​CMP_X and CMP_Y that optimize the image rejection ratio (i.e., minimize the energy of the image signal) during the correction operation, and provide them to the compensation device 111. The compensation device 111 reduces or suppresses the generation of image signals by applying the compensation values ​​CMP_X and CMP_Y to pre-compensate for the IQ imbalance on the transmit signal processing path, so that the processed signal on the transmit signal processing path 110 is almost equal to the original input signal.

[0024] In an embodiment of the present invention, the components on the transmit signal processing path 110, as well as the power amplifier 117 and the antenna, can be regarded as a transmitter as a whole, while one or more components on the feedback signal processing path 120 can be regarded as a compensation value correction device as a whole to assist in the execution of the correction operation.

[0025] According to an embodiment of the present invention, in the correction operation, the compensation device 111 can sequentially process a set of input signals according to multiple sets of compensation values ​​to generate multiple sets of compensated signals. A transmission signal processing device configured on the transmission signal processing path 110 can sequentially process the multiple sets of compensated signals to generate multiple output signals. The output signals are provided to the digital signal processor 125 as multiple feedback signals through the feedback signal processing path 120. The digital signal processor 125 determines a set of imbalance equivalent parameters based on the multiple sets of compensation values ​​and the feedback signals, determines a set of corrected compensation values ​​based on the set of imbalance equivalent parameters, and provides the set of corrected compensation values ​​to the compensation device 111. After determining the corrected compensation values, the correction operation can end. After receiving the set of corrected compensation values, the compensation device 111 can process subsequently received input signals according to the set of corrected compensation values. The subsequently received input signals can be the aforementioned set of sinusoidal signals. With cosine signal Alternatively, it could be a signal that other transmitter circuits 100 need to transmit.

[0026] Figure 4 An example flowchart of a compensation value correction method according to an embodiment of the present invention is shown, which may include the following steps performed by a compensation value correction device:

[0027] Step S402: Obtain multiple output signals generated by the transmitter sequentially processing a set of input signals according to multiple sets of compensation values ​​as multiple feedback signals, wherein each feedback signal corresponds to one of the multiple sets of compensation values.

[0028] Step S404: Obtain the signal component of the feedback signal at a given frequency as part of the feedback signal.

[0029] Step S406: Determine a set of unbalanced equivalent parameters based on the multiple sets of compensation values ​​and the corresponding portion of the feedback signal.

[0030] Step S408: Determine a set of corrected compensation values ​​based on the set of unbalanced equivalent parameters, and provide the set of corrected compensation values ​​to the compensation device.

[0031] More specifically, in embodiments of the present invention, a portion of the feedback signal can be obtained by a digital signal processor 125, and the set of unbalanced equivalent parameters can be determined based on the plurality of compensation values ​​and the portion, wherein the portion is the signal component of the feedback signal at the given frequency. For example, a fast Fourier transform device 121 can be used to perform a fast Fourier transform on the plurality of feedback signals received from the transmitter to generate a frequency domain feedback signal, and the digital signal processor 125 can extract the signal component of the feedback signal at the given frequency from the signal output by the fast Fourier transform device 121.

[0032] Reference Figure 1 According to an embodiment of the present invention, in the process of determining the set of unbalanced equivalent parameters, the digital signal processor 125 may first establish an equivalent signal model at node T, and then use the signal component at the given frequency in the equivalent signal model and the signal component at the given frequency of the feedback signal obtained at node T to calculate the set of unbalanced equivalent parameters.

[0033] Assume (Xt, Yt) are the equivalent unbalance parameters to be determined in the correction operation, and (Xcmp, Ycmp) are the compensation values ​​used by the compensation device 111 to perform IQ unbalance compensation on the received signal, i.e. Figure 1 The relationship between the signal component of the feedback signal obtained at node T at the given frequency and the unbalance equivalent parameters (Xt, Yt) and compensation values ​​(Xcmp, Ycmp) shown in the figure can be expressed as follows:

[0034] T@ = f(Xt,Yt, Xcmp, Ycmp) Equation (1)

[0035] The description The feedback signal obtained at node T represents the frequency at the given frequency (e.g., negative second harmonic). The signal component of ) is given by function f, which is the negative second harmonic function of the input signal from the input terminal of the transmitter circuit to node T. The digital signal processor 125 can establish function f in equation (1) based on at least two sets of preset compensation values ​​and their corresponding feedback signals, and determine the unbalanced equivalent parameters (Xt, Yt).

[0036] For example, the digital signal processor 125 can first set a first set of compensation values ​​(Xcmp_1, Ycmp_1), and input a set of angular frequencies at the input terminal of the transmitter. Single-frequency signals, such as Figure 1 The angular frequency shown is A pair of sinusoidal signals With cosine signal The single-frequency signal, after being processed on the transmit signal processing path 110, is transmitted to node T via the feedback signal processing path 120. The digital signal processor 125 can then extract the feedback signal obtained at node T at its negative second harmonic. signal component T@ =FFT1. Similarly, the digital signal processor 125 can set a second set of compensation values ​​(Xcmp_2, Ycmp_2) and input the same single-frequency signal as the input signal at the input of the transmitter. Then, the digital signal processor 125 can extract the feedback signal obtained at node T at the negative second harmonic. signal component T@ = FFT2. Applying the result to equation (1), we obtain the following result:

[0037] T@ = FFT1 = f(Xt,Yt, Xcmp_1, Ycmp_1) Formula (2)

[0038] T@ = FFT2 = f(Xt,Yt, Xcmp_2, Ycmp_2) Formula (3)

[0039] The feedback signal is at -2 times the negative second harmonic. The signal components FFT1 and FFT2 are multiple (complex number). After establishing the function f, the digital signal processor 125 can determine the unbalanced equivalent parameters (Xt, Yt).

[0040] Figure 5 An equivalent baseband circuit diagram of a transmitter circuit 100 according to an embodiment of the present invention is shown. (Refer to...) Figure 1 ,exist Figure 5In this context, the imbalance equivalent parameters (Xt, Yt) represent the IQ imbalance generated on the transmit signal processing path 110, the gain value G represents the gain generated on the transmit signal processing path 110, and the delay t0 represents the delay generated on the transmit signal processing path 110. Furthermore, in the equivalent baseband circuit 500, the up-conversion and down-conversion operations of mixers 114-1 and 114-2 and mixer 124 are equivalent to converting the signals on the in-phase (I) channel and quadrature (Q) channel into multiple (complex) signals and directly transmitting them to the mixer input in the feedback signal processing path 520. One of these signals needs to undergo conjugate conversion (as shown in the operation Conj[.]), and then be multiplied by another signal through the mixer in the feedback signal processing path 520.

[0041] In the equivalent fundamental frequency circuit 500, the signal at node S can be represented as follows:

[0042] S = G[ * Xcmp*Xt + j( * (Xcmp*Yt+Ycmp)+ Equation (4).

[0043] The signal at node T can be represented as follows:

[0044] T = S * conj(S)

[0045] Assumption The signal at node T is at its negative second harmonic. The signal components can be represented as follows:

[0046] T@ = G 2 e -j2p [(Xcmp 2 *Xt 2 -1+( Xcmp*Yt+ Ycmp) 2 ) / 4 + j*2(Xcmp *Yt+Ycmp) / 4 ] Formula (5).

[0047] In an embodiment of the present invention, equation (5) can be the negative second harmonic function f of the input single-frequency signal to node T after passing through the equivalent fundamental frequency circuit 500. The digital signal processor 125 can use the equivalent fundamental frequency circuit 500 to establish function f, or use the equivalent fundamental frequency circuit 500 to establish the signal at node T as shown in equation (5) at the negative second harmonic. The relationship between the signal components and the unbalanced equivalent parameters (Xt, Yt), compensation values ​​(Xcmp, Ycmp), gain value G, and delay t0 is established. After establishing the function f or the aforementioned relationship, the digital signal processor 125 can further determine the unbalanced equivalent parameters (Xt, Yt) and find the optimal compensation values ​​(Xcmp, Ycmp) that optimize the image rejection ratio by following the following process. In the embodiments of the present invention, the optimal compensation value is the aforementioned corrected compensation value, that is... Figure 1 The corrected (or optimal) compensation values ​​(CMP_X, CMP_Y) are uniformly denoted as (Xopt, Yopt) in the following paragraphs.

[0048] Figure 6 A detailed flowchart of the correction operation according to an embodiment of the present invention is shown, including the following steps performed by the digital signal processor 125:

[0049] Step S602: Set the first set of compensation values ​​(Xcmp_1, Ycmp_1), and input a set of angular frequencies at the input terminal of the transmitter. A single-frequency signal is used as the input signal, for example Figure 1 The angular frequency shown is A pair of sinusoidal signals With cosine signal And extract the feedback signal obtained at node T at a given frequency (e.g., negative second harmonic). The signal component T@ = FFT1. As described above, the input signal is processed via the signal processing path 110 and then transmitted to node T via the feedback signal processing path 120. In an embodiment of the present invention, the first set of compensation values ​​(Xcmp_1, Ycmp_1) can be set to (0,1), and assuming FFT1=C+jD, the relationship between parameters C, D, p and gain value G and unbalanced equivalent parameters (Xt,Yt) can be obtained by applying the function f shown in equation (5).

[0050] Step S604: Set the second set of compensation values ​​(Xcmp_2, Ycmp_2), input the same single-frequency signal as the input signal at the input terminal of the transmitter, and extract the feedback signal obtained at node T at a given frequency (e.g., negative second harmonic). The signal component T@ = FFT2. In an embodiment of the present invention, the second set of compensation values ​​(Xcmp_2, Ycmp_2) can be set to (1,0), and assuming FFT2=E+jF, the relationship between parameters E, F, p and gain value G and unbalanced equivalent parameters (Xt,Yt) can be obtained by applying the function f shown in equation (5).

[0051] Step S606: Calculate the unbalance equivalent parameters (Xt, Yt) at the given frequency based on the compensation value provided to the compensation device 111 and the signal component of the feedback signal obtained at node T. According to an embodiment of the present invention, the digital signal processor 125 can combine the parameter relationships obtained after applying the preset compensation values ​​(Xcmp, Ycmp) in steps S602 and S604 in different ways, or combine the feedback signal obtained in steps S602 and S604 at the negative second harmonic. The signal components are combined in different ways to obtain different relationships, and from this, the unbalanced equivalent parameters (Xt,Yt) are derived.

[0052] According to an embodiment of the present invention, the digital signal processor 125 can derive the relationship between the unbalanced equivalent parameters (Xt, Yt) and the values ​​C, D, E, F (i.e., the FFT result) based on the different combinations as follows:

[0053] Yt = (C*E+D*F) / (C 2 +D 2 Equation (6)

[0054] Xt 2 = 1-Yt 2 +2*(D*EC*F) / (C 2 +D 2 Equation (7)

[0055] It should be noted that the relationship between the unbalanced equivalent parameters (Xt,Yt) and the values ​​C, D, E, F (i.e., the FFT results) shown in equations (6) and (7) is the result obtained by setting the compensation values ​​to (0,1) and (1,0). Those skilled in the art will understand that in steps S602 and S604, the setting of the compensation values ​​is not limited to (0,1) and (1,0), but can also be other sets of values. The relationship between the FFT results, parameters p, and gain values ​​G obtained according to different compensation value settings and the unbalanced equivalent parameters (Xt,Yt) may not be the same as in the above embodiments. Therefore, the relationship between the unbalanced equivalent parameters (Xt,Yt) and the FFT results derived in step S606 may not be the same as in equations (6) and (7), but the relationship between the unbalanced equivalent parameters (Xt,Yt) and the FFT results can still be derived in the same way.

[0056] Step S608: Derive the optimal compensation value (Xopt, Yopt) based on the unbalanced equivalent parameters (Xt, Yt).

[0057] According to an embodiment of the present invention, the digital signal processor 125 can determine the optimal compensation value (Xopt, Yopt) based on the result of the operation between the obtained unbalanced equivalent parameters (Xt, Yt) and the identity matrix.

[0058] More specifically, assuming that the input signals of the in-phase channel and the positive-mode channel (hereinafter represented by the symbols I and Q) are obtained after applying the optimal compensation values ​​(Xopt, Yopt) and the unbalanced equivalent parameters (Xt, Yt), the original input signals I and Q can be obtained. Therefore, the following relationship can be established:

[0059] Equation (8)

[0060] As can be understood from equation (8), the matrix multiplication of the optimal compensation value (Xopt, Yopt) and the unbalanced equivalent parameter (Xt, Yt) will result in an identity matrix.

[0061] Equation (9)

[0062] Therefore, the digital signal processor 125 can directly derive the optimal compensation value (Xopt, Yopt) based on the following relationship:

[0063] Equation (10)

[0064] Equation (11)

[0065] After obtaining the optimal compensation values ​​(Xopt, Yopt), the digital signal processor 125 can provide the optimal compensation values ​​as corrected compensation values ​​to the compensation device 111. Upon receiving the corrected compensation values, the compensation device 111 can further process subsequently received input signals (e.g., a set of input signals received at the input terminals of the in-phase channel and the positive-mode channel, respectively) according to the corrected compensation values ​​CMP_X and CMP_Y (i.e., the optimal compensation values ​​(Xopt, Yopt)). In embodiments of the present invention, by adjusting the input signals according to the corrected compensation values ​​to compensate for the IQ imbalance on the transmit signal processing path, the generation of mirror signals can be effectively reduced or suppressed, thereby improving the mirror rejection ratio on the signal processing path 110 or maximizing the mirror rejection ratio. Therefore, the corrected compensation values ​​can also be a set of compensation values ​​that minimizes the energy of the processed signal on the feedback signal processing path 120 (e.g., the feedback signal obtained at node T) at a given frequency.

[0066] In embodiments of the present invention, the digital signal processor 125 only needs to... Figure 6The four steps shown can find the optimal compensation values ​​(Xopt, Yopt). Therefore, compared with the existing technology, which usually requires multiple iterations or training operations to find the optimal compensation values, the present invention can find the optimal compensation values ​​CMP_X and CMP_Y that optimize the image suppression ratio more quickly in the correction operation.

[0067] In particular, since the transmitter circuit (e.g., transmitter circuit 100) of a communication device needs to recalibrate the compensation values ​​CMP_X and CMP_Y according to the change in oscillation frequency LO whenever the communication device switches channels, the compensation value calibration performed based on the prior art becomes a burden on channel switching due to its time-consuming operation when the communication device needs to switch channels frequently. The present invention improves upon this problem. Since the compensation value calibration method and corresponding compensation value calibration device and transmitter circuit proposed in this invention can quickly find the corresponding optimal compensation values ​​CMP_X and CMP_Y each time a frequency switch occurs, the compensation value calibration time required in channel or frequency switching operations can be significantly reduced, thereby effectively reducing the aforementioned burden.

[0068] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

[0069] [Symbol Explanation]

[0070] 100: Transmitter circuit

[0071] 110: Send signal processing path

[0072] 111: Compensation device

[0073] 112-1, 112-2: Digital-to-Analog Converters

[0074] 113-1, 113-2: Filters

[0075] 114-1, 114-2, 124: Mixers

[0076] 115: Adder

[0077] 116: Buffer circuit

[0078] 117: Power Amplifier

[0079] 120, 520: Feedback signal processing path

[0080] 121, 521: Fast Fourier Transform Device

[0081] 122: Analog-to-digital converter

[0082] 123: Programmable gain amplifier

[0083] 125, 525: Digital Signal Processors

[0084] 500: Equivalent fundamental frequency circuit

[0085] CMP_X, CMP_Y, Xcmp_1, Ycmp_1: Compensation values

[0086] Input signal

[0087] G: Gain value

[0088] Img: Mirror signal

[0089] LO _Sig: Oscillation signal

[0090] LO: Oscillation frequency

[0091] Sig: Input signal

[0092] Sig*Img: Signal

[0093] t0: Delay

[0094] Angular frequency.

Claims

1. A transmitter circuit, comprising: A compensation device is configured on the signal processing path to sequentially process a set of input signals according to multiple sets of compensation values ​​to generate multiple sets of compensated signals. At least one transmitting signal processing device is configured on the transmitting signal processing path to sequentially process the multiple sets of compensated signals to generate multiple output signals; as well as A digital signal processor (DSP) is configured on a feedback signal processing path and coupled to the compensation device. The feedback signal processing path is coupled to the output of the transmit signal processing path. The output signal is provided to the DSP as multiple feedback signals through the feedback signal processing path, and the DSP performs a correction operation based on the feedback signals and the multiple sets of compensation values. In this correction operation, the digital signal processor determines a set of unbalanced equivalent parameters based on the multiple sets of compensation values ​​and the feedback signal, determines a set of corrected compensation values ​​based on the set of unbalanced equivalent parameters, and provides the set of corrected compensation values ​​to the compensation device.

2. The transmitter circuit of claim 1, wherein the digital signal processor acquires a portion of the feedback signal, the portion being the signal component of the feedback signal at a given frequency, and the digital signal processor determines the set of unbalanced equivalent parameters based on the plurality of compensation values ​​and the portion of the feedback signal.

3. The transmitter circuit according to claim 2, wherein the set of input signals is a set of single-frequency signals having an input frequency, and the absolute value of the given frequency is twice the input frequency.

4. The transmitter circuit according to claim 1, wherein after receiving the set of corrected compensation values, the compensation device further processes the subsequently received set of input signals according to the set of corrected compensation values.

5. A compensation value correction device for correcting one or more compensation values ​​used by a compensation device of a transmitter, comprising: A fast Fourier transform device is used to perform a fast Fourier transform on multiple feedback signals received from the transmitter to generate the feedback signal in the frequency domain, wherein each feedback signal corresponds to one of multiple sets of compensation values. as well as A digital signal processor, coupled to the fast Fourier transform device and the compensation device, is used to determine a set of corrected compensation values ​​based on the multiple sets of compensation values ​​and the frequency domain feedback signal during the correction operation, and to provide the set of corrected compensation values ​​to the compensation device. The digital signal processor obtains the signal component of the feedback signal at a given frequency based on the feedback signal in the frequency domain as part of the feedback signal, determines a set of unbalanced equivalent parameters based on the multiple sets of compensation values ​​and the part of the feedback signal, and determines the set of corrected compensation values ​​based on the set of unbalanced equivalent parameters.

6. The compensation value correction device according to claim 5, wherein the absolute value of the given frequency is twice the input frequency of the input signal of the transmitter.

7. The compensation value correction device according to claim 5, wherein the set of corrected compensation values ​​is a set of compensation values ​​that minimize the energy of the processed signal generated by the transmitter in response to the input signal at the given frequency.

8. A compensation value correction method for correcting one or more compensation values ​​used by a compensation device of a transmitter, comprising: The transmitter sequentially processes a set of input signals according to multiple sets of compensation values ​​to obtain multiple output signals as multiple feedback signals, wherein each feedback signal corresponds to one of the multiple sets of compensation values. The signal component of the feedback signal at a given frequency is obtained as part of the feedback signal; During the correction operation, a set of unbalanced equivalent parameters is determined based on the multiple sets of compensation values ​​and the corresponding portion of the feedback signal; as well as A set of corrected compensation values ​​is determined based on the set of unbalanced equivalent parameters, and the set of corrected compensation values ​​is provided to the compensation device.

9. The compensation value correction method according to claim 8, wherein the set of input signals is a set of single-frequency signals having an input frequency, and the absolute value of the given frequency is twice the input frequency.

10. The compensation value correction method according to claim 8, further comprising: The received input signals are then processed based on the corrected compensation values.

Images