CN217116077U - Signal demodulation circuit and signal receiving module - Google Patents
Signal demodulation circuit and signal receiving module Download PDFInfo
- Publication number
- CN217116077U CN217116077U CN202220106484.8U CN202220106484U CN217116077U CN 217116077 U CN217116077 U CN 217116077U CN 202220106484 U CN202220106484 U CN 202220106484U CN 217116077 U CN217116077 U CN 217116077U
- Authority
- CN
- China
- Prior art keywords
- signal
- frequency
- frequency signal
- circuit
- unit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Noise Elimination (AREA)
Abstract
A signal demodulation circuit and a signal receiving module, the signal demodulation circuit includes: the frequency selection unit, the frequency locking unit and the filtering unit are connected in sequence; the frequency selection unit is connected with the signal acquisition circuit at the front end and used for extracting a first frequency signal and a second frequency signal from the frequency signal output by the signal acquisition circuit; the frequency locking unit is used for acquiring a difference frequency signal and a sum frequency signal of the first frequency signal and the second frequency signal and outputting the difference frequency signal and the sum frequency signal to the filtering unit; the filtering unit is used for filtering the signal output by the filtering unit and sending the signal after filtering to a post-stage signal processing circuit. The utility model discloses a signal demodulation circuit is used for demodulating the processing to the signal under two different frequency points, can reduce because the influence that the randomness of frequency point signal caused the system in the network reduces the requirement to the environment in the testing process, has improved the interference killing feature of system.
Description
Technical Field
The utility model belongs to the technical field of signal detection, concretely relates to a signal demodulation circuit and signal receiving module for weak signal processing.
Background
In a power line carrier communication system, since an original signal generally has a very low frequency spectrum component and is not suitable for direct transmission in a channel, the original signal needs to be modulated into a frequency signal suitable for transmission in the channel. After the frequency signal is transmitted to the receiving end, the signal acquisition circuit acquires the frequency signal and then sends the frequency signal to the signal demodulation circuit, and the signal demodulation circuit demodulates the frequency signal into the frequency spectrum component with low frequency originally and then sends the frequency spectrum component to the back end circuit for analysis and processing. The existing carrier communication network usually uses a certain frequency point as a communication means, which requires that the background noise of the frequency point cannot exist in the communication environment. However, in the power network, there are also different and random frequency signals such as oscillations generated when loads such as various electric appliances and switches are operated, and these random frequency signals cause interference to the communication system.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a can improve communication system's interference immunity ability's signal demodulation circuit and signal receiving module.
In order to achieve the above object, the present invention adopts the following technical solutions:
a signal demodulation circuit, comprising: the frequency selection unit, the frequency locking unit and the filtering unit are connected in sequence; the frequency selection unit is connected with the signal acquisition circuit at the front end and used for extracting a first frequency signal and a second frequency signal from the frequency signal output by the signal acquisition circuit; the frequency locking unit is used for acquiring a difference frequency signal and a sum frequency signal of the first frequency signal and the second frequency signal and outputting the difference frequency signal and the sum frequency signal to the filtering unit; the filtering unit is used for filtering the signal output by the filtering unit and sending the signal after filtering to a post-stage signal processing circuit.
Further, the frequency selecting unit is composed of a first band pass filter and a second band pass filter, a center frequency of the first band pass filter is a frequency of the first frequency signal, and a center frequency of the second band pass filter is a frequency of the second frequency signal.
Further, the frequency locking unit is a multiplier.
Furthermore, the filtering unit extracts one or two of the sum frequency signal and the difference frequency signal and transmits the extracted sum frequency signal and/or difference frequency signal to a signal processing circuit at a later stage.
The utility model also provides a signal receiving module, include: the signal demodulation circuit comprises a signal acquisition circuit, a signal demodulation circuit and a signal processing circuit which are connected in sequence, wherein the signal demodulation circuit is the signal demodulation circuit.
Further, the signal acquisition circuit is a magnetic field sensor, and the magnetic field sensor acquires current signals in a communication channel and outputs voltage signals to the frequency selection unit.
According to the above technical scheme, the utility model discloses a signal demodulation circuit is used for demodulating the processing to the signal under two different frequency points, can reduce because the influence that the randomness of frequency point signal caused the system in the network reduces the requirement to the environment in the testing process, has improved the interference killing feature of system.
Drawings
In order to illustrate the embodiments of the present invention more clearly, the drawings that are needed in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained by those skilled in the art without inventive effort.
Fig. 1 is a block diagram of a signal receiving module according to an embodiment of the present invention;
fig. 2 is a block diagram of a signal demodulation circuit according to an embodiment of the present invention.
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings, wherein for convenience of illustration, the drawings showing the structure of the device are not to scale and are partially enlarged, and the drawings are only examples, which should not limit the scope of the invention. It should be noted that the drawings are in simplified form and are not to precise scale, which is only used for the purpose of facilitating and clearly assisting in the description of the embodiments of the present invention. Meanwhile, in the description of the present application, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated; the terms "front," "back," "bottom," "upper," "lower," and the like refer to an orientation or positional relationship relative to an orientation or positional relationship shown in the drawings, which is for convenience and simplicity of description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention.
In order to reduce interference caused by randomness of frequency point signals in a communication network to a communication system, one technical means is to adopt two different frequency points as communication modes, inject two characteristic currents with different frequencies into a power grid system through a signal injection module, and detect and analyze the two characteristic current signals with different frequencies through a signal receiving module to obtain the power grid condition. As shown in fig. 1, the signal receiving module generally includes a signal acquisition circuit for acquiring a signal from a line, a signal demodulation circuit for demodulating the signal acquired by the signal acquisition circuit, and a signal processing circuit for analyzing the demodulated signal. The utility model discloses a signal demodulation circuit is used for carrying out demodulation processing to the current signal under two different frequency points to reduce the requirement to the environment in the testing process, improve the interference killing feature of system.
As shown in fig. 2, the signal demodulation circuit of the present embodiment includes: the frequency selecting unit a is connected with a signal acquiring circuit (not shown), the signal acquiring circuit acquires a frequency signal containing a characteristic frequency from a communication network and then inputs the frequency signal to the frequency selecting unit a, the frequency selecting unit a is used for extracting the characteristic frequency signal, the frequency selecting unit a extracts a first frequency signal and a second frequency signal from the input frequency signal, the frequencies of the first frequency signal and the second frequency signal are different, the first frequency signal is used as a modulation signal, the second frequency signal is used as a carrier frequency signal, for example, when characteristic currents with two different frequencies are injected into a power grid, the frequencies of the characteristic current signals are 94KHz and 47KHz respectively, accordingly, the frequency f1 of the first frequency signal is 94KHz, and the frequency f2 of the second frequency signal is 47 KHz. The frequency selecting unit A extracts a first frequency signal and a second frequency signal and then transmits the first frequency signal and the second frequency signal to the frequency locking unit B, and the frequency locking unit B is used for extracting useful signals from the first frequency signal and the second frequency signal, namely acquiring a difference frequency signal and a sum frequency signal of the two frequency signals and transmitting the difference frequency signal and the sum frequency signal to the filtering unit C for filtering so as to improve the signal-to-noise ratio of the signals and reduce the processing difficulty of a signal processing circuit at the rear stage. The filtering unit C is used for filtering out unwanted harmonic components, and sending the filtered signal to a signal processing circuit at a later stage for further processing. The unnecessary harmonic component comprises circuit noise, direct current component and the like, the filtered signal comprises difference frequency signal and/or sum frequency signal, the filtering processing can be specifically carried out according to the requirement of the signal processing circuit at the later stage, if the signal processing circuit needs the sum frequency signal and the difference frequency signal, the two paths of signals can be reserved, and the circuit noise and the direct current component are removed and then sent to the signal processing circuit; if the signal processing circuit only needs one of the signals, for example, only the difference frequency signal or the sum frequency signal, the other frequency signal can be filtered together with the circuit noise and the like.
The frequency selection unit A of the embodiment is composed of a first band-pass filter and a second band-pass filter, the input ends of the first band-pass filter and the second band-pass filter are connected with the output end of a signal acquisition circuit at the front end, and the output ends of the first band-pass filter and the second band-pass filter are connected with the input end of a frequency locking unit B. The center frequency of the first band-pass filter is equal to the frequency f1 of the first frequency signal, the center frequency of the second band-pass filter is equal to the frequency f2 of the second frequency signal, the band-pass filter can adopt a ceramic filter, a crystal filter and the like according to requirements, or adopt a resistor, a capacitor, an operational amplifier and the like to build a filter circuit, for example, an MC33079 type operational amplifier and a resistance-capacitance are adopted to build an active band-pass filter with the center frequency points of 94KHz and 47 KHz. The two-path band-pass filter respectively extracts the first frequency signal and the second frequency signal from the signals output by the signal acquisition circuit, and can simultaneously filter other unnecessary frequency signals so as to reduce the influence of useless signals on a system and improve the signal-to-noise ratio.
The frequency locking unit B of this embodiment is a multiplier, and inputs the first frequency signal as a modulation signal and the second frequency signal as a carrier frequency signal to the multiplier for multiplication, and outputs a difference frequency signal (| f1-f2|) and a sum frequency signal (f1+ f 2). The first frequency signal and the second frequency signal are processed through the multiplier, and phase information and strength information of the frequency signals can be obtained. The difference frequency signal and the sum frequency signal contain phase information of the frequency signal and strength relation of the frequency signal, when the phases of the first frequency signal and the second frequency signal are constant, the strength of the signal output by the multiplier changes along with the strength change of the first frequency signal and the second frequency signal, and when the strengths of the first frequency signal and the second frequency signal are constant, the strength of the signal output by the multiplier increases and decreases along with the phase change situation of the first frequency signal and the second frequency signal.
The sum frequency signal and the difference frequency signal are useful signals containing characteristic frequencies, any one of the signals can be extracted and transmitted to the filtering unit C, and the filtering unit C filters out unnecessary harmonic components and then transmits the harmonic components to a post-stage circuit for further analysis and processing. The filtering unit C may adopt a low-pass filter, such as an RC passive low-pass filter, or a band-pass filter. The cut-off frequency of the low-pass filter or the center frequency of the band-pass filter is set correspondingly according to the signal required by the post-stage circuit, for example, when the post-stage signal processing circuit requires a sine wave signal only with the frequency of 47KHz, the output signal of the multiplier can be filtered to remove the frequency multiplication component of 142KHz by the RC passive low-pass filter with the cut-off frequency of 47KHz, or the frequency multiplication component of 142KHz can be filtered by the band-pass filter with the center frequency of 47 KHz.
Due to the magnetic effect of the current, a certain amount of response magnetic field is generated around the current, and the winding direction of the magnetic induction wire of the current magnetic field can be determined by ampere's rule. When current signal vibrates with certain frequency, can obtain a change magnetic field of taking frequency information, it is preferred, signal acquisition circuit can adopt magnetic field sensor to the information of current signal is obtained through gathering change magnetic field to indirect mode, and input the magnetic field information that magnetic field sensor detected with voltage signal's form extremely the utility model discloses a carry out signal processing among the signal demodulation circuit.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (6)
1. A signal demodulation circuit, comprising: the frequency selection unit, the frequency locking unit and the filtering unit are connected in sequence;
the frequency selection unit is connected with the signal acquisition circuit at the front end and used for extracting a first frequency signal and a second frequency signal from the frequency signal output by the signal acquisition circuit;
the frequency locking unit is used for acquiring a difference frequency signal and a sum frequency signal of the first frequency signal and the second frequency signal and outputting the difference frequency signal and the sum frequency signal to the filtering unit;
the filtering unit is used for filtering the signal output by the filtering unit and sending the signal after filtering to a post-stage signal processing circuit.
2. The signal demodulation circuit of claim 1 wherein: the frequency selection unit is composed of a first band-pass filter and a second band-pass filter, the central frequency of the first band-pass filter is the frequency of the first frequency signal, and the central frequency of the second band-pass filter is the frequency of the second frequency signal.
3. The signal demodulation circuit of claim 1 wherein: the frequency locking unit is a multiplier.
4. The signal demodulation circuit of claim 1 wherein: the filtering unit extracts one or two of the sum frequency signal and the difference frequency signal and sends the extracted sum frequency signal and/or difference frequency signal to a signal processing circuit at the later stage.
5. A signal receiving module comprising: the signal acquisition circuit, signal demodulation circuit and the signal processing circuit that connect gradually, its characterized in that: the signal demodulation circuit according to any one of claims 1 to 4.
6. The signal receiving module of claim 5, wherein: the signal acquisition circuit is a magnetic field sensor which acquires current signals in a communication channel and outputs voltage signals to the frequency selection unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220106484.8U CN217116077U (en) | 2022-01-14 | 2022-01-14 | Signal demodulation circuit and signal receiving module |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220106484.8U CN217116077U (en) | 2022-01-14 | 2022-01-14 | Signal demodulation circuit and signal receiving module |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN217116077U true CN217116077U (en) | 2022-08-02 |
Family
ID=82596823
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202220106484.8U Active CN217116077U (en) | 2022-01-14 | 2022-01-14 | Signal demodulation circuit and signal receiving module |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN217116077U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117805466A (en) * | 2023-12-27 | 2024-04-02 | 珠海多创科技有限公司 | Weak current signal detection method, weak current signal detection device, topology identification device and station area identification system |
-
2022
- 2022-01-14 CN CN202220106484.8U patent/CN217116077U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117805466A (en) * | 2023-12-27 | 2024-04-02 | 珠海多创科技有限公司 | Weak current signal detection method, weak current signal detection device, topology identification device and station area identification system |
| CN117805466B (en) * | 2023-12-27 | 2024-05-17 | 珠海多创科技有限公司 | Weak current signal detection method, weak current signal detection device, topology identification device and station area identification system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6590400B2 (en) | Inductive signature measurement circuit | |
| CN217116077U (en) | Signal demodulation circuit and signal receiving module | |
| CN110350634B (en) | Wireless charging receiver double-decoding circuit and wireless charging receiver using same | |
| KR20120112836A (en) | Delay detector circuit and receiver apparatus | |
| CN103227664A (en) | Field sampling, isolation and power detection system of signal of low-voltage power line | |
| JPH0758330B2 (en) | Sync detector | |
| US4306112A (en) | Stereophonic receiver noise eliminating device | |
| CN111025983A (en) | Weak signal detection device with strong anti-interference performance | |
| CN108933748B (en) | Method and system for demodulating frequency-modulated signal capable of locking frequency change | |
| US20030002600A1 (en) | FSK/GFSK demodulator with digital frequency offset compensation and the demodulating method of the same | |
| CN210983072U (en) | Weak signal detection device with strong anti-interference performance | |
| CN204142915U (en) | For the device of testing circuit phase-frequency characteristic | |
| CN109818654B (en) | Carrier network load detection device and method based on intelligent electric energy meter | |
| CN107017879B (en) | System and method for subcarrier decoding of high-frequency signal with subcarrier modulation | |
| CN110138701A (en) | A kind of spaceborne low bit- rate BPSK demodulation Costas loop circuit | |
| CN215768747U (en) | Ripple voltage acquisition device | |
| JPH06284049A (en) | Data transmission equipment using electric circuit | |
| JPH05273281A (en) | Acquisition system of information on contact | |
| CN212163274U (en) | Broadband envelope detection circuit demodulator with temperature compensation | |
| CN114884467B (en) | Signal demodulation device and wireless charging equipment | |
| CN211264741U (en) | Teaching experiment circuit capable of detecting amplitude-modulated signals and frequency-modulated signals | |
| CN105337578A (en) | ASK demodulator | |
| KR910003231B1 (en) | Single frequency detector | |
| RU2223609C1 (en) | Device for receiving start-stop messages | |
| CN117526860A (en) | Pulse temperature and pressure sensor analog modulation and demodulation method and circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |