Radio frequency transceiver intermediate frequency cross channel loopback calibration circuit and calibration method

Abstract

The invention provides a radio frequency transceiver intermediate frequency cross channel loopback calibration circuit and a calibration method, which are applied to the technical field of wireless communication and realize transmitting and receiving functions through at least two radio frequency circuit channels. The cross-channel intermediate-frequency switch and the multi-channel intermediate-frequency switches flexibly switch signal paths in different working modes, and in the loopback calibration mode, the signal processing assembly loops back a preset proportion of transmitting signals to a receiving link, so that accurate I / Q signal calibration is realized, the calibration accuracy and the communication performance of the system are improved, and the system reliability is improved. And multi-channel parallel calibration is supported, so that the calibration efficiency and the overall reliability of the system are remarkably improved.

Description

Technical Field

[0001] The present application relates to the field of wireless communication technologies, and particularly relates to an intermediate frequency cross-channel loopback calibration circuit and a calibration method for a radio frequency transceiver. Background Art

[0002] In modern wireless communication systems, quadrature modulation technology is usually used for spectrum shifting, and in-phase / quadrature (I / Q) signal components are generated in both the transmitting and receiving links. However, due to the non-ideal characteristics of circuit components, such as amplitude mismatch or phase offset, the I / Q signals will be distorted, resulting in the deterioration of channel performance. To ensure the performance of the link system, a transmit-receive (TX-RX) loopback calibration circuit is usually introduced to monitor and eliminate these distortions.

[0003] In existing WiFi systems, the architecture usually considers multiplexing a low-pass filter (LPF) and an intermediate frequency IQ circuit to the transmitting (TX) link and the receiving (RX) link respectively through a switching method. Although it can optimize the chip area and reduce the number of intermediate frequency signal pins more or less according to the complexity of different systems, the transmitting link and the receiving link cannot work simultaneously and can only be multiplexed time-division, resulting in the inability to perform TX-RX loopback calibration of I / Q imbalance components.

[0004] Based on this, a new intermediate frequency cross-channel loopback calibration circuit and a calibration method for a radio frequency transceiver are needed. Summary of the Invention

[0005] In view of this, the embodiments of the present specification provide an intermediate frequency cross-channel loopback calibration circuit and a calibration method for a radio frequency transceiver, which can support the simultaneous operation of the TX link and the RX link, so that effective I / Q imbalance calibration can be performed without sacrificing performance, significantly improving the overall performance of the wireless communication system.

[0006] The embodiments of the present specification provide the following technical solutions:

[0007] The embodiments of the present specification provide an intermediate frequency cross-channel loopback calibration circuit for a radio frequency transceiver, including:

[0008] At least two radio frequency circuit channels, each of the radio frequency circuit channels includes: a transmitting link and a receiving link;

[0009] A loopback switching switch module for switching between the normal operation mode and the loopback calibration mode of the radio frequency transceiver, including a cross-channel intermediate frequency switch and an intra-channel intermediate frequency switch. The cross-channel intermediate frequency switch is connected to the intermediate frequency signal paths of adjacent radio frequency circuit channels, and the intra-channel intermediate frequency switch is arranged in the intermediate frequency signal path of each radio frequency circuit channel;

[0010] A signal processing component, which is disposed at the output end of the power amplifier in the transmitting link and is used to loop back a preset proportion of the transmitted signal to the input end of the low-noise amplifier in the receiving link during the loopback calibration mode for calibrating the imbalance components of the in-phase / quadrature signals.

[0011] Wherein, the loopback switching switch module is configured as:

[0012] In the normal operation mode, the cross-channel intermediate frequency switch is in an off state to disconnect the transmission of the intermediate frequency signals between adjacent radio frequency circuit channels; and the in-channel intermediate frequency switch is switched to the transmitting link or the receiving link to enable the transmitting link or the receiving link to operate independently.

[0013] In the loopback calibration mode, the cross-channel intermediate frequency switch is in a closed state, and the transmitted signal of the first radio frequency circuit channel is looped back to the receiving link of the first radio frequency circuit channel through the intermediate frequency path of the second radio frequency circuit channel; the in-channel intermediate frequency switch is switched according to a preset logic to block the intermediate frequency path of the transmitting link of the first radio frequency circuit channel and enable the intermediate frequency path of the second radio frequency circuit channel as the calibration channel to form a calibration loop.

[0014] Further, the cross-channel intermediate frequency switch is connected between the input end of the first mixer in the first transmitting link of the first radio frequency circuit channel and the output end of the second low-pass filter in the second radio frequency circuit channel.

[0015] Further, in the transmitting link of each radio frequency circuit channel, in-channel intermediate frequency switches are respectively arranged at the input end and the output end of the low-pass filter for controlling the on / off of the intermediate frequency signal path.

[0016] Further, the signal processing component includes: a coupler or a phase shifter.

[0017] Further, the intermediate frequency signal path of the radio frequency circuit channel includes: a low-pass filter and an in-phase / quadrature circuit;

[0018] The low-pass filter is multiplexed as a digital-to-analog converter calibration signal filter in the loopback calibration mode;

[0019] The in-phase / quadrature circuit is multiplexed in the loopback calibration mode for calibrating the amplitude and phase imbalance between the in-phase / quadrature signals.

[0020] Further, the radio frequency transceiver intermediate frequency cross-channel loopback calibration circuit further includes: a digital baseband circuit channel connected to the radio frequency circuit channel, and the digital baseband circuit channel includes:

[0021] A digital signal processor, which is used to receive the loopback signal output by the analog-to-digital converter of the receiving link in the loopback calibration mode;

[0022] A calibration module, configured to adjust the amplitude and phase parameters of the transmitting link based on the loopback signal in the loopback calibration mode.

[0023] An embodiment of the present specification further provides a calibration method for an intermediate-frequency cross-channel loopback calibration circuit of a radio frequency transceiver, which is implemented based on the radio frequency transceiver intermediate-frequency cross-channel loopback calibration circuit described in any one of the present applications. The calibration method of the radio frequency transceiver intermediate-frequency cross-channel loopback calibration circuit includes:

[0024] In the normal working mode, disconnect the cross-channel intermediate-frequency switch to disconnect the intermediate-frequency signal transmission between adjacent radio frequency circuit channels, and switch the in-channel intermediate-frequency switch to the transmitting link or the receiving link to enable the transmitting link or the receiving link to work independently;

[0025] In the loopback calibration mode, close the cross-channel intermediate-frequency switch to loop back the transmitted signal of the first radio frequency circuit channel to the receiving link of the first radio frequency circuit channel through the intermediate-frequency path of the second radio frequency circuit channel; the in-channel intermediate-frequency switch is switched according to a preset logic to block the intermediate-frequency path of the transmitting link of the first radio frequency circuit channel and enable the intermediate-frequency path of the second radio frequency circuit channel as the calibration channel to form a calibration loop for in-phase / quadrature imbalance component calibration.

[0026] Further, in the loopback calibration mode, the calibration module in the digital baseband circuit channel compares the in-phase / quadrature components of the loopback signal with the in-phase / quadrature components of the original signal, and adjusts the amplitude and phase parameters of the transmitting link to eliminate distortion.

[0027] Further, in the loopback calibration mode, a signal processing component loops back a preset proportion of the transmitted signal to the input end of the low-noise amplifier of the receiving link.

[0028] Further, by sequentially closing the cross-channel intermediate-frequency switches corresponding to each radio frequency circuit channel, independent calibration of the I / Q signal imbalance of each radio frequency circuit channel is achieved;

[0029] Alternatively, multiple cross-channel intermediate-frequency switches are closed simultaneously, and the in-channel intermediate-frequency switches in each radio frequency circuit channel are independently controlled to achieve parallel calibration of different radio frequency circuit channels.

[0030] Compared with the prior art, the at least one technical solution adopted in the embodiment of the present specification can achieve at least the following beneficial effects:

[0031] The loopback calibration circuit with at least two radio frequency circuit channels can be seamlessly switched between the normal operating mode and the loopback calibration mode through the loopback switch module. In the loopback calibration mode, the cross-channel intermediate frequency switch is closed, allowing signals to loop back from the transmit link of the second radio frequency circuit channel to the receive link of the first radio frequency circuit channel, thereby achieving precise calibration of the I / Q signal imbalance component. At the same time, the in-channel intermediate frequency switch is switched according to the preset logic to form an effective calibration loop, which not only improves the flexibility and accuracy of calibration, but also supports multi-channel parallel calibration, significantly enhancing the calibration efficiency and communication performance of the system and optimizing the cost-effectiveness. Brief Description of the Drawings

[0032] To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0033] Figure 1 is the circuit schematic diagram of the existing radio frequency transceiver system;

[0034] Figure 2 is the circuit schematic diagram of the radio frequency transceiver system in the present application;

[0035] Figure 3 is the circuit schematic diagram of the radio frequency transceiver loopback calibration circuit in the present application;

[0036] In the figure: 10, radio frequency circuit in the discrete chip; 20, baseband circuit of the discrete chip; 100, first radio frequency circuit channel; 110, second radio frequency circuit channel; 120, switch SW1 between radio frequency circuit channels; 200, first baseband circuit channel; 210, second baseband circuit channel; 101, in-channel switch circuit SW2 of the first radio frequency circuit channel; 102, in-channel switch circuit SW3 of the first radio frequency circuit channel; 103, in-channel switch circuit SW4 of the first radio frequency circuit channel; 104, first coupler; 111, in-channel switch circuit SW5 of the second radio frequency circuit channel; 112, in-channel switch circuit SW6 of the second radio frequency circuit channel; 113, in-channel switch circuit SW7 of the second radio frequency circuit channel; 114, second coupler. Detailed Description of the Embodiments

[0037] The embodiments of the present application will be described in detail below with reference to the drawings.

[0038] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand the other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0039] It should be noted that the following describes various aspects of the embodiments within the scope of the appended claims. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is illustrative only. Based on the present application, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects described herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using other structures and / or functionality in addition to one or more of the aspects described herein.

[0040] It should also be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present application schematically, and only show the components related to the present application in the drawings, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in its actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0041] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the examples can be practiced without these specific details.

[0042] In modern wireless communication systems, orthogonal modulation technology (I / Q modulation) is the core means to achieve spectrum shifting. However, due to the non-ideal characteristics of circuit components (such as component tolerances, temperature drift, process deviations, etc.), the in-phase (I) and quadrature (Q) signal components in the transmit link (TX) and receive link (RX) often exhibit amplitude mismatches and phase offsets, resulting in signal distortion and seriously affecting system performance (such as reduced transmission efficiency).

[0043] Traditional solutions share the intermediate frequency circuit through time-division multiplexing of the TX / RX link, thereby optimizing the chip area more or less according to the complexity of different systems, optimizing the cost, reducing the number of IQ traces at the same time, reducing the number of intermediate frequency signal output pins for discrete chips, and further optimizing the packaging cost.

[0044] As Figure 1 shown, part 10 is the intermediate and radio frequency part of the discrete chip, and part 20 is the digital baseband part of the discrete chip. The existing TX link multiplexes the IQ traces and low-pass filter (LPF) in part 10 through switch switching for the digital baseband signal in 20, and then transmits it through the upconverter from the radio frequency output of the power amplifier (TX PPA) in the transmit link. The RX link is that the external radio frequency signal passes through the low-noise amplifier (LNA) and downconverter in part 10, passes through the multiplexed LPF and IQ traces through switch switching, and is transmitted to 20 for baseband signal processing.

[0045] Although this circuit design can reduce the hardware cost, there are the following problems:

[0046] First, it cannot be calibrated in real time: The TX link and RX link work in a time-division manner and cannot be turned on simultaneously to achieve signal loopback, resulting in the I / Q imbalance that can only be statically calibrated during the production stage and cannot cope with dynamic environmental changes (such as temperature fluctuations).

[0047] Second, the calibration accuracy is limited: The existing loopback calibration relies on external test equipment, introducing additional noise and delay, and it is difficult to meet the requirements of high-precision communication systems.

[0048] In view of this, the inventor found through research and improvement exploration that in the existing WiFi system, I / Q imbalance is the main reason for performance deterioration. However, the existing TX and RX links use time-division multiplexing to share the LPF and intermediate frequency IQ circuits through switch switching. Although the hardware cost is reduced, the TX and RX links cannot be opened simultaneously, resulting in the inability to perform TX-RX loopback calibration of the I / Q imbalance component when multiplexing the intermediate frequency circuit.

[0049] Based on this, the embodiments of this specification propose a radio frequency transceiver intermediate frequency cross-channel loopback calibration circuit: As Figure 2As shown in the figure, the overall idea is as follows: By introducing a cross-channel intermediate-frequency switch SW1, the transmitted TX signal can borrow the intermediate-frequency path of the adjacent channel (such as the low-pass filter LPF and the intermediate-frequency IQ trace) and loop back to the receiving RX link, breaking through the limitation that the TX / RX link cannot work simultaneously under the time-division multiplexing architecture. Combining the dynamic configuration of multiple groups of in-channel switches, the signal path is controlled to switch in different modes (normal working mode and loopback calibration mode), so as to achieve seamless switching between multiple modes and enable multi-channel calibration, significantly improving the flexibility of the system. In addition, a signal processing component is integrated at the output end of the TX link to accurately feedback a preset proportion of the transmitted signal to the input end of the RX link, forming a closed-loop calibration path, effectively solving the problem that the traditional time-division multiplexing scheme cannot perform real-time dynamic calibration, and significantly improving the dynamic calibration accuracy of the radio frequency transceiver and the flexibility of the system on the basis of maintaining low cost.

[0050] The following will describe the technical solutions provided by the embodiments of the present application with reference to the accompanying drawings.

[0051] As Figure 2 shown, an intermediate-frequency cross-channel loopback calibration circuit for a radio frequency transceiver provided by an embodiment of this specification includes: at least two radio frequency circuit channels, and each of the radio frequency circuit channels includes: a transmitting link and a receiving link;

[0052] Generally, the transmitting link is responsible for converting the baseband signal into a radio frequency signal, amplifying it, and then transmitting it through the antenna, and includes a digital-to-analog converter DAC, a low-pass filter LPF, a mixer Mixer, and a power amplifier PPA connected in sequence.

[0053] The receiving link is responsible for receiving the radio frequency signal from the antenna, converting it into a baseband signal, and processing it, and includes a low-noise amplifier LNA, a mixer Mixer, a low-pass filter LPF, and an analog-to-digital converter ADC connected in sequence.

[0054] A loopback switching switch module is used to switch between the normal working mode and the loopback calibration mode of the radio frequency transceiver, and includes a cross-channel intermediate-frequency switch and an in-channel intermediate-frequency switch. The cross-channel intermediate-frequency switch connects the intermediate-frequency signal paths of adjacent radio frequency circuit channels, so that the TX signal can borrow the intermediate-frequency path of the adjacent channel and loop back to the RX link to achieve dynamic calibration. The in-channel intermediate-frequency switch is arranged in the intermediate-frequency signal path of each radio frequency circuit channel;

[0055] A signal processing component is arranged at the output end of the power amplifier PPA of the transmitting link, and is used to loop back a preset proportion of the transmitted signal to the input end of the low-noise amplifier LNA of the receiving link in the loopback calibration mode for in-phase / quadrature signal imbalance component calibration;

[0056] Among them, the loopback switching switch module is configured as:

[0057] In the normal operating mode, the cross-channel IF switch 120 is in an open state to disconnect the IF signal transmission between adjacent RF circuit channels; and the in-channel IF switch is switched to the transmit TX link or the receive RX link to enable the transmit link or the receive link to operate independently.

[0058] Specifically, in the normal operating mode, the cross-channel IF switch 120 is open to isolate adjacent RF circuit channels and prevent signals from leaking from one channel to another. For example, when the first RF circuit channel is in the transmit mode, the open cross-channel IF switch 120 can prevent the transmit signal of the first RF circuit channel from affecting the reception of the second RF circuit channel.

[0059] In implementation, the in-channel IF switch is responsible for switching the signal path within each RF circuit channel to meet the requirements of the transmit or receive mode.

[0060] As Figure 3 shown, in the transmit mode, the IF switch 103 in the first RF circuit channel 100 is closed to select the lower TX0 link, and TX0 normally outputs RF signals.

[0061] For example, the IF switch 102 is closed to allow the signal to pass through LPF0, the IF switch 102 is closed to direct the signal to the PFA for amplification, the cross-channel IF switch 120 is open to ensure that the signal is not misrouted to the second RF circuit channel, and the signal amplified by the PFA is sent out through TX0.

[0062] In the receive mode, the IF switch 103 in the first RF circuit channel 100 is closed to select the upper RX0 link, and RX0 normally receives RF signals.

[0063] For example, an external RF signal enters through RX0, is amplified by the LNA, down-converted to the intermediate frequency by the Mixer, then filtered by LPF0 and converted to the baseband signal through IQ0.

[0064] In the loopback calibration mode, the cross-channel IF switch is in a closed state, and the transmit signal of the first RF circuit channel is looped back to the receive link of the first RF circuit channel through the IF path of the second RF circuit channel; the in-channel IF switch switches according to a preset logic to block the IF path of the transmit link of the first RF circuit channel and enable the IF path of the second RF circuit channel as the calibration channel to form a calibration loop.

[0065] In implementation, in the TX-RX loopback calibration mode, the cross-channel intermediate frequency switch 120 is closed, and the intermediate frequency switches within the RF circuit channels switch their states according to a preset logic: the intermediate frequency switch 102 disconnects the intermediate frequency path of the transmit link TX0 of the first RF circuit channel 100 to prevent signals from being directly transmitted to the antenna or interfering with other signal paths. At the same time, the intermediate frequency switch 113 is closed to enable the intermediate frequency path of the second RF circuit channel 110 as a calibration channel, so that the loopback signal passes through and finally reaches the receive link RX0 of the first RF circuit channel 100, thus forming a calibration loop to accurately calibrate the imbalance components between the in-phase I and quadrature Q signals.

[0066] For example, as Figure 3 shown, the signal enters through the IQ1 of the adjacent second RF circuit channel 110. The intermediate frequency switch 113 selects the above TX1 link, the intermediate frequency switch 112 is closed to allow the signal to pass through the LPF1, the intermediate frequency switch 111 is disconnected to ensure that the signal is not misrouted to other paths, the cross-channel intermediate frequency switch 120 is closed to allow the signal to be coupled from the TX1 link to the RX0 link, the intermediate frequency switch 102 is disconnected to prevent the signal from passing through the LPF0, the intermediate frequency switch 101 is closed to direct the signal to the PFA for amplification, the TX RF signal is looped back to the RX0 circuit through the CP coupler 104, the intermediate frequency switch 103 is closed to select the above RX0 link, and the signal returns to the IQ0 of this channel (the first RF circuit channel). In this way, TX-RX can perform loopback calibration normally, accurately monitor and compensate for I / Q signal distortion to eliminate the I / Q imbalance component.

[0067] The circuit design method in this application allows TX-RX loopback calibration while multiplexing the intermediate frequency LPF and IQ circuits for TX and RX, thereby enabling the circuit to achieve the best working performance, optimizing the circuit performance and improving the flexibility.

[0068] In some embodiments, the cross-channel intermediate frequency switch is connected between the input end of the first mixer in the first transmit link of the first RF circuit channel and the output end of the second low-pass filter in the second RF circuit channel.

[0069] In some embodiments, within the transmit link of each RF circuit channel, the in-channel intermediate frequency switches are respectively arranged at the input end and the output end of the low-pass filter to control the on / off of the intermediate frequency signal path.

[0070] For example, in the transmit mode, the configuration of the intermediate frequency switch allows the signal to pass through the LPF and enter the power amplifier PPA for amplification and transmission; in the loopback calibration mode, the intermediate frequency switch switches the signal from the transmit link to the loopback path for internal calibration.

[0071] In some embodiments, in the loopback calibration mode, the cross-channel IF switch is connected to the IF path of the adjacent channel through a low-pass filter.

[0072] During implementation, a temporary signal path is established between different RF circuit channels through the cross-channel IF switch for loopback calibration.

[0073] For example, one end of the cross-channel IF switch 120 is connected to the transmit link IF path of the first RF circuit channel 100, and the other end is connected to the receive link through the low-pass filter LPF of the second RF circuit channel 110.

[0074] For example, a buffer amplifier is inserted between the low-pass filter LPF and the cross-channel IF switch 120 to compensate for signal attenuation during cross-channel transmission and ensure the amplitude stability of the loopback signal.

[0075] The low-pass filter LPF is not only used to filter out high-frequency noise and harmonics introduced by the transmit link, but also to suppress crosstalk between adjacent channels and avoid interference from signals in other frequency bands during the calibration process.

[0076] In some embodiments, the cut-off frequency of the low-pass filter LPF is dynamically adjusted through the baseband circuit channel 20 to adapt to the calibration requirements of different frequency bands or modulation methods;

[0077] In some embodiments, a multi-order switchable LPF group is adopted, and the matching filter order is selected through an additional switch to optimize the calibration accuracy of the signal.

[0078] By deeply integrating the cross-channel IF switch 120 with the low-pass filter LPF, this application not only realizes the transmission of IF signals, but also expands the dynamic frequency adaptation, multi-channel collaborative optimization and anti-interference capabilities, significantly improves the calibration robustness in complex environments, and maintains the efficiency of hardware cost and chip area.

[0079] In some embodiments, the signal processing component includes: a coupler or a phase shift switcher.

[0080] During implementation, as Figure 3 shown, the coupler is set at the output end of the power amplifier PPA in the transmit link. In the TX-RX loopback calibration mode, a part of the transmit signal (preset ratio) is coupled to the input end of the low-noise amplifier LNA in the receive link to form a closed-loop calibration path.

[0081] A directional coupler can be selected to ensure that the signal only transmits unidirectionally from TX to RX and avoid interference from reverse signals.

[0082] Or, as Figure 2As shown, a phase shift switch is arranged at the output end of the power amplifier PPA in the transmitting link. In the loopback calibration mode, the phase of the signal is dynamically adjusted to compensate for the phase offset between the I / Q channels.

[0083] In some embodiments, the intermediate frequency cross-channel loopback calibration circuit of the radio frequency transceiver further includes:

[0084] A digital baseband circuit channel 200 connected to the radio frequency circuit channel 100, and the digital baseband circuit channel 200 includes:

[0085] A digital signal processor, which is used to receive the loopback signal output by the analog-to-digital converter in the receiving link in the loopback calibration mode;

[0086] A calibration module, configured to adjust the amplitude and phase parameters of the transmitting link based on the loopback signal in the loopback calibration mode.

[0087] Specifically, by analyzing the I / Q components of the loopback signal through the baseband circuit 20, the amplitude and phase parameters of the transmitting link are dynamically adjusted to eliminate the quadrature modulation error.

[0088] Based on the same inventive concept, the present application also provides a calibration method for the intermediate frequency cross-channel loopback calibration circuit of a radio frequency transceiver, which is implemented based on the intermediate frequency cross-channel loopback calibration circuit described in any one of the present application. The calibration method of the intermediate frequency cross-channel loopback calibration circuit of the radio frequency transceiver includes:

[0089] In the normal working mode, the cross-channel intermediate frequency switch is disconnected to disconnect the intermediate frequency signal transmission between adjacent radio frequency circuit channels, and the in-channel intermediate frequency switch is switched to the transmitting link or the receiving link to enable the transmitting link or the receiving link to work independently;

[0090] In the loopback calibration mode, the cross-channel intermediate frequency switch is closed to loop the transmitted signal of the first radio frequency circuit channel back to the receiving link of the first radio frequency circuit channel through the intermediate frequency path of the second radio frequency circuit channel; the in-channel intermediate frequency switch is switched according to a preset logic to block the intermediate frequency path of the transmitting link of the first radio frequency circuit channel and enable the intermediate frequency path of the second radio frequency circuit channel as the calibration channel to form a calibration loop for in-phase / quadrature imbalance component calibration.

[0091] In some embodiments, in the loopback calibration mode, the calibration module in the digital baseband circuit channel compares the in-phase / quadrature components of the loopback signal with the in-phase / quadrature components of the original signal, and adjusts the amplitude and phase parameters of the transmitting link to eliminate distortion.

[0092] In some embodiments, in the loopback calibration mode, a preset proportion of the transmitted signal is looped back to the input end of the low-noise amplifier in the receiving link through the signal processing component.

[0093] In some embodiments, by sequentially closing the cross-channel intermediate-frequency switches corresponding to each radio-frequency circuit channel, independent calibration of the I / Q signal imbalance of each radio-frequency circuit channel is achieved.

[0094] In some embodiments, multiple cross-channel intermediate-frequency switches are closed simultaneously, and the in-channel intermediate-frequency switches within each radio-frequency circuit channel are independently controlled to achieve parallel calibration of different radio-frequency circuit channels.

[0095] The purpose of this application is to design a circuit that can still perform TX-RX loopback correction when the TX and RX share the intermediate-frequency LPF and IQ circuits. By adding an intermediate-frequency switch between the intermediate-frequency multiplexing circuits of the two channels and adding multiple intermediate-frequency switches to the normal TX links of each channel, free switching in different operating modes is achieved, solving the pain point that the traditional solution cannot calibrate the I / Q imbalance in real time.

[0096] In this specification, for the same and similar parts between various embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the embodiments described later, the description is relatively simple, and reference can be made to the relevant parts of the foregoing embodiments for the relevant content.

[0097] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in this application should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A radio frequency transceiver intermediate frequency cross-channel loopback calibration circuit, characterized in that: include: At least two radio frequency circuit channels, each of the radio frequency circuit channels comprising: a transmitting link and a receiving link; A loopback switching module, used for switching between a normal working mode and a loopback calibration mode of the RF transceiver, including an inter-channel intermediate frequency switch and an intra-channel intermediate frequency switch, wherein the inter-channel intermediate frequency switch connects the intermediate frequency signal paths of adjacent RF circuit channels, and the intra-channel intermediate frequency switch is arranged in the intermediate frequency signal path of each RF circuit channel; A signal processing component, arranged at the output end of the power amplifier of the transmitting link, is used to loop back a preset proportion of the transmitting signal to the input end of the low noise amplifier of the receiving link in the loopback calibration mode to calibrate the unbalanced components of the in-phase / orthogonal signals; Wherein, the loopback switching module is configured as follows: In the normal working mode, the cross-channel intermediate frequency switch is in an off state to disconnect the intermediate frequency signal transmission of the adjacent radio frequency circuit channel; and the intermediate frequency switch in the channel is switched to the transmitting link or the receiving link to enable the transmitting link or the receiving link to work independently; In the loopback calibration mode, the cross-channel IF switch is in a closed state, and the transmit signal of the first RF circuit channel is looped back to the receive link of the first RF circuit channel through the IF path of the second RF circuit channel; the intra-channel IF switch is switched according to a preset logic, blocking the IF path of the transmit link of the first RF circuit channel and enabling the IF path of the second RF circuit channel as a calibration channel to form a calibration loop.

2. The RF transceiver intermediate frequency cross-channel loopback calibration circuit according to claim 1, characterized in that: The cross-channel intermediate frequency switch is connected between the input end of the first mixer in the first transmission link of the first radio frequency circuit channel and the output end of the second low-pass filter in the second radio frequency circuit channel.

3. The RF transceiver intermediate frequency cross-channel loopback calibration circuit according to claim 1, characterized in that: In the transmission link of each of the radio frequency circuit channels, the intra-channel intermediate frequency switches are respectively arranged at the input and output ends of the low-pass filter to control the on-off of the intermediate frequency signal path.

4. The RF transceiver intermediate frequency cross-channel loopback calibration circuit according to claim 1, characterized in that: The signal processing component includes: a coupler or a phase shifter.

5. The RF transceiver intermediate frequency cross-channel loopback calibration circuit according to claim 1, characterized in that: The intermediate frequency signal path of the radio frequency circuit channel includes: a low-pass filter and an in-phase / quadrature circuit; The low-pass filter is multiplexed in the loopback calibration mode and used as a digital-to-analog converter calibration signal filter; The in-phase / quadrature circuit is multiplexed in the loopback calibration mode to calibrate the amplitude and phase imbalance between the in-phase / quadrature signals.

6. The RF transceiver intermediate frequency cross-channel loopback calibration circuit according to claim 1, characterized in that: The RF transceiver intermediate frequency cross-channel loopback calibration circuit further includes: a digital baseband circuit channel connected to the RF circuit channel, the digital baseband circuit channel including: A digital signal processor, in the loopback calibration mode, for receiving a loopback signal output by an analog-to-digital converter of the receiving link; The calibration module is configured to adjust the amplitude and phase parameters of the transmission link based on the loopback signal in the loopback calibration mode.

7. A calibration method for an intermediate frequency cross-channel loopback calibration circuit of a radio frequency transceiver, characterized in that: Based on the implementation of the radio frequency transceiver intermediate frequency cross-channel loopback calibration circuit according to any one of claims 1 to 6, the calibration method of the radio frequency transceiver intermediate frequency cross-channel loopback calibration circuit includes: In normal working mode, the cross-channel intermediate frequency switch is disconnected to disconnect the intermediate frequency signal transmission of the adjacent RF circuit channel, and the intermediate frequency switch in the channel is switched to the transmission link or the receiving link to make the transmission link or the receiving link work independently; In the loopback calibration mode, the cross-channel IF switch is closed so that the transmit signal of the first RF circuit channel is looped back to the receive link of the first RF circuit channel through the IF path of the second RF circuit channel; the IF switch in the channel is switched according to a preset logic to block the IF path of the transmit link of the first RF circuit channel, and enable the IF path of the second RF circuit channel as a calibration channel to form a calibration loop for in-phase / quadrature unbalanced component calibration.

8. The calibration method of the RF transceiver intermediate frequency cross-channel loopback calibration circuit according to claim 7, characterized in that: In the loopback calibration mode, the calibration module in the digital baseband circuit channel compares the in-phase / quadrature components of the loopback signal with the in-phase / quadrature components of the original signal, and adjusts the amplitude and phase parameters of the transmission link to eliminate distortion.

9. The calibration method of the RF transceiver intermediate frequency cross-channel loopback calibration circuit according to claim 7, characterized in that: In the loopback calibration mode, a preset proportion of the transmit signal is looped back to the input end of the low noise amplifier of the receiving link through the signal processing component.

10. The calibration method of the RF transceiver intermediate frequency cross-channel loopback calibration circuit according to claim 7, characterized in that: By closing the cross-channel intermediate frequency switches corresponding to each RF circuit channel in sequence, independent calibration of the I / Q signal imbalance of each RF circuit channel is achieved; Alternatively, a plurality of the cross-channel intermediate frequency switches are closed simultaneously, and the intra-channel intermediate frequency switches in each radio frequency circuit channel are independently controlled to achieve parallel calibration of different radio frequency circuit channels.

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