阅读说明：本技术 信号调理装置及信号调理方法 (Signal conditioning device and signal conditioning method ) 是由 井立 曹坤 李彦明 夏曙东 于 2020-12-30 设计创作，主要内容包括：本申请公开了一种信号调理装置及信号调理方法。信号调理电路包括依次连接的中频调理模块、对数检波模块和基带调理模块；中频调理模块用于对中频信号进行窄带滤波、放大以及再滤波；对数检波模块用于对来自中频调理模块的中频信号进行检波解调得到基带信号,并将检波功率对数化,以使对数化得到的功率与输出电压成线性比例；基带调理模块,用于对来自对数检波模块的基带信号依次进行缓冲、同信道干扰抑制处理、低通滤波以及滞回比较的处理,得到调理后的信号。本申请的信号调理装置所调理后的信号抗同信道干扰能力强,能够在无线信号干扰多、同信道数据相互碰撞严重的情况下,实现较强的同信道抑制,提升交易成功率,且成本低,一致性好。(The application discloses a signal conditioning device and a signal conditioning method. The signal conditioning circuit comprises an intermediate frequency conditioning module, a logarithmic detection module and a baseband conditioning module which are sequentially connected; the intermediate frequency conditioning module is used for carrying out narrow-band filtering, amplification and re-filtering on the intermediate frequency signal; the logarithm detection module is used for detecting and demodulating the intermediate frequency signal from the intermediate frequency conditioning module to obtain a baseband signal, and carrying out logarithm conversion on detection power so as to enable the power obtained by logarithm conversion to be in linear proportion with the output voltage; and the baseband conditioning module is used for sequentially carrying out buffering, co-channel interference suppression processing, low-pass filtering and hysteresis comparison processing on the baseband signal from the logarithmic detection module to obtain a conditioned signal. The signal conditioned by the signal conditioning device has strong co-channel interference resistance, can realize stronger co-channel inhibition under the conditions of more wireless signal interference and serious co-channel data collision, improves the transaction success rate, and has low cost and good consistency.)

1. A signal conditioning circuit is characterized by comprising an intermediate frequency conditioning module, a logarithmic detection module and a baseband conditioning module which are sequentially connected;

the intermediate frequency conditioning module is used for carrying out narrow-band filtering, amplification and re-filtering on the intermediate frequency signal;

the logarithmic detection module is used for detecting and demodulating the intermediate frequency signal from the intermediate frequency conditioning module to obtain a baseband signal and logarithmizing detection power so that the logarithmized power is in linear proportion to output voltage;

and the baseband conditioning module is used for sequentially carrying out buffering, co-channel interference suppression processing, low-pass filtering and hysteresis comparison processing on the baseband signal from the logarithmic detection module to obtain a conditioned signal.

2. The signal conditioning circuit of claim 1, wherein the intermediate frequency conditioning module comprises a first band pass filter, a variable gain amplifier, and a second band pass filter connected in sequence;

the first band-pass filter is used for filtering the intermediate frequency signal and outputting the filtered intermediate frequency signal;

the variable gain amplifier is used for performing variable gain amplification on the filtered intermediate frequency signal and outputting the intermediate frequency signal subjected to variable gain amplification;

the second band-pass filter is used for filtering the intermediate frequency signal subjected to variable gain amplification so as to filter out-of-band noise and improve the signal-to-noise ratio.

3. The signal conditioning circuit of claim 1, wherein the logarithmic detection module comprises a detection circuit and a logarithmic operation circuit connected to each other;

the detection circuit is used for detecting and demodulating the intermediate frequency signal from the intermediate frequency conditioning module to obtain a baseband signal;

the logarithm operation circuit is used for logarithmizing the detection power so that the power obtained by logarithmization is in linear proportion to the output voltage.

4. The signal conditioning circuit of claim 1 wherein the baseband conditioning module comprises a first buffer, a first composite detector, a capacitor, an arithmetic subtractor, a second composite detector, a second buffer, a baseband filter, and a hysteresis comparator;

the first composite wave detecting tube is provided with a first path of output end and a second path of output end; the second composite wave detecting tube is provided with a first path of input end and a second path of input end; the first output end of the first composite detecting tube is connected with the first input end of the second composite detecting tube; the second output end of the first composite detection tube is respectively connected with the capacitor and the operation subtracter, and the operation subtracter is connected with the second input end of the second composite detection tube;

the first buffer is used for adjusting the baseband signal from the logarithmic detection module to a proper amplitude;

the first composite detection tube is used for receiving the signal from the first buffer and outputting a first path of signal and a second path of signal through the first path of output end and the second path of output end respectively;

the capacitor is used for detecting the first path of signal in a matching manner to obtain a direct current signal;

the arithmetic subtracter is used for reducing the voltage of the direct current signal and outputting the reduced voltage signal;

the second composite detection tube is used for combining the second path of signal with the reduced voltage signal and outputting a combined signal;

the second buffer is used for adjusting the amplitude of the combined signal;

the baseband filter is used for low-pass filtering the signal from the second buffer;

the hysteresis comparator is used for performing hysteresis comparison on signals from the baseband filter.

5. The signal conditioning circuit of claim 4, wherein the baseband conditioning module further comprises a resistor, one end of the resistor is connected to the output end of the second signal, and the other end of the resistor is grounded; the resistor is used for adjusting the current of the second path of signal.

6. A signal conditioning method, which is realized by the signal conditioning apparatus according to any one of claims 1 to 5; the signal conditioning method comprises the following steps:

the intermediate frequency conditioning module performs narrow-band filtering, amplification and re-filtering on the intermediate frequency signal;

the logarithm detection module detects and demodulates the intermediate frequency signal from the intermediate frequency conditioning module to obtain a baseband signal, and logarithmically converts detection power so that the logarithmically obtained power is in linear proportion to output voltage;

and the baseband conditioning module sequentially performs buffering, co-channel interference suppression processing, low-pass filtering and hysteresis comparison processing on the baseband signal from the logarithmic detection module to obtain a conditioned signal.

7. The signal conditioning method according to claim 6, wherein the intermediate frequency conditioning module comprises a first band-pass filter, a variable gain amplifier and a second band-pass filter connected in sequence; the intermediate frequency conditioning module performs narrow-band filtering, amplification and re-filtering on the intermediate frequency signal, and comprises:

the first band-pass filter filters the intermediate frequency signal and outputs the filtered intermediate frequency signal;

the variable gain amplifier performs variable gain amplification on the filtered intermediate frequency signal and outputs the intermediate frequency signal subjected to variable gain amplification;

and the second band-pass filter filters the intermediate frequency signal amplified by the variable gain so as to filter out-of-band noise and improve the signal-to-noise ratio.

8. The method of claim 6, wherein the logarithmic detection module comprises a detection circuit and a logarithmic operation circuit connected to each other; the logarithm detection module detects and demodulates the intermediate frequency signal from the intermediate frequency conditioning module to obtain a baseband signal, and logarithmically converts detection power so that the power obtained by logarithmization is linearly proportional to output voltage, and the method comprises the following steps:

the detection circuit detects and demodulates the intermediate frequency signal from the intermediate frequency conditioning module to obtain a baseband signal;

the logarithmic operation circuit logarithmically converts the detection power so that the power obtained by the logarithmization is linearly proportional to the output voltage.

9. The signal conditioning method of claim 6, wherein the baseband conditioning module comprises a first buffer, a first complex detector, a capacitor, an arithmetic subtractor, a second complex detector, a second buffer, a baseband filter, and a hysteresis comparator; the baseband conditioning module sequentially performs buffering, co-channel interference suppression processing, low-pass filtering and hysteresis comparison processing on the baseband signal from the logarithmic detection module to obtain a conditioned signal, and the processing method comprises the following steps:

the first buffer adjusts the baseband signal from the logarithmic detection module to an appropriate amplitude;

the first composite detection tube receives the signal from the first buffer and outputs a first path of signal and a second path of signal;

the capacitor is matched to detect the first path of signal to obtain a direct current signal;

the arithmetic subtracter is used for reducing the voltage of the direct current signal and outputting the reduced voltage signal;

the second composite detection tube combines the second path of signal with the reduced voltage signal and outputs a combined signal;

the second buffer adjusts the amplitude of the combined signal;

the baseband filter low-pass filters the signal from the second buffer;

the hysteretic comparator makes a hysteretic comparison on the signal from the baseband filter.

10. The signal conditioning method of claim 9, wherein the baseband conditioning module further comprises a resistor, one end of the resistor is connected to the output end of the second signal, and the other end of the resistor is grounded;

the baseband conditioning module sequentially performs buffering, co-channel interference suppression processing, low-pass filtering and hysteresis comparison processing on the baseband signal from the logarithmic detection module to obtain a conditioned signal, and the resistance adjusts the current of the second path of signal before the second composite detection tube combines the second path of signal and the reduced voltage signal;

and the second composite detection tube combines the second path of signal and the reduced voltage signal and replaces the combined signal with the second composite detection tube to combine the second path of signal after the resistance adjustment and the reduced voltage signal.

Technical Field

The present application relates to the field of signal processing technologies, and in particular, to a signal conditioning apparatus and a signal conditioning method.

Background

ETC (Electronic Toll Collection), which is a full-automatic Electronic Toll Collection system applied to expressways or bridges. The ETC system performs wireless communication and information exchange between an on-vehicle device mounted on a vehicle and an antenna mounted on a lane of a toll station, and mainly comprises an automatic vehicle identification system, a central management system, other auxiliary facilities, and the like. The automatic vehicle identification system is composed of an on-board unit (OBU) (also called a transponder or an electronic tag), a Road Side Unit (RSU), a loop sensor and the like. The on-board unit OBU stores identification information of the vehicle, and is generally installed on a windshield in front of the vehicle, the road side unit RSU is installed beside a toll station, and the loop sensor is installed under the ground of a lane. The central management system has a large database storing information on a large number of registered vehicles and users. When the vehicle passes through the toll station port, the loop sensor senses the vehicle, the RSU sends out an inquiry signal, the OBU responds, and bidirectional communication and data exchange are carried out; the central management system obtains the vehicle identification information, compares the vehicle identification information with the corresponding information in the database, controls the management system to generate different actions according to different conditions, such as deducting the road toll to be paid from the prepaid account of the vehicle by the computer toll management system, or sending an instruction to other auxiliary facilities to work. Due to the conditions of more vehicles and more people in the region with dense people such as a toll station, the RSU of the road side unit puts higher requirements on transaction performance under the conditions of wireless interference resistance and collision of a plurality of OBUs. The physical layer standard (GB/T20851.1-2019) of the short-range communication special for electronic charging specifies that the co-channel interference suppression ratio of the RSU is less than 10dB, which puts high requirements on the co-channel interference resistance of the RSU. The existing technology has the defects of complex structure, poor consistency, high cost and the like.

Disclosure of Invention

The application aims to provide a signal conditioning device and a signal conditioning method. The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed embodiments. This summary is not an extensive overview and is intended to neither identify key/critical elements nor delineate the scope of such embodiments. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.

According to an aspect of an embodiment of the present application, a signal conditioning apparatus is provided, which includes an intermediate frequency conditioning module, a logarithmic detection module, and a baseband conditioning module, which are connected in sequence;

the intermediate frequency conditioning module is used for carrying out narrow-band filtering, amplification and re-filtering on the intermediate frequency signal;

the logarithmic detection module is used for detecting and demodulating the intermediate frequency signal from the intermediate frequency conditioning module to obtain a baseband signal and logarithmizing detection power so that the logarithmized power is in linear proportion to output voltage;

and the baseband conditioning module is used for sequentially carrying out buffering, co-channel interference suppression processing, low-pass filtering and hysteresis comparison processing on the baseband signal from the logarithmic detection module to obtain a conditioned signal.

Further, the intermediate frequency conditioning module comprises a first band-pass filter, a variable gain amplifier and a second band-pass filter which are connected in sequence;

the first band-pass filter is used for filtering the intermediate frequency signal and outputting the filtered intermediate frequency signal;

the variable gain amplifier is used for performing variable gain amplification on the filtered intermediate frequency signal and outputting the intermediate frequency signal subjected to variable gain amplification;

the second band-pass filter is used for filtering the intermediate frequency signal subjected to variable gain amplification so as to filter out-of-band noise and improve the signal-to-noise ratio.

Further, the logarithm detection module comprises a detection circuit and a logarithm operation circuit which are connected with each other;

the detection circuit is used for detecting and demodulating the intermediate frequency signal from the intermediate frequency conditioning module to obtain a baseband signal;

the logarithm operation circuit is used for logarithmizing the detection power so that the power obtained by logarithmization is in linear proportion to the output voltage.

Further, the baseband conditioning module comprises a first buffer, a first composite detection tube, a capacitor, an arithmetic subtracter, a second composite detection tube, a second buffer, a baseband filter and a hysteresis comparator;

the first composite wave detecting tube is provided with a first path of output end and a second path of output end; the second composite wave detecting tube is provided with a first path of input end and a second path of input end; the first output end of the first composite detecting tube is connected with the first input end of the second composite detecting tube; the second output end of the first composite detection tube is respectively connected with the capacitor and the operation subtracter, and the operation subtracter is connected with the second input end of the second composite detection tube;

the first buffer is used for adjusting the baseband signal from the logarithmic detection module to a proper amplitude;

the first composite detection tube is used for receiving the signal from the first buffer and outputting a first path of signal and a second path of signal through the first path of output end and the second path of output end respectively;

the capacitor is used for detecting the first path of signal in a matching manner to obtain a direct current signal;

the arithmetic subtracter is used for reducing the voltage of the direct current signal and outputting the reduced voltage signal;

the second composite detection tube is used for combining the second path of signal with the reduced voltage signal and outputting a combined signal;

the second buffer is used for adjusting the amplitude of the combined signal;

the baseband filter is used for low-pass filtering the signal from the second buffer;

the hysteresis comparator is used for performing hysteresis comparison on signals from the baseband filter.

Furthermore, the baseband conditioning module further comprises a resistor, one end of the resistor is connected with the output end of the second path of signal, and the other end of the resistor is grounded; the resistor is used for adjusting the current of the second path of signal.

According to another aspect of the embodiments of the present application, there is provided a signal conditioning method implemented by the signal conditioning apparatus described above; the signal conditioning method comprises the following steps:

the intermediate frequency conditioning module performs narrow-band filtering, amplification and re-filtering on the intermediate frequency signal;

the logarithm detection module detects and demodulates the intermediate frequency signal from the intermediate frequency conditioning module to obtain a baseband signal, and logarithmically converts detection power so that the logarithmically obtained power is in linear proportion to output voltage;

and the baseband conditioning module sequentially performs buffering, co-channel interference suppression processing, low-pass filtering and hysteresis comparison processing on the baseband signal from the logarithmic detection module to obtain a conditioned signal.

Further, the intermediate frequency conditioning module comprises a first band-pass filter, a variable gain amplifier and a second band-pass filter which are connected in sequence; the intermediate frequency conditioning module performs narrow-band filtering, amplification and re-filtering on the intermediate frequency signal to adjust the power of the intermediate frequency signal and filter out-of-band interference, and the method comprises the following steps:

the first band-pass filter filters the intermediate frequency signal and outputs the filtered intermediate frequency signal;

the variable gain amplifier performs variable gain amplification on the filtered intermediate frequency signal and outputs the intermediate frequency signal subjected to variable gain amplification;

and the second band-pass filter filters the intermediate frequency signal amplified by the variable gain so as to filter out-of-band noise and improve the signal-to-noise ratio.

Further, the logarithm detection module comprises a detection circuit and a logarithm operation circuit which are connected with each other; the logarithm detection module detects and demodulates the intermediate frequency signal from the intermediate frequency conditioning module to obtain a baseband signal, and logarithmically converts detection power so that the power obtained by logarithmization is linearly proportional to output voltage, and the method comprises the following steps:

the detection circuit detects and demodulates the intermediate frequency signal from the intermediate frequency conditioning module to obtain a baseband signal;

the logarithmic operation circuit logarithmically converts the detection power so that the power obtained by the logarithmization is linearly proportional to the output voltage.

Further, the baseband conditioning module comprises a first buffer, a first composite detection tube, a capacitor, an arithmetic subtracter, a second composite detection tube, a second buffer, a baseband filter and a hysteresis comparator; the baseband conditioning module sequentially performs buffering, co-channel interference suppression processing, low-pass filtering and hysteresis comparison processing on the baseband signal from the logarithmic detection module to obtain a conditioned signal, and the processing method comprises the following steps:

the first buffer adjusts the baseband signal from the logarithmic detection module to an appropriate amplitude;

the first composite detection tube receives the signal from the first buffer and outputs a first path of signal and a second path of signal;

the capacitor is matched to detect the first path of signal to obtain a direct current signal;

the arithmetic subtracter is used for reducing the voltage of the direct current signal and outputting the reduced voltage signal;

the second composite detection tube combines the second path of signal with the reduced voltage signal and outputs a combined signal;

the second buffer adjusts the amplitude of the combined signal;

the baseband filter low-pass filters the signal from the second buffer;

the hysteretic comparator makes a hysteretic comparison on the signal from the baseband filter.

Furthermore, the baseband conditioning module further comprises a resistor, one end of the resistor is connected with the output end of the second path of signal, and the other end of the resistor is grounded;

the baseband conditioning module sequentially performs buffering, co-channel interference suppression processing, low-pass filtering and hysteresis comparison processing on the baseband signal from the logarithmic detection module to obtain a conditioned signal, and the resistance adjusts the current of the second path of signal before the second composite detection tube combines the second path of signal and the reduced voltage signal;

and the second composite detection tube combines the second path of signal and the reduced voltage signal and replaces the combined signal with the second composite detection tube to combine the second path of signal after the resistance adjustment and the reduced voltage signal.

The technical scheme provided by one aspect of the embodiment of the application can have the following beneficial effects:

the signal conditioning device provided by the embodiment of the application has the advantages that the conditioned signal has strong co-channel interference resistance, stronger co-channel inhibition can be realized under the conditions of more wireless signal interference and serious co-channel data collision, the transaction success rate is improved, and the cost is lower.

Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the embodiments of the application, or may be learned by the practice of the embodiments. The objectives and other advantages of the application may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 shows a signal diagram of a baseband signal of a transaction on-board unit and a baseband signal of an interfering on-board unit in a field station environment;

FIG. 2 shows a signal diagram of a baseband signal of a transaction on-board unit superimposed with a baseband signal of an interfering on-board unit in a field station environment;

FIG. 3 illustrates a schematic diagram of a signal conditioning circuit of one embodiment of the present application;

FIG. 4 shows a schematic diagram of an intermediate frequency conditioning module in one embodiment of the present application;

FIG. 5 illustrates a schematic diagram of a logarithmic detection module in one embodiment of the present application;

FIG. 6 shows a schematic diagram of a baseband conditioning module in one embodiment of the present application;

FIG. 7 shows a signal diagram obtained after conditioning by a signal conditioning circuit according to one embodiment of the present application;

FIG. 8 shows a flow diagram of a signal conditioning method of an embodiment of the present application;

FIG. 9 shows a flowchart of step S10 in the embodiment shown in FIG. 8;

FIG. 10 shows a flowchart of step S20 in the embodiment shown in FIG. 8;

fig. 11 shows a flowchart of step S30 in the embodiment shown in fig. 8.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is further described with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It will be understood by those within the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

The station environment of using ETC is relatively complicated, and on-board unit OBU is more, and the collision probability is very high. When the signals returned by the two OBUs collide, the baseband signals received by the road side unit RSU are as shown in fig. 2. Because the modulation depth of each OBU is within a fixed range, after passing through the logarithmic detector, the peak-to-peak values of the radio frequency signals with different powers of different OBUs are basically the same on the baseband signals after passing through the logarithmic detector. As shown in fig. 1, 411 is the baseband signal of the currently transacted OBU, and 412 is the baseband signal of the interfering OBU in the vehicle yard, and the power of the signal reaching the RSU is lower than that of the transacted OBU because the interfering OBU is far away from the main lobe direction of the antenna. The superposition of the two signals causes waveform distortion, which causes a great problem in decoding, as shown in fig. 2. Based on the characteristics of parking lot transaction, the transaction OBU is close to the antenna, the RSU receives larger power, and the signal power of the interference OBU is lower.

An embodiment of the present application provides a signal conditioning circuit, which is a conditioning circuit for an intermediate frequency signal and a baseband signal of a road side unit RSU that is capable of resisting co-channel interference and can be applied to an ETC system.

As shown in fig. 3, the signal conditioning circuit of the present embodiment includes an intermediate frequency conditioning module 110, a logarithmic detection module 210, and a baseband conditioning module 300, which are connected in sequence.

The intermediate frequency conditioning module 110 is configured to perform narrowband filtering, amplification, and re-filtering on an intermediate frequency signal obtained through superheterodyne (ultrasonic heterodyne) frequency conversion, so as to adjust the power of the intermediate frequency signal and filter out-of-band interference.

As shown in fig. 4, the intermediate frequency conditioning module 110 includes a first band pass filter 111, a variable gain amplifier 112, and a second band pass filter 113 connected in sequence.

The first band-pass filter 111 is configured to filter the intermediate frequency signal and output the filtered intermediate frequency signal;

the variable gain amplifier 112 is configured to perform variable gain amplification on the filtered intermediate frequency signal, and output the intermediate frequency signal subjected to variable gain amplification;

the second band-pass filter 113 is configured to filter the intermediate frequency signal amplified by the variable gain to filter out-of-band noise and improve a signal-to-noise ratio.

An intermediate frequency signal obtained by superheterodyne (ultrasonic heterodyne) frequency conversion firstly enters a first band-pass filter 111 for filtering; the first bandpass filter 111 generally adopts a bandpass surface acoustic wave filter, which has a high Q value and a steep transition band, and can well filter out-of-band interference. The intermediate frequency signal is filtered by the first band-pass filter 111, and the obtained signal enters the variable gain amplifier 112, and is subjected to variable gain amplification according to different input powers, so that the dynamic range of the variable gain is enlarged. The signal output by the variable gain amplifier 112 finally passes through the second band-pass filter 113, and the second band-pass filter 113 filters out-of-band noise introduced by the variable gain amplifier 112, thereby improving the signal-to-noise ratio of the signal.

The logarithmic detection module 210 is configured to detect and demodulate the if signal processed by the if conditioning module 110 to obtain a baseband signal, and logarithmize the detection power, so that the power obtained by logarithmization is linearly proportional to the output voltage, thereby facilitating the next baseband signal processing.

In some embodiments, as shown in FIG. 5, the logarithmic detection module 210 may comprise a structure of a detection circuit 212 and a logarithmic operation circuit 211 connected to each other. The detection circuit 212 is configured to detect and demodulate the intermediate frequency signal from the intermediate frequency conditioning module 110 to obtain a baseband signal; the logarithmic operation circuit 211 is configured to logarithmize the detected power so that the logarithmized power is linearly proportional to the output voltage.

In some embodiments, the logarithmic detection module 210 may also employ a separate logarithmic detection chip. The logarithmic detection chip detects and demodulates the intermediate frequency signal obtained after the preprocessing by the intermediate frequency conditioning module 110 to obtain a baseband signal, and logarithmically converts the detection power so that the power obtained by the logarithmization is linearly proportional to the output voltage, thereby facilitating the next baseband signal processing.

The baseband conditioning module 300 is configured to buffer the baseband signal from the logarithmic detection module 210, perform co-channel interference suppression processing on the buffered baseband signal, perform low-pass filtering on the co-channel interference suppression processed signal, perform hysteresis comparison on the low-pass filtered signal, and finally output a conditioned baseband signal.

As shown in fig. 6, the baseband conditioning module 300 includes a first buffer 310, a first complex detector 321, a resistor 322, a capacitor 323, an arithmetic subtractor 324, a second complex detector 326, a second buffer 330, a baseband filter 340, and a hysteresis comparator 350.

The first composite detection tube 321 has two output ends, which are the first output end and the second output end respectively. The second composite detector tube 326 has two inputs, a first input and a second input. The first output terminal of the first composite detecting tube 321 is connected to the resistor 322 and the first input terminal of the second composite detecting tube 326, respectively. The second output end of the first composite detection tube 321 is connected to the capacitor 323 and the operation subtracter 324, respectively, and the operation subtracter 324 is connected to the second input end of the second composite detection tube 326. The operational subtractor 324 is also connected to a voltage reference 325.

The first buffer 310 is used to adjust the baseband signal from the log detection module 210 to an appropriate amplitude.

The first composite detection tube 321 is configured to receive the signal from the first buffer 310, and output a first path of signal and a second path of signal through a first path of output end and a second path of output end, respectively.

The capacitor 323 is used for detecting the first path of signal to obtain a direct current signal.

The operation subtractor 324 is configured to step down the dc signal and output the stepped-down signal.

The second composite detection tube 326 is used for combining the second path of signal with the reduced voltage signal and outputting the combined signal.

The second buffer 330 is used for adjusting the amplitude of the combined signal.

The baseband filter 340 is used to low-pass filter the signal from the second buffer 330.

The hysteresis comparator 350 is used to perform a hysteresis comparison on the signal from the baseband filter 340.

One end of the resistor 322 is connected with the output end of the second path of signal, and the other end of the resistor 322 is grounded; the resistor 322 is used to adjust the average current of the second signal, so that the two outputs of the first composite detection tube have better temperature complementation characteristics.

The baseband signal output by the logarithmic detection module 210 enters the first buffer 310, and the first buffer 310 is used to adjust the signal to a proper amplitude and improve the driving capability.

321-326 are core circuits for implementing co-channel interference suppression, a signal output by the first buffer 310 enters the first composite detection tube 321, the first composite detection tube 321 outputs two paths of signals, one path of signals is detected by the capacitor 323 to obtain a direct current, and the other path of signals is directly output by the resistor 322. The dc detected by the capacitor 323 is stepped down by the operation subtractor 324 (the step-down reference is provided by the voltage reference source 325), and the two signals enter the second composite detection tube 326, so as to combine the two signals. The signal below the dc voltage in the combination will be cut off at this time as shown in fig. 7. The combined signal enters the second buffer 330, and the second buffer 330 adjusts the amplitude of the signal and simultaneously improves the driving capability. And then the signal enters a base band filter 340 of 340 to carry out low-pass filtering, so that harmonic waves are filtered out, and the distortion caused by the waveform cutting is improved. Finally, the signal enters 350 a hysteresis comparator 350 for hysteresis comparison, completing baseband conditioning.

The first and second composite detection tubes 321 and 326 are each a structure formed by two diodes packaged together. The temperature-compensated composite detection tube has high parameter consistency and temperature complementation, can resist the pressure drop change caused by temperature drift, thereby keeping higher stability under the temperature change exceeding 100 ℃, and the 322 resistor 322 can finely adjust the current of the first composite detection tube 321, thereby achieving better temperature stability.

The co-channel interference suppression function is mainly implemented by the baseband conditioning module 300. The co-channel interference suppression circuit formed by 321-326 can obviously improve the co-channel interference suppression capability, and is matched with the surface acoustic wave filter to filter out-of-band interference, so that the decoding capability of the RSU when the signal replied by the OBU collides at an air interface is improved, the decoding capability under the co-frequency Wi-Fi interference is improved, and the transaction success rate of the station type RSU in a dense place is improved. Meanwhile, the co-channel interference suppression circuit also has temperature stability, and the consistency under the wide-temperature condition of an external field is ensured.

When the power of the interfering OBU is lower than the power of the transaction OBU to a predetermined degree, the 321-326 circuit portion in the baseband conditioning module 300 can remove the interfering signal, so as to obtain a signal that is easy to decode as shown in fig. 7.

The signal conditioning device provided by the embodiment of the application has the advantages that the conditioned signal has strong co-channel interference resistance, stronger co-channel inhibition can be realized under the conditions of more wireless signal interference and serious co-channel data collision, the transaction success rate is improved, the cost is low, and the consistency is good.

As shown in fig. 8, another embodiment of the present application further provides a signal conditioning method, which is implemented by the signal conditioning device of any of the above embodiments; the signal conditioning method comprises the following steps:

s10, the if conditioning module 110 performs narrowband filtering, amplifying, and re-filtering on the if signal to adjust the power of the if signal and filter out-of-band interference.

In some embodiments, the intermediate frequency conditioning module 110 includes a first band-pass filter 111, a variable gain amplifier 112, and a second band-pass filter 113 connected in series; as shown in fig. 9, step S10 includes:

s101, the first band-pass filter 111 filters the intermediate frequency signal, and outputs the filtered intermediate frequency signal.

S102, the variable gain amplifier 112 performs variable gain amplification on the filtered intermediate frequency signal, and outputs the intermediate frequency signal subjected to variable gain amplification.

S103, the second band-pass filter 113 filters the intermediate frequency signal amplified by the variable gain to filter out-of-band noise and improve the signal-to-noise ratio.

S20, the logarithmic detection module 210 detects and demodulates the intermediate frequency signal from the intermediate frequency conditioning module 110 to obtain a baseband signal, and logarithmically converts the detected power so that the logarithmically converted power is linearly proportional to the output voltage.

In some embodiments, the logarithmic detection module 210 includes a detection circuit and a logarithmic operation circuit connected to each other; as shown in fig. 10, step S20 includes:

s201, the detection circuit detects and demodulates the intermediate frequency signal from the intermediate frequency conditioning module 110 to obtain a baseband signal;

s202, the logarithm operation circuit logarithmically converts the detection power so that the power obtained by the logarithm is linearly proportional to the output voltage.

S30 and the baseband conditioning module 300 sequentially performs buffering, co-channel interference suppression, low-pass filtering, and hysteresis comparison on the baseband signal from the logarithmic detection module 210 to obtain a conditioned signal.

In some embodiments, the baseband conditioning module 300 includes a first buffer 310, a first complex detector 321, a capacitor 323, an operational subtractor 324, a second complex detector 326, a second buffer 330, a baseband filter 340, and a hysteresis comparator 350. As shown in fig. 11, step S30 includes:

s301, the first buffer 310 adjusts the baseband signal from the logarithmic detection module 210 to a proper amplitude;

s302, the first composite detection tube 321 receives the signal from the first buffer 310, and outputs a first path of signal and a second path of signal;

s303, detecting the first path of signal by the aid of the capacitor 323 to obtain a direct current signal;

s304, the operation subtracter 324 reduces the voltage of the direct current signal and outputs the reduced voltage signal;

s305, the second composite detection tube 326 combines the second path of signal with the reduced voltage signal, and outputs a combined signal;

s306, adjusting the amplitude of the combined signal by the second buffer 330;

s307, the baseband filter 340 performs low-pass filtering on the signal from the second buffer 330;

s308, the hysteresis comparator 350 performs hysteresis comparison on the signal from the baseband filter 340.

In some embodiments, the baseband conditioning module 300 further includes a resistor 322, one end of the resistor 322 is connected to the output end of the first signal, and the other end of the resistor 322 is grounded; step S30 further includes: s304', the resistor 322 adjusts the current of the first path of signal to make the current of the first path of signal equal to the current of the signal after voltage reduction. Step S305 is replaced with S305': the second composite detection tube 326 combines the second signal adjusted by the resistor 322 with the stepped-down signal.

By the signal conditioning method, interference signals can be filtered, variable gain can be amplified, the signal to noise ratio of the signals can be improved, the signals can be adjusted to a proper amplitude, the driving capability of the signals can be improved, distortion can be improved, and baseband signals convenient to decode can be obtained.

It should be noted that:

the terms "first," "second," and the like as used herein may be used in the present disclosure to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another.

It should be appreciated that in the foregoing description of exemplary embodiments of the application, various features of the application are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. However, the disclosed method should not be interpreted as reflecting an intention that: this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this application.

It should be understood that, although the steps in the flowcharts of the figures are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and may be performed in other orders unless explicitly stated herein. Moreover, at least a portion of the steps in the flow chart of the figure may include multiple sub-steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, which are not necessarily performed in sequence, but may be performed alternately or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

The above-mentioned embodiments only express the embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.