A pilot carrier phase recovery circuit, a reverse antenna array system

Abstract

This invention discloses a pilot-type carrier phase recovery circuit and a reverse antenna array system, belonging to the field of 5G millimeter-wave communication. The pilot-type carrier phase recovery circuit includes a digital phase detector, a quadrature mixer, a quadrature voltage-controlled oscillator, a low-pass filter, a high-pass filter, a polyphase filter, a loop filter, a first intermediate frequency amplifier, a second intermediate frequency amplifier, a first shaping circuit, and a second shaping circuit. Applied to a reverse antenna array system, this invention performs carrier phase recovery on the data signal and pilot signal output from the receiver, separating the data signal without spatial phase information and the spatial phase information used for reverse transmission. This invention enables high-order modulation full-duplex communication and real-time tracking of moving targets, featuring high integration, small area, high communication speed, and strong anti-interference capability.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit design technology, and in particular to a pilot-type carrier phase recovery circuit and a reverse antenna array system. Background Technology

[0002] Millimeter wave frequencies range from 30 GHz to 300 GHz, offering higher frequencies and a wider spectrum compared to the sub-6 GHz band. This allows for greater transmission bandwidth and higher communication rates, making it a crucial research area for 5G and 6G technologies. However, higher frequencies also result in greater spatial losses, severely limiting communication distance. Therefore, antenna beamforming techniques are widely used to enhance signal power in specific directions while suppressing interference from other directions.

[0003] Traditional phased arrays achieve beam control through phase shifters. By changing the phase of each channel, the direction and state of the beam are controlled, enabling directional transmission and reception. However, the use of numerous phase shifters increases system cost and complexity. Phase control also requires high-precision hardware circuitry and high-performance digital algorithms. Inverse arrays, on the other hand, can automatically track the signal transmitted by the target and point the array beam towards the target. Inverse arrays do not require prior knowledge of the target's position to achieve inversion, and they do not require complex phase shifters, control circuits, or any digital algorithms. Inverse arrays are characterized by low cost, low power consumption, and system simplicity.

[0004] Traditional inverting arrays achieve phase conjugation directly through a mixer with twice the local oscillator, but this does not enable full-duplex communication, and its output power is affected by the input power. Currently, phase-locked loops (PLLs) are mainly used to implement carrier phase recovery circuits, enabling inverting arrays to simultaneously extract phase information and demodulate data signals. In some existing circuit architectures, square loops, Costa loops, and frequency-doubled locked loops all suffer from phase ambiguity; the recovered signals may be in phase or out of phase by 180°, making them unusable directly. Reference carrier phase recovery circuits are structurally complex and difficult to integrate; they sacrifice additional receiving channels, leading to resource waste, and the unequal number of input and output channels greatly limits antenna array design. Furthermore, obtaining phase information through phase detection between modulated signals is also affected by the modulation rate, resulting in system instability at high modulation rates and limiting the maximum communication transmission rate. Summary of the Invention

[0005] To address the issue that existing carrier phase recovery circuits are not suitable for high-speed communication reverse array systems with high-order phase modulation, the present invention aims to provide a pilot-type carrier phase recovery circuit and a reverse antenna array system, which features high integration, small area, high communication speed, and strong anti-interference capability.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A pilot-type carrier phase recovery circuit for use in a reverse antenna array system includes a digital phase detector, a quadrature mixer, a quadrature voltage-controlled oscillator, a low-pass filter, a high-pass filter, a polyphase filter, a loop filter, a first intermediate frequency amplifier, a second intermediate frequency amplifier, a first shaping circuit, and a second shaping circuit.

[0008] The input signals of the circuit include a first input signal and a second input signal;

[0009] The first input signal is amplified by the first intermediate frequency amplifier and then input to the quadrature mixer, where it is mixed with the oscillation signal output by the quadrature voltage-controlled oscillator. The mixed first intermediate frequency signal is then passed through a multiphase filter and output to a low-pass filter and a high-pass filter, respectively. The pilot component extracted by the low-pass filter is amplified by the second intermediate frequency amplifier and converted into a first digital signal by the first shaping circuit. The high-pass filter outputs the second intermediate frequency signal.

[0010] The second input signal is converted into a second digital signal by the second shaping circuit. The first digital signal and the second digital signal are compared in phase by the digital phase detector. The output error signal is filtered by the loop filter and then controls the quadrature voltage-controlled oscillator. The quadrature voltage-controlled oscillator outputs an oscillation signal containing spatial phase information.

[0011] Furthermore, the first input signal contains both a pilot signal and a data signal. The pilot signal is a sinusoidal signal, and the data signal is a modulation signal. The first input signal contains spatial phase information generated by the antenna array.

[0012] Furthermore, the pilot signal and the data signal have a frequency difference sufficient to be separated by an on-chip filter.

[0013] Furthermore, the second input signal is a reference signal, which is a sinusoidal signal with the same phase provided by an external signal source to the chip of each channel.

[0014] In some preferred embodiments of the present invention, the quadrature mixer is composed of two Gilbert mixers, which are respectively connected to the quadrature voltage-controlled oscillator, the first intermediate frequency amplifier, and the polyphase filter.

[0015] Furthermore, the polyphase filter is used to suppress interference signals at specific frequencies.

[0016] Furthermore, the high-pass filter is used to suppress the low-frequency components and noise of the first intermediate frequency signal to obtain a clean data signal as the second intermediate frequency signal.

[0017] Furthermore, the low-pass filter is used to suppress the high-frequency components of the first intermediate frequency signal, so as to obtain a clean pilot signal output to the second intermediate frequency amplifier.

[0018] Furthermore, the low-pass filter is connected to the second intermediate frequency amplifier, which is used to amplify the extracted pilot signal and output the fourth intermediate frequency signal to the first shaping circuit.

[0019] Furthermore, the first shaping circuit is used to convert the fourth intermediate frequency signal into a first digital signal.

[0020] Furthermore, the second shaping circuit is connected to the digital phase detector and is used to shape the second input signal into a second digital signal.

[0021] In some preferred embodiments of the present invention, the digital phase detector is a charge pump type frequency phase detector, which is connected to the first shaping circuit and the second shaping circuit respectively.

[0022] Furthermore, the loop filter is implemented as a second- or third-order filter using capacitors and resistors, which is used to adjust the loop parameters.

[0023] Furthermore, the quadrature voltage-controlled oscillator is an LC-type voltage-controlled oscillator or a ring oscillator. Under the control signal output by the loop filter, it generates an oscillation signal and outputs four signals with a phase difference of 90° to the quadrature mixer. The output signal contains the extracted spatial phase information.

[0024] A reverse antenna array system includes two or more channels, each channel including the same transceiver antenna, radio frequency front-end, carrier phase recovery circuit and quadrature mixer; phase conjugation operation is implemented at the receiver downmixer or transmitter upmixer of the radio frequency front-end;

[0025] The carrier phase recovery circuit, as an intermediate frequency processing circuit, is used to separate the pilot and data signals, extract the spatial phase information, output it at the quadrature voltage-controlled oscillator, mix it with the data signal used for transmission at the quadrature mixer, and then enter the transmitter to realize automatic reverse tracking of the transmitted signal. At the same time, the data signal is extracted, amplified, and output for demodulation.

[0026] Furthermore, the antennas of each channel are kept at the same spacing to obtain the correct spatial phase information; the receiver local oscillator signal is kept in phase; the transmitter local oscillator signal is kept in phase; and the second input signal reference signal is kept in phase to achieve correct spatial phase information extraction and transmission.

[0027] Furthermore, the received signal contains both pilot signals and data signals. The pilot signal is a sinusoidal signal, and the data signal is a modulated signal. The received signal contains spatial phase information and is generated by the antenna array; the transmitted signal is a modulated signal.

[0028] In some preferred embodiments of the present invention, the frequency of the signal that the interference signal leaked from the transmitter to the receiver enters the polyphase filter together with the first intermediate frequency signal after down-conversion is set as the suppression frequency of the polyphase filter; the antenna is a high isolation antenna shared by the transmitter and receiver; the frequency of the received pilot signal is greater than the frequency of the received data signal is greater than the frequency of the transmitted signal, so as to achieve correct signal separation and pointing error compensation.

[0029] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0030] 1. The pilot-type carrier phase recovery circuit proposed in this invention extracts spatial phase information by aligning the phases between different channels, achieving accurate carrier phase recovery without phase ambiguity. It does not require additional hardware circuits or complex digital algorithms to assist in phase judgment. At the same time, each module has a simple structure and small area, and can be integrated with the RF front end into a complete inverted array system chip.

[0031] 2. The pilot-type carrier phase recovery circuit proposed in this invention restores the phase of the pilot signal by inserting a pilot signal outside the received data signal, thus avoiding the waste of channels in the reference circuit. At the same time, the spectrum of the pilot signal is cleaner than that of the reference signal containing modulation information, ensuring a more stable loop-locked state and resulting in a higher communication rate.

[0032] 3. The pilot-type carrier phase recovery circuit proposed in this invention uses a quadrature mixer, a quadrature oscillator, and a polyphase filter module, providing stronger anti-interference capability. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the pilot carrier phase recovery circuit proposed in this invention;

[0034] Figure 2 This is a schematic diagram illustrating the application of the pilot-type carrier phase recovery circuit in the reverse antenna array system of the present invention.

[0035] Figure 3 This is a schematic diagram showing the frequency and phase of each signal when the pilot carrier phase recovery circuit in this invention is working;

[0036] Figure 4 This is a schematic diagram showing the structure and connection relationship of the quadrature mixer, quadrature oscillator, and polyphase filter in this invention.

[0037] Figure 5 This is an example of the input signal spectrum of the pilot carrier phase recovery circuit in this invention;

[0038] Figure 6 This is an example of the output signal spectrum of the pilot carrier phase recovery circuit in this invention. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Example 1

[0041] This embodiment provides a pilot-type carrier phase recovery circuit for a reverse antenna array system, comprising a digital phase detector, a quadrature mixer, a quadrature voltage-controlled oscillator, a low-pass filter, a high-pass filter, a polyphase filter, a loop filter, a first shaping circuit, a second shaping circuit, a first intermediate frequency amplifier, and a second intermediate frequency amplifier, as shown below. Figure 1 As shown. This circuit processes the first input signal. Second output signal The signal is processed and output as an oscillation signal from a quadrature voltage-controlled oscillator. Second intermediate frequency signal .

[0042] First input signal Simultaneously, pilot signals and data signals exist. The pilot signal is a sinusoidal signal, and the data signal is a modulated signal. The first input signal... It also contains spatial phase information, generated by the antenna array; the pilot signal and the data signal have a certain frequency difference, sufficient for signal separation by an on-chip filter; the second input signal is a reference signal. An external signal source provides each channel's chip with a sinusoidal signal of the same phase.

[0043] The quadrature mixer is connected to the quadrature voltage-controlled oscillator, the first intermediate frequency amplifier, and the polyphase filter, respectively, and the first input signal is input to the pilot-type carrier phase recovery circuit. After being amplified by the first intermediate frequency amplifier, the signal is mixed with the signal generated by the quadrature voltage-controlled oscillator to output the first intermediate frequency. Signal to multiphase filter.

[0044] The polyphase filter is connected to a low-pass filter and a high-pass filter respectively to suppress interference signals at specific frequencies. The first intermediate frequency signal is then passed through the high-pass filter. By suppressing low-frequency components and noise, a clean data signal is obtained, and a second intermediate frequency signal is output. The first intermediate frequency signal is filtered through a low-pass filter. High-frequency components are suppressed to obtain a clean pilot signal, and a third intermediate frequency signal is output. To the second intermediate frequency amplifier.

[0045] The low-pass filter is connected to the intermediate frequency amplifier to amplify the extracted pilot signal and output the fourth intermediate frequency signal. To the first shaping circuit.

[0046] The second intermediate frequency amplifier is connected to the first shaping circuit and is used to convert the fourth intermediate frequency signal. Convert to a digital signal and output the first digital signal. To the digital phase detector.

[0047] The second shaping circuit is connected to the digital phase detector and is used to convert the second output signal. Shaped into a second digital signal .

[0048] The digital phase detector is connected to the first shaping circuit and the second shaping circuit to compare the first digital signal. Second digital signal The phase of the output first electrical signal To loop filter.

[0049] The loop filter adjusts the loop parameters for the first electrical signal. Filtering, outputting a second electrical signal To orthogonal voltage-controlled oscillator.

[0050] Quadrature voltage-controlled oscillator in the second electrical signal Under control, an oscillation signal of a certain frequency is generated, which can output four signals with a phase difference of 90°. The output signal of the quadrature mixer contains the extracted spatial phase information.

[0051] As can be seen, this circuit achieves the separation of the pilot signal containing spatial phase information and the data signal, and outputs the data signal as... It can be directly demodulated to extract spatial phase information. It is used to achieve reverse transmission of signals.

[0052] Example 2

[0053] This embodiment, based on Embodiment 1, proposes a reverse antenna array system based on a pilot-type carrier phase recovery circuit, including a transceiver antenna, an RF front-end, a quadrature mixer, and a pilot-type carrier phase recovery circuit, such as... Figure 2 As shown.

[0054] In this embodiment, the receiving antenna receives an input signal containing spatial phase information. After being amplified by a low-noise amplifier, a phase conjugation operation is performed at the receiver's downmixer to obtain an output signal from the receiver containing inverted spatial phase information. This output signal is then input to the pilot carrier phase recovery circuit as the first input signal. The pilot-type carrier phase recovery circuit extracts the inverted spatial phase information and outputs... . In the quadrature mixer, the transmitted data signal is... The frequency is mixed to adjust it to the transmit intermediate frequency carrier frequency, while giving it inverse spatial phase information. The output signal of the quadrature mixer is transmitted through the transmitter and transmit antenna.

[0055] As can be seen, this system can separate spatial phase information and data information, and can transmit the reverse phase information and data signals to the transmitter to realize the reverse signal transmission, thereby realizing the reverse tracking and full-duplex communication functions of the reverse antenna array system.

[0056] Now combined Figure 3 The working principle of the carrier phase recovery circuit proposed in this embodiment is further explained.

[0057] In this embodiment, the first input signal contains two components: a pilot signal and a data signal. Both components contain spatial phase information. The pilot signal is a sinusoidal signal, which can be represented as: The data signal is a high-order modulated signal, which can be represented as .in, It is the amplitude of the pilot signal. It is the frequency of the pilot signal. It is spatial phase information generated by the antenna array. It is the amplitude of the data signal. It is the carrier frequency of the data signal. This refers to data information modulated in a higher order.

[0058] The output signal of a quadrature voltage-controlled oscillator can be expressed as: The second intermediate frequency signal after mixing and filtering can be expressed as: The third intermediate frequency signal can be represented as .in, The amplitude of the quadrature voltage-controlled oscillator. The frequency of the quadrature voltage-controlled oscillator. It is the phase of the quadrature voltage-controlled oscillator. It is the amplitude of the second intermediate frequency signal. It is the frequency of the second intermediate frequency signal. It is the phase of the second intermediate frequency signal. It is the amplitude of the third intermediate frequency signal. It is the frequency of the third intermediate frequency signal. It is the phase of the third intermediate frequency signal.

[0059] The second input signal can be represented as, .in, It is the amplitude of the second input signal. It is the frequency of the second input signal. It is the phase of the second input signal.

[0060] Phase detector for the first digital signal Second digital signal Phase detection is performed, and the feedback signal is transmitted to the quadrature voltage-controlled oscillator. The frequency and phase are adjusted through negative feedback, and finally... and Phase locking maintains phase consistency. When locked, the circuit exhibits the following phase-frequency relationship:

[0061] = - ;

[0062] = - ;

[0063] ;

[0064] ;

[0065] = - ;

[0066] = - ;

[0067] Since the second input signal is a sinusoidal signal uniformly generated by an external signal source, and the phase of different channels is guaranteed to be consistent, it is denoted here. It can be exported:

[0068] = ;

[0069] It can be seen that the quadrature voltage-controlled oscillator has achieved the extraction of spatial phase information from the pilot signal and the recovery of the carrier phase of the input signal containing high-order modulation data signal.

[0070] Now combined Figure 4 The structure and connection relationship of the quadrature mixer, quadrature oscillator and polyphase filter proposed in this embodiment are further explained.

[0071] The quadrature oscillator is implemented using a ring oscillator structure, consisting of four ring oscillator amplification units connected end-to-end. Three amplification units are connected in the forward direction to the next amplification unit, and one amplification unit is connected in the reverse direction to the next amplification unit to meet the phase conditions required for oscillation. At the outputs of two opposing amplification units, four differential 90° quadrature signals can be output.

[0072] Two mixers form an orthogonal mixer, using four differential 90° quadrature signals as the local oscillator.

[0073] A polyphase filter consists of two sets of capacitors and resistors, the values ​​of which are determined by the frequency of the interference signal to be suppressed.

[0074] The RF output port of the quadrature mixer is connected to the four input ports of the polyphase filter in a specific order to ensure the correct passage of useful signals, namely pilot and data signals, while correctly suppressing interference signals. The output signal of the polyphase filter is the intermediate frequency signal with interference signals correctly suppressed.

[0075] Figure 5 The first input signal of the pilot-type carrier phase recovery circuit is given. The spectrum contains both pilot and data signals. The data signal has a certain spectral width and carries data information at a certain rate, while the pilot signal is a single-frequency sinusoidal signal. The data signal and pilot signal have a certain frequency interval to facilitate accurate separation by the filter.

[0076] Figure 6 The second intermediate frequency signal output by the pilot carrier phase recovery circuit is given. The spectrum contains only the data signal output after frequency conversion; the pilot signal has been accurately separated by the filter. The data signal passes through multiple intermediate frequency amplifiers in the circuit, gaining a certain gain, and can be directly demodulated.

[0077] The above description is merely a preferred embodiment of the present invention. It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of the present invention are used to distinguish different objects, rather than to describe a specific order. The reference to "embodiment" herein means that a specific feature, structure, or characteristic described in conjunction with an embodiment may be included in at least one embodiment of the present invention. For those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A pilot-type carrier phase recovery circuit applied to a reverse antenna array system, characterized in that: It includes a digital phase detector, a quadrature mixer, a quadrature voltage-controlled oscillator, a low-pass filter, a high-pass filter, a multiphase filter, a loop filter, a first intermediate frequency amplifier, a second intermediate frequency amplifier, a first shaping circuit, and a second shaping circuit. The input signals of the circuit include a first input signal and a second input signal; The first input signal is amplified by the first intermediate frequency amplifier and then input to the quadrature mixer, where it is mixed with the oscillation signal output by the quadrature voltage-controlled oscillator. The mixed first intermediate frequency signal is then output to the low-pass filter and the high-pass filter after passing through the polyphase filter. The pilot component extracted by the low-pass filter is amplified by the second intermediate frequency amplifier and converted into a first digital signal by the first shaping circuit; the high-pass filter outputs the second intermediate frequency signal. The second input signal is converted into a second digital signal by the second shaping circuit. The first digital signal and the second digital signal are compared in phase by the digital phase detector. The output error signal is filtered by the loop filter and then controls the quadrature voltage-controlled oscillator. The quadrature voltage-controlled oscillator outputs an oscillation signal containing spatial phase information.

2. The circuit according to claim 1, characterized in that: The first input signal contains both a pilot signal and a data signal. The pilot signal is a sinusoidal signal, and the data signal is a modulation signal. The first input signal contains spatial phase information generated by the antenna array. The pilot signal and the data signal have a frequency difference sufficient to be separated by an on-chip filter; The second input signal is a reference signal, which is a sinusoidal signal with the same phase provided by an external signal source to the chip of each channel.

3. The circuit according to claim 1, characterized in that: The quadrature mixer consists of two Gilbert mixers, which are connected to the quadrature voltage-controlled oscillator, the first intermediate frequency amplifier, and the polyphase filter, respectively.

4. The circuit according to claim 1, characterized in that: The polyphase filter is used to suppress interference signals at a specific frequency; the high-pass filter is used to suppress the low-frequency components and noise of the first intermediate frequency signal to obtain a clean data signal as the second intermediate frequency signal; the low-pass filter is used to suppress the high-frequency components of the first intermediate frequency signal to obtain a clean pilot signal output to the second intermediate frequency amplifier.

5. The circuit according to claim 4, characterized in that: The low-pass filter is connected to the second intermediate frequency amplifier, which amplifies the extracted pilot signal and outputs the fourth intermediate frequency signal to the first shaping circuit. The first shaping circuit converts the fourth intermediate frequency signal into a first digital signal.

6. The circuit according to claim 1, characterized in that: The second shaping circuit is connected to the digital phase detector and is used to shape the second input signal into a second digital signal; the digital phase detector is a charge pump type frequency phase detector and is connected to the first shaping circuit and the second shaping circuit respectively.

7. The circuit according to claim 1, characterized in that: The loop filter is a second- or third-order filter implemented by capacitors and resistors, used to adjust the loop parameters; the quadrature voltage-controlled oscillator is an LC type voltage-controlled oscillator or a ring oscillator, which generates an oscillation signal under the control signal output by the loop filter, and outputs four signals with a phase difference of 90° to the quadrature mixer. The output signal contains the extracted spatial phase information.

8. A reverse antenna array system, characterized in that: It contains two or more channels, each including the same transceiver antenna, RF front-end, carrier phase recovery circuit and quadrature mixer; phase conjugation operation is implemented at the receiver downmixer or transmitter upmixer of the RF front-end; The carrier phase recovery circuit is the carrier phase recovery circuit according to any one of claims 1 to 7; the carrier phase recovery circuit serves as an intermediate frequency processing circuit, used to separate the pilot signal and the data signal, extract the spatial phase information, output it at the quadrature voltage-controlled oscillator, mix it with the data signal used for transmission at the quadrature mixer and then enter the transmitter to realize automatic reverse tracking of the transmitted signal, and simultaneously extract the data signal, amplify it and output it for demodulation.

9. The system according to claim 8, characterized in that: The antennas in each channel are kept at the same spacing to obtain the correct spatial phase information; the receiver local oscillator signal is kept in phase; the transmitter local oscillator signal is kept in phase; and the second input signal reference signal is kept in phase to achieve correct spatial phase information extraction and transmission.

10. The system according to claim 8, characterized in that: The received signal contains both pilot and data signals. The pilot signal is a sinusoidal signal, and the data signal is a modulated signal. The received signal contains spatial phase information and is generated by the antenna array. The transmitted signal is a modulated signal.

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