A V / I analog signal transmission system and method based on sigma-delta

Abstract

The present application discloses a sigma-delta-based V / I analog signal transmission system and method, which belongs to the field of signal processing, including a modulation unit, a filtering unit, a truncation unit, a smoothing unit, a transmission unit and a feedback unit. The modulation unit modulates the analog input signal into a digital signal, the filtering unit filters out its high-frequency noise, the truncation unit truncates the filtered signal into a 1-bit analog signal for output, the smoothing unit outputs an analog output signal after smoothing and filtering the current truncation signal, and the transmission unit changes the properties of the analog output signal and outputs an analog transmission signal. In addition, the feedback unit can feed back the analog output signal to the input end for re-modulation. Through the above-mentioned system and method, an analog voltage signal or an analog current signal can be transmitted into an analog current output signal and an analog voltage output signal, which improves the compatibility of the system, and can modulate different types of analog signal sources, so that it can process a wider range of signals and adapt to different application requirements.

Description

Technical Field

[0001] The present application relates to the field of signal processing, and more specifically, to a sigma-delta based V / I analog signal transmission system and method. Background Art

[0002] Signal transmitters play a vital role in the fields of industrial automation, process control and data acquisition. The working principle of the transmitter is based on the negative feedback mechanism, which mainly includes the measurement part, amplifier and feedback part. The measurement part detects the measured variable and converts it into an input signal acceptable to the amplifier; the feedback part converts the output signal of the transmitter into a feedback signal, which is compared with the input signal and amplified by the amplifier and converted into a standard output signal. According to the output signal type, the transmitter can be divided into two types: current output type and voltage output type. These signals can then be further processed or used to control various industrial processes.

[0003] In the field of analog signal processing, many transmitters may lack sufficient accuracy and stability, or perform poorly in long-distance transmission and noise suppression. In addition, as industrial environments place increasingly higher demands on equipment, existing technologies may find it difficult to meet new challenges, such as maintaining performance in extreme temperatures or electromagnetic interference environments, and existing transmitters can only transmit input signals within a signal range and cannot adapt to a variety of application scenarios. Therefore, a new type of analog signal transmission system is urgently needed that can provide higher accuracy and stability and be compatible with input signals of different ranges. Summary of the invention

[0004] Based on the deficiencies of the prior art and in view of the problems that the existing analog input signal range is small and the application is limited, an embodiment of the present application provides a sigma-delta-based V / I analog signal transmission system, including a modulation unit, specifically a sigma-delta modulator, for modulating an analog input signal into a digital signal; a filtering unit, for filtering the noise in the modulated digital signal and outputting a filtered signal; a truncation unit, specifically a 1-bit truncation unit, for truncating the filtered signal into a 1-bit analog signal after filtering, and outputting the current truncated signal; a smoothing unit, for smoothing the truncated signal after truncation, removing high-frequency noise and interference and outputting an analog output signal; a transmission unit, for converting the properties of the smoothed analog output signal and outputting an analog transmission signal; a feedback unit, including an ADC and a loop filter, for feeding back the analog output signal to the input end of the modulation unit or feeding back the analog output signal to the input end of the truncation unit after modulation by the ADC and the loop filter, and re-transmitting it.

[0005] Optionally, the analog input signal is an analog voltage signal or an analog current signal.

[0006] Optionally, the filtering unit includes a CIC filter or a FIR filter.

[0007] The embodiment of the present application also provides a V / I analog signal transmission method based on sigma-delta, comprising the following steps:

[0008] Modulating the analog voltage signal or the analog current signal into a digital signal through the modulation unit;

[0009] The high-frequency noise of the digital signal is filtered out by the filtering unit and a filtered signal is output;

[0010] The filtered signal is truncated into a 1-bit analog signal by the truncation unit, and a current truncated signal is output;

[0011] The truncated signal is subjected to low-pass filtering by the smoothing unit, the truncated signal is smoothed and the noise of the high-frequency part is filtered out, and then an analog output signal is output;

[0012] Changing the property of the smoothed analog output signal through the transmission unit and outputting an analog transmission signal;

[0013] The analog output signal is fed back to the input end of the modulation unit through the feedback unit or is modulated by the ADC and the loop filter and then fed back to the input end of the truncation unit, and then retransmitted.

[0014] The beneficial effects of the present application are as follows: the present application proposes a sigma-delta-based V / I analog signal transmission system, which includes a modulation unit, a filtering unit, a truncation unit, a smoothing unit, a transmission unit, and a feedback unit. The analog input signal is modulated into a digital signal by the modulation unit. The current digital signal is filtered out by the filtering unit to remove the corresponding high-frequency noise and then outputs the filtered signal. The truncation unit truncates the filtered signal into a 1-bit analog signal and outputs the current truncation signal. The truncation signal is then smoothed and filtered by the smoothing unit, and the analog output signal is output after filtering out the high-frequency noise. The transmission unit then changes the properties of the current analog output signal and outputs the analog transmission signal. When the output analog transmission signal does not meet the demand, the feedback unit modulates the analog output signal and then feeds it back to the input end of the modulation unit or the truncation unit for retransmission until the demand is met. The above system and method can transform an analog voltage signal or an analog current signal into an analog current signal and an analog voltage signal, thereby improving the flexibility of signal transmission and being suitable for a variety of signal processing application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0016] Figure 1 It is a schematic diagram of a structure in which an input analog voltage signal is modulated by a V / I analog signal transmission system based on sigma-delta;

[0017] Figure 2 It is a schematic diagram of a structure in which an analog current signal is modulated by a V / I analog signal transmission system based on sigma-delta;

[0018] Figure 3 It is a schematic diagram of a structure in which an analog current signal is modulated by another V / I analog signal transmission system based on sigma-delta;

[0019] Figure 4 The present invention is a flow chart of a V / I analog signal transmission method based on sigma-delta.

[0020] The above drawings include the following reference numerals:

[0021] 1-sigma-delta modulator, 2-FIR (Finite Impulse Response) filter, 3-1-bit truncation, 4-low-pass filter, 5-resistance, 6-ADC (Analog to Digital Converter), 7-loop filter, 8-CIC (Cascade Integrator Comb) filter. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only embodiments of a part of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present application.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] The present application discloses a V / I signal transmission system based on sigma-delta, such as Figure 1 and Figure 2 As shown, it includes: a modulation unit, specifically a sigma-delta modulator 1, which is used to modulate the analog input signal into a 1-bit stream digital signal; a filtering unit, which can be one of an FIR filter 2 or a CIC filter 8, and is not specifically limited in the present application, and is used to filter the modulated digital signal and output the filtered signal; a truncation unit, specifically a 1-bit truncation unit, which is used to truncate the filtered signal into a 1-bit analog signal and output the current truncation signal; a smoothing unit, specifically a low-pass filter 4, which is used to smooth and filter the truncation signal, reduce its high-frequency noise and interference, and then output an analog output signal; a transmission unit, specifically a resistor 5, which is used to convert the properties of the analog output signal and then output an analog transmission signal, and the analog transmission signal specifically includes an analog voltage output signal and an analog current output signal; a feedback unit, the feedback unit includes an ADC 6 and a loop filter 7, which is used to convert the analog output signal into a digital signal and feed it back to the input for re-modulation and transmission.

[0025] The analog input signal may be an analog voltage signal or an analog current signal, which is not specifically limited in the present application.

[0026] The specific working principle includes: the analog voltage signal or the analog current signal is modulated by a sigma-delta modulator and then outputs a 1-bit stream digital signal, and then the modulated digital signal is filtered out by a filtering unit to remove high-frequency noise and output a filtered signal, and the filtered signal is truncated into a 1-bit analog signal by a 1-bit truncation, and then the current truncated signal is smoothed by a low-pass filter, and the analog output signal is output after removing the high-frequency noise in the analog signal. At this time, the smoothed analog output signal and the resistor are converted into an analog transmission signal through Ohm's theorem, specifically, it is converted into an analog current output signal or an analog voltage output signal for output.

[0027] When the output analog transmission signal does not meet the requirements, the analog output signal is fed back to the input end of the modulator through the feedback unit, or is modulated and then fed back to the input end of the truncation device for retransmission. The specific modulation process of the analog output signal includes first converting the analog output signal into a digital signal through the ADC, then feeding it back to the input through the loop filter and accumulating it, and then modulating it again through the truncation device and the low-pass filter to finally output the analog transmission signal.

[0028] In one embodiment, Figure 1 FIG. 1 is a schematic diagram showing a structure in which an input analog voltage signal is modulated by a V / I analog signal transmission system based on sigma-delta. Figure 1 As shown, the analog voltage signal V in After being modulated by the sigma-delta modulator, the digital signal is output. The current digital signal is filtered by the FIR filter to remove the noise and then the filtered signal is output. The current filtered signal is then truncated to a 1-bit analog signal by the 1-bit truncation. At this time, the current truncated signal is low-pass filtered by the low-pass filter to remove the high-frequency noise and then output the analog output signal. At this time, a resistor R is also set on the current system to convert the current analog output signal into an analog current output signal I through Ohm's theorem. out And output.

[0029] If the output analog current output signal is not the required analog current signal, the analog output signal is converted into a digital signal through the ADC, and negatively fed back to the input end of the 1-bit truncation circuit through the loop filter and accumulated, and then re-modulated and transmitted until the requirements are met.

[0030] In another embodiment, Figure 2 FIG. 1 is a schematic diagram showing a structure in which an analog current signal is modulated by a V / I analog signal transmission system based on sigma-delta. Figure 2 As shown, the analog current signal I in After being modulated by the sigma-delta modulator, the digital signal is output. The current digital signal is filtered by the CIC filter to remove the noise and output the filtered signal. The current filtered digital signal is truncated into a 1-bit analog signal by the 1-bit truncation device, and then the current truncated signal is low-pass filtered by the low-pass filter to remove the high-frequency noise and output the analog output signal. At this time, a resistor R is also set on the current system to convert the current analog output signal into an analog voltage output signal V through Ohm's theorem. out And output.

[0031] If the output analog voltage output signal is not the required analog voltage signal, the analog output signal is converted into a digital signal through the ADC, and then negatively fed back to the input end of the 1-bit truncation circuit through the loop filter and accumulated, and then re-modulated and transmitted until the requirements are met.

[0032] When the output analog transmission signal cannot meet the demand and needs to be re-modulated and transmitted through the feedback unit, the analog output signal can also be directly fed back to the input end of the sigma-delta modulator for modulation, such as Figure 3 FIG. 2 is another schematic diagram of a structure for performing modulation by a sigma-delta based V / I analog signal transmission system. Figure 3 As shown, the analog current signal I in After being modulated by the sigma-delta modulator, the digital signal is output. The current digital signal is filtered by the CIC filter to remove the noise and then the filtered signal is output. The current filtered signal is then truncated to a 1-bit analog signal by the 1-bit truncation. The current truncated signal is low-pass filtered by the low-pass filter to remove the high-frequency noise and then the analog output signal is output. At this time, a resistor R is also set on the current system to convert the current analog output signal into an analog voltage output signal V by Ohm's theorem. out And output.

[0033] When the output analog voltage output signal does not meet the requirements, the analog output signal is fed back to another sigma-delta modulator for modulation, the modulated digital signal is filtered through a CIC filter, and the filtered signal is filtered through a loop filter to remove the high-frequency noise of the output voltage, and then re-transmitted and modulated through a 1-bit truncation device, a low-pass filter and a resistor until the output analog voltage output signal meets the requirements.

[0034] Based on the sigma-delta based V / I analog signal transmission system proposed in the above embodiment, Figure 4 The flowchart of a V / I analog signal transmission method based on sigma-delta is shown, which specifically includes the following steps:

[0035] S401: modulating an analog voltage signal or an analog current signal into a digital signal through a modulation unit;

[0036] S402: filtering high-frequency noise of the digital signal through a filtering unit and outputting a filtered signal;

[0037] S403: truncating the filtered digital signal into a 1-bit analog signal through a truncation unit, and outputting the current truncation signal;

[0038] S404: low-pass filtering the truncated signal through a smoothing unit, smoothing the truncated signal and filtering out the high-frequency noise, and then outputting an analog output signal;

[0039] S405: changing the property of the smoothed analog output signal through the transmission unit and outputting the analog transmission signal;

[0040] S406: Feedback the analog output signal to the input end of the modulation unit through the feedback unit or feed back the analog output signal to the input end of the truncation unit after being modulated through the ADC and the loop filter, and retransmit it.

[0041] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0042] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0043] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0044] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0045] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A V / I analog signal transmission system based on sigma-delta, characterized in that: It includes a modulation unit, specifically a sigma-delta modulator, which is used to modulate an analog input signal into a digital signal; a filtering unit, which is used to filter out noise in the modulated digital signal and output a filtered signal; a truncation unit, specifically a 1-bit truncation unit, which is used to truncate the filtered signal into a 1-bit analog signal after filtering and output the current truncation signal; a smoothing unit, which is used to smooth the truncated signal after truncation and output an analog output signal after removing high-frequency noise and interference; a transmission unit, which is used to convert the properties of the smoothed analog output signal and output an analog transmission signal; a feedback unit, which includes an ADC and a loop filter, which is used to feed back the analog output signal to the input end of the modulation unit or to feed back the analog output signal to the input end of the truncation unit after being modulated by the ADC and the loop filter, and then re-transmit it.

2. A sigma-delta based V / I analog signal transmission system according to claim 1, characterized in that: The analog input signal is an analog voltage signal or an analog current signal.

3. A sigma-delta based V / I analog signal transmission system according to claim 1, characterized in that: The filter unit includes a CIC filter or a FIR filter.

4. A sigma-delta based V / I analog signal transmission method, used to implement the V / I analog signal transmission system according to any one of claims 1 to 3, characterized in that: The following steps are involved: Modulating the analog voltage signal or the analog current signal into a digital signal through the modulation unit; The high-frequency noise of the digital signal is filtered out by the filtering unit and a filtered signal is output; The filtered signal is truncated into a 1-bit analog signal by the truncation unit, and a current truncated signal is output; The truncated signal is subjected to low-pass filtering by the smoothing unit, the truncated signal is smoothed and the noise of the high-frequency part is filtered out, and then an analog output signal is output; Changing the property of the smoothed analog output signal through the transmission unit and outputting an analog transmission signal; The analog output signal is fed back to the input end of the modulation unit through the feedback unit or is modulated by the ADC and the loop filter and then fed back to the input end of the truncation unit, and then retransmitted.

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