CN113890559B - Two architectures of multi-mode reconfigurable ultra-wideband integrated transceiver and transmitter - Google Patents

Abstract

The invention provides a multi-mode reconfigurable ultra-wideband integrated transceiver for realizing time difference ranging, frequency difference ranging, phase difference ranging and wireless communication based on a sub-module integrated technology, and provides two realizable innovative transmitter architectures. The multiplexing degree of the integrated transceiver exceeds 90%, the resolution is higher than that of the existing transceiver, and the impasse that the resolution of the traditional transceiver is low is broken. The purpose is to realize the functions of two chips of communication and radar by the area and power consumption of one chip through the common-framework integrated design of the submodules. The two innovative transmitter structures replace relaxation oscillators with simple digital modules, so that the power consumption is greatly reduced, and the reusability is high. The low-power-consumption design based on current multiplexing enables the invention to be applied to ultra-low power-consumption scenes, innovatively breaks through the advantage of low resolution of the traditional transceiver, and enables the invention to be applied to high-resolution scenes.

Description

Two Architectures for a Multimode Reconfigurable Ultra-Wideband Integrated Transceiver and Transmitter

technical field

The present invention proposes a multi-mode reconfigurable ultra-wideband integrated transceiver based on sub-module integration technology to realize time difference ranging, frequency difference ranging, phase difference ranging and wireless communication, and proposes two achievable transmitting machine architecture, and all have the advantages of low cost and low power consumption, and belong to the field of wireless communication technology and radar ranging technology.

Background technique

In recent years, UWB FM technology has been widely used in the medical field at home and abroad, and the combination of medical care and communication has become closer. People have begun to shift their attention to wireless body area networks and wireless personal networks. Systems such as wireless body area network and wireless personal network require wireless communication transceivers, and require them to have low power consumption, short distance, and low cost characteristics, but do not require data rates. Electronic systems such as non-contact heart rate/respiration measurement require high-resolution, penetrating, low-emission radar ranging transceivers. Compared with commonly used narrowband technologies such as Bluetooth, the application of ultra-wideband technology can use a simpler transceiver architecture to achieve lower power consumption and achieve higher ranging resolution.

In terms of ranging resolution, narrowband technology is far inferior to ultra-wideband; in terms of transceiver architecture, power consumption and cost comparison, ultra-wideband is superior to narrowband; in terms of system integration, only ultra-wideband technology can simultaneously realize radar ranging and Wireless communication. Therefore, the development of integrated transceiver chips can only use ultra-wideband technology. Among the many existing UWB implementation schemes, the UWB FM scheme has many advantages (no need for RF synchronization, simple transceiver architecture, greatly reduced transceiver architecture complexity, loose phase noise and antenna requirements, etc.), making it Become a favored short-range, low-power, low-cost technology. Considering the low power consumption, low cost, and low radiation characteristics required by the special environment of the human body, ultra-wideband frequency modulation technology is the first choice to build communication and radar integrated transceivers. This is the technical background of the present invention. And frequency modulation continuous wave radar ranging integrated transceiver.

Contents of the invention

Both the ultra-wideband frequency modulation wireless communication transceiver and the frequency modulation continuous wave radar transceiver are based on radio frequency modulation technology to obtain ultra-wideband signals. First discuss the UWB FM wireless communication transceiver. Its transmitter adopts dual-frequency modulation technology: analog 2-frequency shift keying modulation and radio frequency frequency modulation; baseband data 0 and 1 are converted into analog triangular wave sequences with frequencies f ₁ and f ₂ respectively through analog 2-frequency shift keying modulation, This process is called 2-frequency shift keying triangular wave (subcarrier) generation; then the analog triangular wave is sent to the voltage control terminal of the RF voltage-controlled oscillator, and under the control of the amplitude-frequency conversion gain of the voltage-controlled oscillator, the RF Frequency modulation to obtain ultra-wideband signals, this process is called radio frequency frequency modulation; in order to correct the center frequency of the voltage-controlled oscillator, a center frequency correction circuit is introduced. The receiver uses dual-frequency demodulation technology: broadband radio frequency FM demodulation and frequency shift keying demodulation; the ultra-wideband signal recovers the analog frequency shift keying triangular wave information through the broadband radio frequency discriminator (slope frequency discrimination or phase frequency discrimination). The frequency f ₁ of the analog signal demodulated at the time represents the baseband data 0, and f ₂ represents the baseband data 1. This process is called broadband FM demodulation, and it does not require radio frequency carrier, let alone carrier synchronization; the subsequent frequency shift keying demodulation The converter reconstructs the digital baseband 0 and 1 data from the recovered analog IF FSK triangle wave.

Discuss the frequency modulation continuous wave radar transceiver again. Its transmitter adopts ultra-wideband radio frequency frequency modulation technology: under the control of the amplitude-frequency conversion gain of the voltage-controlled oscillator, or by controlling the fractional frequency division ratio of the fractional frequency-division phase-locked loop, the instantaneous frequency is linear with the amplitude of the fixed-frequency triangular wave. Varying UWB signals. The ranging principle of the FM continuous wave receiver is based on radio frequency difference technology: the down-mixer combines the instantaneous frequency of the local oscillator (transmitter) FM continuous wave signal with the ultra-wideband signal of the receiver (that is, the ultra-wideband signal of the transmitter after space transmission delay). Broadband signal) as the difference frequency, the difference frequency is just proportional to the space transmission time (ranging distance); the subsequent processing of analog filter, analog-to-digital converter, Fourier transform, etc., is to extract the difference frequency and Convert to distance data.

The structure of the existing ultra-wideband frequency modulation wireless communication and frequency modulation continuous wave radar ranging integrated transceiver is shown in Figure 1. Its wireless communication part is based on phase frequency discrimination (delay multiplication structure), which leads to complex implementation of the receiver and high power consumption; its radar part is based on radio frequency difference ranging mode, and the ranging resolution is limited by the radio frequency bandwidth, which satisfies the formula c/2BW, where c is the speed of light, and BW is the radio frequency bandwidth; that is to say, if you want to obtain centimeter-level ranging resolution, the radio frequency bandwidth must be at least 5GHz, which undoubtedly brings huge challenges to the low power consumption and low cost realization of radar transceivers. challenge.

The purpose of the present invention is to realize the integrated design of the common architecture by combining the ultra-wideband frequency modulation transceiver and the frequency modulation continuous wave radar, so that the transceiver system has the functions of time difference ranging, frequency difference ranging, phase difference ranging and wireless communication, and breaks the It overcomes the deadlock that the ranging resolution of traditional transceivers is limited by the radio frequency bandwidth. Under the same 500MHz bandwidth, the traditional transceiver achieves decimeter-level resolution, while the integrated transceiver designed by the present invention achieves millimeter-level resolution, and while achieving high resolution, it also adopts multi-module integration to achieve The method greatly reduces power consumption and cost, achieves a multiplexing degree of more than 90%, and can realize the functions of time difference ranging, frequency difference ranging, phase difference ranging and wireless communication.

The architecture of the integrated transceiver designed in the present invention is shown in FIG. 2 . The ultra-wideband FM transceiver proposed by the present invention includes two parts: a transmitter and a receiver. Transmitter includes relaxation oscillator, three-stage ring voltage-controlled oscillator, single-stage push-pull power amplifier, successive approximation frequency automatic correction and other modules; receiver includes low-noise amplifier, band-pass filter, envelope detector, etc. module. The low-noise amplifier and band-pass filter in the receiver realize the common architecture design based on the radio frequency current multiplexing method, which greatly reduces the circuit power consumption and design cost.

The transmitter adopts the method of radio frequency voltage-controlled oscillator frequency modulation and ultra-wideband frequency band center frequency correction; the receiver introduces differential slope frequency discrimination, and is based on the intermediate frequency time-difference ranging mechanism; this is not only conducive to the high compatibility of communication and radar, but also greatly reduces Design complexity and system power consumption, and improved ranging resolution. First, the IF time-of-flight ranging mechanism converts the time delay between sending and receiving RF ultra-wideband signals into the time delay between sending and receiving IF subcarrier signals. As shown in Figure 3, the ranging resolution is no longer limited by the RF bandwidth, but only by the The processing accuracy of the time-to-digital converter itself enables millimeter resolution. Secondly, the radio frequency discriminator is converted from a delay multiplication or regenerative structure to a differential slope frequency discrimination structure, which reduces the power consumption and cost of the receiver and improves the linearity of frequency discrimination.

The slew rate controlled relaxation oscillator generates 2-frequency shift keying frequency or fixed frequency analog triangle wave signal and receiver local oscillator IF signal; the low-cost, low-power dual-channel ring voltage-controlled oscillator realizes the RF Frequency modulation; successive approximation type automatic frequency correction loop of intermittent operation Single-pole multi-throw type simultaneously corrects the center oscillation frequency of the triangular wave generator and the ring voltage-controlled oscillator. The slope discriminator based on differential bandpass filter and envelope detection realizes the demodulation of UWB signal and recovers the information of intermediate frequency triangular wave; the subsequent digital frequency shift keying demodulator based on energy detection recovers the baseband of transmission data, or a subsequent time-to-digital converter based on IF time-delayed sampling decisions yields multi-bit range data. In order to be compatible with the three ranging modes of time difference, frequency difference, and phase difference, an additional mixer is added, and the off-chip Fourier transform processing module is used to construct the frequency difference ranging mode; then the two-channel frequency difference ranging can be used by time A digitizer-type phase detector constitutes a phase difference ranging mode.

By comparing the ultra-wideband frequency modulation wireless communication transceiver proposed by the present invention, the intermediate frequency time difference frequency modulation continuous wave radar transceiver, and the radio frequency frequency difference frequency modulation continuous wave radar transceiver structure, it is not difficult to find that: the radio frequency high current modules of the three (including power amplifier, low-noise amplifier, RF discriminator, ring voltage-controlled oscillator), frequency correction loop, and medium and low frequency modules (including intermediate frequency amplifier, subtractor, bandgap reference source, crystal oscillator, serial peripheral interface controller, etc. ), can be multiplexed completely; even the intermediate frequency analog triangular wave generator can also be multiplexed (the difference between 2-frequency shift keying frequency modulation and fixed frequency); except for low-power and low-cost passive mixers, only digital The frequency shift keying demodulator, time-to-digital converter and Fourier transform need to be switched in parallel, or cannot be multiplexed. Therefore, the proposed ultra-wideband FM wireless communication transceiver and multi-mode FM continuous wave radar transceiver have a multiplexing degree of more than 90% in terms of structure and circuit implementation; the integrated design of the common architecture can be carried out. The area and power consumption realize the functions of two chips of communication and radar.

The ranging mechanism based on intermediate frequency time difference not only gets rid of the dilemma of pulse radio ultra-wideband and traditional FM continuous wave transceivers limited by radio frequency bandwidth, but also gets rid of the existing high-precision (or phase difference) FM continuous wave radar that cannot be realized The lack of wide-range linear phase tracking and low power consumption performance is only limited by the accuracy of the time-to-digital converter itself, and the optimized design of a single intermediate frequency digital time-to-digital converter can compare with the bandwidth expansion and power of several RF high-current modules. The power consumption optimization design is too simple; under the same 500MHz bandwidth, the traditional or existing type can achieve decimeter-level resolution and 10mW power consumption, while the proposed type can achieve millimeter-level resolution and 2mW power consumption, and the resolution is increased by two orders of magnitude. 5x lower power consumption and cost.

While the integrated transceiver designed in the present invention can realize time difference ranging and frequency difference ranging, the function of phase difference ranging can also be realized by using two or more groups of integrated transceiver structures, which can be measured by two-channel frequency difference, A phase difference ranging mode is formed by means of a time-to-digital converter type phase detector. Therefore, the integrated transceiver designed in the present invention realizes millimeter-level resolution, and while achieving high resolution, it also adopts the method of multi-module integration, which greatly reduces power consumption and cost, reaching more than 90%. degree of reuse. Fig. 4 is a timing diagram of a multi-mode high-multiplexing reconfigurable ultra-wideband integrated transceiver operating in a wireless communication mode according to the present invention, wherein the transmitted data changes between 0 and 1, and the relaxation oscillator outputs The frequency of the signal also changes accordingly, and the recovered data after demodulation by the receiver is still the same as the transmitted data even after a delay. FIG. 5 is a sequence diagram of a multi-mode high multiplexing reconfigurable ultra-wideband integrated transceiver working in a ranging mode according to the present invention. There is a delay between the transmitted signal and the received signal. This delay is the time Δt for the signal to propagate in space from transmission to reception. This time information can be converted into distance information by a time-to-digital converter. This can realize time difference ranging function. Send the ultra-wideband signal transmitted by the transmitter and the ultra-wideband signal received by the receiver into the mixer to obtain the frequency difference, and then realize the frequency difference ranging function through off-chip Fourier transform. By using two or more sets of integrated transceiver structures, the phase difference ranging mode can also be formed by means of a time-to-digital converter type phase detector by two-channel frequency difference ranging.

The present invention also proposes a transmitter architecture, as shown in FIG. 6 . The transmitter includes two modes, namely: mode "1" correction and mode "2" work. In the calibration mode, input 25 (6b'011001) into the digitally controlled oscillator, and control the output frequency F _VCO of the digitally controlled oscillator to be a sine wave signal around 4GHz (the output signal will fluctuate around 4GHz, in order to The follow-up calibration module is required only when it is stable at 4GHz), at this time, the N ₁ /N ₂ frequency divider (N ₁ is 36; N ₂ is 40) works in the 40 frequency division mode, and the sine wave signal around 4GHz passes through the 40 frequency divider The frequency is divided into a square wave signal of about 100MHz, and the square wave signal of about 100MHz is input into the frequency discriminator based on the digital counter as the high-frequency input clock of the frequency discriminator, and F _REF (1MHz) is used as the low-frequency input clock of the frequency discriminator , count the high-frequency clock in a low-frequency clock, if the output frequency of the digitally controlled oscillator is a sine wave signal less than 4GHz, then F _REF (1MHz) counts the square wave with a frequency less than 100MHz and the result is less than 100 (F _VCO /F _REF ＝100), if the output frequency of the digital control oscillator is a sine wave signal greater than 4GHz, then F _REF (1MHz) counts square waves with a frequency greater than 100MHz and the result is greater than 100 (F _VCO /F _REF ＝100) . Since the counter needs to output a result equivalent to about 100, and due to the influence of temperature, process, and power supply voltage, the frequency of the oscillator will fluctuate by 20%-30%, and the result of F _VCO /F _REF will be based on 100 For 20%-30% fluctuations, the counter needs to leave a certain margin so that the frequency discrimination effect can also be achieved in the case of fluctuations, so an 8-bit counter is required. The UP/DN signal is controlled by comparing the output of the 8-bit counter with the built-in 100 of the discriminator to further control the 6-bit output of the digital successive approximation register, so as to achieve the correction of the frequency of the digital controlled oscillator at 4GHz. the goal of. The working mode of the integrated transceiver is divided into radar working mode and communication working mode according to the specific functions it wants to realize. In the radar working mode, the 6-bit digital bidirectional counter increases from 0 to 50 and then decreases from 50 to 0, and the trapezoidal wave generator generates a 6-bit output, which is equivalent to a trapezoidal wave form with a frequency of 1MHz (100MHz/1MHz =100, 100/2=50, so in order to generate a trapezoidal wave with a frequency of 1MHz, a 6-bit counter is required), at this time the N ₁ /N ₂ frequency divider (N ₁ is 36; N ₂ is 40) works In the 40-frequency division mode, the output signal of the oscillator with a center frequency of 4GHz is frequency-divided into a clock signal with a frequency jittering around 100MHz to control the trapezoidal wave generator based on a digital two-way counter. The 6-bit output of the trapezoidal wave generator controls the oscillator to generate a sine wave whose center frequency is 4GHz and whose frequency varies between 3.75GHz and 4.25GHz (the frequency of the sine wave signal frequency is affected by the fixed frequency of the trapezoidal wave generator and remains constant ). The output signal of the digitally controlled oscillator is transmitted through the push-pull power amplifier and then through the antenna. After a series of subsequent processing, the ranging function is finally realized, and the multi-mode functions of time difference ranging, frequency difference ranging, and phase difference ranging can be realized. In the communication working mode, when the transmitted data is 0, the N ₁ /N ₂ frequency divider (N ₁ is 36; N ₂ is 40) works in the 40 frequency division mode, which divides the output signal of the oscillator with a center frequency of 4GHz The frequency is a clock signal with a jitter frequency of about 100MHz to control the trapezoidal wave generator based on the digital two-way counter. The 6-bit digital bidirectional counter increases from 0 to 50 and then decreases from 50 to 0. The trapezoidal wave generator generates a 6-bit output, which is equivalent to a trapezoidal wave form with a frequency of 1MHz; when the transmitted data is 1, N ₁ The /N ₂ frequency divider (N ₁ is 36; N ₂ is 40) works in 36 frequency division mode, divides the output signal of the oscillator with a center frequency of 4GHz into a clock signal with a frequency of jitter around 110MHz, to control the digital based Trapezoidal generator for bi-directional counters. The 6-bit digital bidirectional counter increases from 0 to 50 and then decreases from 50 to 0. The trapezoidal wave generator generates a 6-bit output, which is equivalent to a trapezoidal wave with a frequency of 1.1MHz. To sum up, in the communication working mode, the trapezoidal wave generator based on the digital two-way counter generates a 6-bit output, which is equivalent to a trapezoidal wave whose frequency switches back and forth between 1MHz and 1.1MHz. The 6-bit output controlled oscillator generates a sine wave with a center frequency of 4 GHz and a frequency varying between 3.75 GHz and 4.25 GHz (the frequency of the sine wave signal frequency is affected by the changing frequency of the trapezoidal wave generator). Finally, the output signal of the digitally controlled oscillator is transmitted through the push-pull power amplifier and then transmitted through the antenna, and then connected to the receiver to receive the signal and finally realize the communication function.

The multi-mode high multiplexing reconfigurable ultra-wideband integrated transceiver described in the present invention not only proposes a transmitter architecture, but also proposes a highly multiplexed transmitter architecture based on this. FIG. 7 is a highly multiplexed new transmitter architecture proposed by the present invention. It can be clearly seen in Figure 6 that there are two digital counters, which we can multiplex into the structure shown in Figure 7. Here, an 8-bit unidirectional and bidirectional selectable digital counter is designed. In mode "1", 8-bit unidirectional counting is selected to form a frequency discriminator; in mode "2", 6-bit bidirectional counting is selected to form a trapezoidal wave generator. In this way, the counter is multiplexed while saving one relaxation oscillator, which further simplifies the system architecture and reduces circuit power consumption and design cost.

The digital modules used by the two kinds of transmitters in the present invention are very simple digital modules, which greatly reduce the design cost, circuit power consumption and architecture complexity, and will not be repeated here. A detailed circuit description of the radio frequency module (digital control oscillator and single-stage push-pull power amplifier) is given.

FIG. 8 is a circuit diagram of a digitally controlled oscillator in the proposed transmitter architecture of the present invention. As shown in Figure 8, the three-stage inverter formed by transistors M ₁ -M ₆ is used as the core of the oscillator. Considering the characteristics of low power consumption, high radio frequency and low noise requirements of the ultra-wideband FM system, the three-stage cascaded oscillator The structure is beneficial to produce greater oscillation frequency, less power consumption and better phase noise. The total resonant current is composed of the discrete controllable current (I _M7 ) provided by the binary switch current array and the discrete controllable current (I _M10 ) provided by the binary switch current array. The oscillation frequency of the digitally controlled oscillator is double-tuned by multi-bit correction data and multi-bit modulation data at the same time, where C<5:0> is a 6-bit correction control word, and T<5:0> is a 6-bit modulation control word. In summary, the digitally controlled oscillator not only realizes the radio frequency modulation, but also realizes the center frequency correction through the binary weight switch current array and the successive approximation frequency automatic calibration module. Among them, the successive approximation frequency automatic calibration module controls the binary weight current array output of the digital control oscillator through the 6-bit correction control word C<5:0>, reversely adjusts the output frequency of the oscillator, and realizes the digital control oscillator Correction of center frequency. During the calibration and working process of the loop, the two modes of calibration mode "1" and working mode "2" are cyclically alternated, that is to say, the digitally controlled oscillator first calibrates the center frequency in a short period of time, and then in Modulation is carried out for a long period of time, and then the center frequency is corrected again, and so on.

After the correction of the center frequency is completed, the correction current I _M7 of the digitally controlled oscillator core is fixed, and the total oscillation current only changes with the modulation current I _M10 . Matched current mirror (M ₇ , M ₈ , M ₉ , M ₁₀ ) design, and digitally controlled oscillator core symmetrical charge and discharge capability (reasonable selection of M ₁ , M ₃ , M ₅ and M ₂ , M ₄ , M ₆ ), which ensures the tuning linearity of digitally controlled oscillators.

On the one hand, the output of the digitally controlled oscillator is sent to the mixer at the receiving end as a radio frequency local oscillator, and on the other hand, it is sent to a single-stage push-pull power amplifier through an isolated inverter. FIG. 9 is a circuit diagram of a single-stage push-pull power amplifier in the transmitter architecture proposed by the present invention. As shown in Figure 9, the output of the digitally controlled oscillator is input to the gates of the push-pull transistors M ₁ and M ₂ through the coupling capacitors C ₁ and C 2 , and the transistors M ₁ and _{M 2 together} constitute the push-pull power amplifier. Push-pull tube, the bias voltage is provided by a low-voltage current mirror composed of transistors M ₃ , M ₄ , M ₆ , and M ₇ . A low-voltage current mirror reduces the need for external current sinks and can also provide higher bias voltages. The power amplifier is followed by a two-stage matching network, the first-stage parasitic inductance-capacitance L-type matching network (L ₁ and C ₄ ) and the second-stage off-chip adjustable L-type matching network (L ₂ and C ₅ ), which together realize broadband Frequency selective amplification. The inductance L ₁ is the inductance of the chip bonding wire, the capacitor C ₄ is the capacitance of the chip bonding pad, and the inductance L ₂ , capacitor C ₅ , and capacitor C ₃ are off-chip inductance and capacitance.

The two transmitter architectures proposed by the present invention only use two radio frequency modules of a digitally controlled oscillator and a push-pull power amplifier, and the others are digital modules with very simple structures and very low power consumption. The transmitter architecture proposed by the present invention greatly saves design cost and circuit power consumption, reduces the complexity of the architecture, and proposes an architecture in which counters are multiplexed, greatly improving the multiplexing degree of the overall architecture. In the subsequent optimized design, it is also possible to consider using RF current multiplexing technology to stack digitally controlled oscillators and push-pull power amplifiers between the power supply and ground, thereby further reducing power consumption.

Beneficial effect

Compared with the existing transceiver architecture and transmitter architecture, the two architectures of a multi-mode reconfigurable ultra-wideband integrated transceiver and transmitter of the present invention have the following beneficial effects:

1. A reconfigurable multi-mode high-multiplexing ultra-wideband integrated transceiver described in the present invention can greatly reduce power consumption. Many modules, including low-noise amplifiers and band-pass filters, can achieve common architecture design through RF current multiplexing technology, which meets the design requirements of ultra-low power consumption;

2. A reconfigurable multi-mode high-multiplexing ultra-wideband integrated transceiver according to the present invention proposes an intermediate frequency time difference ranging mechanism. Compared with the existing radio frequency time difference and radio frequency difference modes, the ranging resolution is improved by 2 An order of magnitude, compared with the existing radio frequency phase difference mode, the power consumption and cost are significantly reduced;

3. A multi-mode high multiplexing reconfigurable ultra-wideband integrated transceiver of the present invention has many functions, and can realize multi-mode use of time difference ranging, frequency difference ranging, phase difference ranging and wireless communication, The reuse of the entire system architecture exceeds 90%;

4. The present invention also proposes two transmitter structures, a transmitter does not need to use a relaxation oscillator but uses a digital two-way counter instead, which greatly saves power consumption and design costs, and the structure is very simple, and the digital two-way counter also It can be multiplexed with the digital counter in the successive approximation frequency automatic calibration module, and a highly multiplexed transmitter is proposed, which further saves power consumption and cost, and greatly improves the multiplexing degree of the system architecture. The transmitter structure integrated into the transceiver can have all the above advantages: realize the multi-mode use of time difference ranging, frequency difference ranging, phase difference ranging and wireless communication, break the deadlock of low resolution of traditional transceivers, and have ultra-low power power consumption and ultra-high multiplexing.

Description of drawings

Fig. 1 is the structure diagram of the integrated transceiver of the existing ultra-wideband frequency modulation wireless communication and frequency modulation continuous wave radar ranging;

Fig. 2 is a structure diagram of a multi-mode high multiplexing reconfigurable ultra-wideband integrated transceiver according to the present invention;

Fig. 3 is that the transceiver of the present invention converts the time delay between sending and receiving radio frequency ultra-wideband signals into the time delay between sending and receiving intermediate frequency subcarrier signals by using the intermediate frequency time difference ranging mechanism, breaking the limitation of the existing transceiver ranging resolution by the radio frequency bandwidth Schematic diagram of deadlock;

Fig. 4 is a timing diagram of a multi-mode high multiplexing reconfigurable ultra-wideband integrated transceiver working in a wireless communication mode according to the present invention;

Fig. 5 is a timing diagram of a multi-mode high-multiplexing reconfigurable ultra-wideband integrated transceiver working in a ranging mode according to the present invention;

Figure 6 is a transmitter architecture proposed on the basis of a multi-mode high multiplexing reconfigurable ultra-wideband integrated transceiver;

Figure 7 is a highly multiplexed transmitter architecture proposed on the basis of a multi-mode high-multiplex reconfigurable ultra-wideband integrated transceiver;

FIG. 8 is a circuit design diagram of a digitally controlled oscillator in the transmitter architecture proposed by the present invention;

FIG. 9 is a circuit design diagram of a single-stage push-pull power amplifier in the transmitter architecture proposed by the present invention.

Detailed ways

The following is a detailed description of each module of a multi-mode reconfigurable ultra-wideband integrated transceiver and transmitter architecture proposed by the present invention in conjunction with the architecture diagram, circuit diagram and sequence diagram, and the working process of the radio frequency front-end module of the transmitter Make further clarification.

The ultra-wideband FM transceiver proposed by the present invention includes two parts: a transmitter and a receiver. The transmitter includes relaxation oscillators, three-stage ring radio frequency oscillators, single-stage push-pull power amplifiers, successive approximation frequency automatic correction and other modules; the receiver includes modules such as low-noise amplifiers, band-pass filters, and envelope detectors . The low-noise amplifier and band-pass filter in the receiver realize the common architecture design based on the radio frequency current multiplexing method, which greatly reduces the circuit power consumption and design cost. The transmitter adopts the method of radio frequency voltage-controlled oscillator frequency modulation and ultra-wideband frequency band center frequency correction; the receiver introduces differential slope frequency discrimination, and is based on the intermediate frequency time-difference ranging mechanism; this is not only conducive to the high compatibility of communication and radar, but also greatly reduces Design complexity and system power consumption, and improved ranging resolution. First of all, the intermediate frequency time difference ranging mechanism converts the delay between sending and receiving RF ultra-wideband signals into the delay between sending and receiving intermediate frequency subcarrier signals. The ranging resolution is no longer limited by the RF bandwidth, but only by the time-to-digital converter itself. Processing precision, thus enabling millimeter-level resolution. Secondly, the radio frequency discriminator is converted from a delay multiplication or regenerative structure to a differential slope frequency discrimination structure, which reduces the power consumption and cost of the receiver and improves the linearity of frequency discrimination.

The invention also proposes a transmitter architecture, which uses a digital counter instead of a relaxation oscillator, greatly reducing power consumption. And integrated into the transceiver architecture can realize multi-mode functions of time difference ranging, frequency difference ranging, phase difference ranging and wireless communication. On this basis, a highly multiplexed transmitter architecture is proposed. An 8-bit unidirectional and bidirectional digital counter is designed. When the mode is "1", the 8-bit unidirectional counting is selected to form a frequency discriminator; when the mode is "2", the 6-bit bidirectional counting is selected to form a trapezoidal wave generator. In this way, the counter is multiplexed while saving one relaxation oscillator, which further simplifies the system architecture and reduces circuit power consumption and design cost.

The invention proposes a method for performing ultra-wideband radio frequency stacking on an oscillator and a power amplifier based on the radio frequency current multiplexing technology. The three-stage inverter formed by transistors M ₁ -M ₆ serves as the core of the oscillator. Considering the low power consumption, high radio frequency and low noise requirements of the ultra-wideband FM system, the three-stage cascaded oscillator structure is conducive to generating larger Oscillation frequency, smaller power consumption and better phase noise. The total resonant current consists of the modulation current and the correction. The oscillation frequency of the oscillator is double-tuned by the correction data and the modulation data at the same time. Therefore, the oscillator not only realizes radio frequency modulation, but also realizes center frequency correction. On the one hand, the output of the oscillator is sent to the mixer at the receiving end as a radio frequency local oscillator, and on the other hand, it is sent to a single-stage push-pull power amplifier through an isolated inverter.

The setting situation of transmitter radio frequency front-end module operating mode described in the present invention, specifically to this embodiment, comprises the following steps:

Step A: power supply and signal connection, including the following sub-steps:

Step A.1 DC power supply voltage setting, DC bias current setting and input control word setting. As _shown in Figure 8 and Figure 9, firstly, the power supply voltage and bias current should be set according to the process deviation during chip manufacturing. The bias current I _B is set to 5µA DC. In the correction mode, the switch current control word C<5:0> controls the correction current; in the modulation mode, the switch current control word T<5:0> controls the modulation current, and the correction control word C<5:0> is in the latch state. The current flowing through the oscillator is determined by two parts: modulation current and correction current;

Step A.2 Impedance matching network setup. Among them, the impedance of antenna _A1 is generally 50Ω. In the present invention, capacitor _C4 is set to 90fF, capacitor _C5 is set to 0.33pF, capacitor _C3 is set to 2.6pF, inductance _L1 is set to 2nH, and inductance _L2 is set to 2.6nH .

Step B: Each module starts to work normally, and the specific workflow includes the following sub-steps:

Step B.1 Digitally controlled oscillator works. The current flowing through the oscillator is determined by the modulation current and the correction current. Since the change of the current will cause the change of the delay of the inverter, the change of the oscillator frequency is determined. In the correction mode, the control word T<5:0> is set to 25 (6b'011001), and the signal T<5:0> is input into the digitally controlled oscillator, and the output frequency F _VCO of the control oscillator is about 4GHz Sine wave signal (the output signal will fluctuate around 4GHz, and a subsequent correction module is required to stabilize it to 4GHz). In the radar working mode, the 6-bit output of the trapezoidal wave generator controls the oscillator to generate a frequency with a center frequency of 4GHz A sine wave that varies between 3.75GHz and 4.25GHz (the frequency of the sine wave signal frequency is affected by the fixed frequency of the trapezoidal wave generator and remains constant); in the communication mode of operation, the 6-bit output of the trapezoidal wave generator controls the oscillation The generator generates a sine wave whose center frequency is 4GHz and whose frequency varies between 3.75GHz and 4.25GHz (the frequency of the sine wave signal frequency is affected by the changing frequency of the trapezoidal wave generator);

Step B.2 The single-stage push-pull power amplifier works. The output signal of the digitally controlled oscillator is input to the power amplifier. The specific working method of the power amplifier is: in the first half cycle of the signal, the NMOS transistor _M1 is turned on, and the PMOS transistor _M2 is a load transistor at this time. In the second half period of the signal, the PMOS transistor M ₂ is turned on, and the NMOS transistor M ₁ is a load transistor at this time. The subsequent first-stage parasitic inductance-capacitance L-type matching network (L ₁ and C ₄ ) and the second-stage off-chip adjustable L-type matching network (L ₂ and C ₅ ) together realize broadband frequency-selective amplification. Finally, the radio frequency signal output by the power amplifier is transmitted through the antenna, and the radio frequency modulation work of the transmitter is completed. The power amplifier can amplify the output signal of the oscillator, which is not only beneficial to the propagation of the signal in space, but also beneficial to the receiver to better identify the signal.

The above description is only a preferred embodiment of the present invention, and the present invention should not be limited to the content disclosed in this embodiment and the accompanying drawings. All equivalents or modifications accomplished without departing from the disclosed spirit of the present invention fall within the protection scope of the present invention.

Claims (5)

1. A multi-mode reconfigurable ultra-wideband integrated transceiver, comprising two parts of a transmitter and a receiver, is characterized in that: the transmitter includes a data selector 1, a relaxation oscillator, a ring oscillator, a power amplifier and a frequency Correction module; receiver includes low-noise amplifier, band-pass filter, envelope detector, data selector 2, IF amplifier, subtractor, delay-to-digital converter, mixer, 2-frequency shift keying demodulation device, off-chip Fourier transform processing module; The connection mode of each module of the ultra-wideband integrated transceiver is as follows: The connection relationship of each module in the transmitter is as follows: the data selector 1 is connected to the relaxation oscillator, the relaxation oscillator is connected to the ring oscillator, the frequency correction module is connected to the relaxation oscillator and the ring oscillator at the same time, and the ring oscillator is connected to the ring oscillator. The power amplifier is connected, and the power amplifier is connected to the antenna; The connection relationship of each module in the receiver is as follows: the antenna is connected to a low noise amplifier, the low noise amplifier is connected to the band-pass filter and the mixer, the band-pass filter is connected to the envelope detector, the envelope detector and the mixer It is connected with data selector 2, data selector 2 is connected with intermediate frequency amplifier, intermediate frequency amplifier is connected with subtractor, and finally it is connected with delay-to-digital converter, 2-frequency shift keying demodulator or off-chip according to the transceiver application scenario Fourier transform processing module; when the ultra-wideband integrated transceiver is used for wireless communication, the subtractor is followed by a 2-frequency shift keying demodulator; when the ultra-wideband integrated transceiver is used for time difference ranging, the subtractor is followed by a time delay -Digital converter; when the ultra-wideband integrated transceiver is used for frequency difference ranging, the subtractor is followed by an off-chip Fourier transform processing module, and the mixer in the receiver cooperates with the off-chip Fourier transform processing module to realize Frequency difference ranging; The working mode of the ultra-wideband integrated transceiver includes a communication mode and a ranging mode; The working process of the transmitter is as follows: Step 1: Determine the working mode of the ultra-wideband integrated transceiver, and perform the following operations according to different working modes: 1.A If the ultra-wideband integrated transceiver is in the communication mode, the data selector 1 in the transmitter selects to load the baseband data 0 and 1 on the triangular wave sequence, and the baseband data 0 and 1 are converted through analog 2-frequency shift keying modulation into triangular wave sequences with frequencies f ₀ and f ₁ respectively, this process is called 2-frequency shift keying triangular wave generation; 1.B If the ultra-wideband integrated transceiver is used as a frequency modulation continuous wave radar transceiver, the relaxation oscillator generates a fixed frequency triangular wave sequence; Step 2: Send the modulated triangular wave sequence output in step 1 to the voltage control terminal of the ring oscillator. Under the control of the amplitude-frequency conversion gain of the ring oscillator, perform RF frequency modulation to obtain an ultra-wideband signal. This process is called radio frequency modulation; Step 3: The ultra-wideband signal output in step 2 passes through the power amplifier and is transmitted through the antenna in the output impedance matching network; A frequency correction circuit is introduced in the working process of the transmitter to correct the center frequency of the relaxation oscillator and ring oscillator; The working process of the receiver is as follows: Step A: The signal received from the antenna is amplified through a low noise amplifier; Step B: Under different working modes, perform different processing on the signal amplified in step A: B.1 If the ultra-wideband integrated transceiver is in the communication mode, the low-noise amplifier is followed by a band-pass filter, and then the envelope is extracted through the envelope detector, and then through the intermediate frequency amplifier and subtractor, and the demodulated The frequency f ₀ of the analog signal represents the baseband data 0, and the frequency f ₁ represents the baseband data 1. This process is called broadband FM demodulation, and then the digital signal can be reconstructed from the recovered analog signal through a 2-frequency shift keying demodulator. Baseband 0 and 1 data, so as to realize the communication function; B.2 If the ultra-wideband integrated transceiver is in the ranging mode, the ranging principle of the receiver is based on radio frequency frequency difference technology: the mixer makes a difference between the instantaneous frequency of the local oscillator signal at the transmitting end and the instantaneous frequency of the ultra-wideband signal at the receiving end The difference frequency is just proportional to the space transmission time or the ranging distance. With the subsequent off-chip Fourier transform processing module, the difference frequency can be taken out and converted into distance data, thereby realizing frequency difference ranging ; B.3 If the ultra-wideband integrated transceiver is in the ranging mode, the ranging principle of the receiver is based on the intermediate frequency time difference ranging mechanism: through the bandpass filter and the envelope detector, the receiver reconstructs the intermediate frequency subcarrier information at the receiving end, and Using the delay-to-digital converter, the time delay between the RF ultra-wideband signals at the two ends of the transceiver is converted into the time delay between the intermediate frequency sub-carrier signals at the two ends of the transceiver, and the space transmission time is proportional to the transmission distance, so as to realize time difference ranging; While the integrated transceiver realizes wireless communication, time difference ranging and frequency difference ranging, it can also realize the function of phase difference ranging by using two or more sets of integrated transceiver structures. 2. A transmitter comprising a digital successive approximation register, a frequency discriminator based on a digital counter, a trapezoidal wave generator based on a digital two-way counter, a digitally controlled oscillator, a data selector, an _N1 / _N2 frequency divider and Push-pull power amplifier; its connection method and working process are as follows: The transmitter has two architectures. The connection mode of each module of the first architecture of the two architectures of a transmitter is: the data selector is connected to the N ₁ /N ₂ frequency divider, and the N ₁ /N ₂ frequency divider It is connected with the frequency discriminator based on the digital counter and the trapezoidal wave generator based on the digital two-way counter, the frequency discriminator based on the digital counter is connected with the digital successive approximation register, and the digital successive approximation register and the trapezoidal wave generator based on the digital two-way counter are both The digital control oscillator is connected, the digital control oscillator is connected to the push-pull power amplifier, and the push-pull power amplifier is connected to the antenna; The first of the two architectures of a transmitter has two operating modes, mode "1" correction and mode "2"operation; in the correction mode, the digitally controlled oscillator outputs a sine wave with a frequency of 4GHz At this time, the N ₁ /N ₂ frequency divider works in the 40 frequency division mode; the 4GHz sine wave signal is divided into a 100MHz square wave signal by the 40 frequency divider, and the 100MHz square wave signal is input to the digital counter-based The frequency discriminator is used as the high-frequency input clock of the frequency discriminator, and the 1MHz F _REF is used as the low-frequency input clock of the frequency discriminator, and the high-frequency clock is counted in a low-frequency clock. If the output frequency of the digitally controlled oscillator is less than 4GHz, Then F _REF counts square waves with a frequency less than 100MHz and the result is less than 100. If the output frequency of the digitally controlled oscillator is a sine wave signal greater than 4GHz, then F _REF counts square waves with a frequency greater than 100MHz and the result is greater than 100; Due to the influence of temperature, process, and power supply voltage, the frequency of the oscillator will fluctuate by 20%-30%, and the frequency discrimination result will fluctuate by 20%-30% on the basis of 100. The counter needs to leave a certain margin. Therefore, an 8-bit counter is required to control the UP/DN signal by comparing the output of the 8-bit counter with the built-in 100 of the frequency discriminator, and further control the digital successive approximation The 6-bit output of the register, so as to achieve the purpose of correcting the frequency of the digitally controlled oscillator and stabilizing it at 4GHz; In the working mode, the two architectures of a transmitter are integrated into the transceiver and divided into ranging working mode and communication working mode according to the functions that the transceiver wants to achieve: In the ranging mode, the 6-bit digital bidirectional counter increases from 0 to 50 and then decreases from 50 to 0, and the trapezoidal wave generator generates a 6-bit output, which is equivalent to a trapezoidal wave with a frequency of 1MHz. The N ₁ /N ₂ frequency divider works in the 40 frequency division mode, and divides the output signal of the oscillator with a center frequency of 4GHz by 40 to obtain a clock signal with a frequency of 100MHz to control the trapezoidal wave generator based on the digital two-way counter. The 6-bit output control oscillator of the wave generator generates a sine wave with a center frequency of 4GHz and an instantaneous frequency between 3.75GHz and 4.25GHz. The output signal of the digital control oscillator is transmitted through the push-pull power amplifier and then through the antenna. After a series of subsequent processing by the receiver, the ranging function is finally realized, and it can be combined with the multi-mode reconfigurable ultra-wideband integrated transceiver to realize the multi-mode functions of time difference ranging, frequency difference ranging, and phase difference ranging ; In the communication working mode, when the transmitted data is 0, the N ₁ /N ₂ frequency divider works in the 40 frequency division mode, and divides the output signal of the oscillator with a center frequency of 4GHz by 40 to obtain a clock signal with a frequency of 100MHz. To control the trapezoidal wave generator based on the digital two-way counter, the 6-bit digital two-way counter increases from 0 to 50 and then decreases from 50 to 0, the trapezoidal wave generator generates a 6-bit output, which is equivalent to a frequency of 1MHz Trapezoidal wave form; when the transmitted data is 1, the N ₁ /N ₂ frequency divider works in the 36 frequency division mode, and the oscillator output signal with a center frequency of 4GHz is divided by 36 to obtain a clock signal with a frequency of 110MHz to control A trapezoidal wave generator based on a digital two-way counter. The 6-bit digital two-way counter increases from 0 to 50 and then decreases from 50 to 0. The trapezoidal wave generator generates a 6-bit output, which is equivalent to a trapezoid with a frequency of 1.1MHz. Wave form; In summary, in the communication mode, the trapezoidal wave generator based on the digital two-way counter generates a 6-bit output, which is equivalent to a trapezoidal wave form with a frequency switching back and forth between 1MHz and 1.1MHz, and the trapezoidal wave The 6-bit output of the generator controls the oscillator to generate a sine wave with a center frequency of 4GHz and an instantaneous frequency between 3.75GHz and 4.25GHz. Finally, the output signal of the digitally controlled oscillator is transmitted through the push-pull power amplifier and then through the antenna. , the follow-up receiver receives the signal and finally realizes the communication function; The second architecture among the two architectures of a transmitter, that is, the connection mode of each module of the multiplexing transmitter architecture is: the data selector is connected to the N ₁ /N ₂ frequency divider, and the N ₁ /N ₂ frequency divider The frequency discriminator/trapezoidal wave generator module based on the bidirectional counter is connected to the frequency discriminator/trapezoidal wave generator module based on the bidirectional counter, and the digital successive approximation register and the digitally controlled oscillator are connected. The digital successive approximation register and the digital control Type oscillator is connected, the digital control type oscillator is connected with N ₁ /N ₂ frequency divider and push-pull type power amplifier, and the push-pull type power amplifier is connected with antenna; the comparison of the two kinds of transmitter architectures can be seen, because the second structure In the frequency discriminator and the counter of the trapezoidal wave generator can be multiplexed, so it is called a multiplexed transmitter; In the second architecture of the two architectures of a transmitter, an 8-bit unidirectional and bidirectional selectable digital counter is designed; when the correction mode is "1", an 8-bit unidirectional counter is selected to form a frequency discriminator for the center frequency Correction; in the working mode "2", select a 6-bit bidirectional counter to form a trapezoidal wave generator to replace the traditional relaxation oscillator. 3. A multi-mode reconfigurable ultra-wideband integrated transceiver according to claim 1, wherein the ring oscillator is a three-stage ring voltage-controlled oscillator. 4. A transmitter according to claim 2, characterized in that: the counter of the frequency discriminator is multiplexed with the counter of the trapezoidal wave generator. 5. A transmitter according to claim 2, characterized in that the power amplifier is a single-stage push-pull type.

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