CN104202050B - Multi-path multi-slope non-uniform sampling circuit - Google Patents

Abstract

The invention discloses a multi-channel multi-slope non-uniform sampling circuit. The circuit includes a subtractor and a plurality of single-slope non-uniform samplers, and the plurality of single-slope non-uniform samplers include a plurality of up-samplers and a plurality of A down-sampler, wherein: the plurality of up-samplers are connected in parallel to the first input terminal Vx of the subtractor, respectively sampling the sensor signal downward from the rated highest point with a fixed slope; the plurality of down-samplers are connected in parallel At the output terminal Vout of the subtractor, the sensor signal transformed by the subtractor is sampled from the rated minimum point upward with a fixed slope. Utilizing the present invention, the point that the original sampling circuit cannot acquire the signal with protrusions can also be acquired after passing through the sampler with a negative slope, increasing part of the sampling data, the circuit widens the applicable frequency range of the sensor signal, and reduces the The bandwidth of the sensor signal greatly improves the possibility of sensor signal recovery.

Description

A Non-Uniform Sampling Circuit with Multiple Channels and Multiple Slopes

technical field

The invention relates to the technical field of detection, transmission and processing of sensor signals, and in particular provides a multi-channel multi-slope non-uniform sampling circuit for the unknown and variable situation of the measured signal.

Background technique

At present, with the development of social technology and the improvement of people's living standards, the demand for sensors for detection in the fields of food safety and medicine and health has become more and more urgent. At the same time, with the development of the Internet of Things, the society has higher and higher requirements for big data transmission and processing, resulting in more and more attention to the compression of sensor data. Signal processing based on conventional sampling is very mature, but its application scenarios are limited by power consumption, bandwidth, hardware, etc., and it is increasingly difficult to meet market requirements. Therefore, signal processing based on compressed sensing has good development potential.

At present, the signal processing process based on compressed sensing is mostly in the theoretical research stage, and there are few types of hardware implementation modules, and each has its own advantages and disadvantages. Its corresponding application scenarios are limited by the signal itself, making it difficult to meet market requirements.

In the prior art, a single-channel non-uniform sampling circuit is used to process signals based on compressed sensing. The disadvantages of this single-channel non-uniform sampling circuit are obvious. For high-frequency signals or when the signal fluctuation range is relatively small, it is easy to The sampling information is not complete enough, that is, the sampled data is too small, which makes it difficult to completely recover the signal when the signal is restored.

Therefore, how to broaden the applicable frequency range of the sensor signal, reduce the bandwidth of the sensor signal, and improve the recovery possibility of the sensor signal has become an urgent technical problem to be solved.

Contents of the invention

(1) Technical problems to be solved

In view of this, the main purpose of the present invention is to provide a multi-channel multi-slope non-uniform sampling circuit to broaden the applicable frequency range of the sensor signal, reduce the bandwidth of the sensor signal, and improve the recovery possibility of the sensor signal.

(2) Technical solution

To achieve the above object, the present invention provides a multi-channel multi-slope non-uniform sampling circuit, the circuit includes a subtractor and a plurality of single-slope non-uniform samplers, the multiple single-slope non-uniform samplers include a plurality of upper A sampler and a plurality of down-samplers, wherein: the plurality of up-samplers are connected in parallel to the first input terminal Vx of the subtractor, respectively sampling the sensor signal downward from the rated highest point with a fixed slope; the plurality of up-samplers The downsampler is connected in parallel to the output terminal Vout of the subtractor, and samples the sensor signal transformed by the subtractor upwards with a fixed slope from a rated minimum point to form a complement to the plurality of upsamplers.

In the above solution, the subtractor also has a reference input terminal Vref, the reference voltage Vref connected to it is the rated maximum voltage of the signal, and the subtractor converts the sensor signal by inverting the sensor signal along the equal pressure line of Vref/2 change.

In the above solution, the subtractor includes a first operational amplifier and a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4, wherein the first resistor R1 and the second resistor R2 are voltage dividing resistors, connected in parallel Connected to the positive input terminal of the first operational amplifier, used to adjust the input voltage of the positive input terminal of the first operational amplifier; one end of the third resistor R3 is connected to the negative input terminal of the first operational amplifier, and the other end is used as the input terminal of the first operational amplifier. The first input terminal Vx of the subtractor; the fourth resistor R4 is a feedback resistor connected between the negative input terminal and the output terminal of the first operational amplifier.

In the above solution, one end of the first resistor R1 is connected to the positive input terminal of the first operational amplifier, and the other end is used as the reference input terminal Vref of the subtractor; one end of the second resistor R2 is connected to the first operational amplifier The positive input terminal, the other end is grounded.

In the above solution, the resistance value of the first resistor R1 is equal to the resistance value of the second resistor R2, and the resistance value of the third resistor R3 is equal to the resistance value of the fourth resistor R4.

In the above solution, the plurality of upsamplers respectively sample the sensor signal downward from the rated highest point with a fixed slope, and then process the sampled signal to obtain a digital signal, and the plurality of downsamplers respectively use a fixed slope from the rated lowest point to obtain a digital signal. point upward to sample the sensor signal transformed by the subtractor, and then process the sampled signal to obtain a digital signal, and combine the digital signals obtained by the multiple up-samplers and the multiple down-samplers during reconstruction and remove the same The data that is repeated at all times is then reconstructed using the compressed sensing reconstruction algorithm to obtain the original signal.

In the above solution, the multiple up-samplers or the multiple down-samplers each include a charge-discharge circuit, a second operational amplifier, and a counter, wherein the charge-discharge circuit is connected to the inverting input terminal of the second operational amplifier, which The specific discharge time is triggered by the counter. When the voltage output by the second operational amplifier changes from negative to positive, the counter outputs the count value and starts counting again from 0, and at the same time sends a signal to trigger the discharge operation of the charging and discharging circuit.

In the above solution, the plurality of upsamplers respectively sample the sensor signal downward from the rated highest point with a fixed slope, that is, the plurality of upsamplers respectively sample the sensor signal downward from the rated highest point with different fixed slopes. sampling.

In the above solution, the plurality of downsamplers respectively sample the sensor signal transformed by the subtractor from the rated minimum point with a fixed slope, and the plurality of downsamplers respectively use different fixed slopes from the rated minimum point The sensor signal transformed by the subtractor is sampled upward.

(3) Beneficial effects

The multi-channel multi-slope non-uniform sampling circuit provided by the present invention, on the basis of the original single-channel non-uniform sampling circuit, constructs a multi-channel non-uniform sampling circuit by combining subtractors. In the non-uniform sampling circuit, due to not only The low voltage (0V) is used as the starting voltage (the prior art uses 0V as the starting voltage), and the high voltage (5V) is used as the starting point voltage of another non-uniform sampler to sample down in the form of a negative slope, so that The original sampling circuit can also collect the points that cannot be collected by the protruding signal through the sampler with a negative slope, and some sampling data is added. This circuit broadens the applicable frequency range of the sensor signal and reduces the bandwidth of the sensor signal. The recovery possibility of the sensor signal is greatly improved.

Description of drawings

FIG. 1 is a schematic circuit structure diagram of a subtractor in a multi-channel multi-slope non-uniform sampling circuit according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a circuit structure of a single-slope non-uniform sampler in a multi-channel multi-slope non-uniform sampling circuit according to an embodiment of the present invention.

Fig. 3 is a sampling schematic diagram of two single-slope non-uniform samplers in a multi-channel multi-slope non-uniform sampling circuit according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a multi-channel multi-slope non-uniform sampling circuit using two single-slope non-uniform samplers according to an embodiment of the present invention.

5 is a schematic diagram of a multi-channel multi-slope non-uniform sampling circuit using four single-slope non-uniform samplers according to an embodiment of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in further detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

The present invention provides a multi-channel multi-slope non-uniform sampling circuit, which includes a subtractor and multiple single-slope non-uniform samplers, and the multiple single-slope non-uniform samplers include multiple up-samplers and multiple down-samplers device, wherein: the plurality of upsamplers are connected in parallel to the first input terminal Vx of the subtractor, respectively sampling the sensor signal downward from the rated highest point with a fixed slope; the plurality of downsamplers are connected in parallel to the The output terminal Vout of the subtractor samples the sensor signal transformed by the subtractor from the rated minimum point upward with a fixed slope, so as to complement the plurality of upsamplers.

Wherein, the circuit structure of the subtractor is shown in Fig. 1. In addition to the first input terminal Vx and the output terminal Vout, it also has a reference input terminal Vref, and the reference voltage Vref connected to the reference input terminal Vref is the maximum signal rating. Voltage, the subtractor transforms the sensor signal by inverting the sensor signal along the isobaric line of Vref/2. Among them, R is the resistance mark, AMP is the mark of the operational amplifier, and U1 represents the first unit of the operational amplifier.

In Fig. 1, the subtractor includes a first operational amplifier and a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4, wherein the first resistor R1 and the second resistor R2 are voltage dividing resistors connected in parallel Connected to the positive input terminal of the first operational amplifier, used to adjust the input voltage of the positive input terminal of the first operational amplifier; one end of the third resistor R3 is connected to the negative input terminal of the first operational amplifier, and the other end is used as the input terminal of the first operational amplifier. The first input terminal Vx of the subtractor is used to receive the input signal that needs to be adjusted, and determine the output voltage value together with the feedback loop; the fourth resistor R4 is a feedback resistor, connected to the negative input terminal of the first operational amplifier and Between the output terminals, it is used to adjust the ratio between the output voltage and the input voltage. The voltages of the positive input terminal and the negative input terminal of the selected op amp are V ₊ and V _- respectively. According to the basic properties of the op amp, V _- = V ₊ , (Vout-V _- )/R4＝-(Vx-V _- )/R3, Vref*(R2/(R1+R2))＝V ₊ , these three equations can be combined to get Vout＝Vref*( R2/(R1+R2))*((R3+R4)/R3)-Vx*(R4/R3). One end of the first resistor R1 is connected to the positive input terminal of the first operational amplifier, and the other end is used as the reference input terminal Vref of the subtractor; one end of the second resistor R2 is connected to the positive input terminal of the first operational amplifier, and the other end is connected to the positive input terminal of the first operational amplifier. grounded.

Preferably, the resistance value of the first resistor R1 is equal to the resistance value of the second resistor R2, and the resistance value of the third resistor R3 is equal to the resistance value of the fourth resistor R4, at this time Vout=Vref−Vx.

In the embodiment of the present invention, the plurality of upsamplers respectively sample the sensor signal from the rated highest point downward with a fixed slope and then process the sampled signal to obtain a digital signal, and the plurality of downsamplers respectively use a fixed slope Sampling the sensor signal transformed by the subtractor upward from the rated minimum point, processing the sampled signal to obtain a digital signal, combining the digital signals obtained by the plurality of upsamplers and the plurality of downsamplers during reconstruction and Remove the repeated data at the same time, and then use the compressed sensing reconstruction algorithm to reconstruct the original signal.

As shown in FIG. 2 , FIG. 2 is a schematic circuit structure diagram of a single-slope non-uniform sampler in a multi-channel multi-slope non-uniform sampling circuit according to an embodiment of the present invention. The multiple up-samplers or the multiple down-samplers all include a charge-discharge circuit, a second operational amplifier U2 and a counter Counter, wherein the charge-discharge circuit is connected to the inverting input terminal of the second operational amplifier, and the specific discharge The time is triggered by the counter. When the voltage output by the second operational amplifier changes from negative to positive, the counter will output the count value and start counting again from 0, and at the same time send a signal to trigger the discharge operation of the charging and discharging circuit. The charging and discharging loop consists of a current source I1, a resistor R5, a capacitor C1 and a switch S1. When the switch is turned off, the current source charges the capacitor. When the switch is turned on, the capacitor and the resistor form a loop through which the capacitor is discharged. The second operational amplifier is used to compare the input signal voltage Vin with the capacitor terminal voltage, so as to reversely control the output signal. The functions of the counter mainly include counting and the above-mentioned control of charging and discharging time. CLK is the count clock, and Digital_OUT1 outputs the count value.

Wherein, the plurality of upsamplers respectively sample the sensor signal downward from the rated highest point with a fixed slope, that is, the plurality of upsamplers respectively sample the sensor signal downward from the rated highest point with different fixed slopes; The plurality of down-samplers respectively sample the sensor signal transformed by the subtractor from the rated minimum point upward with a fixed slope, so that the multiple down-samplers respectively use different fixed slopes from the rated minimum point upward to the The sensor signal transformed by the subtractor is sampled.

Fig. 3 is a sampling schematic diagram of two single-slope non-uniform samplers in a multi-channel multi-slope non-uniform sampling circuit according to an embodiment of the present invention. The solid line part is the measured signal, and the upper and lower part of the oblique line indicates that the measured signal is sampled by two samplers, and the part with the dotted line from the bottom to the top is called the downsampler, and the part from the top to the bottom is called the upsampler. The two-way samplers respectively sample the measured signal, and the sampling basis is that the difference between the signal generated by the sampler and the measured signal is smaller than the quantization error of the sampler itself. Compared with a single sampler, the hardware part will be doubled, but the sampling frequency of the signal under test is greatly improved. It can be seen from Fig. 3 that the up-sampler can perform supplementary sampling for data signals that are difficult to be collected by the down-sampler. In addition, the sampling of the multi-channel multi-slope non-uniform sampling circuit has randomness, which is closely related to the form of the sensor signal.

Since the upsampling slope of the downsampler is constant when it is upsampled from only one end, it is difficult to sample the peak value or a value near the peak value for a steep signal, resulting in an error. Here, it is assumed that there is another sampler, that is, an upsampler, which samples down from the rated highest point with a fixed slope every time, so that it is easy to sample the peak value or the value near the peak value, which is complementary to the original signal. . In Figure 3, the up-sampling path from 0 is the basic non-uniform sampler; the down-sampling path from the sensor rated maximum value is an increased non-uniform sampler, which consists of a simple subtractor and a basic non-uniform sampler. Uniform sampler composition.

Compared with the basic non-uniform sampler, the multi-channel multi-slope non-uniform sampling circuit shown in Figure 3 has a wider range of signal applications and can adapt to more test scenarios.

FIG. 4 is a schematic diagram of a multi-channel multi-slope non-uniform sampling circuit using two single-slope non-uniform samplers according to an embodiment of the present invention. Among them, R is the resistance mark, AMP is the operational amplifier mark, U1 represents the first unit of the operational amplifier, C is the capacitor, and SW is the switch. The multi-channel multi-slope non-uniform sampling circuit is composed of two sub-sampling circuits (structure shown in FIG. 2 ) and a subtractor (structure shown in FIG. 1 ), as shown in FIG. 4 . For the sake of convenience, a power supply is drawn for each single-slope sampling circuit, namely I1 and I2. In practical applications, the same power supply can be used. The output Vout of the subtractor structure is used as the input Vin of one of the sampling circuits. In the figure, Vx is the conditioned signal, Vref is the reference input voltage, U1, U2 and U3 are three sub-budget amplification modules of the integrated operational amplifier LT1017, C1 and C2 Represents capacitance, R1, R2, R3, R4, R5 and R6 represent resistance, S1 and S2 represent switches, counter is used as a counter, clock CLK is used as a clock to control counter counting, and the digital signals Digital_OUT1 and Digital_OUT2, the back-end digital processing part stores the obtained digital signals, and merges the stored signals during reconstruction and removes the repeated data at the same time. The original signal is then reconstructed using a compressed sensing reconstruction algorithm (optimization algorithm).

Although this method adds a sampler, it can be sampled with a lower slope, so that each channel can obtain less data without missing the fast-changing signal, which expands the scope of application of the circuit to the signal.

Further, Fig. 4 shows a schematic diagram of a multi-channel multi-slope non-uniform sampling circuit using two single-slope non-uniform samplers. In practical applications, the multi-channel multi-slope non-uniform sampling circuit provided by the present invention can be Multiple single-slope non-uniform samplers are used, as shown in FIG. 5 , which is a schematic diagram of a multi-channel multi-slope non-uniform sampling circuit using four single-slope non-uniform samplers according to an embodiment of the present invention. Wherein, two up-samplers are connected in parallel to the first input terminal Vx of the subtractor, and respectively sample the sensor signal downward from the rated highest point with a fixed slope; two down-samplers are connected in parallel to the output of the subtractor The terminal Vout respectively samples the sensor signal transformed by the subtractor from the rated minimum point upward with a fixed slope, so as to complement the two up-samplers. In the figure, Vref is the reference input voltage, U1, U2, U3, U4 and U5 are the sub-budget amplification modules of the integrated operational amplifier LT1017, I1, I2, I3 and I4 represent the power supply, C1, C2, C3 and C4 represent the capacitors, and R1 , R2, R3, R4, R5, R6, R7, and R8 represent resistors, S1, S2, S3, and S4 represent switches, the counter is used as a counter, and the clock CLK is used as a clock to control the counting of the counter. After processing the output of the four circuits, it is obtained Digital signals Digital_OUT1, Digital_OUT2, Digital_OUT3 and Digital_OUT4.

In practical applications, due to cost and circuit complexity considerations, the number of single-slope non-uniform samplers used in the multi-channel multi-slope non-uniform sampling circuit provided by the present invention is preferably 2 to 10, some of which It is connected in parallel to the first input terminal Vx of the subtractor, and another part is connected in parallel to the output terminal Vout of the subtractor. The number of single-slope non-uniform samplers at the output terminal Vout of the subtractor may be equal or different, and is closely related to the form of the sensor signal.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (9)

1. a kind of non-uniform sampling circuit of multichannel multi slope, it is characterised in that the circuit includes a subtracter and multiple lists Slope nonuniform sampling device, the plurality of single-slope nonuniform sampling device includes multiple up-samplers and multiple down-samplers, wherein：

The plurality of up-sampler is connected in parallel in the first input end Vx of the subtracter, respectively with a fixed slope from specified highest Point is sampled downwards to sensor signal；

The plurality of down-sampler is connected in parallel in the output end vo ut of the subtracter, respectively with a fixed slope from specified minimum point The sensor signal after being converted through the subtracter is sampled upwards.

2. the non-uniform sampling circuit of multichannel multi slope according to claim 1, it is characterised in that the subtracter also has One reference input Vref, its reference voltage Vref accessed is signal rated maximum voltage, and the subtracter is to sensor signal It is the isobar reversion by sensor signal along Vref/2 to enter line translation.

3. the non-uniform sampling circuit of multichannel multi slope according to claim 2, it is characterised in that the subtracter includes the One operational amplifier and first resistor R1, second resistance R2,3rd resistor R3 and the 4th resistance R4, wherein,

First resistor R1 and second resistance R2 is divider resistance, is connected in parallel in the positive input of first operational amplifier, Input voltage for adjusting the first operational amplifier positive input；

3rd resistor R3 one end is connected to the negative input of first operational amplifier, and the other end is used as the first of the subtracter Input Vx；

4th resistance R4 is feedback resistance, is connected between the negative input of first operational amplifier and output end.

4. the non-uniform sampling circuit of multichannel multi slope according to claim 3, it is characterised in that the first resistor R1 One end is connected to the positive input of first operational amplifier, the other end as the subtracter reference input Vref；Institute State the positive input that second resistance R2 one end is connected to first operational amplifier, other end ground connection.

5. the non-uniform sampling circuit of multichannel multi slope according to claim 4, it is characterised in that the first resistor R1 Resistance be equal to the resistance of the second resistance R2, the resistance of the 3rd resistor R3 is equal to the resistance of the 4th resistance R4.

6. the non-uniform sampling circuit of multichannel multi slope according to claim 1, it is characterised in that the plurality of up-sampler Sampled signal is handled after being sampled respectively with a fixed slope from specified peak to sensor signal downwards Data signal, the biography of the plurality of down-sampler respectively with a fixed slope after specified minimum point is upward to being converted through the subtracter Sensor signal handles sampled signal progress after being sampled and obtains data signal, reconstruct when merge the plurality of up-sampler and Data signal that the plurality of down-sampler is obtained simultaneously picks out the data that synchronization is repeated, and then utilizes compressed sensing restructing algorithm Reconstruct obtains primary signal.

7. the non-uniform sampling circuit of multichannel multi slope according to claim 6, it is characterised in that the plurality of up-sampler Or the plurality of down-sampler includes charging and discharging circuit, the second operational amplifier and counter, wherein, charging and discharging circuit connection In the reverse input end of second operational amplifier, its specific discharge time is triggered by counter, when second operational amplifier When the voltage of output is changed into positive from bearing, count value is just exported and counted again since 0 by counter, is simultaneously emitted by signal Discharge operation triggering is carried out to charging and discharging circuit.

8. the non-uniform sampling circuit of multichannel multi slope according to claim 6, it is characterised in that the plurality of up-sampler Sensor signal is sampled downwards from specified peak with a fixed slope respectively, is the plurality of up-sampler respectively with not Same fixed slope is sampled downwards from specified peak to sensor signal.

9. the non-uniform sampling circuit of multichannel multi slope according to claim 6, it is characterised in that the plurality of down-sampler The sensor signal after being converted through the subtracter is sampled upwards from specified minimum point with a fixed slope respectively, is that this is more The sensor signal of individual down-sampler respectively with different fixed slopes after specified minimum point is upward to being converted through the subtracter Sampled.