CN104811201A - Multi-path signal bipolar square wave modulated single-path synchronous collection device and method - Google Patents

Abstract

The invention discloses a multi-path signal bipolar square wave modulated single-path synchronous collection device and method. The collection device collects N paths of signals by a single-path analog-digital converter, and specifically comprises that the connection and disconnection of at least two switch circuits are controlled by square waves, at least two paths of measured signals pass through a switch circuit consisting of an analogue switch and a resistor, and the switch circuit achieves bipolar square wave amplitude modulation; the signals with different frequencies after amplitude modulation are added by an add operation circuit, and then subjected to the analog-digital conversion of the single-path analog-digital converter to obtain a digital signal; the multi-path signal bipolar square wave modulated single-path synchronous collection device and method achieve that the multi-path measured signals are synchronously collected by the single-path analog-digital converter, and has the characteristics of being simple in circuit, low in cost and accurate in measurement.

Description

Single-path synchronous acquisition device and method for multi-path signal bipolar square wave modulation

Technical Field

The invention relates to the field of signal measurement, in particular to a single-path synchronous acquisition device and method for multi-path signal bipolar square wave modulation.

Background

The information-carrying variations of the voltage signals and the like are represented in their natural state in analog form, but are usually converted into digital signals by an ADC (analog-to-digital converter) for the convenience of computer processing, transmission and storage, and thus analog-to-digital conversion is indispensable in signal processing.

The inventor finds that in the process of realizing the invention, in the existing multi-channel signal acquisition, a scheme of combining a plurality of ADCs or multi-channel analog switches with a single ADC is usually adopted, and the former has the defects of complex circuit, high system power consumption and large circuit size; in the latter, switching noise is introduced due to switching of the multi-way switch during the acquisition process, and adjacent channel signals are interfered with each other due to the existence of the setup time of the multi-way switch.

Disclosure of Invention

The invention provides a single-path synchronous acquisition device and a single-path synchronous acquisition method for bipolar square wave modulation of multipath signals, which realize analog-to-digital conversion of the multipath signals through a single-path ADC (analog-to-digital converter), and are described in detail in the following:

a single-path synchronous acquisition device for multi-path signal bipolar square wave modulation comprises: a microprocessor outputting square waves with different frequencies and 2 times of ratio relationship,

the single-path synchronous acquisition device further comprises: at least 2 switching circuits, an addition operation circuit and a single-channel analog-to-digital converter;

the square wave controls the on-off of at least 2 paths of switch circuits, at least 2 paths of tested signals pass through the switch circuit, the switch circuit is composed of an analog switch, a resistor and an operational amplifier, and the switch circuit realizes the bipolar square wave amplitude modulation;

after the amplitude-modulated signals with different frequencies are added by the addition operation circuit, the single-path analog-to-digital converter performs analog-to-digital conversion to obtain digital signals;

and the microprocessor processes the digital signals and demodulates the digital signals to obtain the detected signals.

The microprocessor adopts any one of MCU, ARM, DSP or FPGA.

An acquisition method of a single-path synchronous acquisition device for multi-path signal bipolar square wave modulation, the method comprises the following steps:

the mixed signal is converted into a digital signal by a single-path analog-to-digital converter and sent to a microprocessor;

the switching circuit is driven by 4 frequency square waves, and 4 paths of measured signals are collected for explanation:

the frequency of square wave signals of the microprocessor output control switch circuit is respectively 8f, 4f, 2f and 1f, and the sampling frequency of the one-way analog-to-digital converter is f_sAnd f is_s16f, and ensuring that the sampling is carried out in the middle of high and low levels of the highest-frequency driving signal;

sampling frequency f_SThe amplitude of each path of square wave signal is unchanged in one period of the lowest driving signal frequency, and the amplitudes of the measured signal in a positive half period and a negative half period are obtained; and calculating by taking 16 digital signals in sequence as a group to obtain the signal amplitude of 16 times of the measured signal.

The technical scheme provided by the invention has the beneficial effects that: the invention controls the on-off of the switch circuit through the square wave, realizes the analog-to-digital conversion of a plurality of paths of measured signals through the single-path analog-to-digital converter, has the advantages of simple circuit, low cost and accurate measurement, and meets various requirements in practical application.

Drawings

FIG. 1 is a schematic structural diagram of a single-channel synchronous acquisition device modulated by multiple bipolar square waves;

fig. 2 is a flowchart of a single-channel synchronous acquisition method for multi-channel signal bipolar square wave modulation.

In the drawings, the components represented by the respective reference numerals are listed below:

1: a switching circuit; 2: an addition operation circuit;

3: a single-channel analog-to-digital converter; 4: a microprocessor.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention are described in further detail below.

Example 1

A single-channel synchronous acquisition device modulated by multi-channel signals with bipolar square waves, referring to fig. 1, the single-channel synchronous acquisition device comprises: at least 2 switch circuits 1, an addition operation circuit 2, a one-way analog-to-digital converter 3 and a microprocessor 4,

the microprocessor 4 outputs square waves with different frequencies and a 2-time ratio relationship, the square waves control the on-off of at least 2 paths of the switch circuit 1, N (N > ═ 2) paths of detected signals pass through the switch circuit 1 (the switch circuit 1 is composed of a resistor, an analog switch and an operational amplifier), and the switch circuit 1 is used for realizing bipolar square wave amplitude modulation. After the amplitude-modulated signals with different frequencies are added by the addition circuit 2, the single-channel analog-to-digital converter 3 performs analog-to-digital conversion to obtain digital signals. The microprocessor 4 processes the digital signals and demodulates the signals to be detected.

The number of the switch circuits 2 is equal to or greater than 2. In the specific implementation, the number and the specific implementation form of the switch circuits 2 are set according to the needs in practical applications, which is not limited in the embodiment of the present invention. The microprocessor 1 may be any one of MCU, ARM, DSP or FPGA.

Example 2

A single-channel synchronous acquisition method of multi-channel signal bipolar square wave modulation, referring to fig. 2, the method comprises the following steps:

101: the mixed signal is converted into a digital signal by the single-path analog-to-digital converter 3 and sent to the microprocessor 4;

102: the microprocessor 4 processes the digital signals and demodulates the signals to be detected.

For the sake of simplicity, 4 kinds of frequency square waves are used to drive the switch circuit 2 and collect 4 measured signals for explanation, and it is assumed that the measured signal V is₁、V₂、V₃And V₄The driving square wave frequencies of the corresponding switch circuits 1 are 8f, 4f, 2f and f, respectively.

Assume that the sampling frequency of the one-way analog-to-digital converter 3 is f_SAnd f is_S16f and ensures that the signal V is measured₁High and low level intermediate sampling.

Digital signal sequenceCan be expressed as:

$D_i^t=D_i^{V_1}+{D_i}^{V_3}+{D_i}^{V_4}+D_i^B---\left(1\right)$

wherein,andare respectively the measured signal V₁、V₂、V₃And V₄The amplitude of the amplitude is,is the dc component amplitude.

Assuming a sampling frequency f_SThe amplitude of each path of square wave signal can be approximately considered to be unchanged in one period of the lowest driving signal frequency, which is far higher than the change frequency of the detected signal, and the first 16 sampling data are taken as an example:

$\left\{\begin{array}{c}{D}_0^{V1}=D_2^{V1}=D_4^{V1}=D_6^{V1}=D_8^{V1}=D_{10}^{V1}=D_{11}^{V1}=D_{14}^{V1}=D_A^{V1}\\ D_1^{V1}=D_3^{V1}=D_5^{V1}=D_7^{V1}=D_9^{V1}=D_{11}^{V1}=D_{13}^{V1}=D_{15}^{V1}=D_B^{V1}\\ D_0^{V2}=D_1^{V2}=D_4^{V2}=D_5^{V2}=D_8^{V2}=D_9^{V2}=D_{12}^{V2}=D_{13}^{V2}=D_A^{V2}\\ D_2^{V2}=D_3^{V2}=D_6^{V2}=D_7^{V2}=D_{10}^{V2}=D_{11}^{V2}=D_{14}^{V2}=D_{15}^{V2}=D_B^{V2}\\ D_0^{V3}=D_1^{V3}=D_2^{V3}=D_3^{V3}=D_8^{V3}=D_9^{V3}=D_{10}^{V3}=D_{11}^{V3}=D_A^{V3}\\ D_4^{V3}=D_5^{V3}=D_6^{V3}=D_7^{V3}=D_{11}^{V3}=D_{13}^{V3}=D_{14}^{V3}=D_{15}^{V3}=D_B^{V3}\\ D_0^{V4}=D_1^{V4}=D_2^{V4}=D_3^{V4}=D_4^{V4}=D_5^{V4}=D_6^{V4}=D_7^{V4}=D_A^{V4}\\ D_8^{V4}=D_9^{V4}=D_{10}^{V4}=D_{11}^{V4}=D_{12}^{V4}=D_{13}^{V4}=D_{14}^{V4}=D_{15}^{V4}=D_A^{V4}\\ D_0^B=D_1^B=D_2^B=D_3^B=D_4^B=D_5^B=D_6^B=D_7^B=D_8^B=D_9^B\\ =D_{10}^8=D_{11}^B=D_{12}^B=D_{13}^B=D_{14}^B=D_{15}^B=D_A^B\end{array}\right.---\left(2\right)$

wherein,andare each V₁、V₂、V₃And V₄Positive and negative half cycle amplitudes，Is the magnitude of the dc component.

In other words, the operation is performed sequentially every 16 digital signals:

$\begin{array}{c}{D}_{16n+0}-D_{16n+1}+D_{16n+2}-D_{16n+3}+D_{16n+4}-D_{16n+5}+D_{16n+6}-D_{16n+7}+D_{16n+8}-D_{16n+9}+\\ D_{16n+10}-D_{16n+11}+D_{16n+12}-D_{16n+13}+D_{16n+14}-D_{16n+15}={16D}_{\mathrm{An}}^{V1},n=\mathrm{0,1,2}\end{array}...\left(3\right)$

namely, 16 times of V is obtained₁Amplitude of signalAnd completely eliminates the DC componentThe influence of (c).

$\begin{array}{c}{D}_{16n+0}+D_{16n+1}-D_{16n+2}-D_{16n+3}+D_{16n+4}+D_{16n+5}-D_{16n+6}-D_{16n+7}+D_{16n+8}+D_{16n+9}-\\ D_{16n+10}-D_{16n+11}+D_{16n+12}+D_{16n+13}-D_{16n+14}-D_{16n+15}={16D}_{\mathrm{An}}^{V2},n=\mathrm{0,1,2}\end{array}...\left(4\right)$

Namely, 16 times of V is obtained₂Amplitude of signalAnd completely eliminateIn addition to the direct current componentThe influence of (c).

$\begin{array}{c}{D}_{16n+0}+D_{16n+1}+D_{16n+2}+D_{16n+3}-D_{16n+4}-D_{16n+5}-D_{16n+6}-D_{16n+7}+D_{16n+8}+D_{16n+9}+\\ D_{16n+10}+D_{16n+11}-D_{16n+12}-D_{16n+13}-D_{16n+14}-D_{16n+15}={16D}_{\mathrm{An}}^{V3},n=\mathrm{0,1,2}\end{array}...\left(5\right)$

Namely, 16 times of V is obtained₃Amplitude of signalAnd completely eliminates the DC componentThe influence of (c).

$\begin{array}{c}{D}_{16n+0}+D_{16n+1}+D_{16n+2}+D_{16n+3}+D_{16n+4}+D_{16n+5}+D_{16n+6}+D_{16n+7}-D_{16n+8}-D_{16n+9}-\\ D_{16n+10}-D_{16n+11}-D_{16n+12}-D_{16n+13}-D_{16n+14}-D_{16n+15}={16D}_{\mathrm{An}}^{V4},n=\mathrm{0,1,2}\end{array}...\left(6\right)$

Namely, 16 times of V is obtained₄Amplitude of signalAnd completely eliminates the DC componentThe influence of (c).

In the embodiment of the present invention, except for the specific description of the model of each device, the model of other devices is not limited, as long as the device can perform the above functions.

Those skilled in the art will appreciate that the drawings are only schematic illustrations of preferred embodiments, and the above-described embodiments of the present invention are merely provided for description and do not represent the merits of the embodiments.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims (3)

1. A single-path synchronous acquisition device for multi-path signal bipolar square wave modulation comprises: a microprocessor outputting square waves of different frequencies and in a 2-fold ratio relationship,

the single-path synchronous acquisition device further comprises: at least 2 switching circuits, an addition operation circuit and a single-channel analog-to-digital converter;

the square wave controls the on-off of at least 2 paths of switch circuits, at least 2 paths of tested signals pass through the switch circuit, the switch circuit is composed of an analog switch, a resistor and an operational amplifier, and the switch circuit realizes the bipolar square wave amplitude modulation;

after the amplitude-modulated signals with different frequencies are added by the addition operation circuit, the single-path analog-to-digital converter performs analog-to-digital conversion to obtain digital signals;

and the microprocessor processes the digital signals and demodulates the digital signals to obtain the detected signals.

2. The single-channel synchronous acquisition device for the multi-channel signal bipolar square wave modulation according to claim 1, wherein the microprocessor adopts any one of MCU, ARM, DSP or FPGA.

3. An acquisition method for a multi-signal bipolar square-wave modulated single-channel synchronous acquisition device as claimed in any one of claims 1-2, the method comprising the steps of:

the mixed signal is converted into a digital signal by a single-path analog-to-digital converter and sent to a microprocessor;

the switching circuit is driven by 4 frequency square waves, and 4 paths of measured signals are collected for explanation:

the frequency of square wave signals of the microprocessor output control switch circuit is respectively 8f, 4f, 2f and 1f, and the sampling frequency of the one-way analog-to-digital converter is f_sAnd f is_s16f, and ensuring that the sampling is carried out in the middle of high and low levels of the highest-frequency driving signal;

sampling frequency f_SThe amplitude of each path of square wave signal is unchanged in one period of the lowest driving signal frequency, and the amplitudes of the measured signal in a positive half period and a negative half period are obtained; and calculating by taking 16 digital signals in sequence as a group to obtain the signal amplitude of 16 times of the measured signal.