Radio frequency receiving device and ETC system

Abstract

The present application relates to a kind of radio frequency receiving device and ETC system, radio frequency receiving device includes: multi-channel receiving unit, intermodulation suppression unit and multi-channel receiving unit;Multi-channel receiving unit is used to receive multi-channel mixed signal;Intermodulation suppression unit is connected with multi-channel receiving unit, for processing, to suppress intermodulation signal to multi-channel mixed signal;Multi-channel receiving unit is connected with intermodulation suppression unit, for processing and transmission to post-stage circuit after multi-channel mixed signal after processing by intermodulation suppression unit.Through the radio frequency receiving device of the present application, one antenna can be realized for multi-channel receiving, which can greatly reduce the physical size of receiver system, greatly reduce the difficulty of implementation, effectively expand channel capacity, realize high-speed transmission;At the same time, it can also suppress intermodulation signal, reduce the interference of intermodulation signal to signal in operating bandwidth and adjacent channel.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of radio frequency transceiving, and more particularly to a radio frequency receiving device and an ETC system. BACKGROUND

[0002] The current ETC roadside base station RSU can only work in one channel (such as 5.830Hz, 5.840GHz) to interact with the on-board unit OBU. Its working characteristics are: 1, frequency division working of uplink and downlink; 2, the modulation mode is ASK modulation; 3, the data transmission rate is very low, only 256KBps; 4, the data link layer, the roadside base station RSU can only interact with one user terminal (such as the on-board unit OBU) at the same time, serial communication, low channel utilization.

[0003] With the development of the ETC industry, the above-mentioned current situation of the ETC industry cannot meet the needs of users and the market. The current market and users need a high data transmission rate roadside base station RSU, which can simultaneously perform one-to-many communication and fully utilize the channel bandwidth to provide better services for users. The roadside base station RSU and the on-board terminal OBU based on vehicle-road cooperation application are born in this background. Its working characteristics are: 1, frequency division working of uplink and downlink; 2, full duplex of uplink and downlink working mode; 3, multiple channels are divided for uplink and downlink to work simultaneously, expanding the channel capacity; 4, high-order modulation and high data rate transmission.

[0004] However, the existing radio frequency receiver usually designs one receiving link for each receiving channel, and each receiving link contains one receiving antenna. Each receiving antenna needs to ensure an isolation of at least 50dB and is placed in the same plane, which can only be realized by increasing the spatial distance. As a result, if the receiving channels are too many, a large number of receiving antennas are needed, and the receiving antennas need to be spaced at least 10CM apart, so the physical size of the entire receiver system is very large, which is difficult to realize. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a radio frequency receiving device and an ETC system in view of the defects of the prior art.

[0006] The technical scheme adopted by the present application to solve the technical problem is: a radio frequency receiving device is constructed, comprising: a multi-channel receiving unit, a intermodulation suppression unit and a multi-path receiving unit;

[0007] The multi-channel receiving unit is used for receiving a multi-channel mixed signal;

[0008] The intermodulation suppression unit is connected with the multi-channel receiving unit and is used for processing the multi-channel mixed signal to suppress the intermodulation signal;

[0009] The multi-channel receiving unit is connected with the intermodulation suppression unit, and is used for processing the multi-channel mixed signal processed by the intermodulation suppression unit and transmitting the processed signal to a subsequent circuit.

[0010] In the radio frequency receiving device, the intermodulation suppression unit comprises an intermodulation signal extraction module and an intermodulation signal elimination module.

[0011] The intermodulation signal extraction module is connected with the multi-channel receiving unit, and is used for extracting the intermodulation signal in the multi-channel mixed signal.

[0012] The intermodulation signal elimination module is connected with the intermodulation signal extraction module, and is used for eliminating the intermodulation signal extracted by the intermodulation signal extraction module to obtain a main signal.

[0013] In the radio frequency receiving device, the intermodulation signal extraction module comprises a coupling circuit, a main processing circuit, a first amplitude shift circuit and a secondary processing circuit.

[0014] The coupling circuit is connected with the multi-channel receiving unit, and is used for receiving the multi-channel mixed signal, processing the multi-channel mixed signal, and outputting a main path signal and a secondary path signal.

[0015] The main processing circuit is connected with the coupling circuit, and is used for receiving the main path signal and amplifying and coupling the main path signal.

[0016] The first amplitude shift circuit is connected with the main processing circuit and the secondary processing circuit respectively, and is used for amplitude shift processing the signal coupled by the main processing circuit.

[0017] The secondary processing circuit is connected with the coupling circuit, and is used for delaying the secondary path signal and canceling the signal output by the first amplitude shift circuit to output the intermodulation signal.

[0018] In the radio frequency receiving device, the coupling circuit comprises a first coupler; the main processing circuit comprises a first-order noise amplifier and a second coupler; the first amplitude shift circuit comprises a first adjustable attenuator and a first adjustable phase shifter; and the secondary processing circuit comprises a first delay circuit and a first amplitude cancellation circuit.

[0019] The first end of the first coupler is connected with the multi-channel receiving unit, the second end of the first coupler is connected with the input end of the first-order noise amplifier, the fourth end of the first coupler is connected with the input end of the first delay circuit, and the third end of the first coupler is grounded.

[0020] The output end of the first noise amplifier is connected with the input end of the second coupler, the first output end of the second coupler is connected with the intermodulation signal elimination module, and the second output end of the second coupler is connected with the input end of the first adjustable attenuator;

[0021] The output end of the first adjustable attenuator is connected with the input end of the first adjustable phase shifter, and the output end of the first adjustable phase shifter is connected with the second input end of the first amplitude cancellation circuit.

[0022] The first input end of the first amplitude cancellation circuit is connected with the output end of the first delay circuit, and the output end of the first amplitude cancellation circuit is connected with the intermodulation signal elimination module.

[0023] In the radio frequency receiving device, the intermodulation signal elimination module comprises a second delay circuit, a second amplitude cancellation circuit and an intermodulation signal processing circuit.

[0024] The input end of the second delay circuit is connected with the output end of the main processing circuit, and the output end of the second delay circuit is connected with the first input end of the second amplitude cancellation circuit.

[0025] The input end of the intermodulation signal processing circuit is connected with the output end of the auxiliary processing circuit, the output end of the intermodulation signal processing circuit is connected with the second input end of the second amplitude cancellation circuit, and the output end of the second amplitude cancellation circuit is connected with the multi-path receiving unit.

[0026] In the radio frequency receiving device, the intermodulation signal processing circuit comprises a second amplitude-phase modulation circuit and a linear processing circuit.

[0027] The input end of the second amplitude-phase modulation circuit is connected with the auxiliary processing circuit, and the second amplitude-phase modulation circuit is used for performing amplitude-phase modulation processing on the intermodulation signal.

[0028] The input end of the linear processing circuit is connected with the output end of the second amplitude-phase modulation circuit, the output end of the linear processing circuit is connected with the second input end of the second amplitude cancellation circuit, and the linear processing circuit is used for performing linear processing on the signal output by the second amplitude-phase modulation circuit and then transmitting the signal to the second amplitude cancellation circuit.

[0029] In the radio frequency receiving device, the second amplitude-phase modulation circuit comprises a second adjustable attenuator and a second adjustable phase shifter, and the linear processing circuit comprises a linear power amplifier.

[0030] The input end of the second adjustable attenuator is connected to the output end of the auxiliary processing circuit, the output end of the second adjustable attenuator is connected to the input end of the second adjustable phase shifter, the output end of the second adjustable phase shifter is connected to the input end of the linear power amplifier, and the output end of the linear power amplifier is connected to the second input end of the second amplitude cancellation circuit.

[0031] In the radio frequency receiving device, the multi-channel receiving unit comprises a power divider, a plurality of parallel multi-channel receiving links connected to the power divider, and a controller connected to the multi-channel receiving links.

[0032] The power divider is configured to divide the multi-channel mixed signal output by the intermodulation suppression unit and transmit the divided signals to the multi-channel receiving links.

[0033] The multi-channel receiving links are configured to process the received signals and transmit the processed signals to the controller.

[0034] The controller is configured to process the signals transmitted by the multi-channel receiving links and transmit the processed signals to a subsequent circuit.

[0035] In the radio frequency receiving device, each of the multi-channel receiving links comprises a second-stage noise amplifier, a band-pass filter, and a radio frequency receiving chip.

[0036] The input end of the second-stage noise amplifier is connected to the power divider, the output end of the second-stage noise amplifier is connected to the input end of the band-pass filter, the output end of the band-pass filter is connected to the input end of the radio frequency receiving chip, and the output end of the radio frequency receiving chip is connected to the controller.

[0037] The present application also provides an ETC system comprising the radio frequency receiving device.

[0038] The radio frequency receiving device and the ETC system have the following advantages: the radio frequency receiving device comprises a multi-channel receiving unit, an intermodulation suppression unit, and a multi-channel receiving unit; the multi-channel receiving unit is configured to receive a multi-channel mixed signal; the intermodulation suppression unit is connected to the multi-channel receiving unit and is configured to process the multi-channel mixed signal to suppress intermodulation signals; and the multi-channel receiving unit is connected to the intermodulation suppression unit and is configured to process the multi-channel mixed signal processed by the intermodulation suppression unit and transmit the processed signal to a subsequent circuit. The radio frequency receiving device can realize multi-channel receiving with one antenna, greatly reduce the physical size of the receiver system, effectively expand the channel capacity, and realize high-speed transmission. Meanwhile, the radio frequency receiving device can suppress intermodulation signals and reduce the interference of the intermodulation signals on the signals in the working bandwidth and adjacent channels. BRIEF DESCRIPTION OF DRAWINGS

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0040] Figure 1 It is a structural diagram of a first embodiment of a radio frequency receiving device provided by the present invention;

[0041] Figure 2 It is a structural diagram of a second embodiment of a radio frequency receiving device provided by the present invention;

[0042] Figure 3 2 is a schematic structural diagram of an intermodulation suppression unit of the present invention;

[0043] Figure 4 1 is a schematic structural diagram of a directional coupler of the present invention;

[0044] Figure 5 It is a structural diagram of the 3DB bridge provided by the present invention;

[0045] Figure 6 It is a schematic diagram of the circuit model of the 3DB bridge provided by the present invention. DETAILED DESCRIPTION

[0046] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0047] refer to Figure 1 , which is a schematic diagram of the structure of an optional embodiment of the RF receiving device provided by the present invention. This RF receiving device supports multi-channel reception, and all channels share a single antenna. This significantly reduces the physical size of the receiver system and its implementation difficulty, while also suppressing intermodulation signals caused by the nonlinearity of RF devices, reducing their interference with signals within the operating bandwidth and adjacent channels.

[0048] Specifically, such as Figure 1 As shown, the radio frequency receiving device includes: a multi-channel receiving unit 10 , an intermodulation suppression unit 20 and a multi-path receiving unit 30 .

[0049] The multi-channel receiving unit 10 is used to receive multi-channel mixed signals. The multi-channel receiving unit 10 is a multi-channel receiving antenna.

[0050] In the embodiment of the present invention, by adopting a multi-channel receiving antenna, multi-channel reception can be achieved with only one antenna, thereby avoiding the problems caused by setting up a receiving antenna for each receiving link, effectively reducing the physical size of the entire receiving system, and reducing both cost and implementation difficulty.

[0051] The intermodulation suppression unit 20 is connected to the multi-channel receiving unit 10 and is used to process the multi-channel mixed signal to suppress the intermodulation signal.

[0052] Since the radio frequency device exists in the radio frequency receiving device, the nonlinear characteristics of the radio frequency device itself can cause the multi-channel mixed signal received by the antenna end to generate a multi-path intermodulation signal after inputting into the radio frequency device, and the intermodulation signal can greatly interfere with the signal of the subsequent receiving link, reduce the receiving sensitivity, and bring a higher bit error rate. Therefore, in the embodiment of the present application, by setting the intermodulation suppression unit 20, the intermodulation signal can be effectively suppressed, the interference caused by the intermodulation signal can be avoided, the receiving sensitivity can be effectively improved, the bit error rate can be reduced, and the reliability, stability and accuracy of the received signal can be improved.

[0053] The multi-path receiving unit 30 is connected with the intermodulation suppression unit 20, and is used for processing the multi-channel mixed signal processed by the intermodulation suppression unit 20 and transmitting the multi-channel mixed signal to the subsequent circuit.

[0054] Some embodiments, as shown in Figure 2 The intermodulation suppression unit 20 includes an intermodulation signal extraction module 21 and an intermodulation signal elimination module 22.

[0055] The intermodulation signal extraction module 21 is connected with the multi-channel receiving unit 10, and is used for extracting the intermodulation signal in the multi-channel mixed signal.

[0056] In the embodiment of the present application, the intermodulation signal extraction module 21 mainly extracts the intermodulation signal generated after the low noise amplification processing, and compensates the group delay of the main signal after the low noise amplification through the delay processing.

[0057] The intermodulation signal elimination module 22 is connected with the intermodulation signal extraction module 21, and is used for eliminating the intermodulation signal extracted by the intermodulation signal extraction module 21 to obtain the main signal.

[0058] In the embodiment of the present application, the intermodulation signal elimination module 22 is mainly used for eliminating the intermodulation signal from the output signal after the low noise amplification processing, and only retaining the main signal, so as to avoid the interference of the generated intermodulation signal to the subsequent link.

[0059] Some embodiments, as shown in Figure 3 The structure schematic diagram of an optional embodiment of the intermodulation suppression unit 20 provided by the embodiment of the present application.

[0060] As shown in Figure 3 In the embodiment, the intermodulation signal extraction module 21 includes a coupling circuit 211, a main processing circuit 212, a first amplitude modulation phase shift circuit 214 and a secondary processing circuit 213.

[0061] The coupling circuit 211 is connected with the multi-channel receiving unit 10, and is used for receiving the multi-channel mixed signal and processing the multi-channel mixed signal to output the main path signal and the secondary path signal.

[0062] The main processing circuit 212 is connected to the coupling circuit 211 and is configured to receive the main signal and perform amplification and coupling processing on the main signal.

[0063] The first amplitude modulation and phase shift circuit 214 is connected to the main processing circuit 212 and the auxiliary processing circuit 213 respectively, and is used to perform amplitude modulation and phase shift processing on the signal coupled by the main processing circuit 212.

[0064] The auxiliary processing circuit 213 is connected to the coupling circuit 211 and is used to delay the auxiliary signal and cancel it with the signal output by the first amplitude modulation and phase shift circuit 214 to output an intermodulation signal.

[0065] like Figure 3 As shown in FIG, ①②③④⑤⑥⑦⑧⑨ represent the distribution of the main signal and the intermodulation signal at the link position. The main signal is located in the middle solid line, and the intermodulation signal is distributed on the dotted lines on both sides.

[0066] Optionally, in some embodiments, the coupling circuit 211 includes: a first coupler; the main processing circuit 212 includes: a first-stage noise amplifier 201 and a second coupler 202; the first amplitude modulation phase shift circuit 214 includes: a first adjustable attenuator 241 and a first adjustable phase shifter 242; the auxiliary processing circuit 213 includes: a first delay circuit 203 and a first amplitude compensation circuit 204.

[0067] The first end of the first coupler is connected to the multi-channel receiving unit 10, the second end of the first coupler is connected to the input end of the first-level noise amplifier 201, the fourth end of the first coupler is connected to the input end of the first delay circuit 203, and the third end of the first coupler is grounded; the output end of the first-level noise amplifier 201 is connected to the input end of the second coupler 202, the first output end of the second coupler 202 is connected to the intermodulation signal elimination module 22, and the second output end of the second coupler 202 is connected to the input end of the first adjustable attenuator 241; the output end of the first adjustable attenuator 241 is connected to the input end of the first adjustable phase shifter 242, and the output end of the first adjustable phase shifter 242 is connected to the second input end of the first amplitude cancellation circuit 204; the first input end of the first amplitude cancellation circuit 204 is connected to the output end of the first delay circuit 203, and the output end of the first amplitude cancellation circuit 204 is connected to the intermodulation signal elimination module 22.

[0068] In some embodiments, the first coupler may be a directional coupler, which can be used to split a multi-channel signal received by a multi-channel receiving antenna into two signals, wherein the two signals are identical.

[0069] Optionally, in an embodiment of the present invention, the directional coupler can be implemented using a microstrip circuit. Specifically, Figure 4 Shown is a schematic diagram of the structure of a directional coupler.

[0070] As shown in Figure 4 The first end of the directional coupler is connected with the multi-channel receiving antenna, the second end of the directional coupler is connected with the input end of the first noise amplifier 201, the third end of the directional coupler is an isolation end which can be connected with the ground through a 50-ohm matching, and the fourth end of the directional coupler is a coupling end which can be connected with the input end of the first delay circuit 203. The main path signal of the main processing circuit 212 is coupled through the fourth end of the directional coupler to output the branch path signal to the branch processing circuit 213.

[0071] As shown in Figure 3 The main path signal is amplified by the first noise amplifier 201 to generate a intermodulation signal, and the frequency distribution of the main signal and the intermodulation signal is shown as a signal ②. The signal ② is coupled through the second coupler 202, and the signal coupled through the second coupler 202 is subjected to amplitude modulation through the first adjustable attenuator 241 and phase modulation through the first adjustable phase shifter 242 to generate a signal ⑤. The signal ⑤ is still composed of the main signal and the intermodulation signal.

[0072] Optionally, as shown in Figure 3 In this embodiment, the intermodulation signal elimination module 22 includes a second delay circuit 221, a second amplitude cancellation circuit 222 and an intermodulation signal processing circuit 223.

[0073] The input end of the second delay circuit 221 is connected with the output end of the main processing circuit 212, and the output end of the second delay circuit 221 is connected with the first input end of the second amplitude cancellation circuit 222. The input end of the intermodulation signal processing circuit 223 is connected with the output end of the branch processing circuit 213, the output end of the intermodulation signal processing circuit 223 is connected with the second input end of the second amplitude cancellation circuit 222, and the output end of the second amplitude cancellation circuit 222 is connected with the multi-channel receiving unit 30.

[0074] Optionally, in the embodiment of the present application, the intermodulation signal processing circuit 223 includes a second amplitude modulation and phase shift circuit 231 and a linear processing circuit 232.

[0075] The input end of the second amplitude modulation and phase shift circuit 231 is connected with the branch processing circuit 213, and the second amplitude modulation and phase shift circuit 231 is used for amplitude modulation and phase shift processing of the intermodulation signal.

[0076] The input end of the linear processing circuit 232 is connected with the output end of the second amplitude modulation and phase shift circuit 231, and the output end of the linear processing circuit 232 is connected with the second input end of the second amplitude cancellation circuit 222. The linear processing circuit 232 is used for linear processing of the signal output by the second amplitude modulation and phase shift circuit 231 and transmitting the signal to the second amplitude cancellation circuit 222.

[0077] Optionally, in an embodiment of the present invention, the second amplitude modulation phase shift circuit 231 includes: a second adjustable attenuator 243 and a second adjustable phase shifter 244; the linear processing circuit 232 includes: a linear power amplifier.

[0078] The input end of the second adjustable attenuator 243 is connected to the output end of the auxiliary processing circuit 213, the output end of the second adjustable attenuator 243 is connected to the input end of the second adjustable phase shifter 244, the output end of the second adjustable phase shifter 244 is connected to the input end of the linear power amplifier, and the output end of the linear power amplifier is connected to the second input end of the second amplitude cancellation circuit 222.

[0079] In some embodiments, both the first delay circuit 203 and the second delay circuit 221 can be implemented using microstrip delay lines. The first delay circuit 203 can compensate for the phase delay of the main signal passing through a first-stage noise amplifier (low-noise amplifier). The second delay circuit 221 can compensate for the phase delay of the extracted intermodulation signal passing through a linear power amplifier.

[0080] Specifically, such as Figure 3 As shown, the secondary signal is identical to the original signal (i.e., primary signal ①), primarily serving as the main signal. After passing through first delay circuit 203, it becomes signal ③. By performing amplitude modulation and phase shifting on signal ⑤, signals ⑤ and ③ have the same amplitude and a 90° phase difference when entering first amplitude cancellation circuit 204 (i.e., a 3dB bridge). First delay circuit 203 primarily compensates for the phase delay incurred by the primary signal passing through first-stage noise amplifier 201 (i.e., low-noise amplifier LNA1). After entering first amplitude cancellation circuit 204, signals ⑤ and ③ cancel each other out due to their identical amplitudes and 90° phase difference, leaving only the frequency distribution of the intermodulation signal. Removing the primary signal leaves only the intermodulation signal, resulting in a new signal, signal ⑥.

[0081] Further, if Figure 3 As shown, intermodulation signal ⑥ is amplitude modulated by second adjustable attenuator 243 and linear processing circuit 232 (i.e., linear power amplifier PA), and phase-modulated by second adjustable phase shifter 244 to generate signal ⑧. The linear power amplifier PA is a highly linear power amplifier to avoid introducing new spurious and distorted signals.

[0082] Signal ② passes through the second coupler 202 to generate signal ④, which is the same as signal ② except for the amplitude difference. Signal ④ passes through the second delay circuit 221 to generate signal ⑦.

[0083] The amplitude modulation phase shift of the signal 7 makes the signal 6 and the signal 7 have the same amplitude and a phase difference of 90° when entering the second amplitude cancellation circuit 222. The signal 6 and the signal 7 have the same amplitude and a phase difference of 90° when entering the bridge of the second amplitude cancellation circuit 222, and thus the cancellation (i.e. the intermodulation signal is cancelled) is generated, and only the frequency distribution of the main signal, i.e. the signal 9, is left. The signal 9 is the multi-channel useful signal transmitted by the vehicle-mounted OBU user after one-stage low-noise amplification and without the intermodulation signal interfering with other channels.

[0084] Optionally, in the embodiment of the present application, the first amplitude cancellation circuit 204 and the second amplitude cancellation circuit 222 can both be implemented by a 3DB bridge. The circuit structure of the 3DB bridge is shown in Figure 5 .

[0085] As shown in Figure 5 , the 1 port and the 4 port of the 3DB bridge are signal input ends, the 3 port is a signal output end, and the 2 port can be matched with a 50-ohm ground.

[0086] The circuit model of the 3DB bridge is shown in Figure 6 .

[0087] Figure 6 The PORT1 and the PORT4 correspond to the 1 port and the 4 port of Figure 5 , respectively, for receiving input signals, the PORT2 corresponds to the 2 port of Figure 5 , and is grounded, and the PORT3 corresponds to the 3 port of Figure 5 , for outputting signals.

[0088] The cancellation principle of the 3DB bridge is as follows:

[0089] Suppose the input signal of the PORT1 is A1COS(W1t+φ1);

[0090] The input signal of the PORT4 is A2COS(W2t+φ2);

[0091] According to the superposition principle:

[0092] The output of the PORT2 is (A1 / 2)COS(W1t+φ1+90°)+(A2 / 2)COS(W2t+φ2+180°);

[0093] The output of the PORT3 is (A1 / 2)COS(W1t+φ1+180°)+(A2 / 2)COS(W2t+φ2+90°);

[0094] Suppose the input signal amplitudes are the same and the phase difference is 90 degrees, i.e. A1=A2, W1t+φ1=W2t+φ2+90°, at this time:

[0095] PORT2 output: A1 COS(W2t + φ2 + 180°);

[0096] PORT3 output: (A1 / 2) COS(W1t + φ1 + 180°) + (A2 / 2) COS(W2t + φ2 + 90°) =

[0097] (A1 / 2) COS(W2t + φ2 + 270°) + (A2 / 2) COS(W2t + φ2 + 90°) = 0.

[0098] At this time, PORT2 can be grounded, and the two input signals (with the same amplitude and a phase difference of 90 degrees) are completely canceled at the PORT3 port, and the output is 0.

[0099] As shown in some embodiments, Figure 2 the multi-path receiving unit 30 includes a power divider 31, a plurality of multi-path receiving links 32 connected with the power divider 31 and arranged in parallel, and a controller 33 connected with the multi-path receiving links 32.

[0100] The power divider 31 is configured to divide the multi-channel mixed signal output by the intermodulation suppression unit 20 and transmit the multi-channel mixed signal to the multi-path receiving links 32 respectively.

[0101] The multi-path receiving links 32 are configured to process the received signals and transmit the processed signals to the controller 33.

[0102] The controller 33 is configured to process the signals transmitted by the multi-path receiving links 32 and transmit the processed signals to a subsequent circuit. The controller 33 can be an MCU, and is mainly configured to perform data processing.

[0103] As shown in some embodiments, Figure 2 each of the multi-path receiving links 32 includes a second-stage noise amplifier LAN2, a band-pass filter BPF, and a radio frequency receiving chip.

[0104] The input end of the second-stage noise amplifier is connected with the power divider 31, the output end of the second-stage noise amplifier is connected with the input end of the band-pass filter, the output end of the band-pass filter is connected with the input end of the radio frequency receiving chip, and the output end of the radio frequency receiving chip is connected with the controller 33.

[0105] As shown in some embodiments, Figure 2 channel 1, channel 2, …, and channel n represent the number of channels transmitted by the terminal user, i.e., the number of channels received by the road side unit RSU. Each of the channels has a working bandwidth of 5 MHz.

[0106] Optionally, in this embodiment of the present invention, power divider 31 may employ a Wilkinson structure. By employing the Wilkinson structure, the multi-channel mixed signal received by the multi-channel receiving antenna can be evenly distributed and transmitted with equal amplitude and phase. That is, the signals are transmitted with equal amplitude and phase to each receiving link, such as channel 1, channel 2, ..., channel n.

[0107] As shown in Figure 2, the secondary noise amplifier in each receiving link can achieve secondary noise amplification of the signal of the current link, which can adopt a low-noise signal amplifier with a noise figure of ≤1dB.

[0108] like Figure 2 As shown, the bandpass filter in each receiving link is mainly used to filter out the interference signal outside the band. The bandpass range of the bandpass filter is determined by the actual requirement of the received signal.

[0109] like Figure 2 As shown in the figure, the RF receiving chip in each receiving chain is the demodulator and decoder chip for the signal received on the current channel. It can be implemented as an integrated chip, down-converting and demodulating the received GFSK high-frequency modulated signal to generate an analog baseband signal, which can then be decoded and processed to ultimately restore the original data sent by the end user.

[0110] The present invention also provides an ETC system, which may include the radio frequency receiving device disclosed in the embodiment of the present invention.

[0111] Of course, it is understandable that the radio frequency receiving device disclosed in the embodiment of the present invention can also be applied to other wireless radio frequency transmission and reception fields, such as wireless image transmission, wireless data transmission, etc.

[0112] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0113] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0114] The steps of a method or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module can reside in random access memory (RAM), flash memory, read-only memory (ROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0115] The above embodiments are only to illustrate the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it accordingly, and cannot limit the protection scope of the present application. Any equivalent changes and modifications made within the scope of the claims of the present application shall belong to the scope of the claims of the present application.

Claims

1. A radio frequency receiving device, characterized in that: include: Multi-channel receiving unit, intermodulation suppression unit and multi-path receiving unit; The multi-channel receiving unit is used to receive a multi-channel mixed signal; The intermodulation suppression unit is connected to the multi-channel receiving unit and is used to process the multi-channel mixed signal to suppress the intermodulation signal; The intermodulation suppression unit includes: an intermodulation signal extraction module and an intermodulation signal elimination module; The intermodulation signal extraction module is connected to the multi-channel receiving unit and is used to extract the intermodulation signal from the multi-channel mixed signal; The intermodulation signal elimination module is connected to the intermodulation signal extraction module, and is used to eliminate the intermodulation signal extracted from the intermodulation signal, offset the intermodulation signal, and obtain the main signal; The intermodulation signal extraction module includes: a coupling circuit, a main processing circuit, a first amplitude modulation phase shift circuit and a sub-processing circuit; The coupling circuit is connected to the multi-channel receiving unit, and is used to receive the multi-channel mixed signal and process the multi-channel mixed signal to output a main channel signal and a secondary channel signal; The main processing circuit is connected to the coupling circuit, and is used to receive the main signal and perform amplification and coupling processing on the main signal; The first amplitude modulation and phase shift circuit is connected to the main processing circuit and the auxiliary processing circuit respectively, and is used to perform amplitude modulation and phase shift processing on the signal after coupling processing by the main processing circuit; The auxiliary processing circuit is connected to the coupling circuit, and is used to delay the auxiliary signal and offset the main signal with a phase difference of 90° with the first amplitude modulation phase shift circuit through a first amplitude cancellation circuit to output the intermodulation signal; the first amplitude cancellation circuit is a 3dB bridge; The multi-channel receiving unit is connected to the intermodulation suppression unit, and is used to process the multi-channel mixed signal processed by the intermodulation suppression unit and transmit it to the subsequent circuit; The multi-channel receiving unit includes: a power splitter, a multi-channel receiving link connected to the power splitter and arranged in parallel, and a controller connected to the multi-channel receiving link; The power divider is used to equally divide the multi-channel mixed signal output by the intermodulation suppression unit and transmit it to the multi-channel receiving link with equal amplitude and phase; The multi-channel receiving link is used to process the received signals and transmit them to the controller; The controller is used to process the signals transmitted by the multi-channel receiving links and transmit them to the subsequent circuit.

2. The radio frequency receiving device according to claim 1, wherein: The coupling circuit includes: a first coupler; the main processing circuit includes: a first-level noise amplifier and a second coupler; the first amplitude modulation phase shift circuit includes: a first adjustable attenuator and a first adjustable phase shifter; the auxiliary processing circuit includes: a first delay circuit and a first amplitude compensation circuit; A first end of the first coupler is connected to the multi-channel receiving unit, a second end of the first coupler is connected to the input end of the first-stage noise amplifier, a fourth end of the first coupler is connected to the input end of the first delay circuit, and a third end of the first coupler is grounded; The output end of the first-stage noise amplifier is connected to the input end of the second coupler, the first output end of the second coupler is connected to the intermodulation signal elimination module, and the second output end of the second coupler is connected to the input end of the first adjustable attenuator; The output end of the first adjustable attenuator is connected to the input end of the first adjustable phase shifter, and the output end of the first adjustable phase shifter is connected to the second input end of the first amplitude cancellation circuit; The first input end of the first amplitude cancellation circuit is connected to the output end of the first delay circuit, and the output end of the first amplitude cancellation circuit is connected to the intermodulation signal elimination module.

3. The radio frequency receiving device according to claim 1, wherein: The intermodulation signal elimination module includes: a second delay circuit, a second amplitude cancellation circuit and an intermodulation signal processing circuit; The input end of the second delay circuit is connected to the output end of the main processing circuit, and the output end of the second delay circuit is connected to the first input end of the second amplitude cancellation circuit; The input end of the intermodulation signal processing circuit is connected to the output end of the auxiliary processing circuit, the output end of the intermodulation signal processing circuit is connected to the second input end of the second amplitude cancellation circuit, and the output end of the second amplitude cancellation circuit is connected to the multi-channel receiving unit.

4. The radio frequency receiving device according to claim 3, wherein: The intermodulation signal processing circuit includes: a second amplitude modulation phase shift circuit and a linear processing circuit; The input end of the second amplitude modulation and phase shift circuit is connected to the auxiliary processing circuit, and is used to perform amplitude modulation and phase shift processing on the intermodulation signal; The input end of the linear processing circuit is connected to the output end of the second amplitude modulation phase shift circuit, and the output end of the linear processing circuit is connected to the second input end of the second amplitude cancellation circuit; the linear processing circuit is used to perform linear processing on the signal output by the second amplitude modulation phase shift circuit and then transmit it to the second amplitude cancellation circuit.

5. The radio frequency receiving device according to claim 4, wherein: The second amplitude modulation phase shift circuit includes: a second adjustable attenuator and a second adjustable phase shifter; the linear processing circuit includes: a linear power amplifier; The input end of the second adjustable attenuator is connected to the output end of the auxiliary processing circuit, the output end of the second adjustable attenuator is connected to the input end of the second adjustable phase shifter, the output end of the second adjustable phase shifter is connected to the input end of the linear power amplifier, and the output end of the linear power amplifier is connected to the second input end of the second amplitude cancellation circuit.

6. The radio frequency receiving device according to claim 5, wherein: Each receiving link in the multiple receiving links includes: a secondary noise amplifier, a bandpass filter and a radio frequency receiving chip; The input end of the secondary noise amplifier is connected to the power divider, the output end of the secondary noise amplifier is connected to the input end of the bandpass filter, the output end of the bandpass filter is connected to the input end of the RF receiving chip, and the output end of the RF receiving chip is connected to the controller.

7. An ETC system, characterized in that: The invention comprises the radio frequency receiving device according to any one of claims 1 to 6.

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