CN-122026839-A - Fully differential Cartesian loop linearization apparatus and radio frequency transceiver

CN122026839ACN 122026839 ACN122026839 ACN 122026839ACN-122026839-A

Abstract

The application provides a fully-differential Cartesian loop linearization device and a radio frequency transceiver, and relates to the technical field of communication. The device comprises a forward path unit, a feedback path unit and an error amplifier unit of a fully differential architecture, wherein signal paths of the forward path unit and the feedback path unit are constructed in a fully differential pair mode. The first input end of the error amplifier unit receives the fully-differential IQ input baseband pair, the second input end receives the fully-differential IQ feedback baseband pair, and the fully-differential IQ error pair is output after the differential subtraction and amplification. The forward path unit is connected to the output end of the error amplifier unit, up-converts and power amplifies the fully differential IQ error pair, and outputs a radio frequency signal. The feedback path unit is coupled to the output end of the forward path unit, samples and down-converts the radio frequency signal, generates a fully differential IQ feedback baseband pair, and feeds back to the second input end of the error amplifier unit. The scheme can improve the integration level and the noise suppression capability.

Inventors

LI MINGQIAN
JIA CHENGWEI

Assignees

深圳市静远达智科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260202

Claims (10)

1. The full-differential Cartesian loop linearization device is characterized by comprising a forward path unit, a feedback path unit and an error amplifier unit with a full-differential architecture, wherein signal paths of the forward path unit and the feedback path unit are constructed in a full-differential pair mode; The first input end of the error amplifier unit is used for receiving the fully-differential in-phase and quadrature input baseband pair, the second input end is used for receiving the fully-differential in-phase and quadrature feedback baseband pair, and the output end is used for outputting the fully-differential in-phase and quadrature error pair obtained after differential subtraction and amplification; the input end of the forward path unit is connected with the output end of the error amplifier unit and is used for carrying out up-conversion and power amplification treatment on the fully-differential in-phase and quadrature error pair to obtain a radio frequency signal and then outputting the radio frequency signal; The input end of the feedback path unit is coupled to the output end of the forward path unit, and is used for sampling and down-converting the radio frequency signal, generating a fully-differential in-phase and quadrature feedback baseband pair, and feeding back the fully-differential in-phase and quadrature feedback baseband pair to the second input end of the error amplifier unit.
2. A fully differential cartesian loop linearization apparatus according to claim 1, wherein the forward path unit comprises an up-conversion modulator, a forward attenuator, a power amplifier and a directional coupler connected in sequence, the input of the up-conversion modulator being connected to the output of the error amplifier unit, the output of the directional coupler being connected to the input of the feedback path unit and being adapted to be connected to the target antenna; The up-conversion modulator is used for receiving the fully-differential in-phase and quadrature error pairs output by the error amplifier unit and mixing with the differential local oscillation signals to generate radio frequency signals, the forward attenuator is used for adjusting signal amplitude and matching impedance of the radio frequency signals, the power amplifier is used for amplifying power of the radio frequency signals, and the directional coupler is used for sending the radio frequency signals to the target antenna and coupling out a part of signals to the input end of the feedback path unit.
3. A fully differential cartesian loop linearization apparatus according to claim 2, wherein the directional coupler is a differential stripline coupler or a differential lange coupler.
4. A fully differential cartesian loop linearization apparatus according to claim 1, wherein the feedback path unit comprises a feedback attenuator, a down-conversion demodulator and a loop filter connected in sequence, the input of the feedback attenuator being coupled to the output of the forward path unit, the output of the loop filter being connected to the second input of the error amplifier unit; the feedback attenuator is used for adjusting the level of the sampled radio frequency signal, the down-conversion demodulator is used for demodulating the radio frequency signal into a fully-differential in-phase and quadrature feedback baseband pair, and the loop filter is used for filtering out-of-band noise and setting loop bandwidth.
5. The apparatus of claim 4, wherein the down-conversion demodulator includes a phase calibration module integrated therein for adjusting the phase of the demodulated local oscillator signal.
6. A fully differential cartesian loop linearization apparatus according to claim 1, wherein the error amplifier unit employs a fully differential cascode structure with a common-mode feedback network integrated therein.
7. A fully differential cartesian loop linearization apparatus according to claim 6, wherein the bandwidth of the common-mode feedback network is greater than 5 times the highest frequency of the rf signal.
8. A fully differential cartesian loop linearization apparatus according to claim 1, wherein the forward path unit and the feedback path unit share the same differential local oscillation source.
9. The fully differential cartesian loop linearization apparatus of claim 1, wherein the forward path unit, the feedback path unit, and the error amplifier unit are implemented using an integrated circuit process or a discrete device process.
10. A radio frequency transceiver comprising a receive processing unit and a fully differential cartesian loop linearization arrangement according to any of claims 1-9, wherein the forward path unit and/or the feedback path unit of the fully differential cartesian loop linearization arrangement are arranged to form a transmit closed loop for linearization correction of power amplification during a transmit period by time division multiplexing, and to switch at least partly to be connected to the receive processing unit during a receive period for jointly processing radio frequency receive signals from an antenna.

Description

Fully differential Cartesian loop linearization apparatus and radio frequency transceiver Technical Field The application relates to the technical field of communication, in particular to a fully-differential Cartesian loop linearization device and a radio frequency transceiver. Background The evolution of wireless communications from analog speech to higher order digital modulation places stringent demands on the linearity of the radio frequency power amplifier. To increase efficiency, the rf power amplifier is often operated near saturation, but this can cause severe spectral regrowth (causing adjacent channel leakage ACPR to exceed standard) and signal distortion (causing the error vector magnitude EVM to deteriorate). Therefore, linearization correction of the power amplifier is necessary. Existing main stream linearization techniques mainly include feed forward cancellation, digital predistortion and cartesian loops. The feedforward technology needs additional power amplifier and delay line, has large volume and power consumption, and the digital predistortion technology needs high-speed data conversion and complex digital processing, and has high cost. In contrast, the cartesian loop realizes linearization through pure analog closed loop feedback, has the remarkable advantages of simple structure, low delay, low power consumption and small area, and is particularly suitable for medium and low power application sensitive to cost. However, conventional cartesian rings are commonly implemented using single-ended circuit structures. The structure is extremely sensitive to common-mode interference such as substrate coupling noise, power supply ripple waves, local oscillation leakage and the like in the chip, and direct current offset and even harmonic distortion are easy to introduce at the input end of the error amplifier. The consequence is that the effective linearization bandwidth of the loop is limited, and ACPR improvement performance drops significantly at high frequency bands and drifts with environmental fluctuations. In addition, the single-ended signal must bear the complete radio frequency voltage swing, so that the working voltage of the circuit cannot be reduced along with the downsizing of the advanced CMOS process, and the development and the application of the single-ended signal in chips with low voltage, high frequency and high integration level are seriously hindered. Therefore, there is a need in the art for a cartesian loop linearization solution that further improves the integration and performance. Disclosure of Invention In order to solve the above-mentioned problems, the present application provides a fully differential cartesian loop linearization apparatus and a radio frequency transceiver, which can further improve the integration level and noise suppression capability. The application is realized in the following way: In a first aspect, the present application provides a fully differential cartesian loop linearization apparatus comprising a forward path unit, a feedback path unit, and a fully differential architecture error amplifier unit. Wherein the signal paths of the forward path unit and the feedback path unit are both constructed in the form of fully differential pairs. The first input end of the error amplifier unit is used for receiving the fully-differential in-phase and quadrature input baseband pair, the second input end is used for receiving the fully-differential in-phase and quadrature feedback baseband pair, and the output end is used for outputting the fully-differential in-phase and quadrature error pair obtained after differential subtraction and amplification. And the input end of the forward path unit is connected with the output end of the error amplifier unit and is used for carrying out up-conversion and power amplification treatment on the fully-differential in-phase and quadrature error pair to obtain a radio frequency signal and then outputting the radio frequency signal. The input end of the feedback path unit is coupled to the output end of the forward path unit, and is used for sampling and down-converting the radio frequency signal, generating a fully-differential in-phase and quadrature feedback baseband pair, and feeding back the fully-differential in-phase and quadrature feedback baseband pair to the second input end of the error amplifier unit. In a second aspect, the present application provides a radio frequency transceiver, which includes a receiving and processing unit and a fully differential cartesian loop linearization device, where the forward path unit and/or the feedback path unit in the fully differential cartesian loop linearization device are configured to form a transmit closed loop to perform linearization correction on power amplification in a transmit period by a time division multiplexing manner, and at least partially switch to be connected to the receiving and processing unit in a receive period to jointly process a radio f