An ultra-wideband radio frequency receiving channel and a method of operation thereof

Abstract

The application provides an ultra-wideband radio frequency receiving channel and a working method thereof. The ultra-wideband radio frequency receiving channel comprises a low-noise amplifier (3), a radio frequency filter group (4), a sample-and-hold device (5), an intermediate frequency filter group (6) and a processing unit (9) connected in sequence, and a choke inductance (7) and a blocking capacitor (8) connected with the sample-and-hold device (5); the low-noise amplifier (3) is connected with a receiving antenna (1) through a limiter (2). In the ultra-wideband radio frequency receiving channel, a sample-and-hold device is multiplexed, and all ultra-wideband radio frequency signals of KU wave band and below are processed in one radio frequency receiving channel, so that the signals can be directly sampled by AD. Compared with other receiving channel schemes, the ultra-wideband and high dynamic range are ensured, and the link is simple.

Description

Technical Field

[0001] This invention relates to the field of broadband microwave receiving technology, and more specifically, to an ultra-wideband radio frequency receiving channel and its operating method. Background Technology

[0002] Currently, there are two main methods for receiving broadband radio frequency signals: one is to perform intermediate frequency sampling through channelization, and the other is to perform direct radio frequency sampling through an ultra-high-speed ADC.

[0003] The first channelization method is to convert a wideband RF signal into a narrowband RF signal using a filter bank, then use a mixer to convert the narrowband RF signal to an intermediate frequency, and finally use a relatively low-speed ADC for Nyquist sampling. Because there are a lot of frequency conversion links in the RF channel, the amplitude and phase consistency of the channel is poor, the in-band fluctuation is large, and the signal distortion is severe, resulting in poor scalability and flexibility.

[0004] The second type of direct RF sampling method is mainly limited to analog-to-digital converters (ADCs). Currently, the most commonly used high-speed ADCs in China generally have sampling frequencies below 3 GHz and bit widths below 10 bits. Therefore, the maximum bandwidth of domestic digital receivers is around 1 GHz. However, due to the limitations of ADC device manufacturing processes, it has become very difficult to increase bandwidth by increasing the ADC sampling frequency. Therefore, both domestically and internationally, the main approach is to extend bandwidth by using multiple ADC devices for interleaved sampling. It has been reported that Agilent Technologies has achieved 80 GHz sampling technology using interleaved multiple ADC devices. However, due to many limitations of interleaved sampling, such as the need for frequent calibration and limited dynamic range, interleaved sampling is currently only used in test instruments such as oscilloscopes. Therefore, this method is generally suitable for L-band and lower frequency RF signals. Summary of the Invention

[0005] The present invention aims to provide an ultra-wideband radio frequency receiving channel and its operating method to adapt to all frequency bands in and below the Ku band.

[0006] The present invention provides an ultra-wideband radio frequency receiving channel, comprising a low-noise amplifier, a radio frequency filter bank, a sample-and-hold circuit, an intermediate frequency filter bank and a processing unit connected in sequence, as well as a choke inductor and a DC blocking capacitor connected to the sample-and-hold circuit; the low-noise amplifier is connected to a receiving antenna via a limiter.

[0007] Furthermore, the radio frequency filter bank is a switched bandpass filter bank.

[0008] Furthermore, the intermediate frequency filter bank is a switched low-pass filter bank.

[0009] Furthermore, the operating method of the ultra-wideband radio frequency receiving channel includes the following steps:

[0010] Step 1: The receiving antenna converts the received radar radiation source signal into a radio frequency signal, which is then sent to the receiving channel after passing through a limiter.

[0011] Step 2: In the receiving channel, the radio frequency signal is first amplified by a low-noise amplifier, and then divided into multiple frequency bands by a radio frequency filter.

[0012] Step 3: Input radio frequency signals from multiple frequency bands into the sample-and-hold circuit for radio frequency sampling;

[0013] Step 4: Input the RF signal output from the sample-and-hold circuit into the intermediate frequency filter bank;

[0014] Step 5: Send the intermediate frequency signal output from the intermediate frequency filter bank to the processing unit for fully digital processing.

[0015] Furthermore, in step 2, the radio frequency signals in multiple frequency bands include:

[0016] The first type of radio frequency signal is a radio frequency signal in a frequency band that does not satisfy the frequency domain sparsity characteristic. After segmenting this type of radio frequency signal, the output of the radio frequency filter bank does not cross octaves and meets the Nyquist sampling requirements. This is named RF1.

[0017] The second type of radio frequency signal is a radio frequency signal in a frequency band that satisfies the frequency domain sparsity characteristic. After segmenting this type of radio frequency signal, the output of the radio frequency filter bank can span octaves and does not meet the Nyquist sampling requirements. This type of signal is named RF2.

[0018] The third type of radio frequency signal is a radio frequency signal in a frequency band that does not satisfy the frequency domain sparsity characteristic. After segmenting this type of radio frequency signal, the output of the radio frequency filter bank does not cross octaves and does not meet the Nyquist sampling requirements. This type of signal is named RF3.

[0019] Furthermore, in step 3, the function of the sample-and-hold circuit includes:

[0020] For the first type of RF signal RF1, the clock of the sample-and-hold circuit is a constant DC voltage DC_IN, which is output to the sample-and-hold circuit through a choke inductor, ensuring that the sample-and-hold circuit is always in a following state and outputs an RF signal with the same frequency as the input signal, i.e., f. out =f in ;

[0021] For the second type of radio frequency signal RF2 and the third type of radio frequency signal RF3, the clock of the sample-and-hold circuit is at a frequency of f. s The sampling clock signal CLK_IN is output to the sample-and-hold circuit through a DC blocking capacitor, and the output signal frequency f out Satisfy the input signal frequency f inand clock frequency f s The following relationship exists between them: f out =|f in -n×f s | where n is a natural number.

[0022] Furthermore, in step 4, the intermediate frequency filter bank filters out frequency components except for the first Nyquist zone, and the frequency f of the output signal is... out Satisfy the input signal frequency f in and clock frequency f s The following relationship exists between them:

[0023] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0024] In the ultra-wideband RF receiving channel of this invention, a sample-and-hold circuit is reused to process ultra-wideband RF signals in the Ku band and below within a single RF receiving channel, enabling them to be directly sampled by an analog-to-digital converter (AD). Compared to other receiving channel schemes, this approach ensures both ultra-wideband performance and high dynamic range while simplifying the link. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a block diagram illustrating the principle of an ultra-wideband radio frequency receiving channel in an embodiment of the present invention.

[0027] Icons: 1-receiving antenna, 2-limiter, 3-low noise amplifier, 4-RF filter bank, 5-sample and hold circuit, 6-IF filter bank, 7-inductor, 8-capacitor, 9-processing unit. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0030] Example

[0031] like Figure 1 As shown, this embodiment proposes an ultra-wideband radio frequency (RF) receiving channel, including a low-noise amplifier (LNO) 3, an RF filter bank 4, a sample-and-hold circuit 5, an intermediate frequency (IF) filter bank 6, and a processing unit 9 connected in sequence, as well as a choke inductor 7 and a DC blocking capacitor 8 connected to the sample-and-hold circuit 5; the LNO 3 is connected to the receiving antenna 1 via a limiter 2. In some preferred embodiments, the RF filter bank 4 is a switched bandpass filter bank. The IF filter bank 6 is a switched low-pass filter bank.

[0032] The working principle of the ultra-wideband radio frequency receiving channel is as follows:

[0033] Step 1: The receiving antenna 1 converts the received radar radiation source signal into a radio frequency signal, which is then sent to the receiving channel after passing through the limiter 2.

[0034] Step 2: In the receiving channel, the radio frequency signal is first amplified by low-noise amplifier 3, and then split into multiple frequency bands by radio frequency filter bank 4; wherein, the multiple frequency bands of radio frequency signals include:

[0035] The first type of radio frequency signal is a radio frequency signal in a frequency band that does not satisfy the frequency domain sparsity characteristic. After segmenting this type of radio frequency signal, the output of radio frequency filter bank 4 is a radio frequency signal that does not cross octaves and meets the Nyquist sampling requirements, named RF1.

[0036] The second type of radio frequency signal is a radio frequency signal in a frequency band that satisfies the frequency domain sparsity characteristic. After segmenting this type of radio frequency signal, the output of radio frequency filter bank 4 is a radio frequency signal that can span octaves and does not meet the Nyquist sampling requirements, named RF2.

[0037] The third type of radio frequency signal is a radio frequency signal in a frequency band that does not meet the frequency domain sparsity characteristic. After segmenting this type of radio frequency signal, the output of radio frequency filter bank 4 is a radio frequency signal that does not cross octaves and does not meet the Nyquist sampling requirements, named RF3.

[0038] Step 3: Input RF signals from multiple frequency bands into sample-and-hold circuit 5 for RF sampling.

[0039] For the first type of radio frequency signal RF1, the clock of sample-and-hold circuit 5 is a constant DC voltage DC_IN, which is output to sample-and-hold circuit 5 through choke inductor 7, so that sample-and-hold circuit 5 is always in a following state and outputs an radio frequency signal with the same frequency as the input signal, i.e., f. out =f in ;

[0040] For the second type of radio frequency signal RF2 and the third type of radio frequency signal RF3, the clock of the sample-and-hold circuit 5 is at a frequency of f. s The sampling clock signal CLK_IN(f s Different values ​​can be set according to the input signal type and frequency band. The signal is output to the sample-and-hold circuit 5 through the DC blocking capacitor 8, and the output signal frequency f out Satisfy the input signal frequency f in and clock frequency f s The following relationship exists between them: f out =|f in -n×f s | where n is a natural number.

[0041] Step 4: Input the RF signal output from sample-and-hold circuit 5 into intermediate frequency filter bank 6. The function of intermediate frequency filter bank 6 is to filter out frequency components except for the first Nyquist zone, and the frequency f of the output signal is... out Satisfy the input signal frequency f in and clock frequency f s The following relationship exists between them:

[0042]

[0043] Step 5: Send the intermediate frequency signal output from the intermediate frequency filter bank 6 to the processing unit 9 for fully digital processing.

[0044] An example:

[0045] (1) Set the AD sampling clock of the processing unit to 2GHz.

[0046] (2) The receiving antenna 1 receives the radar radiation source signal, which is an ultra-wideband signal with a frequency band of 0.3GHz to 7GHz, and sends it into the receiving channel through the limiter 2.

[0047] (3) The receiving channel sends the received weak radio frequency signal to the low noise amplifier 3 for low noise amplification, and then sends it to the radio frequency filter group 4; thus obtaining radio frequency signals in 5 frequency bands, namely 0.3GHz~0.5GHz, 0.5GHz~0.9GHz, 0.9GHz~1.6GHz, 1.6GHz~2GHz, and 2GHz~7GHz.

[0048] (4) The radio frequency signals of the five frequency bands are sent to the sample-and-hold circuit 5 for radio frequency sampling, and then sent to the intermediate frequency filter bank 6 for filtering:

[0049] (a) Among them, the radio frequency signals in the frequency bands of 0.3GHz to 0.5GHz and 0.5GHz to 0.9GHz are Class I radio frequency signals RF1 (i.e., radio frequency signals that do not meet the frequency domain sparsity characteristics, do not cross octaves, and meet the Nyquist sampling requirements). For this radio frequency signal, the sampling frequency of the sample-and-hold circuit 5 is set to DC. After the radio frequency signal output by the sample-and-hold circuit passes through the intermediate frequency filter bank 6, the frequency of the output intermediate frequency signal is 0.3GHz to 0.5GHz and 0.5GHz to 0.9GHz.

[0050] (b) Among them, the radio frequency signal in the 2GHz to 7GHz band is a second type of radio frequency signal RF2 (i.e., a radio frequency signal that satisfies the frequency domain sparsity characteristic, can span octaves, and does not meet the Nyquist sampling requirements). For this radio frequency signal, the sampling frequency of the sample-and-hold circuit 5 is set to 1.9GHz, and the radio frequency signal output by the sample-and-hold circuit passes through the intermediate frequency filter bank 6, and the frequency of the output intermediate frequency signal is DC-0.85GHz.

[0051] (c) Among them, the radio frequency signals in the frequency bands of 0.9GHz to 1.6GHz and 1.6GHz to 2GHz are Class III radio frequency signals RF3 (i.e., signals that do not meet the frequency domain sparsity characteristics, do not cross octaves, and do not meet the Nyquist sampling requirements). For these radio frequency signals, the sampling frequencies of the sample-and-hold circuit 5 are set to 1.7GHz and 2.1GHz, respectively. After the radio frequency signal output from the sample-and-hold circuit passes through the intermediate frequency filter bank 6, the frequency of the output intermediate frequency signal is 0.1GHz to 0.8GHz and 0.1GHz to 0.5GHz.

[0052] (5) After passing through the intermediate frequency filter bank 6, the frequencies of all intermediate frequency signals are less than 0.9 GHz, which meets the Nyquist sampling requirements of the AD of the processing unit 9, so it can be directly processed into full digital.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An ultra-wideband radio frequency receiving channel, characterized in that, It includes a low-noise amplifier (3), a radio frequency filter bank (4), a sample-and-hold circuit (5), an intermediate frequency filter bank (6), and a processing unit (9) connected in sequence, as well as a choke inductor (7) and a DC blocking capacitor (8) connected to the sample-and-hold circuit (5); the low-noise amplifier (3) is connected to the receiving antenna (1) via a limiter (2); The sample-and-hold device (5) is configured as follows: When the clock of the sample-and-hold circuit (5) is a constant DC voltage DC_IN, it is output to the sample-and-hold circuit (5) through the choke inductor (7), so that the sample-and-hold circuit (5) is always in the following state and outputs an RF signal with the same frequency as the input signal, that is... ; When the clock of the sample-and-hold circuit (5) is at a frequency of f s The sampling clock signal CLK_IN is output to the sample-and-hold circuit (5) through the DC blocking capacitor (8), and the output signal frequency is... f out Satisfy the frequency of the input signal f in and clock frequency f s The following relationship exists between them: , n It is a natural number.

2. The ultra-wideband radio frequency receiving channel according to claim 1, characterized in that, The radio frequency filter bank (4) is a switched bandpass filter bank.

3. The ultra-wideband radio frequency receiving channel according to claim 1, characterized in that, The intermediate frequency filter bank (6) is a switched low-pass filter bank.

4. A method for operating an ultra-wideband radio frequency receiving channel as described in any one of claims 1-3, characterized in that, Includes the following steps: Step 1: The receiving antenna (1) converts the received radar radiation source signal into a radio frequency signal, which is then sent to the receiving channel after passing through the limiter (2); Step 2: The radio frequency signal is first amplified by a low noise amplifier (3) in the receiving channel, and then divided into multiple frequency bands by a radio frequency filter bank (4); Step 3: Input radio frequency signals from multiple frequency bands into the sample-and-hold circuit (5) for radio frequency sampling; Step 4: Input the RF signal output from the sample-and-hold circuit (5) into the intermediate frequency filter bank (6); Step 5: Send the intermediate frequency signal output by the intermediate frequency filter bank (6) to the processing unit (9) for full digital processing.

5. The operating method of the ultra-wideband radio frequency receiving channel according to claim 4, characterized in that, In step 2, the radio frequency signals in multiple frequency bands include: The first type of radio frequency signal is a radio frequency signal in a frequency band that does not meet the frequency domain sparsity characteristics. After the radio frequency signal is segmented, the radio frequency filter bank (4) outputs a radio frequency signal that does not cross octaves and meets the Nyquist sampling requirements, which is named RF1. The second type of radio frequency signal is a radio frequency signal in a frequency band that satisfies the characteristics of frequency domain sparsity. After the radio frequency signal is segmented, the radio frequency filter bank (4) outputs a radio frequency signal that can span octaves and does not meet the Nyquist sampling requirements, which is named RF2. The third type of radio frequency signal is a radio frequency signal in a frequency band that does not meet the frequency domain sparsity characteristics. After the radio frequency signal is segmented, the output of the radio frequency filter bank (4) is a radio frequency signal that does not cross octaves and does not meet the Nyquist sampling requirements, named RF3.

6. The operating method of the ultra-wideband radio frequency receiving channel according to claim 5, characterized in that, In step 3, the function of the sample-and-hold device (5) includes: For the first type of radio frequency signal RF1, the clock of the sample-and-hold circuit (5) is a constant DC voltage DC_IN, which is output to the sample-and-hold circuit (5) through the choke inductor (7), so that the sample-and-hold circuit (5) is always in a following state and outputs an radio frequency signal with the same frequency as the input signal, i.e. ; For the second type of radio frequency signal RF2 and the third type of radio frequency signal RF3, the clock of the sample-and-hold circuit (5) is at a frequency of f s The sampling clock signal CLK_IN is output to the sample-and-hold circuit (5) through the DC blocking capacitor (8), and the output signal frequency is... f out Satisfy the frequency of the input signal f in and clock frequency f s The following relationship exists between them: , n It is a natural number.

7. The operating method of the ultra-wideband radio frequency receiving channel according to claim 6, characterized in that, In step 4, the intermediate frequency filter bank (6) filters out frequency components except for the first Nyquist zone, and the frequency of the output signal is... f out Satisfy the frequency of the input signal f in and clock frequency f s The following relationship exists between them: .

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