Transmit-receive system and closed-loop calibration method

Abstract

The invention discloses a transmitting and receiving system and a closed-loop calibration method. The transmitting and receiving system comprises a receiver, a transmitter, a digital calibration module and a calibration loop, the radio frequency front-end module of the receiver is connected with the analog intermediate frequency module of the receiver; the digital calibration module is connected with the analog intermediate frequency module of the receiver and the analog intermediate frequency module of the transmitter; the radio frequency module of the transmitter is connected with the analog intermediate frequency module of the transmitter and the calibration loop, and the calibration loop is connected with the radio frequency front end module of the receiver and the analog intermediate frequency module of the transmitter. Compared with the prior art, the receiving and transmitting system has the advantages that closed-loop calibration between the receiver and the transmitter is achieved through the calibration loop, so that direct-current bias mismatch, amplitude mismatch and phase mismatch generated by the receiver and the transmitter are eliminated, local oscillator leakage and sideband suppression of the receiver and the transmitter are optimized, and the receiving and transmitting efficiency is improved. Therefore, the performance of the transceiver system is greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technologies, and in particular, to a transceiver system and a closed-loop calibration method. Background Art

[0002] With the development of wireless communication technologies, frequencies are widely used, and high-precision radio frequency transceiver systems have become the mainstream of the era. Therefore, the requirements for transceiver systems are getting higher and higher. In particular, it is very difficult for the transmitter of a transceiver system to achieve high linearity under high output power. During signal transmission, due to factors such as process device packaging, the signals in the link have the situation of IQ path inequality and PN inequality. These mismatches are ultimately infinitely amplified by the power amplifier, thus affecting the overall performance of the transmitter. Therefore, in order to solve the problems of amplitude inequality, phase inequality, and DC bias inequality in the IQ paths of a transceiver system, a transceiver system with a closed-loop calibration function is urgently needed. During power-on, through initialization loop calibration, the mismatches generated in the channels are eliminated, and carrier leakage and sideband suppression are eliminated, thereby improving the performance of the transmitter in the transceiver system. Summary of the Invention

[0003] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a transceiver system and a closed-loop calibration method, which perform closed-loop calibration between a receiver and a transmitter to eliminate the mismatches generated by the receiver and the transmitter, and optimize the local oscillator leakage and sideband suppression of the receiver and the transmitter, thereby greatly improving the performance of the transceiver system.

[0004] In order to solve the above technical problems, the present invention is implemented according to the following solutions: A transceiver system is provided, including: a receiver, a transmitter, a digital calibration module, and a calibration loop; The radio frequency front-end module of the receiver is connected to the analog intermediate frequency module of the receiver; the digital calibration module is connected to the analog intermediate frequency module of the receiver and the analog intermediate frequency module of the transmitter; the radio frequency module of the transmitter is connected to the analog intermediate frequency module of the transmitter and the calibration loop; the calibration loop is connected to the radio frequency front-end module of the receiver and the analog intermediate frequency module of the transmitter.

[0005] Compared with the prior art, the beneficial effects of a transceiver system of the present invention are as follows: Through the calibration loop, closed-loop calibration between the receiver and the transmitter is achieved to eliminate the DC bias mismatch, amplitude mismatch, and phase mismatch generated by the receiver and the transmitter, and optimize the local oscillator leakage and sideband suppression of the receiver and the transmitter, thereby greatly improving the performance of the transceiver system.

[0006] Optionally, the calibration loop includes: an auxiliary frequency conversion module, a down-conversion module, a switch module, and a frequency divider; The auxiliary frequency conversion module is connected to the radio frequency module of the transmitter, the analog intermediate frequency module of the transmitter, and the down-conversion module; the down-conversion module is connected to the switch module and the frequency divider; the switch module is connected to the radio frequency front-end module of the receiver.

[0007] Optionally, the auxiliary frequency conversion module includes an I-channel auxiliary frequency conversion circuit, a Q-channel auxiliary frequency conversion circuit, a first resistor, and a second resistor; The P terminal of the I-channel auxiliary frequency conversion circuit is connected to the P terminal of the Q-channel auxiliary frequency conversion circuit through the first resistor; the N terminal of the I-channel auxiliary frequency conversion circuit is connected to the N terminal of the Q-channel auxiliary frequency conversion circuit through the second resistor; the first resistor and the second resistor are connected to the power supply voltage; the down-conversion module is connected to the I-channel auxiliary frequency conversion circuit and the Q-channel auxiliary frequency conversion circuit; The I-channel auxiliary frequency conversion circuit and the Q-channel auxiliary frequency conversion circuit have the same structure; the I-channel auxiliary frequency conversion circuit and the Q-channel auxiliary frequency conversion circuit respectively include an auxiliary transconductance amplification unit and an auxiliary mixer; the analog intermediate frequency module of the transmitter is sequentially connected to the first resistor and the second resistor through the auxiliary transconductance amplification unit and the auxiliary mixer.

[0008] Optionally, the auxiliary transconductance amplification unit includes a third transconductance tube and a fourth transconductance tube; The auxiliary mixer is connected to the drain of the third transconductance tube and the drain of the fourth transconductance tube; the analog intermediate frequency module of the transmitter is connected to the gate of the third transconductance tube and the gate of the fourth transconductance tube; the source of the third transconductance tube and the source of the fourth transconductance tube are both grounded.

[0009] Optionally, the switch module includes: a first switch, a second switch, a third switch, a fourth switch, a fifth switch, and a sixth switch; The first switch is connected to the down-conversion module, the second switch, and the sixth switch; the third switch is connected to the down-conversion module, the fourth switch, and the fifth switch; the fifth switch and the sixth switch share the same ground; the radio frequency front-end module of the receiver is connected to the second switch and the fourth switch.

[0010] Optionally, the radio frequency front-end module of the receiver includes a low-noise amplifier, a second-stage frequency converter, and a transimpedance amplifier; the analog intermediate frequency module of the receiver includes a filter and an analog-to-digital converter; The low-noise amplifier is sequentially connected to the digital calibration module through the second-stage frequency converter, the transimpedance amplifier, the filter, and the analog-to-digital converter; the calibration loop is connected to the second-stage frequency converter.

[0011] Optionally, the analog intermediate frequency module of the transmitter includes a digital-to-analog converter, a filter, and a transconductance amplifier, and the radio frequency module of the transmitter includes a main frequency conversion unit and a balun unit; The digital calibration module is connected to the balun unit through the digital-to-analog converter, the filter, the transconductance amplifier, and the main frequency conversion unit in sequence; the transconductance amplifier is connected to the switch module through the auxiliary frequency conversion module and the down-conversion module; The main frequency conversion unit, the auxiliary frequency conversion module, and the down-conversion module achieve frequency conversion in the form of a common local oscillator; the local oscillator frequencies of the main frequency conversion unit and the auxiliary frequency conversion module are simultaneously generated by the voltage-controlled oscillator of the transmitter; the local oscillator frequency of the down-conversion module in the calibration loop is directly generated by the voltage-controlled oscillator of the transmitter through the frequency divider.

[0012] Optionally, the main frequency conversion unit includes an I-channel main frequency conversion circuit, a Q-channel main frequency conversion circuit, and a capacitor array; The capacitor array is connected to the I-channel main frequency conversion circuit, the Q-channel main frequency conversion circuit, and the balun unit; the analog intermediate frequency module of the transmitter is connected to the I-channel main frequency conversion circuit and the Q-channel main frequency conversion circuit; The I-channel main frequency conversion circuit and the Q-channel main frequency conversion circuit have the same structure; the I-channel main frequency conversion circuit and the Q-channel main frequency conversion circuit respectively include a main transconductance amplification unit and a main mixer.

[0013] Optionally, the main transconductance amplification unit includes a first transconductance tube and a second transconductance tube; The main mixer is connected to the drain of the first transconductance tube and the drain of the second transconductance tube; the analog intermediate frequency module of the transmitter is connected to the gate of the first transconductance tube and the gate of the second transconductance tube; the source of the first transconductance tube and the source of the second transconductance tube are both grounded.

[0014] A closed-loop calibration method is also provided, which is applied to the above transceiver system, and includes: The baseband signal is subjected to digital-to-analog conversion and filtering through a digital-to-analog converter and a filter to obtain an intermediate frequency voltage signal, and the intermediate frequency voltage signal is converted into an intermediate frequency current signal through a transconductance amplifier; the baseband signal is the signal received by the transmitter; When calibration is enabled, the intermediate frequency current signal is up-converted by the auxiliary frequency conversion module and down-converted by the down-conversion module in sequence to obtain a radio frequency signal within the same frequency range as the input signal; the input signal is the signal received by the receiver; The radio frequency signal is input into the radio frequency front-end module of the receiver through the switch module, and undergoes secondary down-conversion to convert the radio frequency signal into an intermediate frequency signal. The intermediate frequency signal is converted into a digital signal through the analog intermediate frequency module of the receiver. The digital signal undergoes a calibration algorithm through the digital calibration module to obtain a calibration offset, and the calibration offset is fed back to the transmitter to achieve closed-loop calibration between the receiver and the transmitter; When the calibration is completed, the calibration is turned off. The intermediate frequency current signal is converted into a high-frequency signal by the main frequency conversion unit, and the high-frequency signal is converted from differential to single-ended output by the balun unit. Description of the Drawings

[0015] Figure 1 is the overall block diagram of the transceiver system of the present invention Figure 1 ; Figure 2 is the overall block diagram of the transceiver system of the present invention Figure 2 ; Figure 3 is the block diagram of the calibration loop of the transceiver system of the present invention; Figure 4 is the local oscillator schematic diagram of the calibration loop of the present invention.

[0016] Description of the reference numerals: 1, receiver; 101, radio frequency front-end module of the receiver; 102, analog intermediate frequency module of the receiver; 2, transmitter; 201, radio frequency module of the transmitter; 2011, main frequency conversion unit; 20111, main transconductance amplification unit; 20112, main mixer; 2012, balun unit; 202, analog intermediate frequency module of the transmitter; 3, digital calibration module; 4, calibration loop; 401, auxiliary frequency conversion module; 4011, auxiliary transconductance amplification unit; 4012, auxiliary mixer; 402, down-conversion module; 403, switch module; 404, frequency divider. Detailed Embodiments

[0017] The following describes the preferred embodiments of the present invention with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0018] When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims. In the description of the present application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects and do not have to be used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0019] Referring to Figure 1 As shown, a transceiver system provided by the present invention includes: a receiver 1, a transmitter 2, a digital calibration module 3, and a calibration loop 4; the radio frequency front-end module 101 of the receiver is connected to the analog intermediate frequency module 102 of the receiver; the digital calibration module 3 is connected to the analog intermediate frequency module 102 of the receiver and the analog intermediate frequency module 202 of the transmitter; the calibration loop 4 is connected to the radio frequency front-end module 101 of the receiver, the radio frequency module 201 of the transmitter, and the analog intermediate frequency module 202 of the transmitter.

[0020] The radio frequency front-end module 101 of the receiver is configured to receive an input signal, perform down-conversion and amplification on it, and send it to the analog intermediate frequency module 102 of the receiver; the analog intermediate frequency module 102 of the receiver is configured to perform filtering processing and analog-to-digital conversion on the signal sent by the radio frequency front-end module 101 of the receiver to obtain a digital signal; the digital calibration module 3 is configured to calibrate the digital signal output by the analog intermediate frequency module 102 of the receiver to obtain a digital calibration signal; the analog intermediate frequency module 202 of the transmitter is configured to process the digital calibration signal output by the digital calibration module 3 to obtain an intermediate frequency analog signal.

[0021] When calibration is turned off, the calibration loop 4 is turned off and does not work, and the intermediate frequency analog signal is converted into a high-frequency signal by the radio frequency front-end module 201 of the transmitter and transmitted; when calibration is turned on, the intermediate frequency analog signal is up-converted and then down-converted through the calibration loop 4 to obtain a radio frequency signal with the same frequency range as the input signal. This radio frequency signal is down-converted again by the radio frequency front-end module 101 of the receiver to convert the radio frequency signal into an intermediate frequency voltage signal; the analog intermediate frequency module 102 of the receiver filters and performs analog-to-digital conversion on the intermediate frequency voltage signal to obtain a digital signal, which is calibrated by the digital calibration module 3 and then the calibration offset is fed back to the transmitter 2 to sequentially achieve the closed-loop calibration between the receiver 1 and the transmitter 2, eliminating the DC offset mismatch, amplitude mismatch, and phase mismatch generated by the receiver 1 and the transmitter 2, optimizing the local oscillator leakage and sideband suppression of the receiver 1 and the transmitter 2, thereby greatly improving the performance of the transceiver system through the calibration loop 4.

[0022] The calibration loop 4 includes: an auxiliary frequency conversion module 401, a down-conversion module 402, a switching module 403, and a frequency divider 404; the auxiliary frequency conversion module 401 is connected to the radio frequency module 201 of the transmitter, the analog intermediate frequency module 202 of the transmitter, and the down-conversion module 402; the down-conversion module 402 is connected to the switching module 403 and the frequency divider 404; the switching module 403 is connected to the radio frequency front-end module 101 of the receiver.

[0023] The auxiliary frequency conversion module 401 includes an I-channel auxiliary frequency conversion circuit, a Q-channel auxiliary frequency conversion circuit, a first resistor R1, and a second resistor R2; the P terminals of the I-channel auxiliary frequency conversion circuit and the Q-channel auxiliary frequency conversion circuit are connected to the first resistor R1; the N terminals of the I-channel auxiliary frequency conversion circuit and the Q-channel auxiliary frequency conversion circuit are connected to the second resistor R2; the first resistor R1 and the second resistor R2 are connected to the power supply voltage AVDD, and the power supply voltage AVDD is used to provide power; the down-conversion module 402 receives signals from the I-channel auxiliary frequency conversion circuit and the Q-channel auxiliary frequency conversion circuit; Since the difference between the two signals lies only in the phase, the processing circuit structures of the two signals are the same. That is, in an embodiment of the present invention, the I-channel auxiliary frequency conversion circuit and the Q-channel auxiliary frequency conversion circuit have the same structure; the I-channel auxiliary frequency conversion circuit and the Q-channel auxiliary frequency conversion circuit respectively include an auxiliary transconductance amplification unit 4011 and an auxiliary mixer 4012; the analog intermediate frequency module 202 of the transmitter is sequentially connected to the first resistor R1 and the second resistor R2 through the auxiliary transconductance amplification unit 4011 and the auxiliary mixer 4012.

[0024] The auxiliary transconductance amplification unit 4011 includes a third transconductance tube M3 and a fourth transconductance tube M4; the auxiliary mixer 4012 is connected to the drain of the third transconductance tube M3 and the drain of the fourth transconductance tube M4; the analog intermediate frequency module 202 of the transmitter is connected to the gate of the third transconductance tube M3 and the gate of the fourth transconductance tube M4; the sources of the third transconductance tube M3 and the fourth transconductance tube M4 are both grounded.

[0025] The switching module 403 includes: a first switch SW1, a second switch SW2, a third switch SW3, a fourth switch SW4, a fifth switch SW5, and a sixth switch SW6; the first switch SW1 is connected to the down-conversion module 402, the second switch SW2, and the sixth switch SW6; the third switch SW3 is connected to the down-conversion module 402, the fourth switch SW4, and the fifth switch SW5; the fifth switch SW5 and the sixth switch SW6 are grounded together; the radio frequency front-end module 101 of the receiver is connected to the second switch SW2 and the fourth switch SW4.

[0026] The radio frequency front-end module 101 of the receiver includes a low-noise amplifier, a second-stage frequency converter, and a transimpedance amplifier; the analog intermediate frequency module 102 of the receiver includes a filter and an analog-to-digital converter ADC; the low-noise amplifier is sequentially connected to the digital calibration module 3 through the second-stage frequency converter, the transimpedance amplifier, the filter, and the analog-to-digital converter ADC; the calibration loop 4 is connected to the second-stage frequency converter.

[0027] The analog intermediate frequency module 202 of the transmitter includes a digital-to-analog converter DAC, a filter, and a transconductance amplifier, and the radio frequency module 201 of the transmitter includes a main frequency conversion unit 2011 and a balun unit; the digital calibration module 3 is sequentially connected to the balun unit 2012 through the digital-to-analog converter DAC, the filter, the transconductance amplifier, and the main frequency conversion unit 2011; the transconductance amplifier is connected to the switch module 403 through the auxiliary frequency conversion module 401 and the down-conversion module 402.

[0028] The main frequency conversion unit 2011 includes an I-channel main frequency conversion circuit, a Q-channel main frequency conversion circuit, and a capacitor array C; the capacitor array C is connected to the I-channel main frequency conversion circuit, the Q-channel main frequency conversion circuit, and the balun unit 2012; the analog intermediate frequency module 202 of the transmitter is connected to the I-channel main frequency conversion circuit and the Q-channel main frequency conversion circuit.

[0029] Since the difference between the two signals of the I and Q channels lies only in the phase difference, the processing circuit structures of the two channels are the same. That is, in an embodiment of the present invention, the I-channel main frequency conversion circuit and the Q-channel main frequency conversion circuit have the same structure; the I-channel main frequency conversion circuit and the Q-channel main frequency conversion circuit respectively include a main transconductance amplification unit 20111 and a main mixer 20112; the analog intermediate frequency module 202 of the transmitter is sequentially connected to the capacitor array C and the balun unit 2012 through the main transconductance amplification unit 20111 and the main mixer 20112.

[0030] Among them, the main transconductance amplification unit 20111 includes a first transconductance tube M1 and a second transconductance tube M2; the main mixer 20112 is connected to the drain of the first transconductance tube M1 and the drain of the second transconductance tube M2; the analog intermediate frequency module 202 of the transmitter is connected to the gate of the first transconductance tube M1 and the gate of the second transconductance tube M2; the source of the first transconductance tube M1 and the source of the second transconductance tube M2 are both grounded.

[0031] In an embodiment provided by the present invention, the digital baseband signal is converted from a digital signal to an analog signal by the digital-to-analog converter DAC, and the analog signal is filtered by the filter and then converted and amplified by the transconductance amplifier to obtain an intermediate frequency signal.

[0032] When calibration is enabled, the main frequency conversion unit 2011 is turned off, and the up-conversion of the calibration loop 4 is completed by the auxiliary frequency conversion module 401. The auxiliary frequency conversion module 401 realizes current amplification through the third cross-conduit M3 and the fourth cross-conduit M4. The current signal is up-converted into a high-frequency signal through the auxiliary mixer 4012. Since the main frequency conversion unit 2011 needs to achieve high output power, usually a high voltage domain of 1.8V is adopted for the voltage, while a low voltage domain of 0.9V is adopted for the voltage of the RF front-end module 101 of the receiver. Therefore, the auxiliary frequency conversion module 4012 adopts a resistive load form, and the first resistor R1 and the second resistor R2 are used to provide common mode for the high-frequency signal respectively, so as to realize the cross-voltage domain conversion (1.8V to 0.9V).

[0033] Since the operating frequencies of the receiver 1 and the transmitter 2 are different, that is, the receiving channel of the receiver 1 and the transmitting channel of the transmitter 2 operate at different frequencies. Therefore, after the intermediate-frequency analog signal is up-converted by the auxiliary frequency conversion module 401, it will be down-converted once, and the transmitting frequency of the transmitter will be converted to the receiving frequency range of the receiver. That is, after the intermediate-frequency analog signal is successively up-converted and down-converted, it is converted into a radio frequency signal with the same frequency range as the input signal received by the receiver 1. The local oscillator signal of the down-conversion module 402 is generated by dividing the LO of the 404tx channel of the frequency divider by 1 / n, where the value of n can be continuously adjusted between 2 and 512. The radio frequency signal (current signal) after down-conversion enters the input end of the secondary mixer through the switch module 403, and is secondarily down-converted with the local oscillator signal (input signal) received by the receiver 1 to be converted into an intermediate-frequency signal, and finally is converted into a voltage signal through a transimpedance amplifier.

[0034] After the voltage signal is filtered by the filter, it is then converted into a digital signal by the analog-to-digital converter ADC and input to the digital calibration module 3. The digital calibration module 3 calibrates the digital signal and then feeds back the digital calibration signal to the input end of the transmitter.

[0035] When the calibration loop 4 is working (the calibration loop 4 is enabled), the first switch SW1, the second switch SW2, the third switch SW3, and the fourth switch SW4 are in the conducting state, and the fifth switch SW5 and the sixth switch SW6 are in the cut-off state. The radio frequency signal is transmitted to the RF front-end module 101 of the receiver through the switch module 403.

[0036] When the calibration loop 4 is not working (the calibration loop 4 is turned off), the first switch SW1, the second switch SW2, the third switch SW3, and the fourth switch SW4 are in the cut-off state, and the fifth switch SW5 and the sixth switch SW6 are in the conducting state.

[0037] When there is partial leakage of the signals on both sides of the receiver 1 and the transmitter 2 through the first switch SW1, the second switch SW2, the third switch SW3, and the fourth switch SW4 respectively, the leaked signals will be conducted to the ground through the fifth switch SW5 and the sixth switch SW6 respectively, thereby reducing the crosstalk between the receiver 1 and the transmitter 2; in addition, the linearity of the calibration loop 4 is limited by the influence of the power supply voltage. The radio frequency front-end module 101 of the receiver adopts a low voltage domain (0.9V). When the power is greater, the linearity deteriorates more seriously. Therefore, the auxiliary frequency conversion module 401 adopts low-gain amplification to achieve low-power output, generally around 0 dBm; while the main frequency conversion unit 2011 adopts a high voltage domain (1.8V) and can achieve a linear output of 5 dBm.

[0038] See Figure 4 As shown, a local oscillator schematic diagram of the calibration loop 4 is shown. The main frequency conversion unit 201 and the auxiliary frequency conversion module 401 adopt the form of sharing the local oscillator to achieve frequency conversion. The local oscillator frequencies of the main frequency conversion unit 201 and the auxiliary frequency conversion module 401 are simultaneously generated by the transmitted voltage-controlled oscillator TX_VCO to generate the local oscillator frequency FLO. The down-conversion module 402 in the calibration loop 4 realizes the frequency difference conversion between the receiver 1 and the transmitter 2. Its local oscillator frequency is directly generated by the transmitted voltage-controlled oscillator TX_VCO through a 1 / n frequency divider 404, and its frequency is FLO / n. The value range of n can be continuously adjusted between 2 and 512, without the need to be provided by an additional transmitted voltage-controlled oscillator TX_VCO, greatly simplifying the complexity of the calibration loop 4 and improving the practicability of the calibration loop 4.

[0039] After the calibration is completed, the calibration loop 4 is turned off, and the main frequency conversion unit 201 works normally. The first switch SW1, the second switch SW2, the third switch SW3, and the fourth switch SW4 change from the conducting state to the cutoff state, and the fifth switch SW5 and the sixth switch SW6 change from the cutoff state to the conducting state; through the auxiliary frequency conversion module 401, it is possible to reduce the influence on the main frequency conversion unit 201 when the calibration loop 4 performs closed-loop calibration, without increasing additional power consumption, improving the reliability of the transmission of the transmitter 2 in the transceiver system, and also realizing the closed-loop calibration between the receiver 1 and the transmitter 2, eliminating the DC bias mismatch, amplitude mismatch, and phase mismatch in the transceiver system, thereby improving the overall performance of the transceiver.

[0040] A closed-loop calibration method provided by the present invention is applied to the above transceiver system. The closed-loop calibration method includes: First, the baseband signal (the signal received by the transmitter 2) is subjected to digital-to-analog conversion and filtering through a digital-to-analog converter DAC and a filter to obtain an intermediate-frequency voltage signal, and the intermediate-frequency voltage signal is converted into an intermediate-frequency current signal through a transconductance amplifier.

[0041] When calibration is enabled (calibration loop 4 is enabled), the intermediate frequency current signal is first up-converted by the auxiliary frequency conversion module 401 and then down-converted by the down-conversion module 402 to obtain a radio frequency signal with the same frequency range as the input signal (the signal received by receiver 1). The radio frequency signal is input to the radio frequency front-end module 101 of the receiver through the switch module 403, that is, input to the second-stage frequency converter for second-stage down-conversion to convert the radio frequency signal into an intermediate frequency signal. The intermediate frequency signal passes through the analog intermediate frequency module 102 of the receiver to obtain a digital signal. The digital signal undergoes a calibration algorithm through the digital calibration module 3 to obtain a calibration offset. The calibration offset is fed back to the input end of the transmitter 2 to achieve closed-loop calibration between the receiver 1 and the transmitter 2.

[0042] When calibration is completed, calibration is disabled (calibration loop 4 is disabled). The intermediate frequency current signal output by the analog intermediate frequency module 202 of the transmitter is converted into a high-frequency single-ended signal through the radio frequency module 201 of the transmitter and finally transmitted. Specifically, the intermediate frequency current signal is converted into a high-frequency signal by the main frequency conversion unit 2011, and the high-frequency signal is then converted from differential to single-ended output through the balun unit 2012, that is, a high-frequency single-ended signal.

[0043] The following combines Figures 2-3 to specifically illustrate the detailed process of calibrating the transceiver system using the closed-loop calibration method: The baseband signal (the signal received by transmitter 2) is converted into an intermediate frequency current signal through digital-to-analog conversion and filtering by the digital-to-analog converter DAC, filter, and transconductance amplifier (the analog intermediate frequency module 202 of the transmitter). When the calibration loop 4 is operating (calibration loop 4 is enabled), the intermediate frequency current signal undergoes transconductance amplification and mixing through the auxiliary transconductance amplification unit 4011 and the auxiliary mixer 4012 (auxiliary frequency conversion module 401) to obtain a high-frequency signal. The first resistor R1 and the second resistor R2 provide bias for the auxiliary frequency conversion module 401 to achieve a certain gain. Then, the high-frequency signal undergoes down-conversion through the down-conversion module 402 to adjust the frequency of the signal to a radio frequency signal with the same frequency range as the input signal RX_IN received by receiver 1. The radio frequency signal is input to the radio frequency front-end module 101 (second-stage frequency converter) of the receiver through the switch module 403 for second-stage down-conversion to convert the radio frequency signal into an intermediate frequency signal. The intermediate frequency signal passes through the analog intermediate frequency module 102 of the receiver to obtain a digital voltage signal. The digital voltage signal undergoes a calibration algorithm through the digital calibration module 3 to obtain a calibration offset. The calibration offset includes the mismatch errors generated by adjusting the analog intermediate frequency module 202 (such as the transconductance amplifier) of the transmitter and the calibration loop 4. And by feeding back the calibration offset to the input end of the transmitter 2 to eliminate the mismatch, closed-loop calibration of the signal processing between the receiver 1 and the transmitter 2 is achieved, improving the overall performance of the transceiver system.

[0044] When the calibration is completed (the calibration loop 4 is turned off), the intermediate-frequency current signal is amplified and mixed by the main transconductance amplification unit 20111, the main mixing unit 20112, and the capacitor array C (the main frequency conversion unit 2011) to obtain a high-frequency signal with differential output. Finally, the high-frequency signal is converted into a single-ended output signal TX_OUT by the balun unit 2012 and transmitted. At the same time, the double-balanced end of the balun unit 2012 provides a load for the main frequency conversion unit 2011 to achieve high-gain amplification.

[0045] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A transceiver system, characterized in that: include: Receivers, transmitters, digital calibration modules and calibration loops; The radio frequency front-end module of the receiver is connected to the analog intermediate frequency module of the receiver; The digital calibration module is connected to the analog intermediate frequency module of the receiver and the analog intermediate frequency module of the transmitter; the radio frequency module of the transmitter is connected to the analog intermediate frequency module of the transmitter and the calibration loop; the calibration loop is connected to the radio frequency front-end module of the receiver and the analog intermediate frequency module of the transmitter.

2. A transceiver system according to claim 1, characterized in that: The calibration loop includes: an auxiliary frequency conversion module, a down-conversion module, a switch module and a frequency divider; The auxiliary frequency conversion module is connected to the radio frequency module of the transmitter, the analog intermediate frequency module of the transmitter, and the down-conversion module; the down-conversion module is connected to the switch module and the frequency divider; and the switch module is connected to the radio frequency front-end module of the receiver.

3. A transceiver system according to claim 2, characterized in that: The auxiliary frequency conversion module includes an I-way auxiliary frequency conversion circuit, a Q-way auxiliary frequency conversion circuit, a first resistor and a second resistor; The P end of the I-way auxiliary frequency conversion circuit and the P end of the Q-way auxiliary frequency conversion circuit are connected to a first resistor; The N-end of the I-way auxiliary frequency conversion circuit and the N-end of the Q-way auxiliary frequency conversion circuit are connected to a second resistor; The first resistor and the second resistor are connected to a power supply voltage; The down-conversion module is connected to the I-way auxiliary frequency conversion circuit and the Q-way auxiliary frequency conversion circuit; The I-way auxiliary frequency conversion circuit and the Q-way auxiliary frequency conversion circuit have the same structure; The I-channel auxiliary frequency conversion circuit and the Q-channel auxiliary frequency conversion circuit respectively include an auxiliary transconductance amplifier unit and an auxiliary mixer; The analog intermediate frequency module of the transmitter is connected to the first resistor and the second resistor through the auxiliary transconductance amplifier unit and the auxiliary mixer in sequence.

4. A transceiver system according to claim 3, characterized in that: The auxiliary transconductance amplification unit includes a third transconductor and a fourth transconductor; The auxiliary mixer is connected to the drain of the third transconductor and the drain of the fourth transconductor; the analog intermediate frequency module of the transmitter is connected to the gate of the third transconductor and the gate of the fourth transconductor; the source of the third transconductor and the source of the fourth transconductor are both grounded.

5. A transceiver system according to claim 4, characterized in that: The switch module includes: a first switch, a second switch, a third switch, a fourth switch, a fifth switch and a sixth switch; The first switch is connected to the down-conversion module, the second switch, and the sixth switch; the third switch is connected to the down-conversion module, the fourth switch, and the fifth switch; the fifth switch and the sixth switch share a common ground; and the RF front-end module of the receiver is connected to the second switch and the fourth switch.

6. A transceiver system according to claim 5, characterized in that: The radio frequency front-end module of the receiver includes a low noise amplifier, a secondary frequency converter and a transimpedance amplifier; the analog intermediate frequency module of the receiver includes a filter and an analog-to-digital converter; The low noise amplifier is connected to a digital calibration module through the secondary frequency converter, the transimpedance amplifier, the filter, and the analog-to-digital converter in sequence; and the calibration loop is connected to the secondary frequency converter.

7. A transceiver system according to claim 6, characterized in that: The analog intermediate frequency module of the transmitter includes a digital-to-analog converter, a filter and a transconductance amplifier, and the radio frequency module of the transmitter includes a main frequency conversion unit and a balun unit; The digital calibration module is connected to the balun unit through the digital-to-analog converter, the filter, the transconductance amplifier, and the main frequency conversion unit in sequence; The transconductance amplifier is connected to the switch module through the auxiliary frequency conversion module and the down-conversion module; The main frequency conversion unit, the auxiliary frequency conversion module and the down-conversion module use a common local oscillator to achieve frequency conversion; the local oscillation frequencies of the main frequency conversion unit and the auxiliary frequency conversion module are simultaneously generated by the transmitting voltage-controlled oscillator; the local oscillation frequency of the down-conversion module in the calibration loop is directly generated by the transmitting voltage-controlled oscillator through the divider.

8. A transceiver system according to claim 7, characterized in that: The main frequency conversion unit includes an I-way main frequency conversion circuit, a Q-way main frequency conversion circuit and a capacitor array; The capacitor array is connected to the I-channel main frequency conversion circuit, the Q-channel main frequency conversion circuit, and the balun unit; The analog intermediate frequency module of the transmitter is connected to the I-channel main frequency conversion circuit and the Q-channel main frequency conversion circuit; The I-way main frequency conversion circuit and the Q-way main frequency conversion circuit have the same structure; The I-channel main frequency conversion circuit and the Q-channel main frequency conversion circuit respectively include a main transconductance amplifier unit and a main mixer.

9. A transceiver system according to claim 8, characterized in that: The main transconductance amplification unit includes a first transconductor and a second transconductor; The main mixer is connected to the drain of the first transconduit and the drain of the second transconduit; the analog intermediate frequency module of the transmitter is connected to the gate of the first transconduit and the gate of the second transconduit; the source of the first transconduit and the source of the second transconduit are both grounded.

10. A closed-loop calibration method, applied to the transceiver system according to claims 1 to 9, characterized in that: include: The baseband signal is converted into an intermediate frequency voltage signal by a digital-to-analog converter and a filter and then filtered, and the intermediate frequency voltage signal is converted into an intermediate frequency current signal by a transconductance amplifier; The baseband signal is a signal received by the transmitter; When the calibration is turned on, the intermediate frequency current signal is sequentially up-converted by the auxiliary frequency conversion module and down-converted by the down-conversion module to obtain a radio frequency signal within the same frequency range as the input signal; the input signal is the signal received by the receiver; The RF signal is input to the RF front-end module of the receiver through the switch module, and is subjected to secondary down-conversion to convert the RF signal into an intermediate frequency signal. The intermediate frequency signal is passed through the analog intermediate frequency module of the receiver to obtain a digital signal. The digital signal is subjected to a calibration algorithm through the digital calibration module to obtain a calibration offset. The calibration offset is fed back to the transmitter to achieve closed-loop calibration between the receiver and the transmitter. When the calibration is completed, the calibration is closed, the intermediate frequency current signal is converted into a high frequency signal by the main frequency conversion unit, and the high frequency signal is converted from differential to single-ended output by the balun unit.

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