CN101453226A - Local oscillation leakage elimination apparatus and method - Google Patents

Abstract

Translated fromChinese

本发明揭示一种本振泄漏消除装置，在基带数字域产生幅度和相位可调的中频辅助信号，并转换成模拟射频调制信号。将中频辅助信号变换成与本振泄漏信号频率相同、幅度相同、相位相反的负本振信号。将负本振信号与本振泄漏信号抵消，从而实现本振泄漏消除的功能。本发明可以根据抵消后的本振泄漏情况在数字域采用尝试法动态调整此信号的幅度和相位，直到本振泄漏的信号能够满足要求为止。由于产生的同本振泄漏信号相抵消的信号是在数字域产生的，可以精确地调整其幅度和相位，方法简单、快捷地实现精确控制本振泄漏消除功能。另外，在调整过程中，不影响发射机的正常工作。

The invention discloses a local oscillator leakage elimination device, which generates an intermediate frequency auxiliary signal with adjustable amplitude and phase in the baseband digital domain, and converts it into an analog radio frequency modulation signal. Transform the intermediate frequency auxiliary signal into a negative local oscillator signal with the same frequency, the same amplitude and opposite phase as the local oscillator leakage signal. The negative local oscillator signal and the local oscillator leakage signal are canceled to realize the function of eliminating the local oscillator leakage. The invention can dynamically adjust the amplitude and phase of the signal in the digital domain according to the canceled local oscillator leakage until the signal of the local oscillator leakage can meet the requirements. Since the generated signal that cancels the local oscillator leakage signal is generated in the digital domain, its amplitude and phase can be precisely adjusted, and the method is simple and quick to realize the precise control of the local oscillator leakage elimination function. In addition, during the adjustment process, the normal operation of the transmitter will not be affected.

Description

Translated fromChinese

本振泄漏消除装置及方法Local oscillator leakage elimination device and method

技术领域technical field

本发明涉及一种本振泄漏消除装置及方法，具体地讲，涉及消除零中频发射机中的本振泄漏信号的装置及方法，能够实时地消除本振泄漏，减少变频器件产生的非有用信号。The present invention relates to a device and method for eliminating local oscillator leakage, in particular to a device and method for eliminating local oscillator leakage signals in zero-IF transmitters, which can eliminate local oscillator leakage in real time and reduce non-useful signals generated by frequency converters .

背景技术Background technique

在无线通信领域，传统的发射机由基带单元、数模转换单元、变频单元、放大单元、滤波单元等组成。其中，发射机通过变频器件完成对信号频谱的搬移。在变频过程中，不可避免地会产生一些非有用信号，例如本振泄漏、其它边带信号、谐波信号。这些非有用信号在不同的发射机结构中会产生不同的影响。有可能影响到发射机的后续功率放大电路，造成发射机的频谱发射不符合相关标准规定。另外，这些非有用信号也有可能影响到发射信号的信噪比，进而影响到接收效果，降低接收机的接收灵敏度。In the field of wireless communication, a traditional transmitter consists of a baseband unit, a digital-to-analog conversion unit, a frequency conversion unit, an amplification unit, and a filter unit. Among them, the transmitter completes the shift of the signal spectrum through the frequency converter. In the process of frequency conversion, some non-useful signals will inevitably be generated, such as local oscillator leakage, other sideband signals, and harmonic signals. These undesired signals will have different effects in different transmitter structures. It may affect the subsequent power amplifying circuit of the transmitter, causing the spectrum emission of the transmitter to fail to comply with relevant standards. In addition, these non-useful signals may also affect the signal-to-noise ratio of the transmitted signal, thereby affecting the receiving effect and reducing the receiving sensitivity of the receiver.

因此，在发射机设计中，应该根据需要加入相应的校准电路，用于对这些非有用信号进行抑制并消除，以满足系统设计需求。校准电路通常包括检测电路和抵消电路两部分。其中，检测电路主要用于对非有用信号进行检测，并将检测到的非有用信号提供给抵消电路，从而对抵消电路进行控制。因此，检测电路获得的检测值的精度、准确度直接影响到抵消电路的精度及准确度。Therefore, in the design of the transmitter, corresponding calibration circuits should be added as needed to suppress and eliminate these unwanted signals to meet the system design requirements. Calibration circuit usually includes two parts of detection circuit and offset circuit. Wherein, the detection circuit is mainly used to detect the non-useful signal, and provide the detected non-useful signal to the cancellation circuit, so as to control the cancellation circuit. Therefore, the precision and accuracy of the detection value obtained by the detection circuit directly affects the precision and accuracy of the offset circuit.

现有的本振泄漏检测电路主要采用模拟电路的形式对本振泄漏信号进行检测，这种检测方法通常存在精度不高，误差大的缺点。特别是，随着电路集成度和模拟器件性能的提高，与传统的超外差发射机结构相比，简单易用、性价比高的零中频发射机得到了广泛应用。The existing local oscillator leakage detection circuit mainly uses an analog circuit to detect the local oscillator leakage signal. This detection method usually has the disadvantages of low precision and large error. In particular, with the improvement of circuit integration and analog device performance, compared with the traditional superheterodyne transmitter structure, the simple-to-use and cost-effective zero-IF transmitter has been widely used.

图1示出了现有技术的零中频发射机的配置方框图。如图1所示，零中频发射机主要包括数字基带处理单元101，数模转换器102，低通滤波器103，本振信号发生器104，正交调制器105，射频放大器106，射频带通滤波器107，功率放大器108，带通滤波器或双工器弹簧109，和发射天线110。Fig. 1 shows a block diagram of a configuration of a prior art zero-IF transmitter. As shown in Figure 1, the zero-IF transmitter mainly includes a digitalbaseband processing unit 101, a digital-to-analog converter 102, a low-pass filter 103, a localoscillator signal generator 104, aquadrature modulator 105, aradio frequency amplifier 106, and a radiofrequency bandpass filter 107 ,power amplifier 108 , bandpass filter ordiplexer spring 109 , and transmitantenna 110 .

在发射机的工作过程中，数字基带处理单元101对产生的正交I/Q信号(其中I、Q分别用来表示正交的两路数据信号，I表示同相数据信号，Q表示正交数据信号)进行插值和滤波处理后提供给数模转换器102。数模转换器102将数字I/Q信号转换成模拟I/Q信号，并将模拟I/Q信号提供给模拟低通滤波器103。模拟I/Q信号经模拟低通滤波器103滤波后，与从本振信号发生器104提供的两路正交的载波信号在正交调制器105中进行混频，然后进行叠加，生成模拟射频调制信号。所生成的模拟射频调制信号输入到射频放大器106进行放大，然后将经放大的模拟射频信号提供给射频带通滤波器107。射频带通滤波器107对放大的模拟射频调制信号进行滤波，得到要发送的射频信号，然后经过功率放大器108对射频信号进行功率放大。最后将经过功率放大的射频信号提供给带通滤波器109或双工器109，然后通过发射天线110发射。During the working process of the transmitter, the digitalbaseband processing unit 101 generates quadrature I/Q signals (wherein I and Q are used to represent two orthogonal data signals respectively, I represents the in-phase data signal, and Q represents the quadrature data signal signal) is provided to the digital-to-analog converter 102 after interpolation and filtering. The digital-to-analog converter 102 converts the digital I/Q signal into an analog I/Q signal, and supplies the analog I/Q signal to the analog low-pass filter 103 . After the analog I/Q signal is filtered by the analog low-pass filter 103, it is mixed with two orthogonal carrier signals provided by the localoscillator signal generator 104 in thequadrature modulator 105, and then superimposed to generate an analog radio frequency Modulated signal. The generated analog radio frequency modulation signal is input to theradio frequency amplifier 106 for amplification, and then the amplified analog radio frequency signal is provided to the radiofrequency bandpass filter 107 . The radiofrequency bandpass filter 107 filters the amplified analog radio frequency modulation signal to obtain the radio frequency signal to be transmitted, and then thepower amplifier 108 amplifies the power of the radio frequency signal. Finally, the amplified radio frequency signal is provided to thebandpass filter 109 or theduplexer 109 , and then transmitted through the transmittingantenna 110 .

当零中频发射机处在正常工作状态的情况下，由于用户有用信号和本振泄漏信号处在同一频段内，无法实时地对本振泄漏进行校准，只能在开机时或者没有有用用户信号存在的状态下进行校准。When the zero-IF transmitter is in the normal working state, since the useful user signal and the local oscillator leakage signal are in the same frequency band, it is impossible to calibrate the local oscillator leakage in real time. Calibrate in the state.

另外，由于外围元器件的制造差异、工艺、温度和正交调制器等本身的原因，很容易在工作过程中产生I、Q支路不平衡，引起本振泄漏。通用的方法是采用调整I、Q支路的直流偏置来降低本振泄漏。但是，这种方法存在着算法复杂、速度慢、成本高的问题。In addition, due to the manufacturing differences of peripheral components, process, temperature and quadrature modulator, etc., it is easy to produce I and Q branch imbalance in the working process, causing local oscillator leakage. A common method is to reduce the local oscillator leakage by adjusting the DC bias of the I and Q branches. However, this method has the problems of complex algorithm, slow speed and high cost.

发明内容Contents of the invention

本发明的目的是针对上述问题提供一种本振泄漏消除装置及方法，通过生成与本振泄漏信号具有相同频率和幅度、但相位相反的负本振信号，使所生成的负本振信号与本振泄漏信号抵消来消除本振泄漏。The object of the present invention is to provide a kind of local oscillation leakage elimination device and method for the above-mentioned problems, by generating the negative local oscillation signal with the same frequency and amplitude as the local oscillation leakage signal, but opposite in phase, so that the generated negative local oscillation signal is consistent with LO leakage signal cancellation is used to eliminate LO leakage.

根据本发明的一个方面，提供一种本振泄漏消除装置，包括：基带数字域部分，用于产生幅度和相位可调的数字中频辅助信号，并将数字中频辅助信号与基带数据合路；数模转换器，用于将合路的信号转换成模拟信号；低通滤波器，用于滤除模拟信号中的高次谐波分量，获得模拟中频辅助信号；本振信号发生器，用于向正交调制器提供本振输入信号；正交调制器，用于将模拟中频辅助信号与从所述本振信号发生器提供的本振信号混频，然后进行叠加，生成模拟射频调制信号；第一耦合器，用于将模拟射频调制信号耦合到副支路；混频器，用于将耦合到副支路的调制信号与频率生成器提供的频率进行混频，以将调制信号中包含的辅助信号的频率下变频到本振信号的频率；带通滤波器，用于对经过下变频的辅助信号滤波以得到纯净的负本振信号；和第二耦合器，用于将负本振信号耦合到主支路，使得负本振信号与主支路的本振泄漏信号抵消。According to one aspect of the present invention, a local oscillator leakage elimination device is provided, including: a baseband digital domain part, which is used to generate a digital intermediate frequency auxiliary signal with adjustable amplitude and phase, and combine the digital intermediate frequency auxiliary signal with baseband data; The analog-to-analog converter is used to convert the combined signal into an analog signal; the low-pass filter is used to filter out the high-order harmonic components in the analog signal to obtain an auxiliary analog intermediate frequency signal; the local oscillator signal generator is used to The quadrature modulator provides the local oscillator input signal; the quadrature modulator is used to mix the analog intermediate frequency auxiliary signal with the local oscillator signal provided from the local oscillator signal generator, and then superimpose to generate an analog radio frequency modulation signal; A coupler is used to couple the analog radio frequency modulation signal to the sub-branch; a mixer is used to mix the modulated signal coupled to the sub-branch with the frequency provided by the frequency generator to mix the modulated signal contained in the the frequency of the auxiliary signal is down-converted to the frequency of the LO signal; a bandpass filter is used to filter the down-converted auxiliary signal to obtain a clean negative LO signal; and a second coupler is used to convert the negative LO signal to Coupled to the main branch such that the negative LO signal cancels the main branch's LO leakage signal.

根据本发明的另一个方面，提供一种本振泄漏消除方法，包括步骤：产生幅度和相位可调的数字中频辅助信号，并将数字中频辅助信号与基带数据合路；将合路的信号转换成模拟信号；滤除模拟信号中的高次谐波分量，获得模拟中频辅助信号；提供本振输入信号；将模拟中频辅助信号与本振输入信号混频，然后进行叠加，生成模拟射频调制信号；将模拟射频调制信号分别耦合到主支路和副支路；对耦合到副支路的调制信号进行混频，以将调制信号中包含的辅助信号的频率下变频到本振信号的频率；对经过下变频的辅助信号滤波以得到纯净的负本振信号；和将负本振信号耦合到主支路，使得负本振信号与主支路本振泄漏信号抵消。According to another aspect of the present invention, a method for eliminating local oscillator leakage is provided, comprising the steps of: generating a digital intermediate frequency auxiliary signal with adjustable amplitude and phase, and combining the digital intermediate frequency auxiliary signal with baseband data; converting the combined signal into an analog signal; filter out the high-order harmonic components in the analog signal to obtain an analog intermediate frequency auxiliary signal; provide a local oscillator input signal; mix the analog intermediate frequency auxiliary signal with the local oscillator input signal, and then superimpose to generate an analog RF modulation signal ; Coupling the analog radio frequency modulation signal to the main branch and the secondary branch respectively; Mixing the modulation signal coupled to the secondary branch to down-convert the frequency of the auxiliary signal contained in the modulation signal to the frequency of the local oscillator signal; filtering the down-converted auxiliary signal to obtain a clean negative LO signal; and coupling the negative LO signal to the main branch such that the negative LO signal cancels out the main branch LO leakage signal.

根据本发明的本振泄漏消除装置，生成幅度和相位可调的单频点信号，经过变换成与本振泄漏信号的频率、幅度相同、相位相反的负本振信号，抵消本振泄漏信号，从而实现本振泄漏消除。According to the local oscillator leakage elimination device of the present invention, a single-frequency point signal with adjustable amplitude and phase is generated, which is converted into a negative local oscillator signal with the same frequency and amplitude as the local oscillator leakage signal and opposite phase to cancel the local oscillator leakage signal, Thereby, the local oscillator leakage is eliminated.

另外，根据本发明的本振泄漏消除装置，生成的同本振泄漏信号相抵消的信号是在数字域产生的，可以精确地调整其幅度和相位，实现精确控制本振泄漏消除的功能。而且本发明只需要调整负本振信号的幅度和相位，而不必分别调整I支路和Q支路两路的不平衡，从而达到方法简单、快捷，节省成本。In addition, according to the local oscillator leakage elimination device of the present invention, the generated signal that cancels the local oscillator leakage signal is generated in the digital domain, and its amplitude and phase can be precisely adjusted to realize the function of precisely controlling the local oscillator leakage elimination. Moreover, the present invention only needs to adjust the amplitude and phase of the negative local oscillator signal, without separately adjusting the unbalance of the I branch and the Q branch, so that the method is simple and fast, and the cost is saved.

附图说明Description of drawings

通过下面结合附图说明本发明的优选实施例，将使本发明的上述及其它目的、特征和优点更加清楚，其中：The above-mentioned and other purposes, features and advantages of the present invention will be made clearer by illustrating preferred embodiments of the present invention in conjunction with the accompanying drawings below, wherein:

图1是显示现有技术的零中频发射机的配置方框图；Figure 1 is a block diagram showing the configuration of a prior art zero-IF transmitter;

图2是显示具有根据本发明实施例的本振泄漏消除装置的零中频发射机的配置方框图；2 is a block diagram showing a configuration of a zero-IF transmitter with a local oscillator leakage canceling device according to an embodiment of the present invention;

图3是显示经过发射机中的低通滤波器之后的信号频谱示意图；Fig. 3 is a schematic diagram showing the signal spectrum after passing through the low-pass filter in the transmitter;

图4是显示经过发射机中的正交调制器之后的信号频谱示意图；Fig. 4 is a schematic diagram showing the signal spectrum after passing through the quadrature modulator in the transmitter;

图5是显示经过发射机中的带通滤波器之后的信号频谱示意图；和Fig. 5 is a schematic diagram showing the signal spectrum after passing through the band-pass filter in the transmitter; and

图6是显示经过发射机中的第二耦合器之后的信号频谱示意图。Fig. 6 is a schematic diagram showing the frequency spectrum of the signal after passing through the second coupler in the transmitter.

具体实施方式Detailed ways

下面参照附图对本发明的实施例进行详细描述，在描述过程中省略了对于本发明来说是不必要的细节和功能，以防止对本发明的理解造成混淆。Embodiments of the present invention will be described in detail below with reference to the accompanying drawings, and unnecessary details and functions for the present invention will be omitted during the description to prevent confusion to the understanding of the present invention.

下面参考图2描述配置有根据本发明一个实施例的本振泄漏消除装置的发射机。A transmitter configured with a local oscillator leakage canceling device according to an embodiment of the present invention will be described below with reference to FIG. 2 .

图2是显示具有根据本发明实施例的本振泄漏消除装置的零中频发射机的配置方框图。如图2所示，根据本实施例，具有本振泄漏消除装置的发射机包括基带数字域部分206，数模转换器207，低通滤波器208，正交调制器209，本振信号发生器210，第一耦合器211，射频放大器212，第二耦合器213，混频器214，带通滤波器215，频率生成器216，射频带通滤波器217，功率放大器218，带通滤波器或双工器弹簧219，发射天线220。FIG. 2 is a block diagram showing a configuration of a zero-IF transmitter having a local oscillator leakage canceling device according to an embodiment of the present invention. As shown in Figure 2, according to this embodiment, the transmitter with the local oscillator leakage elimination device includes a basebanddigital domain part 206, a digital-to-analog converter 207, a low-pass filter 208, aquadrature modulator 209, and a localoscillator signal generator 210, afirst coupler 211, aradio frequency amplifier 212, asecond coupler 213, amixer 214, abandpass filter 215, afrequency generator 216, a radiofrequency bandpass filter 217, apower amplifier 218, a bandpass filter or Duplexerspring 219, transmitantenna 220.

基带数字域部分206产生用于抵消本振泄露信号的数字中频辅助信号。基带数字域部分206产生幅度和相位可调的辅助信号，通过根据本振泄露信号对产生的辅助信号进行幅度和相位调整来产生用于抵消本振泄露信号的本振泄露抵消信号。The basebanddigital domain section 206 generates a digital IF auxiliary signal for canceling the LO leakage signal. The basebanddigital domain part 206 generates an auxiliary signal with adjustable amplitude and phase, and generates an LO leakage cancellation signal for canceling the LO leakage signal by adjusting the amplitude and phase of the generated auxiliary signal according to the LO leakage signal.

具体地讲，如图2所示，基带数字域部分206包括数字中频辅助信号产生单元201，幅度调整单元202，相位调整单元203，基带数据产生单元204，和合路单元205。Specifically, as shown in FIG. 2 , the basebanddigital domain part 206 includes a digital intermediate frequency auxiliarysignal generation unit 201 , anamplitude adjustment unit 202 , aphase adjustment unit 203 , a basebanddata generation unit 204 , and acombiner unit 205 .

下面描述本振泄露抵消装置的操作。首先，数字中频辅助信号产生单元201在数字域构造一个单频点的中频辅助信号，作为辅助信号。所构造的辅助信号的中心频率可以是ω₁，I/Q支路归一化的幅度可以是G₁，相位是φ₀。可以用下面的表达式(1)来表示在数字域生成的单频点中频辅助信号。The operation of the local oscillator leakage canceling device will be described below. First, the digital intermediate frequency auxiliarysignal generating unit 201 constructs an intermediate frequency auxiliary signal of a single frequency point in the digital domain as the auxiliary signal. The center frequency of the constructed auxiliary signal may be ω₁ , the normalized amplitude of the I/Q branch may be G₁ , and the phase may be φ₀ . The following expression (1) can be used to represent the single-frequency point IF auxiliary signal generated in the digital domain.

I₁(t)＝cos(ω₁t)       (1)I₁ (t)=cos(ω₁ t) (1)

Q₁(t)＝sin(ω₁t)Q₁ (t)=sin(ω₁ t)

该中频辅助信号的中心频率为F1，数据的位数由需要调整的精度而定，其频谱如图3中的F1信号302所示。The center frequency of the intermediate frequency auxiliary signal is F1, and the number of data bits depends on the precision to be adjusted. Its frequency spectrum is shown as theF1 signal 302 in FIG. 3 .

幅度调整单元202调整所产生的中频辅助信号的幅度，使I/Q支路归一化幅度为G₁，所得到的信号可以用下面的表达式(2)表示。Theamplitude adjustment unit 202 adjusts the amplitude of the generated intermediate frequency auxiliary signal, so that the normalized amplitude of the I/Q branch is G₁ , and the obtained signal can be expressed by the following expression (2).

I₁(t)＝G₁cos(ω₁t)     (2)I₁ (t)＝G₁ cos(ω₁ t) (2)

Q₁(t)＝sin(ω₁t)Q₁ (t)=sin(ω₁ t)

经过幅度调整的中频辅助信号被输入到相位调整单元203。相位调整单元203调整该中频辅助信号的相位φ₀，使中频辅助信号的初始相位与理论设计的真实本振泄漏信号反相。经过相位调整的中频辅助信号如下面的表达式(3)所示。The amplitude-adjusted IF auxiliary signal is input to thephase adjustment unit 203 . Thephase adjustment unit 203 adjusts the phase φ₀ of the intermediate frequency auxiliary signal, so that the initial phase of the intermediate frequency auxiliary signal is inverse to the theoretically designed real local oscillator leakage signal. The phase-adjusted IF auxiliary signal is shown in Expression (3) below.

I₁(t)＝G₁cos(ω₁t+φ₁)  (3)I₁ (t)＝G₁ cos(ω₁ t+φ₁ ) (3)

Q₁(t)＝sin(ω₁t)Q₁ (t)=sin(ω₁ t)

另外，基带数据产生单元204按照正常方式产生基带数据。基带数据的中心频率为ω₀，I/Q支路归一化幅度为G₀，相位为φ₀，如图3中的信号301所示。可以用下面的表达式(4)表示按照正常方式产生的基带数据。In addition, the basebanddata generating unit 204 generates baseband data in a normal manner. The center frequency of the baseband data is ω₀ , the normalized amplitude of the I/Q branch is G₀ , and the phase is φ₀ , as shown bysignal 301 in FIG. 3 . The baseband data generated in the normal manner can be represented by the following expression (4).

I₀(t)＝G₀cos(ω₀t+φ₀)  (4)I₀ (t)＝G₀ cos(ω₀ t+φ₀ ) (4)

Q₀(t)＝sin(ω₀t)Q₀ (t)=sin(ω₀ t)

应该指出，所产生的基带数据不限于单载波信号，也可以是多载波信号。如果是多载波信号，可以取其中一个载波为例。It should be noted that the generated baseband data is not limited to single-carrier signals, and may also be multi-carrier signals. If it is a multi-carrier signal, one of the carriers can be taken as an example.

经过幅度和相位调整的中频辅助信号和按照正常方式产生的基带数据分别从相位调整单元203和基带数据产生单元204输入到合路单元205。合路单元205将输入的中频辅助信号和基带数据进行合路。将合路后的信号发送到数模转换器207。数模转换器207将合路后的中频辅助信号和基带数据转换成模拟信号。应该指出，数模转换器207包括第一数模转换器和第二数模转换器，分别用于转换I支路和Q支路的信号。为了简单起见，将第一数模转换器和第二数模转换器合并在一起描述，而不会影响其工作原理和造成对操作过程的误解。转换成的模拟信号被按照I支路和Q支路输入到低通滤波器208，由低通滤波器208滤除模拟信号中的高次谐波分量，生成如图3中所示的模拟中频辅助信号302。低通滤波器的截止频率需要高于基带产生的中心频率为F1的数字中频辅助信号的频率，以便于中频辅助信号通过。应该指出，低通滤波器208包括分别对I支路和Q支路的信号进行低通滤波的第一低通滤波器和第二低通滤波器，并且为了简单起见而将第一低通滤波器和第二低通滤波器合并在一起描述。The amplitude- and phase-adjusted IF auxiliary signal and the baseband data generated in a normal manner are respectively input from thephase adjustment unit 203 and the basebanddata generation unit 204 to thecombiner unit 205 . The combiningunit 205 combines the input intermediate frequency auxiliary signal and baseband data. Send the combined signal to the digital-to-analog converter 207 . The digital-to-analog converter 207 converts the combined intermediate frequency auxiliary signal and baseband data into an analog signal. It should be noted that the digital-to-analog converter 207 includes a first digital-to-analog converter and a second digital-to-analog converter for converting signals of the I branch and the Q branch, respectively. For simplicity, the first digital-to-analog converter and the second digital-to-analog converter are described together without affecting their working principles and causing misunderstandings about the operation process. The converted analog signal is input to the low-pass filter 208 according to the I branch and the Q branch, and the high-order harmonic components in the analog signal are filtered out by the low-pass filter 208 to generate the analog intermediate frequency as shown in Figure 3Auxiliary signal 302 . The cutoff frequency of the low-pass filter needs to be higher than the frequency of the digital intermediate frequency auxiliary signal generated by the baseband whose center frequency is F1, so as to facilitate the passing of the intermediate frequency auxiliary signal. It should be noted that the low-pass filter 208 includes a first low-pass filter and a second low-pass filter for low-pass filtering the signals of the I branch and the Q branch respectively, and the first low-pass filter filter and the second low-pass filter are combined and described together.

应该指出，由于辅助信号中的数据保留精度和数模转换器的I/Q支路不平衡等问题，会在辅助信号中添加直流偏差D₁，在基带数据信号中添加直流偏差D₀。因此，经过数模转换和低通滤波后的合路信号构成了下面的表达式(5)表示的合成信号。It should be pointed out that due to issues such as data retention accuracy in the auxiliary signal and I/Q branch imbalance of the digital-to-analog converter, a DC offset D₁ will be added to the auxiliary signal, and a DC offset D₀ will be added to the baseband data signal. Therefore, the combined signal after digital-to-analog conversion and low-pass filtering constitutes the combined signal represented by the following expression (5).

I(t)＝I₀(t)+I₁(t)＝G₀cos(ω₀t+φ₀)+D₀+G₁cos(ω₁t+φ₁)+D₁    (5)I(t)＝I₀ (t)+I₁ (t)＝G₀ cos(ω₀ t+φ₀ )+D₀ +G₁ cos(ω₁ t+φ₁ )+D₁ (5)

Q(t)＝Q₀(t)+Q₁(t)＝sin(ω₀t)+sin(ω₁t)Q(t)＝Q₀ (t)+Q₁ (t)＝sin(ω₀ t)+sin(ω₁ t)

接下来，将经过低通滤波的合路信号提供给正交调制器209。另外，从本振信号发生器210向正交调制器209提供本振输入信号。输入到正交调制器209的本振信号发生器104产生的信号为F_LO，其中心频率为ω_LO，经过正交调制器209中的相位变换后，形成为正交信号F_{LO_I}和F_{LO_Q}，归一化幅度为G_LO，相位为φ_LO，直流偏差为D_LO。因此，可以用下面的表达式(6)表示经正交相位变换的本振信号。Next, the low-pass filtered combined signal is provided to thequadrature modulator 209 . In addition, a local oscillator input signal is supplied from the localoscillator signal generator 210 to thequadrature modulator 209 . The signal generated by the localoscillator signal generator 104 input to thequadrature modulator 209 is F_LO , and its center frequency is ω_LO . After phase transformation in thequadrature modulator 209, it is formed into quadrature signals F_{LO_I} and F_{LO_Q} , the normalized magnitude is G_LO , the phase is φ_LO , and the DC deviation is D_LO . Therefore, the quadrature phase-converted local oscillator signal can be expressed by the following expression (6).

F_{LO_I}＝G_LOcos(ω_LOt+φ_LO)+D_LO     (6)F_{LO_I} ＝G_LO cos(ω_LO t+φ_LO )+D_LO (6)

F_{LO_Q}＝sin(ω_LOt)F_{LO_Q} = sin(ω_LO t)

经上述正交相位变换的本振信号被输入到正交调制器209。正交调制器209对输入的由表达式(5)表示的合成信号和由表达式(6)表示的本振信号进行正交调制变换，以实现频率搬移。具体地讲，首先对输入的信号进行正交变化，即，将经过低通滤波的模拟信号与从本振信号发生器210提供的两路正交的载波信号在正交调制器209的第一和第二混频器中进行混频，然后进行叠加，生成模拟射频调制信号。如下面的表达式(7)所示。The quadrature phase-converted local oscillator signal described above is input toquadrature modulator 209 . Thequadrature modulator 209 performs quadrature modulation transformation on the input synthetic signal expressed by expression (5) and the local oscillator signal expressed by expression (6), so as to realize frequency shift. Specifically, the input signal is firstly changed in quadrature, that is, the low-pass filtered analog signal and the two quadrature carrier signals provided from the localoscillator signal generator 210 are placed in the first phase of thequadrature modulator 209. mixed with the second mixer, and then superimposed to generate an analog radio frequency modulation signal. As shown in Expression (7) below.

F_RF＝I(t)×F_{LO_I}-Q(t)×F_{LO_Q}F_RF ＝I(t)×F_{LO_I} -Q(t)×F_{LO_Q}

   ＝[I₀(t)+I₁(t)]×F_{LO_I}-[Q₀(t)+Q₁(t)]×F_{LO_Q}     (7)=[I₀ (t)+I₁ (t)]×F_{LO_I} −[Q₀ (t)+Q₁ (t)]×F_{LO_Q} (7)

   ＝[G₀cos(ω₀t+φ₀)+D₀+G₁cos(ω₁t+φ₁)+D₁]×[G_LOcos(ω_LOt+φ_LO)+D_LO]＝[G₀ cos(ω₀ t+φ₀ )+D₀ +G₁ cos(ω₁ t+φ₁ )+D₁ ]×[G_LO cos(ω_LO t+φ_LO )+D_LO ]

   -[sin(ω₀t)+sin(ω₁t)]×sin(ω_LOt)-[sin(ω₀ t)+sin(ω₁ t)]×sin(ω_LO t)

然后，对经过正交变化的信号，以取上边带的系统为例，经过隔直电路滤除支流分量后，可以得到其频谱如图4所示的本振泄漏信号，如图4中的标号401所示，其中心频率为F_lo。可以用下面的表达式(8)表示该本振泄漏信号。Then, for the orthogonally changed signal, taking the upper sideband system as an example, after filtering the tributary component through the DC blocking circuit, the local oscillator leakage signal whose frequency spectrum is shown in Figure 4 can be obtained, and the label in Figure 4 As shown in 401, its center frequency is F_lo. This local oscillator leakage signal can be represented by the following expression (8).

F_{LO_leakage}＝(D₀+D₁)G_LOcos(ω_LOt+φ_LO)                (8)F_{LO_leakage} ＝(D₀ +D₁ )G_LO cos(ω_LO t+φ_LO ) (8)

正交调制器209输出的辅助信号的频率等于本振频率加上中频。辅助信号F_aux如图4中的标号403所示，其中心频率等于本振泄漏信号的中心频率加辅助信号的中心频率，即，F_lo+F1。可以用下面的表达式(9)表示辅助信号。The frequency of the auxiliary signal output by thequadrature modulator 209 is equal to the local oscillator frequency plus the intermediate frequency. The auxiliary signal F_aux is shown by reference numeral 403 in FIG. 4 , and its center frequency is equal to the center frequency of the local oscillator leakage signal plus the center frequency of the auxiliary signal, that is, F_lo+F1. The auxiliary signal can be represented by the following expression (9).

${\mathrm{<span><span>F</span>f</span>}}_{<span><span>\_</span>\_</span>\mathrm{<span><span>aux</span>aux</span>}}<span><span>=</span>=</span><span><span>[</span>[</span>\frac{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>2</span>2</span>}}{\mathrm{<span><span>G</span>G</span>}}_{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>G</span>G</span>}}_{\mathrm{<span><span>LO</span>LO</span>}}\mathrm{<span><span>cos</span>cos</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&phi;</span>\&phi;</span>}}_{\mathrm{<span><span>1</span>1</span>}}<span><span>+</span>+</span>{\mathrm{<span><span>\&phi;</span>\&phi;</span>}}_{\mathrm{<span><span>LO</span>LO</span>}}<span><span>)</span>)</span><span><span>+</span>+</span>\frac{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>2</span>2</span>}}<span><span>]</span>]</span>\mathrm{<span><span>cos</span>cos</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>1</span>1</span>}}\mathrm{<span><span>t</span>t</span>}<span><span>+</span>+</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>LO</span>LO</span>}}\mathrm{<span><span>t</span>t</span>}<span><span>)</span>)</span><span><span>-</span>-</span>\frac{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>2</span>2</span>}}{\mathrm{<span><span>G</span>G</span>}}_{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>G</span>G</span>}}_{\mathrm{<span><span>LO</span>LO</span>}}\mathrm{<span><span>sin</span>sin</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&phi;</span>\&phi;</span>}}_{\mathrm{<span><span>1</span>1</span>}}<span><span>+</span>+</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>LO</span>LO</span>}}<span><span>)</span>)</span>\mathrm{<span><span>sin</span>sin</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>1</span>1</span>}}\mathrm{<span><span>t</span>t</span>}<span><span>+</span>+</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>LO</span>LO</span>}}\mathrm{<span><span>t</span>t</span>}<span><span>)</span>)</span><span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span><span><span>(</span>(</span>\mathrm{<span><span>9</span>9</span>}<span><span>)</span>)</span>$

经正交调制器209正交调制的信号被提供给耦合器211。耦合器211将包括辅助信号和本振泄露信号提供给由射频放大器212和第二耦合器213，射频带通滤波器217，功率放大器218，带通滤波器或双工器弹簧219，发射天线220构成的主支路。同时，耦合器211将包括辅助信号和本振泄露信号提供给由混频器214，频率发生器216和带通滤波器215构成的副支路。混频器214将通过耦合器211输入的调制信号与频率生成器216提供的频率进行混频，从而对辅助信号的频率进行下变换。具体地讲，将本振频率设置为要将辅助信号的频率变换到的中心频率。预先设置频率生成器216产生此频率的本振信号，即能够通过混频使辅助信号的中心频率变换到与本振泄露信号的中心频率相同。频率生成器216将所产生的本振信号提供给混频器214。混频器214将辅助信号与频率生成器216提供的本振信号进行频率混频，对辅助信号的频率进行下变频，从而将辅助信号的频率搬移到本振信号的频率的位置。然后，将经过下变频的辅助信号提供给中心频率为F_LO的带通滤波器215。经过下变频的辅助信号通过带通滤波器215的滤波后得到纯净的负本振信号。所获得的负本振信号可以用下面的表达式(10)表示。The signal quadrature-modulated byquadrature modulator 209 is supplied tocoupler 211 . Thecoupler 211 will include the auxiliary signal and the leakage signal of the local oscillator to be provided by theradio frequency amplifier 212 and thesecond coupler 213, the radiofrequency bandpass filter 217, thepower amplifier 218, the bandpass filter orduplexer spring 219, the transmittingantenna 220 constitute the main branch. At the same time, thecoupler 211 supplies the auxiliary signal and the leakage signal of the local oscillator to the sub-branch composed of themixer 214 , thefrequency generator 216 and the band-pass filter 215 . Themixer 214 mixes the modulation signal input through thecoupler 211 with the frequency provided by thefrequency generator 216, thereby down-converting the frequency of the auxiliary signal. Specifically, the local oscillator frequency is set to the center frequency to which the frequency of the auxiliary signal is to be shifted. Thefrequency generator 216 is preset to generate the local oscillator signal at this frequency, that is, the center frequency of the auxiliary signal can be transformed to be the same as the center frequency of the local oscillator leakage signal through frequency mixing. Thefrequency generator 216 provides the generated local oscillator signal to themixer 214 . Themixer 214 frequency-mixes the auxiliary signal and the local oscillator signal provided by thefrequency generator 216, and down-converts the frequency of the auxiliary signal, thereby moving the frequency of the auxiliary signal to the frequency of the local oscillator signal. The down-converted auxiliary signal is then provided to a band-pass filter 215 centered at F_LO . The down-converted auxiliary signal is filtered by the band-pass filter 215 to obtain a pure negative local oscillator signal. The obtained negative local oscillation signal can be represented by the following expression (10).

${\stackrel{<span><span>\&OverBar;</span>\&OverBar;</span>}{\mathrm{<span><span>F</span>f</span>}}}_{\mathrm{<span><span>LO</span>LO</span>}<span><span>\_</span>\_</span>\mathrm{<span><span>leakage</span>leakage</span>}}<span><span>=</span>=</span><span><span>[</span>[</span>\frac{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>4</span>4</span>}}{\mathrm{<span><span>G</span>G</span>}}_{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>G</span>G</span>}}_{\mathrm{<span><span>LO</span>LO</span>}}\mathrm{<span><span>cos</span>cos</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&phi;</span>\&phi;</span>}}_{\mathrm{<span><span>1</span>1</span>}}<span><span>+</span>+</span>{\mathrm{<span><span>\&phi;</span>\&phi;</span>}}_{\mathrm{<span><span>LO</span>LO</span>}}<span><span>)</span>)</span><span><span>+</span>+</span>\frac{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>4</span>4</span>}}<span><span>]</span>]</span>\mathrm{<span><span>cos</span>cos</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>LO</span>LO</span>}}\mathrm{<span><span>t</span>t</span>}<span><span>)</span>)</span><span><span>-</span>-</span><span><span>[</span>[</span>\frac{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>4</span>4</span>}}{\mathrm{<span><span>G</span>G</span>}}_{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>G</span>G</span>}}_{\mathrm{<span><span>LO</span>LO</span>}}\mathrm{<span><span>cos</span>cos</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&phi;</span>\&phi;</span>}}_{\mathrm{<span><span>1</span>1</span>}}<span><span>-</span>-</span>{\mathrm{<span><span>\&phi;</span>\&phi;</span>}}_{\mathrm{<span><span>LO</span>LO</span>}}<span><span>)</span>)</span><span><span>-</span>-</span>\frac{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>4</span>4</span>}}<span><span>]</span>]</span>\mathrm{<span><span>sin</span>sin</span>}<span><span>(</span>(</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>LO</span>LO</span>}}\mathrm{<span><span>t</span>t</span>}<span><span>)</span>)</span>$

     

     

                                                  (10)(10)

对于表达式(10)，可以设置，其中C为常数，ξ(φ₁)和

为φ₁的函数。由于在上述过程中已经对信号幅度做了归一化处理，使得辅助信号具有可变幅度_A(t)。因此，可以用下面的表达式(11)表示该辅助信号，其信号频谱如图5中的F_aux”信号501所示。从图5中可以看到，经过带通滤波器215的滤波后，获得了纯净的负本振信号。For expression (10), one can set , where C is a constant, ξ(φ₁ ) and

is a function of_φ1 . Since the signal amplitude has been normalized in the above process, the auxiliary signal has a variable amplitude_A(t) . Therefore, the auxiliary signal can be represented by the following expression (11), and its signal frequency spectrum is shown in the F_aux"signal 501 in Figure 5. As can be seen from Figure 5, after filtering by thebandpass filter 215, the obtained A clean negative LO signal is obtained.

系统可以通过在发射端口的反馈回路(图中未示出)耦合的实际信号检测出本振泄漏的强度和调整变化趋势来调整负本振信号。调整时，可以调整φ₁的值，也可以调整生成的数字中频辅助信号的幅度_A(t)，从而达到抵消本振泄漏的功能。此后，将所获得的负本振信号通过第二耦合器213耦合到主支路，从而与主支路中的射频放大器212输出的主支路信号中的本振泄漏信号相抵消。可以用下面的表达式(12)表示该处理过程。The system can adjust the negative local oscillator signal by detecting the strength of the local oscillator leakage and adjusting the variation trend through the actual signal coupled in the feedback loop (not shown in the figure) at the transmitting port. When adjusting, the value of_φ1 can be adjusted, and the amplitude_A(t) of the generated digital intermediate frequency auxiliary signal can also be adjusted, so as to achieve the function of offsetting the leakage of the local oscillator. Thereafter, the obtained negative local oscillator signal is coupled to the main branch through thesecond coupler 213 , so as to cancel out the local oscillator leakage signal in the main branch signal output by theradio frequency amplifier 212 in the main branch. This processing procedure can be represented by the following expression (12).

第二耦合器213将本振泄漏信号已经抵消的信号提供给射频带通滤波器217。此后，射频带通滤波器217，功率放大器218，带通滤波器或双工器弹簧219，发射天线220的操作与图1中所示的射频带通滤波器107，功率放大器108，带通滤波器或双工器弹簧109，和发射天线110的操作相同。为了简单起见，在此省略对其的描述。Thesecond coupler 213 supplies the signal in which the local oscillator leakage signal has been canceled to the radiofrequency bandpass filter 217 . Thereafter, the radiofrequency bandpass filter 217,power amplifier 218, bandpass filter orduplexer spring 219, and transmittingantenna 220 operate in the same manner as theradiofrequency bandpass filter 107,power amplifier 108, and bandpass filtering shown in FIG. Diplexer orduplexer spring 109, and transmitantenna 110 operate the same. For simplicity, its description is omitted here.

根据本发明，本振泄漏信号被抵消后不会对有用信号的带内部分造成损伤，并得到如图6中的601所示的信号频谱。另外，由于辅助信号与有用信号具有一倍中频频率的距离，因此可以通过带通滤波器消除，不会产生很大的杂散信号。According to the present invention, after the local oscillator leakage signal is canceled, the in-band part of the useful signal will not be damaged, and a signal spectrum as shown by 601 in FIG. 6 is obtained. In addition, since the auxiliary signal has a distance of twice the frequency of the intermediate frequency from the useful signal, it can be eliminated by a band-pass filter without generating a large spurious signal.

作为实例，根据本实施例的本振泄露信号消除装置可以应用于WCDMA系统。下面对此进行描述。例如，在WCDMA四载波系统中，可以假设在数字域构造频率为140MHz的单频点的中频辅助信号，其频谱如图3中的数字中频辅助信号频谱302所示。同时，按照基带数据取四载波系统中的一个载波为例，中心频率为2.5MHz，如图3中的四载波数字基带信号频谱301所示。正交调制器的本振输入信号F_LO中心频率为2140MHz。经过正交调制器的正交变换和频谱搬移之后，以输出信号取上边带为例，经过隔直电路滤除支流分量后，本振泄漏信号的频率为2140MHz，如图4中的本振泄漏信号频谱401所示。调制器输出的辅助信号频率等于本振信号的频率加上辅助信号的中频，因此调制后的辅助信号F_aux的频率为2280MHz，如图4中的辅助信号频谱403所示。As an example, the apparatus for canceling local oscillator leakage signals according to this embodiment can be applied to a WCDMA system. This is described below. For example, in a WCDMA four-carrier system, it may be assumed that a single-frequency IF auxiliary signal with a frequency of 140 MHz is constructed in the digital domain, and its spectrum is shown as the digital IFauxiliary signal spectrum 302 in FIG. 3 . Meanwhile, according to the baseband data, one carrier in the four-carrier system is taken as an example, and the center frequency is 2.5 MHz, as shown in thespectrum 301 of the four-carrier digital baseband signal in FIG. 3 . The center frequency of the local oscillator input signal F_LO of the quadrature modulator is 2140MHz. After the orthogonal transformation and spectrum shift of the quadrature modulator, taking the upper sideband of the output signal as an example, after the DC blocking circuit filters out the branch components, the frequency of the local oscillator leakage signal is 2140MHz, as shown in Figure 4. Signal spectrum 401 is shown. The frequency of the auxiliary signal output by the modulator is equal to the frequency of the local oscillator signal plus the intermediate frequency of the auxiliary signal, so the frequency of the modulated auxiliary signal F_aux is 2280 MHz, as shown in the auxiliary signal spectrum 403 in FIG. 4 .

通过耦合器211，将调制器输出的信号耦合后，检测用频率生成器216产生的本振频率为140MHz。调制后的信号通过与频率生成器216提供的本振信号混频后进行下变频，以使辅助信号频率被搬移到2280MHz±140MHz。此后由带通滤波器对频率被搬移的辅助信号进行带通滤波，产生出纯净频谱为2140MHz的负本振信号，如图5中的F_aux”负本振信号501所示。After the signal output by the modulator is coupled through thecoupler 211, the local oscillator frequency generated by thefrequency generator 216 for detection is 140 MHz. The modulated signal is mixed with the local oscillator signal provided by thefrequency generator 216 and then down-converted, so that the frequency of the auxiliary signal is shifted to 2280MHz±140MHz. Afterwards, the frequency-shifted auxiliary signal is band-pass filtered by a band-pass filter to generate a negative local oscillator signal with a pure frequency spectrum of 2140 MHz, as shown by the F_aux” negativelocal oscillator signal 501 in FIG. 5 .

将此负本振信号耦合到主支路，同主支路信号中的频率相同、相位相反的本振泄漏相抵消，得到的信号频谱如图6中的发送信号601。The negative local oscillator signal is coupled to the main branch to cancel out the local oscillator leakage with the same frequency and opposite phase in the main branch signal, and the obtained signal spectrum is the transmitted signal 601 in FIG. 6 .

此后，WCDMA系统可以根据抵消后的本振泄漏情况在数字域采用尝试法动态调整中频辅助信号的幅度和相位，直到本振泄漏的信号能够满足系统要求为止。在此调整过程中，不影响正常的业务。Afterwards, the WCDMA system can dynamically adjust the amplitude and phase of the IF auxiliary signal in the digital domain by trial and error according to the offset LO leakage until the LO leakage signal meets the system requirements. During this adjustment process, normal business will not be affected.

下面描述根据本发明检消除本振泄漏信号的方法的流程。基带数字域部分206在数字域产生幅度和相位可调的单频点数字中频辅助信号，经过幅度和相位调整的辅助信号和按照正常方式产生的基带数据合路。对合路后的信号进行数模转换，从而使合路的信号转换成模拟信号。此后，对所得到的模拟信号进行低通滤波，以滤除模拟信号中的高次谐波分量，生成模拟中频辅助信号。正交调制器209对输入的模拟信号和本振信号发生器210输入的本振信号进行正交调制，以获得射频信号并实现频率搬移。调制器输出的辅助信号频率等于本振信号的频率加上辅助信号的中频，The flow of the method for detecting and eliminating local oscillator leakage signals according to the present invention will be described below. The basebanddigital domain part 206 generates a single-frequency point digital intermediate frequency auxiliary signal with adjustable amplitude and phase in the digital domain, and the auxiliary signal after amplitude and phase adjustment is combined with the baseband data generated in the normal way. Digital-to-analog conversion is performed on the combined signal, so that the combined signal is converted into an analog signal. Thereafter, low-pass filtering is performed on the obtained analog signal to filter out high-order harmonic components in the analog signal to generate an analog intermediate frequency auxiliary signal. Thequadrature modulator 209 performs quadrature modulation on the input analog signal and the local oscillator signal input by the localoscillator signal generator 210 to obtain a radio frequency signal and implement frequency shifting. The frequency of the auxiliary signal output by the modulator is equal to the frequency of the local oscillator signal plus the intermediate frequency of the auxiliary signal,

由第一耦合器211将射频信号分路成主支路信号和副支路信号。混频器214利用频率生成器216提供的频率将副支路信号下变频成以本振信号为中心的信号。此后由带通滤波器对频率被搬移的辅助信号进行带通滤波，产生出纯净的负本振信号。将此负本振信号耦合到主支路，同主支路信号中的幅度和频率相同、相位相反的本振泄漏相抵消。最后，通过发射天线将消除了本振泄露信号的信号发射出去。The radio frequency signal is split by thefirst coupler 211 into a main branch signal and a secondary branch signal. Themixer 214 uses the frequency provided by thefrequency generator 216 to down convert the sub-branch signal to a signal centered on the local oscillator signal. Afterwards, the frequency-shifted auxiliary signal is band-pass filtered by a band-pass filter to produce a pure negative local oscillator signal. This negative LO signal is coupled to the main branch to cancel out the LO leakage in the main branch signal with the same amplitude and frequency and opposite phase. Finally, the signal from which the leakage signal of the local oscillator has been eliminated is transmitted through the transmitting antenna.

根据本发明，同本振泄漏信号相抵消的信号是在数字域产生的，可以精确地调整其幅度和相位，实现精确控制本振泄漏消除功能。另外，发明只需要调整此信号的幅度和相位，而不必分别调整I支路和Q支路两路的不平衡，因此方法简单、快捷，节省成本。According to the present invention, the signal that cancels the local oscillator leakage signal is generated in the digital domain, its amplitude and phase can be adjusted precisely, and the precise control of the local oscillator leakage elimination function is realized. In addition, the invention only needs to adjust the amplitude and phase of the signal, without separately adjusting the imbalance of the I branch and the Q branch, so the method is simple, quick and cost-saving.

至此已经结合优选实施例对本发明进行了描述。本领域技术人员应该理解，在不脱离本发明的精神和范围的情况下，可以进行各种其它的改变、替换和添加。因此，本发明的范围不应该被理解为被局限于上述特定实施例，而应由所附权利要求所限定。So far the invention has been described with reference to the preferred embodiments. It should be understood by those skilled in the art that various other changes, substitutions and additions can be made without departing from the spirit and scope of the present invention. Accordingly, the scope of the present invention should not be construed as limited to the particular embodiments described above, but should be defined by the appended claims.

Claims (8)

Translated fromChinese

1.一种本振泄漏消除装置，包括：1. A local oscillator leakage elimination device, comprising:基带数字域部分(206)，用于产生幅度和相位可调的数字中频辅助信号，并将数字中频辅助信号与基带数据合路；The baseband digital domain part (206) is used to generate a digital intermediate frequency auxiliary signal with adjustable amplitude and phase, and combine the digital intermediate frequency auxiliary signal with the baseband data;数模转换器(207)，用于将合路的信号转换成模拟信号；A digital-to-analog converter (207), used to convert the combined signal into an analog signal;低通滤波器(208)，用于滤除模拟信号中的高次谐波分量，获得模拟中频辅助信号；A low-pass filter (208), used to filter out high-order harmonic components in the analog signal, to obtain an analog intermediate frequency auxiliary signal;本振信号发生器(210)，用于向正交调制器(209)提供本振输入信号；A local oscillator signal generator (210), for providing a local oscillator input signal to the quadrature modulator (209);正交调制器(209)，用于将模拟中频辅助信号与从所述本振信号发生器提供的本振信号混频，然后进行叠加，生成模拟射频调制信号；A quadrature modulator (209), used to mix the analog intermediate frequency auxiliary signal with the local oscillator signal provided from the local oscillator signal generator, and then superimpose to generate an analog radio frequency modulation signal;第一耦合器(211)，用于将模拟射频调制信号耦合副支路；The first coupler (211) is used to couple the analog radio frequency modulation signal to the sub-branch;混频器(214)，用于将耦合到副支路的调制信号与频率生成器(216)提供的信号进行混频，以将调制信号中包含的辅助信号的频率下变频到本振信号的频率；a mixer (214) for mixing the modulated signal coupled to the sub-branch with the signal provided by the frequency generator (216) to down-convert the frequency of the auxiliary signal contained in the modulated signal to that of the local oscillator signal frequency;带通滤波器(215)，用于对经过下变频的辅助信号滤波以得到纯净的负本振信号；和A bandpass filter (215) for filtering the down-converted auxiliary signal to obtain a pure negative local oscillator signal; and第二耦合器(213)，用于将负本振信号耦合到主支路，使得负本振信号与主支路本振泄漏信号抵消。The second coupler (213) is used for coupling the negative local oscillator signal to the main branch, so that the negative local oscillator signal cancels the main branch local oscillator leakage signal.2.根据权利要求1所述的本振泄漏消除装置，其中所述基带数字域部分包括：2. The local oscillator leakage elimination device according to claim 1, wherein the baseband digital domain part comprises:幅度调整单元(202)，用于调整中频辅助信号的幅度，使同相和正交支路的中频辅助信号的幅度归一化；和An amplitude adjustment unit (202), configured to adjust the amplitude of the intermediate frequency auxiliary signal, so as to normalize the amplitude of the intermediate frequency auxiliary signal of the in-phase and quadrature branches; and相位调整单元(203)，用于调整中频辅助信号的相位，以使中频辅助信号的初始相位与理论设计的真实本振泄漏信号反相。A phase adjustment unit (203), configured to adjust the phase of the intermediate frequency auxiliary signal, so that the initial phase of the intermediate frequency auxiliary signal and the theoretically designed real local oscillator leakage signal are out of phase.3.根据权利要求1所述的本振泄漏消除装置，其中所述基带数字域部分包括数字中频辅助信号产生单元(201)，用于产生单频点的中频辅助信号。3. The device for eliminating local oscillator leakage according to claim 1, wherein the baseband digital domain part includes a digital intermediate frequency auxiliary signal generating unit (201), configured to generate an intermediate frequency auxiliary signal of a single frequency point.4.根据权利要求1所述的本振泄漏消除装置，其中所述低通滤波器(208)的截止频率高于基带产生的数字中频辅助信号的频率，以使中频辅助信号通过。4. The local oscillator leakage elimination device according to claim 1, wherein the cut-off frequency of the low-pass filter (208) is higher than the frequency of the digital intermediate frequency auxiliary signal generated by the baseband, so as to pass the intermediate frequency auxiliary signal.5.根据权利要求1所述的本振泄漏消除装置，其中调整负本振信号的相位和归一化的幅度值，使得负本振信号能够抵消本振泄漏。5. The device for eliminating LO leakage according to claim 1, wherein the phase and the normalized amplitude value of the negative LO signal are adjusted so that the negative LO signal can cancel the LO leakage.6.一种本振泄漏消除方法，包括步骤：6. A method for eliminating local oscillator leakage, comprising the steps of:产生幅度和相位可调的数字中频辅助信号，并将数字中频辅助信号与基带数据合路；Generate a digital intermediate frequency auxiliary signal with adjustable amplitude and phase, and combine the digital intermediate frequency auxiliary signal with the baseband data;将合路的信号转换成模拟信号；Convert the combined signal into an analog signal;滤除模拟信号中的高次谐波分量，获得模拟中频辅助信号；Filter out the high-order harmonic components in the analog signal to obtain the analog intermediate frequency auxiliary signal;提供本振输入信号；Provide local oscillator input signal;将模拟中频辅助信号与本振输入信号混频，然后进行叠加，生成模拟射频调制信号；The analog intermediate frequency auxiliary signal is mixed with the local oscillator input signal, and then superimposed to generate an analog radio frequency modulation signal;将模拟射频调制信号分别耦合到主支和副支路；Coupling the analog radio frequency modulation signal to the main branch and the auxiliary branch respectively;将耦合到副支路的调制信号进行混频，以将调制信号中包含的辅助信号的频率下变频到本振信号的频率；mixing the modulation signal coupled to the sub-branch to down-convert the frequency of the auxiliary signal contained in the modulation signal to the frequency of the local oscillator signal;对经过下变频的辅助信号滤波以得到纯净的负本振信号；和filtering the down-converted auxiliary signal to obtain a clean negative LO signal; and将负本振信号耦合到主支路，使得负本振信号与主支路本振泄漏信号抵消。The negative LO signal is coupled to the main branch such that the negative LO signal cancels out the main branch LO leakage signal.7.根据权利要求6所述的方法，进一步包括：7. The method of claim 6, further comprising:调整中频辅助信号的幅度，使同相和正交支路的中频辅助信号的幅度归一化的步骤；和adjusting the amplitude of the IF auxiliary signal to normalize the amplitudes of the IF auxiliary signals of the in-phase and quadrature branches; and调整中频辅助信号的相位，以使中频辅助信号的初始相位与理论设计的真实本振泄漏信号反相的步骤。The step of adjusting the phase of the IF auxiliary signal so that the initial phase of the IF auxiliary signal is out of phase with the theoretically designed real LO leakage signal.8.根据权利要求6所述的方法，进一步包括调整负本振信号的相位和归一化的幅度值，使得负本振信号能够抵消本振泄漏信号的步骤。8. The method of claim 6, further comprising the step of adjusting the phase and normalized magnitude of the negative LO signal such that the negative LO signal cancels the LO leakage signal.

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