Radio frequency transceiver structure and reader

Abstract

The embodiment of the present application provides a radio frequency transceiving structure and a reader-writer, a programmable logic module is used to generate a digital carrier signal, the digital carrier signal is a signal containing different frequency bands; a radio frequency transmitting module is used to convert the digital carrier signal into an analog carrier signal and transmit the analog carrier signal outward, so that a radio frequency tag reflects a target signal back after receiving the analog carrier signal; a radio frequency receiving module is used to receive the analog carrier leakage signal and the target signal, and carrier cancellation is performed on the analog carrier leakage signal by taking the analog carrier signal of the radio frequency transmitting module as a reference signal, and the remaining useful signal is converted into a digital useful signal after the carrier cancellation; the programmable logic module is also used to divide the digital useful signal into processing signals of different frequency bands, and the processing signals are processed. The embodiment of the present application widens the frequency spectrum resource, and the target signal reflected by the radio frequency tag can carry more useful information.

Description

Technical Field

[0001] This application relates to the field of radio frequency technology, and in particular to a radio frequency transceiver structure and a reader / writer. Background Technology

[0002] RFID (Radio Frequency Identification) technology is an automatic identification technology that uses radio frequency for non-contact, two-way communication to identify targets and exchange data. Currently, RFID technology is widely used in logistics, anti-counterfeiting and traceability, industrial manufacturing, parking management, and other fields.

[0003] Specifically, an RFID reader / writer was implemented based on RFID technology. The RFID reader / writer uses the reflection of electromagnetic waves to identify target objects and acquire data, without human intervention, making operation quick and convenient. The biggest advantages of RFID technology are: (1) Radio frequency tags (tags) do not require batteries. The low cost of radio frequency tags makes the overall deployment cost of the RFID system very low, thus making the large-scale application of RFID possible. Currently, RFID technology has the lowest cost for achieving the Internet of Things. (2) Electromagnetic waves can pass through / be around most objects, so RFID technology is not afraid of being blocked by objects compared to optical recognition technology, greatly improving recognition efficiency. (3) RFID technology has group reading characteristics, and it can identify 1,000 times per second, which is something that optical recognition simply does not have.

[0004] However, most RFID readers on the market currently only support the 920MHz frequency band, meaning they only support a single frequency band and can only transmit signals of a single frequency band. As a result, the RFID tag reflection is also a target signal of a single frequency band, and the useful information carried by a target signal of a single frequency band is limited. Summary of the Invention

[0005] This application provides a radio frequency transceiver structure and a reader / writer to address the problem that the useful information carried by a target signal in a single frequency band is limited.

[0006] To address the aforementioned problems, this application discloses a radio frequency transceiver structure, including a programmable logic module, and a radio frequency transmitting module and a radio frequency receiving module respectively connected to the programmable logic module, wherein:

[0007] The programmable logic module is used to generate digital carrier signals, which are signals containing different frequency bands;

[0008] The radio frequency transmission module is used to convert the digital carrier signal into an analog carrier signal and transmit it outward, so that the radio frequency tag reflects the target signal back after receiving the analog carrier signal;

[0009] The radio frequency receiving module is used to receive the analog carrier leakage signal and the target signal, and to perform carrier cancellation on the analog carrier leakage signal using the analog carrier signal of the radio frequency transmitting module as a reference signal, and to convert the retained useful signal into a digital useful signal after carrier cancellation.

[0010] The programmable logic module is further configured to divide the digital useful signal into processing signals of different frequency bands and process the processing signals.

[0011] Optionally, the programmable logic module includes an encoding module, a first signal generation module, a second signal generation module, and a combining module, wherein:

[0012] The encoding module is used to generate a baseband signal and transmit the baseband signal to the first signal generation module and the second signal generation module respectively.

[0013] The first signal generation module is used to perform spectrum shifting on the baseband signal to obtain a first carrier signal in a first frequency band;

[0014] The second signal generation module is used to perform spectrum shifting on the baseband signal to obtain a second carrier signal in a second frequency band;

[0015] The combining module is used to combine the first carrier signal and the second carrier signal into a dual-band digital carrier signal.

[0016] Optionally, the first signal generation module includes a first finite-length unit impulse response filter, a first mixer, and a first digitally controlled oscillator, wherein: the input terminal of the first finite-length unit impulse response filter is connected to the encoding module, and the output terminal is connected to the input terminal of the first mixer; the input terminal of the first mixer is connected to the first digitally controlled oscillator, and the output terminal is connected to the input terminal of the combining module.

[0017] The second signal generation module includes a second finite-length unit impulse response filter, a second mixer, and a second digitally controlled oscillator, wherein: the input terminal of the second finite-length unit impulse response filter is connected to the encoding module, and the output terminal is connected to the input terminal of the second mixer; the input terminal of the second mixer is connected to the second digitally controlled oscillator, and the output terminal is connected to the input terminal of the combining module.

[0018] Optionally, the radio frequency transmitting module includes a digital-to-analog converter module, an analog signal processing module, and a transmitting module. The analog signal processing module includes a digital step attenuator, a dual-band filter, and a power amplifier. The transmitting module includes a transmitting antenna. The input terminal of the digital-to-analog converter module is connected to the output terminal of the combining module via an interface, and its output terminal is connected to the input terminal of the digital step attenuator. The output terminal of the digital step attenuator is connected to the input terminal of the dual-band filter, and the output terminal of the dual-band filter is connected to the input terminal of the power amplifier. The output terminal of the dual-band filter is also connected to the transmitting antenna.

[0019] Optionally, the digital-to-analog conversion module includes a first low-pass filter, a third mixer, a third digitally controlled oscillator, a gain compensator, and a digital-to-analog converter, wherein: the input terminal of the first low-pass filter is connected to the output terminal of the combining module via an interface, the output terminal of the first low-pass filter is connected to the input terminal of the third mixer, the input terminal of the third mixer is connected to the third digitally controlled oscillator, the output terminal of the third mixer is connected to the input terminal of the gain compensator, the output terminal of the gain compensator is connected to the input terminal of the digital-to-analog converter, and the output terminal of the digital-to-analog converter is connected to the input terminal of the digital step attenuator.

[0020] Optionally, the digital-to-analog conversion module includes a digital-to-analog converter and a quadrature mixer, wherein: the input terminal of the digital-to-analog converter is connected to the output terminal of the combining module through an interface, the output terminal is connected to the input terminal of the quadrature mixer, and the output terminal of the quadrature mixer is connected to the input terminal of the digital step attenuator.

[0021] Optionally, the radio frequency receiving module includes a receiving module, a carrier cancellation module, and an analog-to-digital conversion module, wherein the receiving module includes a receiving antenna, wherein:

[0022] The receiving module is used to receive the target signal and the analog carrier leakage signal;

[0023] The carrier cancellation module is used to perform carrier cancellation on the analog carrier leakage signal using the analog carrier signal of the radio frequency transmission module as a reference signal;

[0024] The analog-to-digital conversion module is used to convert the retained useful signal into a digital useful signal after carrier cancellation.

[0025] Optionally, the carrier cancellation module includes a coupler, a first duplexer, a second duplexer, a third duplexer, a first vector combining circuit, a second vector combining circuit, a first combiner, and a second combiner. The coupler is used to receive the analog carrier signal transmitted by the transmitting antenna. The first duplexer is located after the dual-frequency filter, wherein:

[0026] The coupler is connected to the first duplexer, the first duplexer is connected to the first vector combining circuit and the second vector combining circuit, the second duplexer is connected to the first combiner and the second combiner respectively, the first combiner is connected to the first vector combining circuit, the second combiner is connected to the second vector combining circuit, and the first combiner and the second combiner are connected to the third duplexer.

[0027] Optionally, a low-noise amplifier is further included between the carrier cancellation module and the analog-to-digital conversion module. The analog-to-digital conversion module includes an analog-to-digital converter, a fourth mixer, a fourth digitally controlled oscillator, and a second low-pass filter. The input terminal of the low-noise amplifier is connected to the third duplexer, and its output terminal is connected to the input terminal of the analog-to-digital converter and the input terminal of the fourth mixer. The input terminal of the fourth mixer is connected to the fourth digitally controlled oscillator, and its output terminal is connected to the input terminal of the second low-pass filter. The output terminal of the second low-pass filter is connected to the programmable logic module via an interface.

[0028] Optionally, the programmable logic module further includes a demultiplexing module, a first signal receiving module, a second signal receiving module, and a decoding module, wherein:

[0029] The splitter module is used to divide the digital useful signal into a first digital useful signal in a first frequency band and a second digital useful signal in a second frequency band.

[0030] The first signal receiving module is used to perform spectrum shifting on the first digital useful signal to obtain a first processed signal;

[0031] The second signal receiving module is used to perform spectrum shifting on the second digital useful signal to obtain a second processed signal;

[0032] The decoding module is used to decode the first processed signal and the second processed signal.

[0033] Optionally, the first signal receiving module includes a fifth mixer, a fifth digitally controlled oscillator, and a first half-band decimation filter, wherein: the input terminal of the fifth mixer is connected to the output terminal of the digital filter, the input terminal of the fifth digitally controlled oscillator is connected to the fifth digitally controlled oscillator, the output terminal of the fifth digitally controlled oscillator is connected to the input terminal of the first half-band decimation filter, and the output terminal of the first half-band decimation filter is connected to the decoding module;

[0034] The second signal receiving module includes a sixth mixer, a sixth digitally controlled oscillator, and a second half-band decimation filter, wherein: the input terminal of the sixth mixer is connected to the output terminal of the digital filter, the input terminal of the sixth digitally controlled oscillator is connected to the sixth digitally controlled oscillator, the output terminal of the sixth digitally controlled oscillator is connected to the input terminal of the second half-band decimation filter, and the output terminal of the second half-band decimation filter is connected to the decoding module.

[0035] Optionally, the splitter module is a digital filter.

[0036] Optionally, the first frequency band is 840MHz to 845MHz, and the second frequency band is 920MHz to 925MHz.

[0037] This application also discloses a reader / writer, including the radio frequency transceiver structure as described above; the reader / writer includes a handheld reader / writer and a non-handheld reader / writer.

[0038] Compared with related technologies, the embodiments of this application have the following advantages:

[0039] In this embodiment, the radio frequency transceiver structure includes a programmable logic module, and a radio frequency transmitting module and a radio frequency receiving module respectively connected to the programmable logic module. The programmable logic module generates digital carrier signals containing different frequency bands. The radio frequency transmitting module converts the digital carrier signals into analog carrier signals and transmits them outward, so that the RFID tag reflects the target signal back after receiving the analog carrier signal. The radio frequency receiving module receives the analog carrier leakage signal and the target signal. Since the carrier leakage signal can severely affect the reader's receiving sensitivity, the analog carrier signal from the radio frequency transmitting module is used as a reference signal to perform carrier cancellation on the analog carrier leakage signal. After carrier cancellation, the remaining useful signal is converted into a digital useful signal. Subsequently, the programmable logic module further divides the digital useful signal into processing signals of different frequency bands and processes the processing signals. This embodiment of the radio frequency transceiver structure broadens the spectrum resources, enabling the transmission of digital carrier signals of different frequency bands, allowing the RFID tag to reflect target signals containing different frequency bands. Therefore, the target signal can carry more useful information. Furthermore, even if processing of a certain frequency band fails, processing signals of other frequency bands can be obtained and processed, improving the recognition rate. Attached Figure Description

[0040] Figure 1 This is a structural block diagram of one embodiment of the radio frequency transceiver structure of this application;

[0041] Figure 2 This is a structural block diagram of a radio frequency transceiver structure according to an embodiment of this application;

[0042] Figure 3 This is a circuit diagram of a radio frequency transceiver structure according to an embodiment of this application;

[0043] Figure 4 This is a circuit diagram of another radio frequency transceiver structure according to an embodiment of this application;

[0044] Figure 5 This is a comparative schematic diagram of a radio frequency receiving module according to an embodiment of this application and a traditional radio frequency receiving circuit. Detailed Implementation

[0045] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] Currently, RFID has two frequency bands in China: 840MHz~845MHz and 920MHz~925MHz. Most readers on the market only support the 920MHz~925MHz frequency band. No reader can support multiple frequency bands at the same time, such as dual-band. That is to say, the reader cannot transmit dual-band signals, so the RFID tag cannot reflect back the target signal that carries more useful information in the dual-band.

[0047] To address the aforementioned issues, this application proposes a radio frequency transceiver structure that can transmit carrier signals of different frequency bands, thereby enabling the RFID tag to reflect target signals containing different frequency bands, allowing the target signals to carry more useful information.

[0048] To facilitate understanding of the embodiments of this application by those skilled in the art, some technical terms involved are first introduced, as follows:

[0049] RF: Radio Frequency.

[0050] ADC: Analog-to-Digital converter.

[0051] DAC: Digital-to-Analog converter.

[0052] Radio frequency (RF) sampling is a technique that directly uses an ADC to digitize RF signals. Before the RF signal undergoes analog-to-digital conversion, there is no need to convert the analog frequency to a lower IF (intermediate frequency) or baseband (zero intermediate frequency).

[0053] Oversampling: When the sampling frequency is higher than twice the highest operating frequency of the signal, this type of sampling is called oversampling.

[0054] Undersampling: When the sampling frequency is less than twice the highest operating frequency of the signal, this type of sampling is called undersampling.

[0055] FPGA: Field Programmable Gate Array.

[0056] Duplexer: A duplexer is a three-port radio frequency device consisting of two sets of bandpass filters of different frequencies, which allows the same antenna or transmission line to be used for two signal paths, thereby enabling the same antenna to receive and transmit radio frequency signals of two different frequencies.

[0057] AVSC Circuit: Arbitrary vector synthesis circuit.

[0058] Mixer: Digital mixer.

[0059] NCO: Numerically controlled oscillator, used to generate controllable sine or cosine waves.

[0060] LPF: Low Pass Filter.

[0061] BPF: Bandpass Filter.

[0062] DSA: Digital Step Attenator.

[0063] LNA: Low Noise Amplifier.

[0064] FIR filter: Finite Impulse Response filter, can guarantee arbitrary amplitude frequency characteristics while having strictly linear phase frequency characteristics. At the same time, its unit sample response is finite in length, so the filter is a stable system.

[0065] HBF: Half Band Filter, a half-band decimation filter, is particularly suitable for implementing decimation by powers of 2, and has high computational efficiency and strong real-time performance.

[0066] PA: Power Amplifier.

[0067] TXLO: TX local oscillator signal.

[0068] TX Antenna: Transmit Antenna.

[0069] RX Antenna: Receiver Antenna.

[0070] x / sin(x): Gain compensator.

[0071] Interface: Interface.

[0072] IF amplifier: Intermediate frequency amplifier.

[0073] Reference Figure 1 This is a structural block diagram of an embodiment of a radio frequency transceiver structure according to this application, including a programmable logic module 101, and a radio frequency transmitting module 102 and a radio frequency receiving module 103 respectively connected to the programmable logic module 101, wherein:

[0074] The programmable logic module 101 is used to generate digital carrier signals, which are signals containing different frequency bands.

[0075] The radio frequency transmission module 102 is used to convert the digital carrier signal into an analog carrier signal and transmit it outward, so that the radio frequency tag reflects the target signal back after receiving the analog carrier signal, and the target signal includes the analog carrier signal and the useful signal.

[0076] The radio frequency receiving module 103 is used to receive the analog carrier leakage signal and the target signal, and to perform carrier cancellation on the analog carrier leakage signal using the analog carrier signal of the radio frequency transmitting module as a reference signal, and to convert the retained useful signal into a digital useful signal after carrier cancellation.

[0077] The programmable logic module 101 is further configured to divide the digital useful signal into processing signals of different frequency bands and process the processing signals.

[0078] The radio frequency transceiver structure can be applied to a reader, which can include handheld and non-handheld readers. The radio frequency tag can be an RFID tag worn on a person or attached to an object, such as clothing, forklifts, goods, or valuables. As an example of this application, the radio frequency tag can be a passive RFID tag.

[0079] In this context, the analog carrier signal does not carry information; from a frequency domain perspective, it is equivalent to a single-tone signal. Specifically, the main functions of the analog carrier signal are: 1. to continuously power the RFID tag; and 2. to provide a carrier signal for the tag's useful signals. Specifically, the reader's RF transceiver structure can generate an analog carrier signal containing different frequency bands. For example, assuming 840MHz and 920MHz, the carrier signal would contain signals from both the 840MHz and 920MHz frequency bands. This type of signal with two frequency bands is commonly referred to as a dual-band signal.

[0080] To enable transmission in a wireless environment, the RF transmitting module 102 converts the digital carrier signal into an analog carrier signal, allowing the analog carrier signal to be transmitted to the RFID tag. Upon receiving the analog carrier signal, the RFID tag superimposes the useful signal onto the analog carrier to obtain the target signal, which is then reflected back to the RF receiving module 103. It is important to note that if the analog carrier signal is dual-band, the RFID tag can superimpose the useful signal onto each of the two analog carrier signals to obtain a dual-band target signal. In this embodiment, each frequency band contains at least one carrier signal. Specifically, assuming two frequency bands, each band contains one carrier signal, and one carrier signal corresponds to one channel. One reader / writer can simultaneously transmit multiple carrier signals from different frequency bands. For ease of understanding, the following explanation primarily uses a dual-band example.

[0081] Specifically, in addition to receiving the target signal reflected back by the RFID tag, the RF receiving module 103 can also receive the analog carrier signal from the RF transmitting module 102. Since the carrier leakage signal from the RF transmitting module 102 to the RF receiving module 103 is significant, it severely affects the receiver's receiving sensitivity. Therefore, this embodiment uses the analog carrier signal from the RF transmitting module 102 as a reference signal to perform carrier cancellation on the analog carrier leakage signal. It should be noted that since the analog carrier signal in this embodiment is a dual-band carrier signal, carrier cancellation is performed separately for each frequency band of the target signal before combining them into a digital useful signal and transmitting it to the programmable logic module 101 for further processing.

[0082] As a concrete example, analog carrier signals containing different frequency bands are transmitted from the reader to the RFID tag. As the internal switches of the RFID tag are turned on and off, the useful information carried by the RFID tag is modulated onto the analog carrier signal to obtain the target signal, which is then transmitted to the reader. The reader demodulates the useful information of the RFID tag from the target signal, thereby completing data communication.

[0083] In practical applications, the advantages of multi-carrier technology for readers are: 1. The distance between the reader and the RFID tag can be calculated by the phase difference between the two carrier signals; 2. Multi-carrier technology helps improve the recognition rate of the RFID system; 3. Multi-carrier technology can increase the data rate of the reader. The basic principle of calculating the distance between the reader and the tag based on the phase difference of the two carrier phases is that the two carrier signals each have two corresponding different carrier frequencies. Electromagnetic waves of two different frequencies travel the same distance in space. (m*2*pi+α)*λ1=(n*2*pi+β)*λ2, where α and β correspond to the phases of different carrier signals, λ1 and λ2 correspond to the wavelengths of different carrier signals, pi is pi, a constant, where wavelength is related to carrier frequency, that is, different carrier frequencies correspond to different wavelengths, and m and n are integers that need to be calculated. In addition, the distance from the reader to the RFID tag is 0.5*(m*2*pi+α)*λ1. The carrier signal emitted by the reader is transmitted to the RFID tag and then returns to the reader, so the distance is half, that is, 0.5.

[0084] In this embodiment of the application, the radio frequency transmitting module 102 can transmit analog carrier signals as single-tone signals as well as multi-tone signals, that is, information is carried on the analog carrier, such as the loop instructions of the anti-collision algorithm.

[0085] As a specific example, PIE (Pulse Interval Encoding) is used as the encoding method for the programmable logic module 101 to transmit data to the RFID tag. Specifically, there are four PIE encoding symbols: data 0, data 1, Start of Frame (SOF), and End of Frame (EOF), each representing a time interval of 1, 2, and 4 times, respectively. The characteristics of PIE encoding are: the bit time can be changed, and its time value can be adjusted according to the locally permitted spectrum; the binary data can be easily detected after it appears because a large number of pulse signals are transmitted; when no information appears, there is a large amount of idle time in the time slot that can be used for remote power supply; it has a longer average charging time than other encoding methods, enabling it to provide a higher energy conversion level for the RFID tag and potentially a longer communication distance.

[0086] Specifically, in addition to transmitting analog carrier signals without information, the RF transmitting module 102 can also transmit analog carrier signals carrying information, namely PIE signals, which mainly contain request information from the reader to the RFID tag, such as sending loop instructions for the anti-collision algorithm. From a frequency domain perspective, the PIE signal is equivalent to a carrier signal plus a useful signal, making it a multi-tone signal.

[0087] It should be noted that in this embodiment, the RF transmitting module 102 transmits only a single-carrier signal when sending the PIE signal, with the carrier frequency located in the 845MHz-850MHz band. The main basis for this approach is that, according to the requirements of the Radio Management Committee, the EIRP (Equivalent Isotropically Radiated Power) of an RFID reader's antenna is 2 watts (W). Therefore, when the reader transmits two carrier signals, each carrier signal has an EIRP of 1 watt. Furthermore, as the carrier frequency increases, the attenuation of electromagnetic waves over the same spatial distance increases; that is, the attenuation of an 840MHz carrier signal over a 1m space is less than that of a 920MHz carrier signal. Therefore, to ensure that the PIE signal strength reaches the RFID tag as high as possible to activate tags at greater distances, this embodiment selects an 840MHz single-carrier signal to modulate the PIE signal. Of course, if the RFID tag is primarily targeted at shorter distances, a dual-band multi-carrier method is also used to transmit the PIE signal; this embodiment does not impose any restrictions on this.

[0088] In the aforementioned radio frequency (RF) transceiver structure, the RF transceiver structure includes a programmable logic module (PLM) and an RF transmitting module and an RF receiving module respectively connected to the PLM. The PLM generates digital carrier signals containing different frequency bands. The RF transmitting module converts the digital carrier signals into analog carrier signals and transmits them, so that the RFID tag reflects the target signal back after receiving the analog carrier signal. The RF receiving module receives the analog carrier leakage signal and the target signal. Since the carrier leakage signal severely affects the reader's receiving sensitivity, the analog carrier signal from the RF transmitting module is used as a reference signal to perform carrier cancellation on the analog carrier leakage signal. After carrier cancellation, the remaining useful signal is converted into a digital useful signal. Subsequently, the PLM also divides the digital useful signal into processing signals of different frequency bands and processes the processing signals. The RF transceiver structure of this embodiment broadens the spectrum resources, enabling the transmission of digital carrier signals of different frequency bands, allowing the RFID tag to reflect target signals containing different frequency bands. Therefore, the target signal can carry more useful information. Furthermore, even if processing of a certain frequency band fails, processing of other frequency bands can be obtained, improving the recognition rate.

[0089] In one exemplary embodiment, reference is made to Figure 2 The programmable logic module includes an encoding module 201, a first signal generation module 202, a second signal generation module 203, and a combining module 204, wherein:

[0090] The encoding module 201 is used to generate a baseband signal and transmit the baseband signal to the first signal generation module 202 and the second signal generation module 203 respectively.

[0091] The first signal generation module 202 is used to perform spectrum shifting on the baseband signal to obtain a first carrier signal in a first frequency band;

[0092] The second signal generation module 203 is used to perform spectrum shifting on the baseband signal to obtain a second carrier signal in the second frequency band;

[0093] The combining module 204 is used to combine the first carrier signal and the second carrier signal into a dual-band digital carrier signal.

[0094] The first frequency band is 840MHz to 845MHz, and the second frequency band is 920MHz to 925MHz.

[0095] Specifically, the encoding module 201 generates a baseband signal, and then transmits the baseband signal to the first signal generation module 202 and the second signal generation module 203 respectively, so that the first signal generation module 202 and the second signal generation module 203 respectively perform spectrum shifting on the baseband signal to obtain a first carrier signal in a first frequency band and a second carrier signal in a second frequency band. For example, the first carrier signal is a signal in the frequency band of 840MHz to 845MHz, and the second carrier signal is a signal in the frequency band of 840MHz to 845MHz. Then, the first carrier signal and the second carrier signal are combined into a digital carrier signal with dual frequency bands through the combining module 204.

[0096] In one exemplary embodiment, reference is made to Figure 3 The first signal generation module 202 includes a first finite-length unit impulse response filter, a first mixer, and a first digitally controlled oscillator, wherein: the input terminal of the first finite-length unit impulse response filter is connected to the encoding module, and the output terminal is connected to the input terminal of the first mixer; the input terminal of the first mixer is connected to the first digitally controlled oscillator, and the output terminal is connected to the input terminal of the combining module.

[0097] The second signal generation module 203 includes a second finite-length unit impulse response filter, a second mixer, and a second digitally controlled oscillator, wherein: the input terminal of the second finite-length unit impulse response filter is connected to the encoding module, and the output terminal is connected to the input terminal of the second mixer; the input terminal of the second mixer is connected to the second digitally controlled oscillator, and the output terminal is connected to the input terminal of the combining module.

[0098] Specifically, the encoding module 201 generates a baseband signal, which includes I and Q signals. The I and Q signals are interpolated by a factor of N (e.g., N = 400) using an FIR filter. Then, the I and Q signals undergo spectral shifting using a mixer and an NCO, referring to... Figure 3 The first carrier signal, designated as the first frequency band, is obtained by spectrum shifting using Mixer and NCO1. The second carrier signal, designated as the second frequency band, is obtained by spectrum shifting using Mixer and NCO2. For example, the first carrier signal (Carrier1) is located within the first frequency band of 840MHz to 845MHz, and the second carrier signal (Carrier2) is located within the first frequency band of 920MHz to 925MHz. The I and Q signals of the same carrier signal have the same NCO frequency value; for example, the NCO frequency value of the first carrier signal is 0–5MHz, spaced 250kHz apart, and the NCO frequency value of the second carrier signal is 80–85MHz, also spaced 250kHz apart. Finally, the first and second carrier signals are combined into a digital carrier signal in the combiner module 204 and then transmitted to the radio frequency transmission module 102 via an interface such as a serial interface.

[0099] In one exemplary embodiment, the radio frequency transmitting module 102 includes a digital-to-analog converter module 205, an analog signal processing module 206, and a transmitting module 207. The analog signal processing module 206 includes a digital step attenuator, a dual-band filter, and a power amplifier. The transmitting module 207 includes a transmitting antenna. The input terminal of the digital-to-analog converter module is connected to the output terminal of the combining module via an interface, and the output terminal is connected to the input terminal of the digital step attenuator. The output terminal of the digital step attenuator is connected to the input terminal of the dual-band filter, the output terminal of the dual-band filter is connected to the input terminal of the power amplifier, and the output terminal is connected to the transmitting antenna.

[0100] Specifically, after the digital carrier signal is combined by the combiner module 204, the digital carrier signal is transmitted from the serial interface to the digital-to-analog converter module 205. The digital-to-analog converter module 205 converts it into an analog carrier signal, which then passes through DSA and BPF (used to filter out spurious signals generated by the digital-to-analog converter module 205), then through the Power Amplifier, and finally output from TXAntenna.

[0101] In the embodiments of this application, the digital-to-analog conversion module 205 can be implemented in various ways, such as an RF sampling scheme or a zero intermediate frequency scheme. Of course, apart from the digital-to-analog conversion module 205, the other parts of the RF transceiver structure are the same.

[0102] If an radio frequency sampling scheme is adopted, refer to... Figure 3The digital-to-analog converter module 205 includes a first low-pass filter, a third mixer, a third digitally controlled oscillator, a gain compensator, and a digital-to-analog converter. The input of the first low-pass filter is connected to the output of the combining module via an interface, and its output is connected to the input of the third mixer. The input of the third mixer is connected to the third digitally controlled oscillator, and its output is connected to the input of the gain compensator. The output of the gain compensator is connected to the input of the digital-to-analog converter, and the output of the digital-to-analog converter is connected to the input of the digital step attenuator.

[0103] Specifically, in the RF sampling scheme, the LPF in the digital-to-analog converter module 205 receives the digital carrier signal, interpolates the I and Q signals of the digital carrier signal by a factor of M (tentatively M=20), then shifts the spectrum to 840MHz via a Mixer and NCO3, performs gain compensation using x / sin(x), and finally outputs an analog carrier signal (RF signal) via a DAC, which is then transmitted to the DAC in the analog signal processing module 206. The sampling rate of the DAC is set to 4000Mbps.

[0104] If a zero-IF scheme is adopted, refer to... Figure 4 The digital-to-analog conversion module 205 includes a digital-to-analog converter and a quadrature mixer, wherein: the input terminal of the digital-to-analog converter is connected to the output terminal of the combining module through an interface, the output terminal is connected to the input terminal of the quadrature mixer, and the output terminal of the quadrature mixer is connected to the input terminal of the digital step attenuator.

[0105] Specifically, in the zero-IF scheme, the DAC in the digital-to-analog converter module 205 receives the digital carrier signal (data bandwidth 100 MHz), the DAC's sampling rate is set to 2000 Mbps, with 10x oversampling, and finally, the analog carrier signal is output through the TXLO and transmitted to the DAS in the analog signal processing module 206. It can be understood that because the zero-IF scheme requires fewer components, it can save considerable costs compared to the RF sampling scheme, which is beneficial for expanding its application range.

[0106] In one exemplary embodiment, reference is made to Figure 2 The radio frequency receiving module 103 includes a receiving module 208, a carrier cancellation module 209, and an analog-to-digital conversion module 210. The receiving module 208 includes a receiving antenna, wherein:

[0107] The receiving module 208 is used to receive the target signal and the analog carrier leakage signal;

[0108] The carrier cancellation module 209 is used to perform carrier cancellation on the analog carrier leakage signal using the analog carrier signal of the radio frequency transmission module as a reference signal;

[0109] The analog-to-digital conversion module 210 is used to convert the retained useful signal into a digital useful signal after carrier cancellation.

[0110] Specifically, after the receiving module 208 receives the analog carrier signal and the target signal, the carrier cancellation module 209 performs carrier cancellation on the target signal using the analog carrier signal as a reference signal. Finally, the analog-to-digital conversion module 210 converts the carrier-cancelled useful signal into a digital useful signal and transmits it to the programmable logic module 101.

[0111] In one exemplary embodiment, reference is made to Figure 3 The carrier cancellation module 209 includes a coupler, a first duplexer, a second duplexer, a third duplexer, a first vector combining circuit, a second vector combining circuit, a first combiner, and a second combiner. The coupler is used to receive the analog carrier signal transmitted by the transmitting antenna. The first duplexer is located after the dual-frequency filter, wherein:

[0112] The coupler is connected to the first duplexer, the first duplexer is connected to the first vector combining circuit and the second vector combining circuit, the second duplexer is connected to the first combiner and the second combiner respectively, the first combiner is connected to the first vector combining circuit, the second combiner is connected to the second vector combining circuit, and the first combiner and the second combiner are connected to the third duplexer.

[0113] The coupler's coupling end is connected to Duplexer2, and its isolation end is grounded. As an example of this application, the coupler is located after the BPF of the RF transmitter module 102. This is because the group delay of the BPF is usually large. With the coupler located after the BPF, the group delay of the analog carrier signal (reference signal) coupled to the coupler and the interfering carrier signal leaking from the TX Antenna to the RX Antenna is smaller, which is beneficial for carrier cancellation.

[0114] Specifically, the analog carrier signal obtained by the coupler is split into two signals of different frequency bands by Duplexer1. One is the first frequency band 840MHz, and the other is the second frequency band 920MHz. The 840MHz signal enters AVS circuit1, and the 920MHz signal enters AVS circuit2.

[0115] The RX Antenna connects to Duplexer2, which outputs signals in two different frequency bands: 840MHz and 920MHz. The RX Antenna receives interference carrier signals leaked from the TX Antenna (analog carrier leakage signals of 840MHz + 920MHz) and target signals reflected from the RFID tag (analog carrier signals of 840MHz + 920MHz and the useful signal carried by the analog carrier signal, the frequency of which is 40kHz to 500kHz away from the carrier frequency in the frequency domain). Duplexer2 separates the 840MHz and 920MHz signals. One output of Duplexer2 only outputs the signal near 840MHz, filtering out the 920MHz signal; the other output only outputs the signal near 920MHz, filtering out the 840MHz signal.

[0116] Then, the 840MHz signal output from one path of Duplexer1, along with the output signal from AVS circuit 1 and the 840MHz signal from Duplexer 2, enters Combiner 1. When the output signal from AVS circuit 1 and the analog carrier leakage signal are of equal amplitude and out of phase, the analog carrier leakage signal is weakened, achieving carrier cancellation. Currently, carrier cancellation capabilities vary in the industry, typically ranging from 20 to 40 dBc. Similarly, the carrier cancellation process for the 920MHz target signal is similar. Specifically, the 920MHz signal output from another path of Duplexer1, along with the output signal from AVS circuit 2 and the 920MHz signal from Duplexer 2, enters Combiner 2. When the output signal from AVS circuit 2 and the analog carrier leakage signal are of equal amplitude and out of phase, the analog carrier leakage signal is weakened, achieving carrier cancellation.

[0117] Finally, the 840MHz and 920MHz carriers are canceled out to obtain two signals, which are then combined by Duplexer3 to form a broadband dual-carrier signal, i.e., the analog useful signal.

[0118] It should be noted that in this embodiment, the signal is first separated using a duplexer before carrier cancellation is performed. This is because the frequency difference between 840MHz and 920MHz is significant, resulting in substantial differences in phase and amplitude attenuation in free space and on the transmission line. To achieve high-performance carrier cancellation, the reference and target signals must be equal in amplitude and inversely phased. That is, if the carrier cancellation effect is good for the 840MHz carrier signal, the effect for the 920MHz carrier signal may be poor. This is mainly because the degree of carrier cancellation depends on the equal amplitude and inverse phase of the reference and target signals. With the same circuit trace length, signals of different frequencies will have different phase delays after passing through the trace. While signals at 840MHz may be equal in amplitude and inversely phased, they may deviate by 30° at 920MHz. Therefore, the carrier cancellation effect at 920MHz is very poor, leading to a severe deterioration in the receiving sensitivity of the 920MHz signal.

[0119] Of course, if the frequencies of the two carrier signals are very close in the frequency domain, say 5MHz, then a duplexer is not needed, and carrier cancellation can be performed directly. The reasons are: 1. It is difficult to implement a duplexer with a transition band of only 5MHz; 2. At this point, the phase and attenuation differences between the two carriers in free space and on the transmission line are relatively small, and the impact on the carrier cancellation effect is within an acceptable range. In summary, a duplexer is essential for achieving high-performance carrier cancellation, enabling the separation of carrier signals in different frequency bands, followed by individual carrier cancellation, and finally combining them to form a broadband dual-carrier signal.

[0120] Furthermore, the advantage of combining the carrier signals after carrier cancellation via Duplexer3 is that, compared to the scheme without carrier cancellation, two additional RF receiving channels are required, which increases cost. Also, using two different RF receiving channels for 840MHz and 920MHz signals is detrimental to calculating transmission path delay (or phase). Additionally, the subsequent LNA and RF ADC (i.e., analog-to-digital converter module 210) are both broadband devices that support high-bandwidth input signals. Therefore, in this embodiment, combining the signals via Duplexer3 after carrier cancellation is chosen.

[0121] In one exemplary embodiment, reference is made to Figure 3The carrier cancellation module 209 and the analog-to-digital conversion module 210 are further connected by a low-noise amplifier. The analog-to-digital conversion module 210 includes an analog-to-digital converter, a fourth mixer, a fourth digitally controlled oscillator, and a second low-pass filter. The input terminal of the low-noise amplifier is connected to the third duplexer, the output terminal is connected to the input terminal of the analog-to-digital converter, and the output terminal is connected to the input terminal of the fourth mixer. The input terminal of the fourth mixer is connected to the fourth digitally controlled oscillator, and the output terminal is connected to the input terminal of the second low-pass filter. The output terminal of the second low-pass filter is connected to the programmable logic module 101 through an interface.

[0122] Specifically, the digital useful signal after being combined by Duplexer3 enters the LNA. The LNA's main function is to reduce cascaded thermal noise in the link, which is crucial for improving the sensitivity of the receiving link (RX link) of the RF receiving module 103. Generally, the higher the LNA gain, the lower the cascaded noise figure of the receiving link. Since the dynamic range of the ADC in the analog-to-digital converter module 210 is limited, when the ADC input power exceeds a certain threshold, ADC saturation occurs, leading to spectrum regeneration, which in turn worsens the ADC noise floor and ultimately degrades the receiving sensitivity of the receiving link.

[0123] Specifically, the impact of carrier cancellation on receiver sensitivity includes two aspects: its impact on thermal noise and its impact on phase noise.

[0124] Among these factors, carrier cancellation has an impact on thermal noise. When carrier cancellation is poor, the amplitude of the carrier signal entering the LNA is larger. To prevent ADC saturation, the gain of the receiving link is lower, resulting in higher cascaded thermal noise and thus lower receiver sensitivity (a lower receiver sensitivity value indicates better receiver performance). For example, assuming an ADC with a full-scale range of 1.3V and an LNA gain of 20dB, the amplitude of the carrier signal entering the LNA cannot exceed -17dBm to prevent ADC saturation. Assuming the TX antenna output power is 33dBm and the isolation between the TX and RX antennas is 10dB, then the required carrier cancellation capability is greater than 33dBm - 10dB - (-17dBm) = 40dB.

[0125] Among these factors, carrier cancellation has an impact on phase noise. The phase noise of the carrier signal affects the demodulation of the useful signal, primarily because the carrier signal has a high power spectral density of 33 dBm / Hz (compared to -30 dBm / Hz in most mobile communications); the useful signal is very close to the carrier signal, within 500 kHz. Since the carrier cancellation module 209 is a relatively wide-spectrum system, it can not only cancel the carrier, but also cancel the carrier phase noise if the reference signal and target signal have the same time delay, and the degree of cancellation is comparable. That is, if the carrier cancellation circuit has a 40 dB cancellation capability for the carrier signal, then it also has a 40 dB cancellation capability for the phase noise of the carrier signal. In RFID communication systems, carrier phase noise usually has a more significant impact on receiver sensitivity; only when the phase noise is very low does the impact of thermal noise on receiver sensitivity become apparent.

[0126] Specifically, the digital useful signal after being combined by Duplexer 3 enters the LNA, then the analog-to-digital converter module 210, and finally the programmable logic module 101. The LNA's function, besides reducing cascaded thermal noise in the link, is to amplify the received digital useful signal for easier ADC sampling. The digital useful signal then enters the analog-to-digital converter module 210, such as an RF ADC chip. RF ADC chips typically include a high-speed ADC, a mixer, an NCO, and an LPF. The high-speed ADC directly samples the RF signal, digitizing it without analog domain mixing. The mixer and NCO perform a spectrum shift in the digital domain, moving the useful signal to near the zero frequency of the first Nyquist domain, thus avoiding signal loss during decimation. The LPF filters and decimates the digital signal, reducing its rate without losing the useful signal, thereby reducing the interface rate between the RF ADC and the programmable logic module 101. The main benefits of reducing the interface rate are: saving power consumption of the analog-to-digital converter module 210 and the programmable logic module 101; the lower the data rate, the lower the transmission power consumption; and reducing the transmission rate can also reduce problems caused by signal integrity.

[0127] In practical applications, according to the Nyquist sampling theorem, to reconstruct a simulated signal without distortion from discrete sampled signals, the sampling rate should be greater than twice the highest frequency of the signal; this type of sampling is called oversampling. When fH□B = fH - fL, where fH and fL are the highest and lowest operating frequencies, respectively, and B is the operating bandwidth, the highest operating frequency is much greater than the operating bandwidth. If the Nyquist sampling rate is still used, the sampling frequency will be very high, making it difficult to implement (ADC costs increase with higher sampling rates), or the speed of subsequent processing stages may not meet the requirements (higher sampling rates require faster signal transmission lines). In this case, bandpass sampling can be used to reduce the sampling rate, i.e., RF undersampling. When the bandwidth B is constant, the center frequency of the bandpass signal satisfies f0 = (n + 0.5)B, and the lowest sampling rate, twice the bandwidth fs = 2B, can be used to sample the bandpass signal. The bandpass sampling theorem applies only if a signal exists in only one frequency band, and not simultaneously in different frequency bands, otherwise aliasing will occur. For example, using a sampling rate of fs = 2B, signals in the 2B and 3B bands can be bandpass sampled, but signals in other bands, such as 4B and 5B, cannot exist. Therefore, signals from other passbands need to be filtered out before bandpass sampling, retaining only the signal from the current passband.

[0128] Reference Figure 5 This diagram illustrates a comparison between an RF receiver module and a traditional RF receiver circuit. It shows the difference between the digital-to-analog converter (DAC) module 205 of the RF sampling scheme in this application and a traditional zero-IF receiver. Specifically, the DAC module 205 of the RF sampling scheme is an RF ADC, replacing the Mixer+IF amplifier+BPF+ADC in a traditional zero-IF receiver. Because the number of components in the RF ADC is significantly reduced, it reduces the amount of materials used, cost, design time, size, weight, and power consumption, while increasing software programmability and system flexibility. RF sampling is crucial for realizing true software-defined radio, and it also has significant advantages in high-bandwidth communication systems.

[0129] Alternatively, the analog-to-digital converter module 210 here can perform real sampling, in which case the analog-to-digital converter module 210 outputs a real signal, which is then orthogonalized in the programmable logic module 101 to generate I and Q signals; or a complex-sampling analog-to-digital converter module 210 can be selected, in which case the I and Q signals output by the analog-to-digital converter module 210 directly enter the programmable logic module 101.

[0130] In one exemplary embodiment, reference is made to Figure 2The programmable logic module 101 further includes a splitter module 211, a first signal receiving module 212, a second signal receiving module 213, and a decoding module 214, wherein:

[0131] The splitting module 211 is used to divide the digital useful signal into a first digital useful signal in a first frequency band and a second digital useful signal in a second frequency band.

[0132] The first signal receiving module 212 is used to perform spectrum shifting on the first digital useful signal to obtain a first processed signal;

[0133] The second signal receiving module 213 is used to perform spectrum shifting on the second digital useful signal to obtain a second processed signal;

[0134] The decoding module 214 is used to decode the first processed signal and the second processed signal.

[0135] The splitter module 211 can be a digital filter, and the programmable logic modules 101GA are connected through a high-speed data interface, such as JESD.

[0136] Specifically, the digital useful signal enters the programmable logic module 101, and then passes through a digital filter to split the received digital useful signal into multiple paths (digital channelization, separating different carrier signals), resulting in a first digital useful signal and a second digital useful signal in a first frequency band and a second frequency band, respectively. Then, in the first signal receiving module 212 and the second signal receiving module 213, the different frequency bands are subjected to spectrum shifting to obtain a first processed signal and a second processed signal. Finally, the demodulation of the first processed signal and the second processed signal is completed in the decoding module 214.

[0137] In an exemplary embodiment, the first signal receiving module includes a fifth mixer, a fifth digitally controlled oscillator, and a first half-band decimation filter, wherein: the input terminal of the fifth mixer is connected to the output terminal of the digital filter, the input terminal of the fifth digitally controlled oscillator is connected to the fifth digitally controlled oscillator, the output terminal of the fifth digitally controlled oscillator is connected to the input terminal of the first half-band decimation filter, and the output terminal of the first half-band decimation filter is connected to the decoding module;

[0138] The second signal receiving module includes a sixth mixer, a sixth digitally controlled oscillator, and a second half-band decimation filter, wherein: the input terminal of the sixth mixer is connected to the output terminal of the digital filter, the input terminal of the sixth digitally controlled oscillator is connected to the sixth digitally controlled oscillator, the output terminal of the sixth digitally controlled oscillator is connected to the input terminal of the second half-band decimation filter, and the output terminal of the second half-band decimation filter is connected to the decoding module.

[0139] Specifically, different frequency bands are further spectrum-shifted using a Mixer and an NCO (shifting the channel of the signal of interest to the baseband). Simultaneously, an LPF is used to filter and decimate the digital domain signal (filtering mainly removes harmonic components and other unwanted signals), further reducing the digital signal rate (decimation is used to achieve sampling rate conversion, reducing the sampling rate and processing burden), resulting in a first processed signal and a second processed signal. Finally, the decoding module 214 demodulates both the first and second processed signals.

[0140] In summary, the embodiments of this application have at least the following advantages: 1. Applying radio frequency sampling to the reader is promising for future high-bandwidth applications; 2. Proposing an implementation scheme for a dual-frequency reader broadens spectrum resources; 3. The reader can support multi-carrier configuration, increasing the transmission rate, and can also obtain phase difference, which has great potential for future positioning.

[0141] Based on the above-described radio frequency transceiver structure embodiments, this application also provides a reader / writer, which includes the above-described radio frequency transceiver structure and may include a handheld reader / writer and a non-handheld reader / writer.

[0142] Specifically, the reader's radio frequency transceiver structure includes a programmable logic module, and a radio frequency transmitting module and a radio frequency receiving module respectively connected to the programmable logic module, wherein:

[0143] The programmable logic module is used to generate digital carrier signals, which are signals containing different frequency bands;

[0144] The radio frequency transmitting module is used to convert the digital carrier signal into an analog carrier signal and transmit it outward, so that the radio frequency tag reflects the target signal back after receiving the analog carrier signal;

[0145] The radio frequency receiving module is used to receive the analog carrier leakage signal and the target signal, and to perform carrier cancellation on the analog carrier leakage signal using the analog carrier signal of the radio frequency transmitting module as a reference signal, and to convert the retained useful signal into a digital useful signal after carrier cancellation.

[0146] The programmable logic module is further configured to divide the digital useful signal into processing signals of different frequency bands and process the processing signals.

[0147] In an exemplary embodiment, the programmable logic module includes an encoding module, a first signal generation module, a second signal generation module, and a combining module, wherein:

[0148] The encoding module is used to generate a baseband signal and transmit the baseband signal to the first signal generation module and the second signal generation module respectively.

[0149] The first signal generation module is used to perform spectrum shifting on the baseband signal to obtain a first carrier signal in a first frequency band;

[0150] The second signal generation module is used to perform spectrum shifting on the baseband signal to obtain a second carrier signal in a second frequency band;

[0151] The combining module is used to combine the first carrier signal and the second carrier signal into a dual-band digital carrier signal.

[0152] In an exemplary embodiment, the first signal generation module includes a first finite-length unit impulse response filter, a first mixer, and a first digitally controlled oscillator, wherein: the input terminal of the first finite-length unit impulse response filter is connected to the encoding module, and the output terminal is connected to the input terminal of the first mixer; the input terminal of the first mixer is connected to the first digitally controlled oscillator, and the output terminal is connected to the input terminal of the combining module.

[0153] The second signal generation module includes a second finite-length unit impulse response filter, a second mixer, and a second digitally controlled oscillator, wherein: the input terminal of the second finite-length unit impulse response filter is connected to the encoding module, and the output terminal is connected to the input terminal of the second mixer; the input terminal of the second mixer is connected to the second digitally controlled oscillator, and the output terminal is connected to the input terminal of the combining module.

[0154] In one exemplary embodiment, the radio frequency transmitting module includes a digital-to-analog converter module and an analog signal processing module. The analog signal processing module includes a digital step attenuator, a dual-band filter, a power amplifier, and a transmitting antenna. The input terminal of the digital-to-analog converter module is connected to the output terminal of the combining module via an interface, and its output terminal is connected to the input terminal of the digital step attenuator. The output terminal of the digital step attenuator is connected to the input terminal of the dual-band filter, the output terminal of the dual-band filter is connected to the input terminal of the power amplifier, and its output terminal is connected to the transmitting antenna.

[0155] In one exemplary embodiment, the digital-to-analog converter module includes a first low-pass filter, a third mixer, a third digitally controlled oscillator, a gain compensator, and a digital-to-analog converter, wherein: the input terminal of the first low-pass filter is connected to the output terminal of the combining module via an interface, the output terminal of the first low-pass filter is connected to the input terminal of the third mixer, the input terminal of the third mixer is connected to the third digitally controlled oscillator, the output terminal of the third mixer is connected to the input terminal of the gain compensator, the output terminal of the gain compensator is connected to the input terminal of the digital-to-analog converter, and the output terminal of the digital-to-analog converter is connected to the input terminal of the digital step attenuator.

[0156] In one exemplary embodiment, the digital-to-analog conversion module includes a digital-to-analog converter and a quadrature mixer, wherein: the input terminal of the digital-to-analog converter is connected to the output terminal of the combining module via an interface, the output terminal is connected to the input terminal of the quadrature mixer, and the output terminal of the quadrature mixer is connected to the input terminal of the digital step attenuator.

[0157] In an exemplary embodiment, the radio frequency receiving module includes a receiving module, a carrier cancellation module, and an analog-to-digital conversion module. The receiving module includes a receiving antenna, wherein:

[0158] The receiving module is used to receive the target signal and the analog carrier leakage signal;

[0159] The carrier cancellation module is used to perform carrier cancellation on the analog carrier leakage signal using the analog carrier signal of the radio frequency transmission module as a reference signal;

[0160] The analog-to-digital conversion module is used to convert the retained useful signal into a digital useful signal after carrier cancellation.

[0161] In an exemplary embodiment, the carrier cancellation module includes a coupler, a first duplexer, a second duplexer, a third duplexer, a first vector combining circuit, a second vector combining circuit, a first combiner, and a second combiner. The coupler is used to receive the analog carrier signal transmitted by the transmitting antenna. The first duplexer is located after the dual-frequency filter, wherein:

[0162] The coupler is connected to the first duplexer, the first duplexer is connected to the first vector combining circuit and the second vector combining circuit, the second duplexer is connected to the first combiner and the second combiner respectively, the first combiner is connected to the first vector combining circuit, the second combiner is connected to the second vector combining circuit, and the first combiner and the second combiner are connected to the third duplexer.

[0163] In one exemplary embodiment, a low-noise amplifier is further included between the carrier cancellation module and the analog-to-digital conversion module. The analog-to-digital conversion module includes an analog-to-digital converter, a fourth mixer, a fourth digitally controlled oscillator, and a second low-pass filter. The input terminal of the low-noise amplifier is connected to the third duplexer, and its output terminal is connected to the input terminal of the analog-to-digital converter and the input terminal of the fourth mixer. The input terminal of the fourth mixer is connected to the fourth digitally controlled oscillator, and its output terminal is connected to the input terminal of the second low-pass filter. The output terminal of the second low-pass filter is connected to the programmable logic module via an interface.

[0164] In one exemplary embodiment, the programmable logic module further includes a demultiplexing module, a first signal receiving module, a second signal receiving module, and a decoding module, wherein:

[0165] The splitter module is used to divide the digital useful signal into a first digital useful signal in a first frequency band and a second digital useful signal in a second frequency band.

[0166] The first signal receiving module is used to perform spectrum shifting on the first digital useful signal to obtain a first processed signal;

[0167] The second signal receiving module is used to perform spectrum shifting on the second digital useful signal to obtain a second processed signal;

[0168] The decoding module is used to decode the first processed signal and the second processed signal.

[0169] In an exemplary embodiment, the first signal receiving module includes a fifth mixer, a fifth digitally controlled oscillator, and a first half-band decimation filter, wherein: the input terminal of the fifth mixer is connected to the output terminal of the digital filter, the input terminal of the fifth digitally controlled oscillator is connected to the fifth digitally controlled oscillator, the output terminal of the fifth digitally controlled oscillator is connected to the input terminal of the first half-band decimation filter, and the output terminal of the first half-band decimation filter is connected to the decoding module;

[0170] The second signal receiving module includes a sixth mixer, a sixth digitally controlled oscillator, and a second half-band decimation filter, wherein: the input terminal of the sixth mixer is connected to the output terminal of the digital filter, the input terminal of the sixth digitally controlled oscillator is connected to the sixth digitally controlled oscillator, the output terminal of the sixth digitally controlled oscillator is connected to the input terminal of the second half-band decimation filter, and the output terminal of the second half-band decimation filter is connected to the decoding module.

[0171] In one exemplary embodiment, the splitter module is a digital filter.

[0172] In one exemplary embodiment, the first frequency band is 840MHz to 845MHz, and the second frequency band is 920MHz to 925MHz.

[0173] As the reader embodiment is basically similar to the radio frequency transceiver structure embodiment, the description is relatively simple. For relevant details, please refer to the description of the radio frequency transceiver structure embodiment. It will not be repeated here.

[0174] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0175] This application describes embodiments with reference to flowchart illustrations and / or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable electronic device terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable terminal device, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0176] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable terminal device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0177] These computer program instructions can also be loaded onto a computer or other programmable terminal device to cause a series of operational steps to be performed on the computer or other programmable terminal device to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable terminal device for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0178] Although preferred embodiments of the present application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present application.

[0179] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0180] The above provides a detailed description of the radio frequency transceiver structure and electronic device provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A radio frequency transceiver structure, characterized in that, It includes a programmable logic module, and an RF transmitting module and an RF receiving module respectively connected to the programmable logic module, wherein: The programmable logic module is used to generate digital carrier signals, which are signals containing different frequency bands; The radio frequency transmission module is used to convert the digital carrier signal into an analog carrier signal and transmit it outward, so that the radio frequency tag reflects the target signal back after receiving the analog carrier signal; The radio frequency receiving module includes a receiving module, a carrier cancellation module, and an analog-to-digital conversion module. The receiving module includes a receiving antenna and is used to receive the target signal and the analog carrier leakage signal. The carrier cancellation module is used to perform carrier cancellation on the analog carrier leakage signal using the analog carrier signal of the radio frequency transmitting module as a reference signal. The analog-to-digital conversion module is used to convert the retained useful signal into a digital useful signal after carrier cancellation. The carrier cancellation module includes a coupler, a first duplexer, a second duplexer, a third duplexer, a first vector combining circuit, a second vector combining circuit, a first combiner, and a second combiner. The coupler is used to receive the analog carrier signal transmitted by the transmitting antenna of the RF transmitting module. The first duplexer is located after the dual-frequency filter of the RF transmitting module. Specifically: the coupler is connected to the first duplexer; the first duplexer is connected to both the first and second vector combining circuits; the second duplexer is connected to both the first and second combiners; the first combiner is connected to the first vector combining circuit; and the second combiner is connected to the second vector combining circuit. The combining circuit includes a first combiner and a second combiner connected to a third duplexer. A low-noise amplifier is further included between the carrier cancellation module and the analog-to-digital conversion module. The analog-to-digital conversion module includes an analog-to-digital converter, a fourth mixer, a fourth digitally controlled oscillator, and a second low-pass filter. The input terminal of the low-noise amplifier is connected to the third duplexer, its output terminal is connected to the input terminal of the analog-to-digital converter, and its output terminal is connected to the input terminal of the fourth mixer. The input terminal of the fourth mixer is connected to the fourth digitally controlled oscillator, and its output terminal is connected to the input terminal of the second low-pass filter. The output terminal of the second low-pass filter is connected to the programmable logic module via an interface. The programmable logic module is further configured to divide the digital useful signal into processing signals of different frequency bands and process the processing signals.

2. The radio frequency transceiver structure according to claim 1, characterized in that, The programmable logic module includes an encoding module, a first signal generation module, a second signal generation module, and a combining module, wherein: The encoding module is used to generate a baseband signal and transmit the baseband signal to the first signal generation module and the second signal generation module respectively. The first signal generation module is used to perform spectrum shifting on the baseband signal to obtain a first carrier signal in a first frequency band; The second signal generation module is used to perform spectrum shifting on the baseband signal to obtain a second carrier signal in a second frequency band; The combining module is used to combine the first carrier signal and the second carrier signal into a dual-band digital carrier signal.

3. The radio frequency transceiver structure according to claim 2, characterized in that, The first signal generation module includes a first finite-length unit impulse response filter, a first mixer, and a first digitally controlled oscillator, wherein: the input terminal of the first finite-length unit impulse response filter is connected to the encoding module, and the output terminal is connected to the input terminal of the first mixer; the input terminal of the first mixer is connected to the first digitally controlled oscillator, and the output terminal is connected to the input terminal of the combining module. The second signal generation module includes a second finite-length unit impulse response filter, a second mixer, and a second digitally controlled oscillator, wherein: the input terminal of the second finite-length unit impulse response filter is connected to the encoding module, and the output terminal is connected to the input terminal of the second mixer; the input terminal of the second mixer is connected to the second digitally controlled oscillator, and the output terminal is connected to the input terminal of the combining module.

4. The radio frequency transceiver structure according to claim 3, characterized in that, The radio frequency transmission module includes a digital-to-analog converter module, an analog signal processing module, and a transmission module. The analog signal processing module includes a digital step attenuator, a dual-band filter, and a power amplifier. The transmission module includes a transmitting antenna. The input terminal of the digital-to-analog converter module is connected to the output terminal of the combiner module via an interface, and its output terminal is connected to the input terminal of the digital step attenuator. The output terminal of the digital step attenuator is connected to the input terminal of the dual-band filter, the output terminal of the dual-band filter is connected to the input terminal of the power amplifier, and its output terminal is connected to the transmitting antenna.

5. The radio frequency transceiver structure according to claim 4, characterized in that, The digital-to-analog converter module includes a first low-pass filter, a third mixer, a third digitally controlled oscillator, a gain compensator, and a digital-to-analog converter. The input of the first low-pass filter is connected to the output of the combining module via an interface, and its output is connected to the input of the third mixer. The input of the third mixer is connected to the third digitally controlled oscillator, and its output is connected to the input of the gain compensator. The output of the gain compensator is connected to the input of the digital-to-analog converter, and the output of the digital-to-analog converter is connected to the input of the digital step attenuator.

6. The radio frequency transceiver structure according to claim 4, characterized in that, The digital-to-analog conversion module includes a digital-to-analog converter and a quadrature mixer, wherein: the input terminal of the digital-to-analog converter is connected to the output terminal of the combining module through an interface, the output terminal is connected to the input terminal of the quadrature mixer, and the output terminal of the quadrature mixer is connected to the input terminal of the digital step attenuator.

7. The radio frequency transceiver structure according to claim 1, characterized in that, The programmable logic module further includes a splitter module, a first signal receiving module, a second signal receiving module, and a decoding module, wherein: The splitter module is used to divide the digital useful signal into a first digital useful signal in a first frequency band and a second digital useful signal in a second frequency band; the splitter module is a digital filter; The first signal receiving module is used to perform spectrum shifting on the first digital useful signal to obtain a first processed signal; The second signal receiving module is used to perform spectrum shifting on the second digital useful signal to obtain a second processed signal; The decoding module is used to decode the first processed signal and the second processed signal; The first signal receiving module includes a fifth mixer, a fifth digitally controlled oscillator, and a first half-band decimation filter, wherein: the input terminal of the fifth mixer is connected to the output terminal of the digital filter, the input terminal of the fifth digitally controlled oscillator is connected to the fifth digitally controlled oscillator, the output terminal of the fifth digitally controlled oscillator is connected to the input terminal of the first half-band decimation filter, and the output terminal of the first half-band decimation filter is connected to the decoding module. The second signal receiving module includes a sixth mixer, a sixth digitally controlled oscillator, and a second half-band decimation filter, wherein: the input terminal of the sixth mixer is connected to the output terminal of the digital filter, the input terminal of the sixth digitally controlled oscillator is connected to the sixth digitally controlled oscillator, the output terminal of the sixth digitally controlled oscillator is connected to the input terminal of the second half-band decimation filter, and the output terminal of the second half-band decimation filter is connected to the decoding module.

8. A reader / writer, characterized in that, It includes the radio frequency transceiver structure as described in any one of claims 1-7; the reader / writer includes a handheld reader / writer and a non-handheld reader / writer.

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