CN102694567A - Front end radio frequency transceiver system for multi-standard fully-compatible mobile user terminal chip - Google Patents

Abstract

The invention discloses a radio frequency front-end transceiver system of a multi-standard fully compatible mobile user terminal chip, including: an LTE diversified receiver, which is used to perform at least tracking filtering, frequency mixing, variable gain intermediate frequency and radio frequency signals on preset spectrums. /or front-end processing of low-noise amplification, power detection and AD conversion; a single frequency synthesizer is used to perform frequency synthesis on the obtained front-end processing results, including at least multi-modulus frequency division, phase detection, oscillation, low-pass filtering and modulation processing; the transmitter is used to perform frequency conversion processing including at least radio frequency DA conversion, signal attenuation and frequency conversion on the obtained frequency synthesis result, and perform high, middle and low three-terminal output. The system of the present invention can overcome the defects of high cost, high system complexity, poor compatibility and large occupied space in the prior art, so as to realize the advantages of low cost, low system complexity, good compatibility and small occupied space.

Description

Multi-standard fully compatible mobile user terminal chip RF front-end transceiver system

technical field

The invention relates to the technical field of fourth-generation mobile communication, in particular to a radio frequency front-end transceiver system of a multi-standard fully compatible mobile user terminal chip.

Background technique

With the development of smart phones and tablets, the traffic volume of mobile data has increased significantly. Time Division Long Term Evolution (TD-LTE for short) is the fourth-generation LTE jointly developed by Alcatel-Lucent, Nokia Siemens Networks, Datang Telecom, Huawei Technologies, ZTE, and China Mobile. 4G mobile communication technology and standard) improves spectrum utilization, increases transmission rate and capacity of data that can be processed. The success of LTE technology depends on the development of the ecosystem in which it exists, and transceiver technology must evolve at the same or faster rate than the infrastructure implementation is in place.

Due to the expected explosive growth of data usage, operators must effectively use spectrum resources and implement LTE technology with a large number of frequency bands as soon as possible. This is a transceiver design challenge. The Third Generation Partnership Project (3GPP) has responded to this challenge by unifying Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD) technologies. Currently, the wireless communication spectrum (up to 3.8 GHz) is divided into 43 bands, with bands 1 to 33 listed as LTE-FDD, and bands 33 to 43 listed as LTE-TDD.

From a transceiver perspective, the challenges are:

(1) Multi-band: so many LTE frequency bands must require multi-band transceivers;

(2) Multi-mode: In traditional business networks, such as Wideband Code Division Multiple Access (WCDMA for short), EVDO [ie EV-DO, is the abbreviation of three Evolution (evolution) and Data Only, the full name is: CDMA2000 1xEV-DO] Time Division-Synchronous Code Division Multiple Access (TD-SCDMA for short), and Code Division Multiple Access (CDMA for short) and Global System for Mobile Communications (Global System of Mobile Communications) Mobile communication (GSM for short) and other roaming requires multi-mode transceivers;

(3) Dual technology: The dual technology transceiver needs to support both TDD and FDD technologies.

Transceivers in the 0.7 to 2.7 GHz frequency band need to handle both FDD and TDD technologies, as shown in Figure 1, to support the FDD frequency bands of 1-21 and the TDD frequency bands of 33-41. Here, the problem of requiring a large amount of digital computing processing power is solved by distributing the computing load between the baseband processor and the transceiver processor. For example, the transceiver is equipped with an embedded ARM?? processor to reduce the requirements for baseband processing. At the same time, power consumption is reduced, dynamic adjustment capability is improved and response time is accelerated.

In addition to the multi-mode and multi-band requirements, the current multi-functional RF transceiver also needs the following features: low power consumption, small size, standardized baseband interface, flexible RF interface, carrier aggregation capability, and compatibility with 3GPP standards.

China Mobile has begun to support four-band Gaussian Filtered Minimum Shift Keying (GMSK)/General Packet Radio Service (GPRS)/enhanced data rate GSM evolution on mobile phones Technology (Enhanced Data Rate for GSM Evolution, referred to as EDGE) (ie GGE), TD-SCDMA, and TD-LTE standards are expected to start large-scale use in 2012.

In order to compete competitively in this developing market, several technical aspects must be resolved. Band allocation, simultaneous voice and data transmission, Browser Object Model (BOM) cost, and performance metrics must be weighed when considering the best strategy to compete in this market.

While smartphones are the primary target initially for entering the Chinese 4G LTE market, hardware and software development plans also consider other market segments. Considerations also include mature markets like Europe and North America, regional shared emerging markets like India that also focus on TD-LTE, and other hardware like dongles, data cards that don't require voice services product.

These additional factors will affect the design of the hardware and software and must be weighed against the design goals for China Mobile. The extremes of targeting high-end world-class phone platforms, such as chipsets from Qualcomm, Fujitsu and ST Ericsson, which are available in all regions, must be avoided. Chipsets that can efficiently address any and all regions. These chips are not cost-effective as mid-range products. Preliminary market research and technical discussions concluded optimized regional handsets with low cost, high performance, and low current. Features such as envelope tracking DCDC converter, antenna tuning/standing wave compensation circuit and closed-loop power control will differentiate the products and solutions designed.

Figure 2 shows the functional block diagram of the Fujitsu MB86Lxxx series chip system, eight transmitter outputs to drive off-chip power amplifiers, nine main inputs and five secondary inputs to support GSM (GSM850, EGSM900, DCS1800 and PCS1900) WCDMA (band I, II, III, IV, V, VI, VIII, IX, X, and XI), LTE (FDD bands 1, 3, 4, 6, 7, 8, 9, 10, 11, 13, 17, and TDD band 38 or 40).

Although the above solutions claim to be compatible with worldwide industrial standards and mobile phone holders can roam around the world, the main problem of such a design is that the cost is too high and it is not suitable for Mid-range mobile phones, tablet PCs and data cards. There are two main reasons for the high cost. First, due to the large number of RF inputs and outputs (27), the chip package is relatively large (6.5mm x 9.0mm x 1.0mm), and the design is limited by the number of interfaces. Secondly, because of the large number of RF front-end amplifiers, the chip area is relatively large, and the price has no competitive advantage.

Since the market for 2G second-generation mobile phones (see Figure 3) is very mature, considering the reuse of hardware and software, and the time to market, the system solution for mobile phones is to add LTE/3G to the original 2G voice solution. Broadband data function, so mobile phone solutions usually include 6 functional modules: 4G/3G/2G RF front-end transceiver, power amplifier (Power Amplifier), baseband processor (Baseband), application system processor (Application Processor), memory (Memory) and power management module (Power Management Unit). One of the reasons why current multi-standard mobile phones cannot be marketed and promoted on a large scale due to technical problems such as power consumption and performance of multi-standard mobile phones is that the design is not specific and detailed enough, and the performance of the chip is sacrificed in the one-sided pursuit of multi-standard and world-class.

In order to cover all frequency bands of TD-LTE, TD-SCDMA and 4-band GSM (Quad-GSM), in the RF front-end transceiver system of the traditional mobile user terminal chip shown in Figure 4, the receiver front-end must use a surface acoustic filter (SAW filter) to reduce mutual interference between frequency bands, 34, 38, 39 and 40 bands, four bands need four surface acoustic filters, LTE receivers require diversity to improve data rate and sensitivity, so in addition Three SAW filters for the three LTE bands, 38, 39, and 40 bands. In order to be compatible with the 2nd generation of mobile phones (see Figure 3), it is necessary to support the 2-band of the Personal Communications Service (PCS) standard, the 3-band of the Distributed Control System (DCS) standard, and the enhanced global mobile Communication system (Enhanced Global System for Mobile Communications, referred to as EGSM) standard 5-band, and GSM standard 8-band, so the receiver needs 11 surface acoustic filters, a total of 11 receiving inputs.

In the process of realizing the present invention, the inventors found that the prior art at least has defects such as high cost, high system complexity, poor compatibility and large occupied space. the

Contents of the invention

The purpose of the present invention is to solve the above problems and propose a radio frequency front-end transceiver system for multi-standard fully compatible mobile user terminal chips to achieve the advantages of low cost, low system complexity, good compatibility and small footprint.

Another object of the present invention is to propose an application system of a radio frequency front-end transceiver system of a multi-standard fully compatible mobile user terminal chip, that is, at least include a radio frequency front-end system based on the multi-standard fully compatible mobile user terminal chip of the radio frequency front-end transceiver system.

In order to achieve the above object, the technical solution adopted in the present invention is: a radio frequency front-end transceiver system of a multi-standard fully compatible mobile user terminal chip, comprising:

LTE diverse receivers, used to perform at least tracking filtering, frequency mixing, variable gain intermediate frequency and/or low noise amplification, and power detection on radio frequency signals of preset spectrum (such as antenna single-ended receiving frequency is 869-2620MHz) Any variety of front-end processing in AD conversion operation;

A single frequency synthesizer, used for performing front-end processing results based on the front-end processing of the LTE diversified receiver, and performing at least any frequency synthesis including multi-modulus frequency division, phase detection, oscillation, low-pass filtering and modulation operations deal with;

The transmitter is configured to perform any frequency conversion processing including at least radio frequency DA conversion, signal attenuation and frequency conversion operations based on the frequency synthesis result sent by the single frequency synthesizer, and convert the frequency conversion result obtained by frequency conversion processing (such as The high-frequency signal with a frequency of 2300-2620MHz, the intermediate-frequency signal with a frequency of 1880-2025MHz, and the low-frequency signal with a frequency of 824-915MHz) are output from the high-frequency output end, intermediate frequency output end and low-frequency output end respectively.

Further, the LTE diversified receiver includes two signal processing channels arranged in parallel, and a power detector cooperatingly arranged between the two signal processing channels;

Each signal processing channel, including LNA/VGA, mixer, PGA/LPF signal connected in turn, and two ADCs arranged in parallel, and at least Q enhanced and/or Q adjustable signal connected at the output of LNA/VGA tuned tracking filter;

The first output terminals of the two ADCs are respectively used as the diversified quadrature I output terminal RXI_diversity and the diversified quadrature Q output terminal RXQ_diversity of the LTE diversified receiver, or as the quadrature I output terminal of the LTE receiver RXI is connected to the quadrature Q output terminal RXQ of the receiver; the second output terminals of the two ADCs are connected to receive the signal from the frequency synthesizer as the sampling frequency;

The power detector is connected between the output ends of the LNA/VGA in the two signal processing channels; the output end of the power detector is used to output the power detection result.

Further, inside the tracking filter, an on-chip Q value correction unit is provided; the on-chip Q value correction unit includes an LNA, a filtering module, a local oscillator generator, a comparator and a digital correction central controller; wherein :

The output end of the LNA is connected with the input end of the filter module and the first input end of the comparator respectively; the output end of the local oscillator generator is connected with the second input end of the comparator, and the output end of the comparator is connected with the digital correction The input terminal of the central controller is connected, and the output terminal of the digital correction central controller is connected with the control terminal of the filter module.

Further, the frequency synthesizer includes an MMD connected to two ADCs in each signal processing channel, and a receiving local oscillator generator connected to a mixer in each signal processing channel, respectively connected to the MMD and The transmitting local oscillator generator connected to the receiving local oscillator generator, the automatic frequency controller, PFD/CP, and numerically controlled crystal oscillator connected to the transmitting local oscillator generator in turn, and the modulator connected to the automatic frequency controller and PFD/CP respectively .

Further, the transmitter includes an intermediate frequency transmitting unit connected to the 1880-2025MHz radio frequency signal output terminal of the transmitting local oscillator generator, a high frequency transmitting unit connected to the 2300-2620MHz radio frequency signal output terminal of the transmitting local oscillator generator, and A low-frequency transmitting unit connected to the low-frequency radio frequency signal output end of the transmitting local oscillator generator;

The first input end of the high-frequency transmitting unit and the first input end of the intermediate frequency transmitting unit are transmitter orthogonal input terminals TXI; the second input end of the high-frequency transmitting unit and the second input end of the intermediate frequency transmitting unit are Transmitter quadrature input TXQ.

Further, the high-frequency transmitting unit includes two RFDACs arranged in parallel, and a high-band transformer whose primary side is cross-connected to the output ends of the two RFDACs;

The intermediate frequency transmitting unit includes two RFDACs arranged in parallel, and an intermediate band transformer whose primary side is cross-connected to the output ends of the two RFDACs;

The low-frequency transmitting unit includes a power amplifier driver (PAD), and a low-band transformer connected to the output end of the PAD.

Further, each RFDAC is used to receive data whose clock is ClockBB provided by the BBIC, including a DAC and a mixer sequentially connected to the BBIC signal.

Further, each RFDAC unit also includes a digital control unit, and the digital control unit is respectively connected to the DAC and the mixer signal;

In Quad-GSM mode, the digital control unit is used to disconnect the data lines of TD-LTD mode and TD-SCDMA mode by programming, so that the frequency mixing and DA conversion functions of RFDAC are suspended, and only the LOGEN Come to the buffer amplification function of the signal Lop and Lon

At the same time, another technical solution adopted by the present invention is: an application system based on the radio frequency front-end transceiver system of the above-mentioned multi-standard fully compatible mobile user terminal chip, at least including a multi-standard fully compatible mobile user system based on the radio frequency front-end transceiver system RF front-end system of terminal chip;

The radio frequency front-end system of the multi-standard fully compatible mobile user terminal chip includes a baseband processing chip (BBIC), which is connected to the BBIC signal to realize multi-band signal transmission and reception, and is based on the radio frequency integrated circuit of the radio frequency front-end transceiver system ( RFIC), a multi-band power amplifier (PA) connected to the RFIC signal, a high-power RF switch connected to the RFIC and the multi-band PA signal, and an antenna connected to the RFIC and the high-power RF switch signal.

Further, the high-power RF switch includes at least a high-power single-pole 5-throw switch (SP5T); the multi-band PA includes 34 and 49-band PAs, 38 and 40-band PAs connected between RFIC and SP5T in parallel , and 800-900MHz band PA.

The radio frequency front-end transceiver system of the multi-standard fully compatible mobile user terminal chip in each embodiment of the present invention, since the system includes: an LTE diversified receiver, which is used to perform at least tracking filtering, frequency mixing, Front-end processing of variable-gain intermediate frequency and/or low-noise amplification, power detection, and AD conversion; a single frequency synthesizer is used to perform at least multi-modulus frequency division, phase detection, oscillation, and low-pass filtering on the obtained front-end processing results and modulation frequency synthesis processing; the transmitter is used to perform frequency conversion processing including at least radio frequency DA conversion, signal attenuation and frequency conversion on the obtained frequency synthesis results, and perform high, medium and low three-terminal output; it can reduce hardware costs and Encapsulate the interface to reduce the complexity of the system and improve the feasibility of the system; thus it can overcome the defects of high cost, high system complexity, poor compatibility and large occupied space in the prior art to achieve low cost, low system complexity, The advantages of good compatibility and small footprint.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, and are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the attached picture:

Figure 1 is a schematic diagram of frequency spectrum allocation for fourth-generation wireless communications;

Figure 2 is a schematic diagram of the working principle of the Fujitsu MB86Lxxx series chip system;

Figure 3 is a schematic diagram of the working principle of a TD-LTE/TD-SCDMA/2G compatible mobile phone;

4 is a schematic diagram of the working principle of the radio frequency front-end system of the traditional mobile user terminal chip;

5 is a schematic diagram of the working principle of the radio frequency front-end system based on the multi-standard fully compatible mobile user terminal chip of the present invention;

6 is a schematic diagram of the working principle of the radio frequency front-end transceiver system [specifically TD-LTE/TD-SCDMA radio frequency integrated circuit (RFIC) front-end part] based on the multi-standard fully compatible mobile user terminal chip of the present invention;

Figure 7 is a block diagram showing the principle of on-chip RF filter correction;

Figure 7a is the filter waveform of different Q values;

Figure 7b is a block diagram of filter Q value correction;

Figure 7c is a schematic diagram of the electrical principle of a radio frequency digital-to-analog converter (RFDAC);

Figure 7d is a schematic diagram of the electrical principle of RFDAC programmed as a buffer;

Figure 7e is a schematic diagram of the electrical principle of the tracking filter;

Fig. 7f is a schematic diagram of the electrical principle of the tracking filter based on the adjustable Q enhancement in Fig. 7e;

Figure 7g is a schematic diagram of the electrical principle of the Q-enhanced broadband tracking filter based on Figure 7e;

Figure 8 is a schematic diagram of the working principle of the front-end transceiver system of the 34-band and 39-band radio frequency integrated circuits (RFIC) in TD-SCDMA mode;

Figure 9 is a schematic diagram of the working principle of the front-end transceiver system of the 40-band radio frequency integrated circuit (RFIC) in TD-SCDMA mode;

Figure 10 is a schematic diagram of the working principle of the front-end transceiver system of the 38-band radio frequency integrated circuit (RFIC) in TD-LTE mode;

Figure 11 is a schematic diagram of the working principle of the front-end transceiver system of the 39-band radio frequency integrated circuit (RFIC) in TD-LTE mode;

Fig. 12 is a schematic diagram of the working principle of the front-end transceiver system of the radio frequency integrated circuit (RFIC) in the 2, 3, 5, and 8 bands of Quad-GSM mode.

Detailed ways

The preferred embodiments of the present invention will be described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

Embodiment of RF front-end transceiver system

According to the embodiment of the present invention, as shown in Figure 6-Figure 12, a radio frequency front-end transceiver system of a multi-standard fully compatible mobile user terminal chip is provided to realize cost and performance optimized TD-LTE/TD-SCDMA/Quad-GSM radio frequency The front-end system architecture focuses on LTE-TDD frequency bands with relatively concentrated spectrum, from 1850MHz to 2660MHz, and supports TD-SCDMA (3G), LTE-TDD (4G) and mature four-band 2G standards at the same time:

Band 2: 1930~1990MHz RX, 1850-1910MHz TX (PCS);

Band 3: 1805~1880MHz RX, 1710-1785MHz TX (DCS);

Band 5: 869~894MHz RX, 824~849MHz TX (EGSM);

Band 8: 925~960MHz RX, 880~915MHz TX (GSM);

Band 34: 2010~2025MHz (TD-SCDMA);

Band 38: 2570~2620MHz (TD-LTE);

Band 39F: 1880~1900MHz (TD-LTE);

Band 39S: 1900~1920MHz (TD-SCDMA);

Band 40: 2300~2400MHz (TD-SCDMA).

As shown in FIG. 6 , the radio frequency front-end transceiver system of the multi-standard fully compatible mobile user terminal chip in this embodiment includes LTE diversified receivers, frequency synthesizers and transmitters connected in sequence.

Among them, the above-mentioned LTE diversified receiver is used to perform at least tracking filtering, frequency mixing, variable gain intermediate frequency and/or low noise amplification on the radio frequency signal of the preset frequency spectrum (such as the antenna single-ended receiving frequency is 869-2620MHz) , Power detection and AD conversion operations in any variety of front-end processing, and the resulting front-end processing results are sent to a single frequency synthesizer.

It should be noted that the receiver (Receiver) includes two channels, and the structure of the two channels is exactly the same. The above receiver is marked with a divercity (Divercity) logo, which is specially designed to meet the standard requirements of LTE, using diversification and multi-channel to improve data rate and sensitivity. The first module of the receiver part is a low noise amplifier (Low Noise Amplifier, referred to as LNA). While ensuring its own low noise, its gain is consistent with the noise of the back-end module; VGA), used to control the gain of the low-noise amplifier to meet the requirements of the dynamic range of the receiver, that is, the receiver can adjust its gain according to the size of the input signal. Tracking Filter (Tracking Filter) adjusts the center frequency of the filter according to the received channel information, filters out out-of-band interference, and protects the subsequent mixer to work within its linearity range. The power detector senses the filtered signal power and provides signal power information to the baseband processor to configure the receiver. The mixer mixes the frequency signal of the local oscillator generator with the receiving frequency, and converts the received frequency signal into a low-frequency signal. The intermediate frequency programmable gain amplifier (Programmable Gain Amplifier, PGA for short) further amplifies the small signal to the modulus The amplitude the converter can handle while controlling the gain to accommodate varying input signal amplitudes. The Low Pass Filter (LPF for short) further filters out-of-band interference signals at the intermediate frequency to ensure that the signal is within the signal dynamic range that can be processed by the Analog to Digital Converter (ADC for short). The digital-to-analog converter converts the analog signal into a digital signal for processing by a digital baseband processor (Baseband, BB for short).

The above-mentioned single frequency synthesizer is used to carry out the front-end processing results obtained by the front-end processing based on the above-mentioned LTE diversified receiver, and perform at least any frequency synthesis including multi-modulus frequency division, phase detection, oscillation, low-pass filtering and modulation operations processing, and send the resulting frequency synthesis result to the transmitter.

It should be noted that the digitally controlled crystal oscillator (Digital Controlled Controlled Crystal Oscilator Oscillator, referred to as DCXO) uses a more accurate off-chip crystal oscillator, combined with the on-chip oscillator circuit to generate an accurate 26MHz frequency signal as a reference source for the frequency synthesizer, and the Voltage Controlled Oscillator (Voltage Controlled Oscillator) The frequency signal generated by the COntroled Ocsilator (VCO for short) is divided by 2 through the analog remover, and then the 26MHz frequency signal after the Multi-Modulas Divider (MMD) is passed through the Phase Frequency Detector (PFD for short). ) compared with the reference source generated by the numerical control crystal oscillator, their frequency and phase differences are converted into voltage through the voltage pump (Charge Pump, CP) to feed back and adjust the voltage of the voltage-controlled oscillator, thereby outputting a stable and accurate frequency signal, In order to suppress the noise introduced by the digital multi-frequency divider, a loop filter (Loop Filter, LP for short) is added between the voltage pump and the voltage-controlled oscillator. Automatic Frequency Control (Automatic Frequency Control, referred to as AFC), coarsely adjusts the frequency of the voltage-controlled oscillator before locking. The Delta-Sigma modulator (Delat-Sigma Modulator, DSM for short) introduces the modulation signal by adjusting the frequency division multiple of the multimode frequency divider. For GMSK frequency synthesizer direct modulation mode use.

The above transmitter is used to perform frequency synthesis results obtained by performing frequency synthesis processing based on a frequency synthesizer, perform at least any frequency conversion processing including radio frequency DA conversion, signal attenuation, and frequency conversion operations, and convert the frequency conversion results obtained by the frequency conversion processing ( Such as high-frequency signal with a frequency of 2300-2620MHz, intermediate frequency signal with a frequency of 1880-2025MHz, and low-frequency signal with a frequency of 824-915MHz), three-terminal output is performed from the high-frequency output terminal, intermediate frequency output terminal and low-frequency output terminal respectively.

It should be noted that the quadrature I output and Q output of the high, medium, and low bands are summed at the transformer to cancel the image signal. Because of the differential design, the local oscillator leakage is also canceled here. The frequency of the LO quadrature I and Q input signals for the mid-band is 1880MHz to 2025MHz, and the frequency of the LO quadrature I and Q input signals for the high-band is 23000MHz to 2620MHz. In TD-SCDMA, TD-LTEh and EDGE modes, the high-band and mid-band parts receive quadrature input signals TXI and TXQ from the baseband processor respectively, and RFDAC is a radio frequency digital-to-analog converter, which will be described in detail later. In GMSK mode, the modulated signal is directly accessed by the Delta-Sigma modulator of the frequency synthesizer, and the mid-frequency (PCS and DCS band) RFDAC will have a baseband processor programmed as a buffer amplifier, as shown in Figure 7d, while the low-frequency (GSM and EGSM ) The GMSK signal will be directly output by the power amplifier driver.

Specifically, as shown in FIG. 6, the above-mentioned LTE diversified receiver includes two signal processing channels arranged in parallel, and a power detector co-located between the two signal processing channels; each signal processing channel includes sequentially Signal-connected LNA/VGA, mixer, PGA/LPF, and two ADCs arranged in parallel, and at least a Q-enhanced and/or Q-tunable tracking filter signal-connected at the output of the LNA/VGA;

The first output terminals of the two ADCs are respectively used as the diversified quadrature I output terminal RXI_diversity and the diversified quadrature Q output terminal RXQ_diversity of the LTE receiver, or as the quadrature I output terminal RXI and Receiver quadrature Q output RXQ; the second output of the two ADCs is connected to receive the signal from the frequency synthesizer as the sampling frequency; the power detector is connected to the LNA/VGA output in the two signal processing channels Between; the output terminal of the power detector, used to output the power detection result.

In the implementation process of using the above-mentioned LTE diverse receiver as a single-ended input multi-band receiver, since there is no front-end filter, the front-end transconductance stage (Gm) of the low-noise amplifier (LNA) can not only amplify weak signals, At the same time, it cannot be distorted when faced with an out-of-band interference signal (Blocker) with a power as high as 0dBm. For this reason, class AB and class A composite transconductance stages can be used. When the out-of-band interference signal comes, class AB provides more current to ensure no distortion, and class A transconductance stage ensures small signal linearity and sensitivity.

A variable gain amplifier (VGA) is used to ensure the dynamic range of the receiver. The RF filter is located at the output end of the LNA and consists of three parts: the output inductor, the capacitor bank and the negative transconductance. The target frequency band of 1880-2620MHz is more conducive to the realization of a higher Q value on-chip inductor. The frequency is not very high and the inductance value does not need to be too large. So that a large chip area is required, the capacitor bank is used to adjust the target frequency band, and the negative transconductance can increase the overall Q value to more than 20. At the same time, combined with the local oscillator signal passive mixer with a duty cycle of 25% and the subsequent intermediate frequency filter, the overall 20dBc 20MHz out-of-band signal suppression capability can be achieved, which can meet the system index requirements.

As shown in Figure 6, the above-mentioned frequency synthesizer includes the MMD connected with two ADCs in each signal processing channel, the receiving local oscillator generator connected with the mixer in each signal processing channel, respectively connected with MMD and The transmitting local oscillator generator connected to the receiving local oscillator generator, the automatic frequency controller, PFD/CP, and numerically controlled crystal oscillator connected to the transmitting local oscillator generator in turn, and the modulator connected to the automatic frequency controller and PFD/CP respectively .

In the process of using the frequency synthesizer as a single frequency synthesizer, because both TD-LTE and TD-SCDMA are time division duplex (time division duplex TDD) systems, receiving and transmitting are performed in time division (not at the same time), so the receiver and The transmitter can use the same frequency synthesizer, reducing system complexity compared to a dual frequency synthesizer system, and reducing cost due to reduced chip area.

As shown in Figure 6, the above-mentioned transmitter includes an intermediate frequency transmitting unit connected to the 1880-2025MHz radio frequency signal output end of the transmitting local oscillator generator, and a high frequency transmitting unit connected to the 2300-2620MHz radio frequency signal output end of the transmitting local oscillator generator , and a low-frequency transmitting unit connected to the low-frequency radio frequency signal output end of the transmitting local oscillator generator;

The first input terminal of the high frequency transmitting unit and the first input terminal of the intermediate frequency transmitting unit are the orthogonal input terminals TXI of the transmitter; the second input terminal of the high frequency transmitting unit and the second input terminal of the intermediate frequency transmitting unit are the transmitter Quadrature Input TXQ.

The above-mentioned high-frequency transmitting unit includes two RFDACs set in parallel, and a high-band transformer cross-connected between the primary side and the output ends of the two RFDACs; the intermediate frequency transmitting unit includes two RFDACs set in parallel, and the primary side and the two RFDACs A mid-band transformer cross-connected at the output of the output; a low-frequency transmitting unit, including a power amplifier driver (PAD), and a low-band transformer connected to the output of the PAD.

Here, the transmitter can be used as a three-output transmitter, as shown in Figure 5. Due to the requirements for the purity, efficiency and linearity of the transmitter output spectrum, the off-chip is divided into three independent high-frequency, intermediate-frequency and low-frequency channels. The high-frequency B38 and B40, midrange B2, B3, B34 and 39, and low frequency B5 and B8. In the same way, the signal channels in the chip are also divided into independent high-frequency, intermediate-frequency and low-frequency channels, so as to optimize the design separately.

Based on the radio frequency front-end transceiver system of the multi-standard fully compatible mobile user terminal chip shown in FIG. 6 , the radio frequency front-end system of the multi-standard fully compatible mobile user terminal chip as shown in FIG. 5 can be constructed. In Figure 5, a frequency synthesizer is used to optimize the front-end part of the RF front-end transceiver system of the multi-standard fully compatible mobile user terminal chip; for example, it can be compatible with the TD-LTE standard, TD-SCDMA standard and Quad-GSM standard.

Among them, the receiver uses an on-chip correctable and reconfigurable tracking filter, so that the frequency signals of bands 2, 3, 5, 8, 34, 38, 39 and 40 share the same input terminal from 869MHz to 2620MHz. The on-chip Q-enhanced filter selects the signal according to the different receiving frequency bands. Compared with the prior art shown in Figure 2, 11 surface acoustic filters are reduced, thereby reducing the cost; the chip package is reduced 10 receiver input terminals are added, thereby reducing the complexity of the system and improving the feasibility of the system; however, such a receiver needs to face the problems of high linearity and low noise front-end device design and on-chip filtering processing.

Figure 7 can show the calibration process of the on-chip RF filter. The dark module in the figure is the functional module activated during the calibration process. At this time, the front-end module is programmed as an oscillator by increasing the negative transconductance value, and the oscillator frequency and frequency synthesizer After the signal is mixed, the baseband intermediate frequency signal is output, and the frequency is detected by the baseband circuit. The RF filter is set by adjusting the capacitor bank at the front end. After setting, the front-end device leaves the oscillation state and enters the amplification state by reducing the negative transconductance. At this time, the Q value of the RF filter is the highest, and the selectivity of the filter is the best. As shown in Figure 7a, the Q value of the filter can be increased from 3 to about 100.

As shown in Figure 7b, inside the above-mentioned tracking filter (i.e., inside the chip of the tracking filter, Chip Inside), there is an on-chip Q value correction unit; the on-chip Q value correction unit includes a low-noise amplifier (LNA), a filter Module, local oscillator generator (Local Oscilator), comparator and digital correction central controller (Digital Calibration Engine); wherein: the output terminal of LNA is respectively connected to the input terminal of the filter module and the first input terminal of the comparator; The output terminal of the local oscillator generator is connected with the second input terminal of the comparator, the output terminal of the comparator is connected with the input terminal of the digital correction central controller, and the output terminal of the digital correction central controller is connected with the control terminal of the filter module.

In Figure 7b, the Q value of the tracking filter is corrected, and the digital correction engine controls the entire correction process and timing. The correction process includes:

(1) Disconnect the LNA input from the antenna and program the filter as an oscillator by increasing the negative transconductance;

⑵Program the local oscillator (ie local oscillator generator) to the center frequency of the desired frequency band.

Oscillator start-up is detected by a DC bias at the IF output of the mixer.

Decrease the negative transconductance value until the front-end oscillations disappear, and record the negative transconductance value setting.

Add a fixed negative transconductance setting margin to ensure the stability of the front-end amplification and filtering. At this time, the Q value is the best.

As shown in Fig. 7c, each RFDAC is used to receive data whose clock is ClockBB provided by the BBIC, including a DAC and a mixer sequentially connected to the BBIC signal.

Fig. 7c can show the RF-DAC type transmitter circuit that above-mentioned embodiment adopts, use fLO/2 frequency as the sampling frequency of DAC, like this DAC sampling frequency 2 times frequency fLO is output signal, does not need to filter out, can be with transmitting The output signal of the machine is directly superimposed and output, which enhances the output signal power, and the DAC repetition spectrum above 3 times frequency can be selectively filtered out by the RF transformer at the output end because of its high frequency, so that the system does not need a low-pass filter. No current-voltage conversion interface module is required, thereby reducing power consumption and noise compared with traditional transmitters. Due to the digital unit design, multi-unit weighting can drive off-chip power amplifiers, so this system does not require a power amplifier driver (PAD) module.

As shown in Figure 7d, each RFDAC unit also includes a digital control unit, which is respectively connected to the DAC and the mixer signal; in the Quad-GSM mode, the digital control unit is used to program the TD-LTD Mode is disconnected from the data line of TD-SCDMA mode, so that the RFDAC's frequency mixing and DA conversion functions are suspended, and only the buffering and amplification functions of the incoming signals Lop and Lon from LOGEN are realized.

In Quad-GSM mode, in order to meet the strict system noise requirements, and because the signal bandwidth of this mode is narrow at 200KHz, it is more suitable for the baseband signal to directly modulate the frequency synthesizer, so the transmitter in this mode does not need a digital-to-analog converter. In order to share the mid-band (MB) output module and on-chip transformer with other modes, the digital-to-analog converter can be programmed as an output buffer through a digital control unit in a programmable way. The data line used in other modes can be disconnected, and the device of the DAC unit can be connected to a fixed level, such as a high level to the NMOS, so that it is in a conductive state. At this time, the RF-DAC has no mixing and digital-to-analog conversion functions. , only to LOGEN comes the signal Lop and Lon buffer amplification function.

The following are the system block diagrams of various modes. The dark functional modules are the modules that need to be activated in this mode, and the light-colored modules are turned off in this mode to save current. In each mode, the frequency synthesizer generates the frequency signal of the corresponding mode, and all receiving and transmitting related modules are set to the frequency and bandwidth of the mode.

，为M1的跨导。但是，共删设计的缺点是噪声系数（Noise Figure）大于3dB，所以我们采用热噪声取消的设计，增加共源的器件M2，信号从M2删极进入，漏极输出，这样M1的删极热噪声Vn1经由M1的源极在M2的删极相位不变，然而在M2的漏极相位相反，经由级联器件相位不变，输出端OUTn的相位与Vn1相反，同时Vn1经由M1的漏极相位反向，经由级联器件会在输出端OUTp的相位也与Vn1相反，这样M1的删极热噪声Vn1在差分输出端OUTp和OUTn体现为共模噪声，从而抑制抵消。为了使噪声抵消，必须满足： In Figure 7e and Figure 7f, a single-ended input co-deletion amplifier design is adopted, the input is added from the source of the device M1, and the drain is output. Its input impedance matching is broadband, as long as 1/g is satisfied

, is the transconductance of M1. However, the disadvantage of the co-deletion design is that the noise figure (Noise Figure) is greater than 3dB, so we adopt the design of thermal noise cancellation, adding a common source device M2, the signal enters through the gate of M2, and the drain outputs, so that the gate of M1 is hot The noise Vn1 passes through the source of M1, and the phase of the gate of M2 remains unchanged, but the phase of the drain of M2 is opposite, and the phase of the cascaded device remains unchanged. The phase of the output terminal OUTn is opposite to Vn1, and Vn1 passes through the phase of the drain of M1. In the reverse direction, the phase of the output terminal OUTp is also opposite to that of Vn1 through cascaded devices, so that the gate thermal noise Vn1 of M1 is reflected as common-mode noise at the differential output terminals OUTp and OUTn, thereby suppressing cancellation. In order for noise to cancel, it must be satisfied:

；

;

和

为输入器件M1和M2的跨导值，

和

为电感L1和L2在工作频率f0的有效阻抗。这样，该低噪声放大器的噪声系数可以表达为：

and

is the transconductance value of the input devices M1 and M2,

and

is the effective impedance of the inductors L1 and L2 at the operating frequency f0. Thus, the noise figure of this LNA can be expressed as:

；

;

为器件通道热噪声系数。为了减小对NF的影响，设计>

,同时

>。这样同时实现了抑制噪声和单端输入到差分输出的转换。 in,

is the thermal noise coefficient of the device channel. to reduce Effects on NF, Design >

,at the same time

> . This achieves simultaneous noise rejection and single-ended input to differential output conversion.

The Peak Detector is used to detect the size of the input signal. Since it is connected to the input without frequency selectivity, it can sense the large signal out of the band. When the interference signal exceeds the threshold, more input devices are connected. M1 and M2 (as shown by the dotted line), reduce their DC bias to make them work in class AB mode instead of the usual class A mode. AB mode is current mode. When the signal is too large, the voltage domain is affected by the power supply voltage. When there is no space for the limit, the current mode is used to keep the signal from saturating.

为调节的频率，

为电感的寄生电阻。Q值接近3，对带外干扰没有太多的抑制效果，所有我们使用

值增强技术，如图7e右边所示，使用负跨导产生

与输出腔有效阻抗Rp并联，因为： In addition, the output inductor is connected to the capacitor bank in parallel, and adjusted according to the control signal Band for different frequency bands, so that the output terminal has frequency selectivity and filters out-of-band interference. Since the quality factor of the on-chip inductor is not high, usually the Q value is in the 10. When increasing the capacitor value to set the system to a low frequency band, the effective Q value is the lowest, because ,in

for the tuned frequency,

is the parasitic resistance of the inductor. The Q value is close to 3, and there is not much suppression effect on out-of-band interference, so we use

The value enhancement technique, shown on the right in Figure 7e, uses negative transconductance to generate

in parallel with the effective impedance Rp of the output cavity because:

；

;

值增加到1/Rp时，

的理论值为无穷大，会使这个放大器开始振荡。 when

When the value increases to 1/Rp, the

The theoretical value of is infinite, causing this amplifier to start oscillating.

值都不同，如图9所示，我们设计可数字编程控制的-

模块，根据不同的频段，设置不同的-

值，使Q值最大化，而不振荡。因为， Because, different frequency bands are required-

The values are all different, as shown in Figure 9, we design a digitally programmable control-

Module, according to different frequency bands, set different-

value, to maximize the Q value without oscillation. because,

；

;

So the lowest frequency band has the smallest Rp value, so the largest value.

In Figure 7g, two measures are used to deal with out-of-band large signal interference. First, the peak detector and CLASS AB current domain design are used to prevent the amplifier from being saturated. As shown in the right part, after the peak detector alarms, the control signal Bias_BLK is used. and BLK to set class AB mode. At this time, due to the large signal mode and the large current, the impedance matching of the input is no longer important. Secondly, the received signal is selected through the Q-enhanced output LC cavity, and the interference signal is filtered out so that it cannot enter the next module, the down-conversion mixer:

。

.

The radio frequency front-end transceiver system of the multi-standard fully compatible mobile user terminal chip of the above embodiment, in view of the problems and deficiencies of the traditional low noise amplifier, adopts a single-ended input, uses a single inductor, meets the noise performance, and can filter out-of-band large Signal, broadband amplifier covering TD-LTE, TD-SCDMA and quad-band GSM.

Figure 8-12 are the system block diagrams of various modes. The dark functional modules are the modules that need to be activated in this mode, and the light-colored modules are turned off in the eating mode to save current. In each mode, the frequency synthesizer generates the frequency signal of the corresponding mode, and all receiving and transmitting related modules are set to the frequency and bandwidth of the mode.

In Figure 8, the bands involved include:

Band 34: 2010~2025MHz (TD-SCDMA);

Band 39 S: 1900~1920MHz (TD-SCDMA).

In Figure 9, the bands involved include:

Band 40: 2300~2400MHz (TD-SCDMA).

In Figure 10, the bands involved include:

Band 38: 2570~2620MHz (TD-LTE).

In Figure 11, the bands involved include:

Band 39 F: 1880~1900MHz (TD-LTE).

In Figure 12, the bands involved include:

Band 2: 1930~1990MHz RX, 1850-1910MHz TX (PCS);

Band 3: 1805~1880MHz RX, 1710-1785MHz TX (DCS);

Band 5: 869~894MHz RX, 824~849MHz TX (EGSM);

Band 8: 925~960MHz RX, 880~915MHz TX (GSM).

In Quad-GSM mode, in order to meet the strict system noise requirements, and because the signal bandwidth of this mode is narrow at 200KHz, it is more suitable for the baseband signal to directly modulate the frequency synthesizer, so the transmitter in this mode does not need a digital-to-analog converter. In order to share the mid-band (MB) output module and on-chip transformer with other modes, the digital-to-analog converter can be programmed as an output buffer through a digital control unit in a programmable way. As shown in Figure 7d, disconnect the data lines used in other modes, and connect the device of the DAC unit to a fixed level, such as a high level to NMOS, so that it is in a conducting state. At this time, the RF-DAC does not mix And the digital-to-analog conversion function, only the buffer amplification function of the signal Lop and Lon coming to LOGEN.

The radio frequency front-end transceiver system of the multi-standard fully compatible mobile user terminal chip of the above embodiment, in view of the problems and deficiencies of the traditional low noise amplifier, adopts a single-ended input, uses a single inductor, meets the noise performance, and can filter out-of-band large Signal, broadband amplifier covering TD-LTE, TD-SCDMA and quad-band GSM.

The radio frequency front-end transceiver system of the multi-standard fully compatible mobile user terminal chip of the present invention in the above-mentioned embodiments can at least achieve the following beneficial effects:

⑴ Less off-chip components are required to reduce system cost;

⑵ Fewer chip pins, reducing system complexity and cost;

⑶Individualized, dedicated TD design, optimized performance, single frequency synthesizer solution, reducing cost and complexity;

⑷Receiver front-end on-site calibration improves performance;

⑸The system solution is compatible with the existing 2G system, shortening the time to market.

Application system (i.e. RF front-end system) embodiment of the RF front-end transceiver system

Based on the embodiment of the radio frequency front-end transceiver system, this embodiment provides one of the application systems based on the radio frequency front-end transceiver system, that is, a radio frequency front-end system based on a multi-standard fully compatible mobile user terminal chip based on the radio frequency front-end transceiver system.

As shown in Figure 5, the radio frequency front-end system of the multi-standard fully compatible mobile user terminal chip of the present embodiment includes BBIC, is connected with BBIC signal, is used to realize multi-band signal transmission and reception, and is based on the radio frequency integrated circuit (RFIC) of the radio frequency front-end transceiver system , a multi-band power amplifier PA connected to the RFIC signal, a high-power RF switch connected to the RFIC and the multi-band PA signal, and an antenna connected to the RFIC and the high-power RF switch signal.

Here, the above-mentioned high-power RF switch includes at least a high-power single-pole 5-throw switch SP5T; multi-band PA, including 34 and 49 band PAs, 38 and 40 band PAs, and 800-900MHz bands connected between RFIC and SP5T in parallel pa.

In Figure 5, a single frequency synthesizer is used to optimize the front-end part of the RF front-end system of the multi-standard fully compatible mobile user terminal chip; for example, it can be compatible with the TD-LTE standard, TD-SCDMA standard and Quad-GSM standard.

Among them, the receiver uses an on-chip correctable and reconfigurable tracking filter, so that the frequency signals of bands 2, 3, 5, 8, 34, 38, 39 and 40 share the same input terminal from 869MHz to 2620MHz. The on-chip Q-enhanced filter selects the signal according to the different receiving frequency bands. Compared with the prior art shown in Figure 4, 11 surface acoustic filters are reduced, thereby reducing the cost; the chip package is reduced 10 receiver input terminals are added, thereby reducing the complexity of the system and improving the feasibility of the system; however, such a receiver needs to face the problems of high linearity and low noise front-end device design and on-chip filtering processing.

In Figure 5, the device names and models used include:

34, 49 band power amplifier (B34, B39 PA; Skyworks SKY77712);

38, 40 band power amplifier (B38, B40PA; Skyworks SKY77441);

800-900MHz high linear power amplifier (B5, B8 PA; Skyworks SKY65126-21);

High-Power Single Pole Five Throw Switch (High-Power Single Pole Five Throw, SP5T; Skyworks, SKY13415-485LF);

LTE baseband chip (BBIC, TD-LTE/TD-SCDMA/GSM Baseband Modem, Spreadtrum, SC9610);

Band 2: 1930~1990MHz RX, 1850-1910MHz TX (PCS);

Band 3: 1805~1880MHz RX, 1710-1785MHz TX (DCS);

Band 5: 869~894MHz RX, 824~849MHz TX (EGSM);

Band 8: 925~960MHz RX, 880~915MHz TX (GSM);

Band 34: 2010~2025MHz (TD-SCDMA);

Band 38: 2570~2620MHz (TD-LTE);

Band 39 F: 1880~1900MHz (TD-LTE);

Band 39 S: 1900~1920MHz (TD-SCDMA);

Band 40: 2300~2400MHz (TD-SCDMA).

In the above RF front-end system embodiment, for the internal structure and performance of the RFIC, refer to FIG. 6-FIG. 12 and related descriptions of the embodiment of the RF front-end transceiver system, which will not be repeated here.

Finally, it should be noted that: the above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, it still The technical solutions recorded in the foregoing embodiments may be modified, or some technical features thereof may be equivalently replaced. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention. the

Claims (10)

1. The radio frequency front-end transceiver system of a multi-standard fully compatible mobile user terminal chip is characterized in that it includes: The LTE diverse receiver is used to perform any variety of front-end processing at least including tracking filtering, frequency mixing, variable gain intermediate frequency and/or low noise amplification, power detection and AD conversion operations on the radio frequency signal of the preset spectrum; A single frequency synthesizer, used for performing front-end processing results based on the front-end processing of the LTE diversified receiver, and performing at least any frequency synthesis including multi-modulus frequency division, phase detection, oscillation, low-pass filtering and modulation operations deal with; The transmitter is used to perform frequency synthesis results obtained by frequency synthesis processing based on the single frequency synthesizer, perform at least any frequency conversion processing including radio frequency DA conversion, signal attenuation, and frequency conversion operations, and convert the obtained frequency The frequency conversion results are output from the high-frequency output terminal, the intermediate frequency output terminal and the low-frequency output terminal respectively. 2. the radio frequency front-end transceiver system of multi-standard fully compatible mobile user terminal chip according to claim 1, is characterized in that, described LTE diversification receiver, comprises two signal processing passages that are arranged in parallel and cooperates to be arranged in the a power detector between the two signal processing channels; Each signal processing channel, including LNA/VGA, mixer, PGA/LPF signal connected in turn, and two ADCs arranged in parallel, and at least Q enhanced and/or Q adjustable signal connected at the output of LNA/VGA tuned tracking filter; The first output terminals of the two ADCs are respectively used as the diversified quadrature I output terminal RXI_diversity and the diversified quadrature Q output terminal RXQ_diversity of the LTE diversified receiver, or as the quadrature I output terminal of the LTE receiver IRXI is connected to the quadrature Q output terminal RXQ of the receiver; the second output terminals of the two ADCs are connected to receive the signal from the frequency synthesizer as the sampling frequency; The power detector is connected between the output ends of the LNA/VGA in the two signal processing channels; the output end of the power detector is used to output the power detection result. 3. the radio frequency front-end transceiver system of multi-standard fully compatible mobile user terminal chip according to claim 2, is characterized in that, in described tracking filter inside, be provided with on-chip Q value correcting unit; Described on-chip Q value Correction unit, including LNA, filter module, local oscillator generator, comparator and digital correction central controller; where: The output end of the LNA is connected with the input end of the filter module and the first input end of the comparator respectively; the output end of the local oscillator generator is connected with the second input end of the comparator, and the output end of the comparator is connected with the digital correction The input terminal of the central controller is connected, and the output terminal of the digital correction central controller is connected with the control terminal of the filter module. 4. the radio frequency front-end transceiver system of multi-standard fully compatible mobile user terminal chip according to claim 1, is characterized in that, described single frequency synthesizer comprises the MMD that is connected with two ADCs in each signal processing channel, A receiving local oscillator generator connected to the mixer in each signal processing channel, a transmitting local oscillator generator connected to the MMD and the receiving local oscillator generator respectively, and an automatic frequency control connected to the transmitting local oscillator generator in turn device, PFD/CP, and digitally controlled crystal oscillator, and a modulator connected to the automatic frequency controller and PFD/CP respectively. 5. the radio frequency front-end transceiver system of multi-standard fully compatible mobile user terminal chip according to claim 4, it is characterized in that, described transmitter comprises the intermediate frequency transmitter that is connected with the 1880-2025MHz radio frequency signal output end of transmitter local oscillator generator A unit, a high-frequency transmitting unit connected to the 2300-2620MHz radio frequency signal output of the transmitting local oscillator generator, and a low-frequency transmitting unit connected to the low-frequency radio frequency signal output of the transmitting local oscillator generator; The first input end of the high-frequency transmitting unit and the first input end of the intermediate frequency transmitting unit are transmitter orthogonal input terminals TXI; the second input end of the high-frequency transmitting unit and the second input end of the intermediate frequency transmitting unit are Transmitter quadrature input TXQ. 6. the radio frequency front-end transceiver system of multi-standard fully compatible mobile user terminal chip according to claim 5, it is characterized in that, described high-frequency transmission unit comprises two RFDACs that are arranged in parallel, and primary side and described two A high-band transformer cross-connected at the output of the RFDAC; The intermediate frequency transmitting unit includes two RFDACs arranged in parallel, and an intermediate band transformer whose primary side is cross-connected to the output ends of the two RFDACs; The low-frequency transmitting unit includes a power amplifier driver PAD, and a low-band transformer connected to the output end of the PAD. 7. the radio frequency front-end transceiver system of multi-standard fully compatible mobile user terminal chip according to claim 6, is characterized in that, each RFDAC is used to receive the data that the clock provided by BBIC is ClockBB, comprises connecting with BBIC signal successively DAC and mixer. 8. the radio frequency front-end transceiver system of multi-standard fully compatible mobile user terminal chip according to claim 7, is characterized in that, each RFDAC unit also comprises digital control unit, and described digital control unit is connected with DAC and mixer signal respectively connect; In Quad-GSM mode, the digital control unit is used to disconnect the data lines of TD-LTD mode and TD-SCDMA mode by programming, so that the frequency mixing and DA conversion functions of RFDAC are suspended, and only the LOGEN Coming to the buffer amplification function of the signals Lop and Lon. 9. Based on the application system of the radio frequency front-end transceiver system of the multi-standard fully compatible mobile user terminal chip according to claim 1, it is characterized in that at least comprising the radio frequency front-end system of the multi-standard fully compatible mobile user terminal chip; The radio frequency front-end system of the multi-standard fully compatible mobile user terminal chip includes a baseband processing chip BBIC, which is connected to the BBIC signal to realize multi-band signal transmission and reception, and is based on the radio frequency integrated circuit RFIC of the radio frequency front-end transceiver system, respectively A multi-band power amplifier PA connected to the RFIC signal, a high-power RF switch connected to the RFIC and the multi-band PA signal respectively, and an antenna connected to the RFIC and the high-power RF switch signal respectively. 10. The application system of the RF front-end transceiver system of the multi-standard fully compatible mobile user terminal chip according to claim 9, wherein the high-power RF switch at least includes a high-power single-pole 5-throw switch SP5T; Band PAs, including 34 and 49 band PAs, 38 and 40 band PAs, and 800-900MHz band PAs with parallel signal connections between RFIC and SP5T.

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