FDD (Frequency Division Duplexing) communication transceiving circuit and transceiver
By using the intermediate frequency oscillator module and the local carrier cancellation module in the FDD communication transceiver circuit, the carrier frequency in the received RF signal is directly used for frequency shifting, which solves the problems of complex design and high power consumption of existing wireless transceivers. , achieving the effects of lower energy consumption and simplified design.
Patent Information
- Application Number
- CN202411611384.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-12
- Publication Date
- 2025-01-21
AI Technical Summary
In the existing mobile wireless communication technology, wireless transceivers are complex in design and high power consumption, mainly due to their dependence on high-precision oscillators.
By introducing an intermediate frequency oscillator module and a local carrier cancellation module into the FDD communication transceiver circuit, the carrier frequency in the received radio frequency signal is directly used for frequency shifting, reducing the accuracy requirements for the local oscillator.
The design complexity and power consumption of the transceiver are reduced, the effective use of low-precision oscillators is realized, and the energy consumption of the system is reduced.
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Figure CN119341592A_ABST
Abstract
Description
Technical Field
[0001] The embodiments of the present application relate to the field of signal processing technology, and in particular to an FDD communication transceiver circuit and a transceiver. Background Art
[0002] In the existing mobile wireless communication technology, the receiving end of the wireless transceiver mixes the high-frequency RF signal received by the antenna and the oscillating signal of a frequency near the carrier frequency output by the local oscillator, outputs a difference intermediate frequency, thereby achieving down-conversion, and then demodulates the intermediate frequency signal; the transmitting end of the wireless transceiver shifts the carrier frequency of the local oscillator up to the high-frequency RF frequency, and then modulates the baseband signal to this RF frequency for transmission through the antenna.
[0003] During the operation of the above-mentioned wireless transceiver, in order to improve the accuracy of frequency shifting, high requirements are placed on the accuracy and phase noise of the local oscillator. However, the design of a high-precision oscillator is more complex and consumes more power. This will result in the design of a wireless transceiver equipped with a high-precision oscillator being more complex and consuming more power. Summary of the invention
[0004] The embodiments of the present application provide an FDD communication transceiver circuit and a transceiver to reduce the design complexity and power consumption of the transceiver.
[0005] In a first aspect, an embodiment of the present application provides an FDD communication transceiver circuit. The FDD communication transceiver circuit includes: an uplink path, a downlink path, and a baseband signal filtering module;
[0006] The uplink path includes an intermediate frequency oscillator module and a local carrier elimination module connected to each other; the downlink path includes a local oscillator;
[0007] The output end of the downlink path is connected to the input end of the baseband signal filtering module, and the output end of the baseband signal filtering module is connected to the first input end of the uplink path, for filtering the front-end baseband signal carried in the radio frequency signal received by the downlink path;
[0008] The second input terminal of the uplink path is connected to the local oscillator;
[0009] The local carrier elimination module is used to obtain the frequency-shifted signal to be transmitted based on the intermediate frequency carrier of the intermediate frequency oscillator module and the pre-modulated signal of the local baseband signal, the local carrier of the local oscillator, and the radio frequency signal after filtering out the front-end baseband signal.
[0010] In a second aspect, an embodiment of the present application provides an FDD communication transceiver, including an FDD communication transceiver circuit as provided in any embodiment of the present application.
[0011] The technical solution of the embodiment of the present application, the FDD communication transceiver circuit includes: an uplink path, a downlink path and a baseband signal filtering module; the uplink path includes an intermediate frequency oscillator module and a local carrier elimination module connected to each other; the downlink path includes a local oscillator; the output end of the downlink path is connected to the input end of the baseband signal filtering module, and the output end of the baseband signal filtering module is connected to the first input end of the uplink path, which is used to filter out the front-end baseband signal carried in the radio frequency signal received by the downlink path; the second input end of the uplink path is connected to the local oscillator; the local carrier elimination module is used to obtain the frequency-shifted signal to be transmitted according to the intermediate frequency carrier of the intermediate frequency oscillator module and the pre-modulated signal of the local end baseband signal, the local carrier of the local oscillator, and the radio frequency signal after filtering the front-end baseband signal. Based on this, the present application directly performs frequency shift based on the carrier frequency in the received radio frequency signal, and can be realized without the help of the local oscillator carrier frequency. Therefore, the solution of the present application does not require the local oscillator to have a high precision, and a low-precision oscillator can be realized, and the power consumption is lower. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 A schematic diagram of the circuit structure of the FDD communication transceiver circuit provided in Example 1 of the present application;
[0013] Figure 2 A schematic diagram of the frequency distribution of each point in the circuit provided in Example 1 of the present application;
[0014] Figure 3 This is a structural diagram of an FDD communication transceiver provided in Example 2 of the present application. DETAILED DESCRIPTION
[0015] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only the parts related to the present application, rather than all structures, are shown in the accompanying drawings.
[0016] Embodiment 1
[0017] Figure 1 The circuit structure diagram of the FDD communication transceiver circuit provided in the first embodiment of the present application is as follows: Figure 1 As shown, the FDD communication transceiver circuit in this embodiment includes: an uplink path 100 , a downlink path 200 and a baseband signal filtering module 300 .
[0018] Among them, the uplink path includes an intermediate frequency oscillator module and a local carrier elimination module connected to each other; the downlink path includes a local oscillator 201; the output end of the downlink path is connected to the input end of the baseband signal filtering module, and the output end of the baseband signal filtering module is connected to the first input end of the uplink path, which is used to filter out the front-end baseband signal carried in the radio frequency signal received by the downlink path.
[0019] The second input end of the uplink path is connected to the local oscillator; the local carrier elimination module is used to obtain the frequency-shifted signal to be transmitted based on the intermediate frequency carrier of the intermediate frequency oscillator module and the pre-modulated signal of the local baseband signal, the local carrier of the local oscillator, and the RF signal after filtering out the front-end baseband signal.
[0020] like Figure 1 As shown, in this embodiment, the input end of the downlink path is connected to a receiving antenna 400, which is used to receive a radio frequency signal carrying a front-end baseband signal. The front-end baseband signal refers to a baseband signal modulated into the radio frequency signal by the sender of the radio frequency signal received at this end.
[0021] The downlink path includes a local oscillator 201 and a first mixer 202. The local oscillator is used to emit a local carrier with a frequency similar to that of the received radio frequency signal. The first mixer is connected to the receiving antenna and the local oscillator respectively.
[0022] After the receiving antenna receives the RF signal, the RF signal is input into the first mixer, and the local carrier generated by the local oscillator is also input into the first mixer. After mixing by the first mixer, the obtained signal frequency is close to the frequency of the original front-end baseband signal.
[0023] In addition, the output end of the downlink path is connected to the demodulation module 500 for demodulating the front-end baseband signal. Specifically, the output end of the first mixer is the output end of the downlink path, and the frequency of the signal obtained by the first mixer is close to the frequency of the original front-end baseband signal, so that the demodulation module can demodulate it, and then obtain the front-end baseband signal to complete the downlink reception process.
[0024] In order to improve the receiving sensitivity of the circuit, an LNA low noise amplifier 203 may be provided between the first mixer and the receiving antenna.
[0025] Still Figure 1 As shown, for the uplink path, the intermediate frequency oscillator module may include an intermediate frequency oscillator 101 and a modulator 102; wherein the output end of the intermediate frequency oscillator is connected to the modulator for sending the intermediate frequency carrier emitted by the intermediate frequency oscillator to the modulator; the modulator modulates the intermediate frequency carrier with the received local baseband signal to obtain a pre-modulated signal.
[0026] In order to utilize the carrier in the radio frequency signal received by the receiving antenna, in this embodiment, a baseband signal filtering module 300 can be set between the uplink path and the downlink path. Since the frequency of the baseband signal is usually very low, a high-pass filter can be used to filter out the low-frequency baseband signal modulated in the radio frequency signal.
[0027] Therefore, in this example, the baseband signal filtering module may include a high-pass filter. When configuring the parameters of the high-pass filter, it is necessary to ensure that the frequency of the RF signal can pass normally and the frequency of the baseband signal cannot pass. The specific parameter configuration can refer to the relevant technology and will not be repeated here.
[0028] It should be noted that since the baseband signal filtering module is arranged after the first mixer, and the first mixer can be set to difference mixing and / or sum mixing, and since the frequency obtained by the difference mixing itself is close to the frequency of the original baseband signal, when filtering the baseband signal, its parameter configuration may need to be more precise, and it is necessary to set a frequency point between the frequency of the original baseband signal and the difference mixing, and then set the frequency selection range to be higher than this frequency point.
[0029] In order to further reduce the complexity of the configuration, in this embodiment, the frequency selection range of the baseband signal filtering module can be set to a range higher than the frequency of the RF signal, so as to ensure that the sum mixing can pass, and the sum mixing can be used subsequently.
[0030] It should be noted that both of the above two frequency selection ranges can be realized. In specific implementation, when configuring parameters for the high-pass filter, the frequency selection range can be set according to one of the methods.
[0031] In addition, in this embodiment, the local carrier elimination module includes a second mixer 103 and a third mixer 104; the output end of the first mixer is the output end of the downlink path, the intermediate frequency oscillator module and the output end of the first mixer are respectively connected to the second mixer; the output end of the second mixer and the local oscillator are respectively connected to the third mixer.
[0032] Based on the above circuit structure, during the uplink transmission, the local baseband signal is modulated into the intermediate frequency carrier generated by the intermediate frequency oscillator to obtain a premodulated signal. Then, the RF signal with the front-end baseband signal filtered out is input into the second mixer together with the premodulated signal, and the signal output by the second mixer is input into the third mixer together with the local carrier to obtain the frequency-shifted signal to be transmitted.
[0033] It should be noted that the RF signal with the front-end baseband signal filtered out is presented by the difference mixing and sum mixing of the aforementioned first mixer. In order to facilitate the description of the signal mixing process, this embodiment describes the signals at various points in the circuit.
[0034] For details, please refer to Figure 2 , Figure 2 This is a schematic diagram of the frequency distribution of each point in the circuit provided in Example 1 of the present application. Figure 2 As shown, the frequency increases from left to right.
[0035] for Figure 1 For point A in the figure, the frequency there only exists ω in , that is, the RF signal carrying the front-end baseband signal received by the receiving antenna;
[0036] for Figure 1 For point B in the figure, the frequency there is the processed ω in , the frequency remains unchanged;
[0037] for Figure 1 For point C in the figure, after the local carrier ω L0 Mixing, get a difference mixing ω in -ω L0 and a sum-valued mixing frequency ω in +ω L0 ;
[0038] for Figure 1 For point D in the figure, after being modulated by the premodulated signal ω IF Mixing is performed to obtain 4 frequencies, namely: ω in -ω L0 -ω IF ,ω in -ω L0 +ω IF ,ω in +ω L0 -ω IF ,ω in +ω L0 +ω IF ;
[0039] for Figure 1 For point E in the figure, after reconnecting with the local carrier ω L0 Mixing, the following 6 frequencies can be obtained: ω in -ω IF ,ω in +ω IF ,ω in +2ω L0 -ω IF ,ω in +2ω L0 +ω IF ,ω in -2ω L0 -ω IF ,ω in -2ω L0 +ωIF Among them, ω in -ω IF Or in +ω IF That is the final frequency-shifted signal to be transmitted.
[0040] In addition, if the frequency selection range of the aforementioned baseband signal filtering module is to set a frequency point between the frequency of the original baseband signal and the difference mixing frequency, and then the frequency selection range is set to be higher than the frequency point, since the value mixing frequency ω is neutralized at point C in +ω L0 will be filtered out, so only ω remains at point D in -ω L0 -ω IF ,ω in -ω L0 +ω IF , correspondingly, only ω remains at point E in -ω IF ,ω in +ω IF ,ω in -2ω L0 -ω IF ,ω in -2ω L0 +ω IF .
[0041] If the frequency range of the baseband signal filtering module is higher than the frequency range of the RF signal, due to the difference mixing ω at point C in -ω L0 will be filtered out, so only ω remains at point D in +ω L0 -ω IF ,ω in +ω L0 +ω IF , correspondingly, only ω remains at point E in -ω IF ,ω in +ω IF ,ω in +2ω L0 -ω IF ,ω in +2ω L0 +ω IF .
[0042] In order to obtain the final signal, only the required frequency-shifted signal to be sent exists, that is, only ω in -ω IF or in +ω IF A first filter module may be provided at the end of the uplink path, and the first filter module is used to filter out the frequency-shifted signal to be transmitted.
[0043] It should be noted that the selection of the frequency range of the first filter module can refer to Figure 2 The arrangement of the frequencies shown will not be described in detail.
[0044] In addition, a second filter module may be provided in the uplink path, and the second filter module is used to filter out redundant signals, which are signals unrelated to the frequency-shifted signal to be transmitted. The second filter module may be point D, and since the number of frequencies at point D is small, redundant signals may be directly filtered out here.
[0045] The redundant signal is defined according to actual needs, for example, the final required signal is ω in -ω IF , then we can in -ω L0 +ω IF Or in +ω L0 +ω IF Filtering is performed, which depends on the frequency selection of the baseband signal filtering module.
[0046] Because ω in -ω L0 +ω IF Or in +ω L0 +ω IF No matter how you mix, you can't get ω in -ω IF , therefore, the signals of these two frequencies can be called redundant signals.
[0047] Embodiment 2
[0048] Figure 3 This is a schematic diagram of the structure of an FDD communication transceiver provided in the second embodiment of the present application. Figure 3 As shown, the FDD communication transceiver provided in this embodiment may include the FDD communication transceiver circuit provided in any embodiment of the present application. The transceiver's transceiver process may refer to the above embodiments and will not be described in detail here.
[0049] Note that the above are only preferred embodiments of the present application and the technical principles used. Those skilled in the art will understand that the present application is not limited to the specific embodiments herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present application. Therefore, although the present application is described in more detail through the above embodiments, the present application is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.
Claims
1. An FDD communication transceiver circuit, characterized in that: The FDD communication transceiver circuit includes: an uplink path, a downlink path and a baseband signal filtering module; The uplink path includes an intermediate frequency oscillator module and a local carrier elimination module connected to each other; the downlink path includes a local oscillator; The output end of the downlink path is connected to the input end of the baseband signal filtering module, and the output end of the baseband signal filtering module is connected to the first input end of the uplink path, for filtering the front-end baseband signal carried in the radio frequency signal received by the downlink path; The second input terminal of the uplink path is connected to the local oscillator; The local carrier elimination module is used to obtain the frequency-shifted signal to be transmitted based on the intermediate frequency carrier of the intermediate frequency oscillator module and the premodulated signal of the local baseband signal, the local carrier of the local oscillator, and the radio frequency signal after filtering out the front-end baseband signal.
2. The FDD communication transceiver circuit according to claim 1, characterized in that: The intermediate frequency oscillator module includes an intermediate frequency oscillator and a modulator; The output end of the intermediate frequency oscillator is connected to the modulator, and is used to send the intermediate frequency carrier emitted by the intermediate frequency oscillator to the modulator; The modulator modulates the intermediate frequency carrier and the received local baseband signal to obtain a premodulated signal.
3. The FDD communication transceiver circuit according to claim 1, characterized in that: The baseband signal filtering module includes a high-pass filter.
4. The FDD communication transceiver circuit according to claim 1, characterized in that: The downlink path also includes a first mixer; The first mixer is connected to the receiving antenna and the local oscillator respectively.
5. The FDD communication transceiver circuit according to claim 4, characterized in that: The local carrier elimination module includes a second mixer and a third mixer; The output end of the first mixer is the output end of the downlink path, and the intermediate frequency oscillator module and the output end of the first mixer are respectively connected to the second mixer; The output end of the second mixer and the local oscillator are connected to the third mixer respectively.
6. The FDD communication transceiver circuit according to claim 4, characterized in that: A low noise amplifier is arranged between the first mixer and the receiving antenna.
7. The FDD communication transceiver circuit according to claim 1, characterized in that: A first filter module is disposed at the end of the uplink path, and the first filter module is used to filter out the frequency-shifted signal to be transmitted.
8. The FDD communication transceiver circuit according to claim 1, characterized in that: A second filter module is provided in the uplink path, and the second filter module is used to filter out redundant signals, where the redundant signals are signals unrelated to the frequency-shifted signal to be transmitted.
9. The FDD communication transceiver circuit according to claim 1, characterized in that: The output end of the downlink path is connected to a demodulation module for demodulating a front-end baseband signal.
10. An FDD communication transceiver, characterized in that: It comprises the FDD communication transceiver circuit as described in any one of claims 1 to 9.