CN102279924A - Fingerprint identification system and testing device - Google Patents

Abstract

A fingerprint identification system and a test device including the fingerprint identification system, the fingerprint identification system comprising: a fingerprint sensor for detecting a fingerprint pattern and converting the fingerprint pattern into a discrete analog signal regarding fingerprint information; a driving circuit unit for performing data processing on the discrete analog signal detected by the fingerprint sensor, the driving circuit unit comprising: a controller for driving the fingerprint sensor; the sampling maintaining circuit is used for acquiring and maintaining the instantaneous voltage of the discrete analog signal to form a continuous analog signal; the analog-to-digital conversion unit is used for converting the continuous analog signals into digital signals; and the full-scale voltage adjusting unit is used for adjusting the full-scale voltage of the analog-to-digital conversion unit, and the full-scale voltage is the maximum input voltage of the analog-to-digital conversion unit for analog-to-digital conversion. The fingerprint identification system has excellent performance and high yield, and overcomes the problem of short service life caused by aging.

Description

Fingerprint identification system and test device

technical field

The invention relates to the technical field of semiconductor sensors, in particular to a fingerprint identification system and a testing device.

Background technique

With the development of fingerprint identification technology, fingerprint identification systems are more and more used in daily life, such as fingerprint identification access control systems, laptops with fingerprint identification, etc. A technical solution of a fingerprint identification device is disclosed in Chinese patent application No. 200810188287.X.

Referring to FIG. 1 , a schematic diagram of a prior art fingerprint identification system is shown. The fingerprint recognition system includes: a fingerprint sensor 100 and a drive circuit unit 200, wherein: the fingerprint sensor 100 is used to detect fingerprint patterns, and converts the fingerprint patterns into discrete analog signals about fingerprint information, and the drive circuit unit 200 is used to drive the The fingerprint sensor 100 is described above, and data processing is performed on the discrete analog signal detected by the fingerprint sensor 100.

Wherein, the drive circuit unit 200 includes: a controller 201 connected to the fingerprint sensor 100 , a sampling and holding circuit 202 connected to the fingerprint sensor 100 , and an analog-to-digital conversion unit 203 connected to the sampling and holding circuit 202 . Wherein, the controller 201 is used to drive the fingerprint sensor 100; the sampling and holding circuit 202 is used to convert the discrete analog signal detected by the fingerprint sensor 100 into a continuous analog signal about fingerprint information; the analog-to-digital conversion unit 203 is used to convert The continuous analog signal is converted into a digital signal with information about the fingerprint.

However, in the prior art, due to the limitation of the manufacturing process, the analog signal about the fingerprint information detected by the fingerprint sensor is usually small, and when the analog-to-digital conversion is performed, the voltage of some analog signals is not within the range of the input voltage of the analog-to-digital conversion unit. The digital signal obtained by analog-to-digital conversion cannot truly reflect the fingerprint information, so that the fingerprint identification system is prone to errors when performing fingerprint identification, resulting in a higher rejection rate (FRR, False Rejection Rate) or false recognition rate (FAR, False Acceptance Rate).

Contents of the invention

The object of the invention is to provide a fingerprint identification system to improve the performance of the fingerprint identification system.

In order to solve the above problems, the present invention provides a fingerprint recognition system, which includes: a fingerprint sensor for detecting a fingerprint pattern and converting the fingerprint pattern into a discrete analog signal about fingerprint information; a drive circuit unit, For performing data processing on the discrete analog signal detected by the fingerprint sensor, the driving circuit unit includes: a controller for driving the fingerprint sensor; a sampling and holding circuit for collecting and maintaining the instantaneous voltage of the discrete analog signal to form A continuous analog signal; an analog-to-digital conversion unit, used to convert the continuous analog signal into a digital signal; a full-scale voltage adjustment unit, used to adjust the full-scale voltage of the analog-to-digital conversion unit, and the full-scale voltage is converted by the analog-to-digital conversion unit The maximum input voltage for digital conversion.

Optionally, the full-scale voltage adjustment unit includes a first register and a regulator, wherein the first register is used to set multiple groups of reference voltages and full-scale voltages corresponding to the reference voltages, and the reference voltages include the first The reference voltage and the second reference voltage; the regulator is used to select the first reference voltage and the second reference voltage from the first register according to the adjustment command, and set the selected first reference voltage and the second reference voltage in the analog-to-digital conversion unit Reference voltage; the analog-to-digital conversion unit obtains a corresponding full-scale voltage based on the first reference voltage and the second reference voltage.

Optionally, the full-scale voltage is 1-1.1 times the maximum voltage of the continuous analog signal.

Optionally, a compensating unit is also included, configured to shift the reference potential of the analog signal to reduce the reference potential before the analog-to-digital conversion according to the offset command.

Optionally, the compensation unit includes a second register and a shifter, the second register is used to set multiple sets of offset voltage values, and the shifter is used to reduce the reference potential of the analog signal according to the offset command An offset, where the offset is the offset voltage value in the second register.

Optionally, the reference potential is less than 0.1 times of the full scale voltage.

Optionally, a gain unit is also included, configured to amplify the analog signal before the analog-to-digital conversion according to the gain command, so as to increase the voltage of the analog signal.

Optionally, the gain unit includes a third register and an amplifier, the third register is used to set multiple groups of gain multiples; the amplifier is used to increase the voltage of the analog signal according to the gain multiples of the third register.

Optionally, the analog signal is a continuous analog signal formed after processing by the sample-and-hold circuit or a discrete analog signal about fingerprint information detected by the fingerprint sensor.

Correspondingly, the present invention also provides a test device including the fingerprint identification system, wherein the test device further includes a measurer and a judger; the measurer is used to measure the digital signal output by the analog-to-digital conversion unit, and sending the measurement result to the judger; the judger is used to judge whether the maximum value of the digital signal measured by the measurer is greater than or equal to the high threshold of the digital signal, and when the maximum value of the digital signal is less than the high threshold of the digital signal, Issue a regulation command to the regulator of the full-scale voltage regulation unit.

Correspondingly, the present invention also provides a test device including the fingerprint identification system, wherein the test device further includes a measurer and a judger; the measurer is used to measure the digital signal output by the analog-to-digital conversion unit, and sending the measurement result to the judger; the judger is used to judge whether the maximum value of the digital signal measured by the measurer is greater than or equal to the high threshold of the digital signal, and when the maximum value of the digital signal is less than the high threshold of the digital signal, Send an adjustment command to the regulator of the full-scale voltage adjustment unit; the judger is also used to judge whether the minimum value of the digital signal measured by the measuring device is less than or equal to the low threshold of the digital signal, when the minimum value of the digital signal is greater than the digital signal When the signal is low threshold, a shift command is sent to the shifter of the compensation unit.

Correspondingly, the present invention also provides a test device including the fingerprint identification system, wherein the test device further includes a measurer and a judger; the measurer is used to measure the digital signal output by the analog-to-digital conversion unit, and sending the measurement result to the judger; the judger is used to judge whether the maximum value of the digital signal measured by the measurer is greater than or equal to the high threshold of the digital signal, and when the maximum value of the digital signal is less than the high threshold of the digital signal, Send an adjustment command to the regulator of the full-scale voltage adjustment unit; the judger is also used to judge whether the minimum value of the digital signal measured by the measuring device is less than or equal to the low threshold of the digital signal, when the minimum value of the digital signal is greater than the digital signal When the signal has a low threshold value, an offset command is sent to the offset device of the compensation unit; the judger is also used to judge the first reference set by the regulator when the maximum value of the digital signal output by the analog-to-digital converter is less than the high threshold value of the digital signal Whether the voltage and the second reference voltage are the minimum value of the first reference voltage and the second reference voltage in the first register, and if it is the minimum value, a gain command is sent to the amplification phase.

Compared with the prior art, the present invention has the following advantages: since the fingerprint recognition system includes a full-scale voltage adjustment unit, the range of the input voltage of the analog-to-digital conversion unit can be expanded, so that the input voltage of a larger range has The higher resolution enables the digital signal obtained after analog-to-digital conversion to more truly reflect the user's fingerprint pattern, thus optimizing the performance of the fingerprint identification system.

Description of drawings

Fig. 1 is the schematic diagram of prior art fingerprint recognition system;

Fig. 2 is the schematic diagram of a preferred embodiment of the fingerprint recognition system of the present invention;

Fig. 3 is the schematic diagram of a preferred embodiment of the fingerprint recognition system of the present invention;

Fig. 4 is the schematic diagram that comprises the testing device of fingerprint identification system shown in Fig. 3;

5 is a schematic diagram of another embodiment of the fingerprint recognition system of the present invention;

6 is a schematic diagram of another embodiment of the fingerprint recognition system of the present invention;

Fig. 7 is a schematic diagram of another embodiment of the fingerprint identification system of the present invention.

Detailed ways

In order to make the above objects, features and advantages of the present invention more comprehensible, specific implementations of the present invention will be described in detail below in conjunction with the accompanying drawings.

Aiming at the problems in the background technology, the present invention provides a fingerprint identification system. Referring to FIG. 2 , it shows a schematic diagram of a preferred embodiment of the fingerprint identification system of the present invention. The fingerprint identification system includes: a fingerprint sensor 100 for detecting a fingerprint pattern and converting the fingerprint pattern into a discrete analog signal about fingerprint information; a drive circuit unit 200 for detecting the discrete analog signal by the fingerprint sensor 100 Performing data processing, wherein the driving circuit unit 200 includes: a controller 201, configured to drive the fingerprint sensor 100 so that the fingerprint sensor 100 starts to detect fingerprint patterns, and the controller 201 may be a timing control circuit;

The sampling and holding circuit 202 is used to collect the instantaneous voltage of the discrete analog signal detected by the fingerprint sensor 100 at a certain moment, and keep the instantaneous voltage unchanged during the subsequent analog-to-digital conversion process, so as to obtain a continuous analog signal;

The analog-to-digital conversion unit 206 is configured to convert the continuous analog signal into a digital signal, the digital signal represents the relative magnitude of the continuous analog signal, the input voltage of the analog-to-digital conversion unit 206 has a certain range, and is located at the analog-to-digital conversion Analog signals within the input voltage range of unit 206 can be converted into corresponding digital signals;

The drive circuit unit 200 also includes: a full-scale voltage adjustment unit 203, a gain unit 204 and a compensation unit 205, wherein,

A full-scale voltage adjustment unit 203, configured to adjust the full-scale voltage of the analog-to-digital conversion unit 206 according to the adjustment command, so as to adjust the range of the input voltage of the analog-to-digital conversion unit 206;

The gain unit 204 is used to amplify the continuous analog signal before the analog-to-digital conversion according to the gain command, so that the voltage of the continuous analog signal is within the range of the input voltage of the analog-to-digital conversion unit 206;

The compensation unit 205 is configured to shift the reference potential of the continuous analog signal to reduce the reference potential according to the offset command.

The full-scale voltage is a parameter of the analog-to-digital conversion unit 206 , and is the maximum input voltage that the analog-to-digital conversion unit 206 can perform analog-to-digital conversion. When the full-scale voltage is used as the input of the analog-to-digital conversion unit 206, the maximum output digital signal of the analog-to-digital conversion unit 206 can be obtained. For example, for an 8-bit analog-to-digital conversion unit, the full-scale voltage is 5V, and during analog-to-digital conversion, the input voltage of 5V corresponds to a digital signal of "11111111".

Since the full-scale voltage is the maximum input voltage at which the analog-to-digital conversion unit 206 can perform analog-to-digital conversion, the full-scale voltage can be used to determine the input voltage range of the analog-to-digital conversion unit 206. In this embodiment, the voltage of the continuous analog signal should be less than full scale voltage.

In addition, in order to improve the resolution of analog-to-digital conversion, the full-scale voltage must be equal to or slightly greater than the maximum voltage of the continuous analog signal. Ideally, the full-scale voltage should be equal to the maximum voltage of the continuous analog signal. All digital signals of the analog-to-digital conversion unit 206 can be obtained. For example, for an 8-bit analog-to-digital conversion unit 206, for example, the full-scale voltage is 5V, and the maximum voltage of the continuous analog signal is 5V. After the analog-to-digital conversion, the analog-to-digital conversion The unit 206 can output 256 kinds of digital signals. The 256 kinds of digital signals well reflect the voltage of the continuous analog signal. In an actual circuit, the maximum value of the continuous analog signal voltage can be slightly smaller than the full-scale voltage of the analog-to-digital conversion unit 206. , after analog-to-digital conversion, the analog-to-digital conversion unit 206 can output nearly 256 kinds of digital signals.

The full-scale voltage adjustment unit 203 adjusts the full-scale voltage of the analog-to-digital conversion unit 206, so that the full-scale voltage is greater than the continuous analog signal voltage, and at the same time, the full-scale voltage is greater than or slightly greater than the maximum voltage of the continuous analog signal. Specifically, the full-scale voltage is 1-1.1 times the maximum voltage of the continuous analog signal.

In the prior art, the analog signal detected by the fingerprint sensor is very small, causing the maximum voltage of the continuous analog signal to be much lower than the full-scale voltage of the analog-to-digital conversion unit. At this time, only a small part of the analog-to-digital conversion unit’s digital signal, resulting in a lower resolution of the analog-to-digital conversion, thus causing the fingerprint identification system to fail to obtain a high-resolution fingerprint pattern. The present invention adjusts the full-scale voltage through the full-scale voltage adjustment unit, so that the maximum voltage of the continuous analog signal is equal to or slightly lower than the full-scale voltage, and a relatively high-resolution fingerprint pattern can be obtained, reducing the false rejection rate or false recognition rate, Make the fingerprint sensor have excellent performance. In addition, the gain unit can amplify the voltage of the continuous analog signal output by the sample-and-hold circuit to meet the condition that the maximum voltage of the continuous analog signal is equal to or slightly less than the full-scale voltage, thereby obtaining a high-resolution fingerprint pattern .

When the reference potential in the continuous analog signal is large, it will be converted into a larger digital signal during the analog-to-digital conversion process, so that the number of digital signals that can be output by the analog conversion unit 206 is reduced, resulting in a lower fingerprint identification resolution . The compensation unit 205 is used to make a potential shift in the reference potential of the continuous analog signal, so that the reference potential of the continuous analog signal is less than 0.1 times of the full scale voltage. Therefore, the reference potential can output a smaller digital signal after analog-to-digital conversion, improve the resolution of fingerprint recognition, reduce the rejection rate or false recognition rate of the fingerprint recognition system, and improve the performance of the fingerprint sensor.

Referring to FIG. 3 , a schematic diagram of a preferred embodiment of the fingerprint identification system is shown. Referring to FIG. 2 at the same time, the full-scale voltage adjustment unit 203 includes a first register 2031 and a regulator 2032, wherein the first register 2031 is used to set multiple sets of reference voltages and the full-scale voltage corresponding to the reference voltages, specifically, The reference voltage includes a first reference voltage and a second reference voltage; the regulator 2032 is used to select the first reference voltage and the second reference voltage from the first register 2031 according to the adjustment command, and set the selected voltage in the analog-to-digital conversion unit 206. The first reference voltage and the second reference voltage; the analog-to-digital conversion unit 206 can obtain the corresponding full-scale voltage based on the first reference voltage and the second reference voltage, thereby completing the adjustment of the full-scale voltage; the gain unit 204 includes a third A register 2041 and an amplifier 2042, the third register 2041 is used to set multiple groups of gain multiples; the amplifier 2042 is used to amplify the voltage of the continuous analog signal according to the gain multiples of the third register 2041.

The compensation unit 205 includes a second register 2051 and a shifter 2052, the second register 2051 is used to set multiple sets of offset voltage values, the shifter 2052 is used to shift the reference potential of the continuous analog signal, and the shifter 2052 The shift amount is the offset voltage value in the second register 2051 .

Referring to FIG. 4 , there is shown a schematic diagram of a testing device including the fingerprint recognition system shown in FIG. 3 . The test device also includes: a measuring device 302 and a judging device 301, wherein,

A measurer 302, configured to measure the digital signal output by the analog-to-digital conversion unit 206, and send the measurement result to the judger 301;

A judging unit 301, configured to judge whether the maximum value of the digital signal measured by the measurer 302 is greater than or equal to the high threshold of the digital signal; The device 2032 issues an adjustment command;

The adjuster 2032 selects from the first register 2031 a first reference voltage and a second reference voltage that are smaller than the first reference voltage and the second reference voltage currently set in the analog-to-digital conversion unit 206 according to the adjustment command sent by the determiner 301 , to obtain a smaller full-scale voltage, and then meet the full-scale voltage equal to or slightly greater than the maximum voltage of the continuous analog signal, so as to obtain a larger digital signal to meet the high threshold of the digital signal;

Wherein, the digital signal high threshold is set by the designer according to design specifications, for example, the digital signal high threshold is 0.9 of the maximum output digital signal of the analog-to-digital conversion unit. Generally, for fingerprint sensors with high performance requirements, the high threshold of digital signals is relatively high, and for fingerprint sensors with general performance requirements, the high threshold of digital signals is low.

The judging unit 301 can also be used to judge whether the first reference voltage and the second reference voltage set by the regulator 2032 are the same as those in the first register 2031 when the maximum value of the digital signal output by the analog-to-digital converter 206 is less than the high threshold of the digital signal. the minimum value of the first reference voltage and the second reference voltage, if yes, then issue a gain command to the amplifier 2042;

The amplifier 2042 of the gain unit 204 selects a larger gain multiple from the third register 2041 according to the gain command to amplify the voltage of the continuous analog signal.

When the first reference voltage and the second reference voltage set by the full-scale voltage regulator are the maximum values of the first reference voltage and the second reference voltage in the first register 2031, it means that the continuous analog signal is too small, even through the full-scale voltage regulation unit 203 is adjusted to the maximum full-scale voltage, and the requirement that the full-scale voltage is equal to or slightly greater than the maximum voltage of the continuous analog signal cannot be realized. At this time, the continuous analog signal is amplified by the gain unit 204, so that the amplified analog signal is equal to or slightly greater than the maximum voltage of the continuous analog signal. Slightly less than the full-scale voltage to achieve high fingerprint recognition performance.

The determiner 301 can also be used to determine whether the minimum value of the digital signal measured by the measurer 302 is less than or equal to the low threshold of the digital signal, and when the minimum value of the digital signal is greater than the low threshold of the digital signal, the compensation unit 205 Shifter 2052 issues a shift command;

The shifter 2052 lowers the reference potential of the continuous analog signal according to the shift command sent by the judger 2032, so that the digital signal obtained after the lowered reference potential passes through the analog-to-digital conversion unit 206 is less than or equal to the low threshold of the digital signal;

Wherein, the low threshold of the digital signal is set by the designer according to design specifications, for example, the low threshold of the digital signal is 0.1 times of the maximum output digital signal of the analog-to-digital conversion unit. Generally, for fingerprint sensors with high performance requirements, the low threshold of digital signals is low, and for fingerprint sensors with general performance requirements, the low threshold of digital signals is relatively high.

The present invention will be further described below in conjunction with other embodiments of the present invention.

Referring to FIG. 5 , it shows a schematic diagram of another embodiment of the driving circuit unit shown in FIG. 2 . The difference between this embodiment and the embodiment shown in FIG. 2 is that in this embodiment, the gain unit 204 in the drive circuit unit is used to amplify the discrete analog signal detected by the fingerprint sensor 100; the compensation unit 205 is used to reduce The reference potential of the amplified discrete analog signal; the sampling and holding circuit 202 is used to collect the instantaneous voltage of the discrete analog signal processed by the gain unit 204 and the compensation unit 205, and keep the instantaneous voltage constant in the subsequent analog-to-digital conversion process , forming a continuous analog signal.

Referring to FIG. 6 , it shows a schematic diagram of another embodiment of the fingerprint identification system of the present invention. The difference between this embodiment and the embodiment shown in FIG. 2 is that the drive circuit unit includes: a controller 201 , a sample hold circuit 202 , an analog-to-digital conversion unit 206 , a full-scale voltage adjustment unit 203 and a compensation unit 205 .

This embodiment is applicable to the case where the discrete analog signal detected by the fingerprint sensor is large, and the condition that the maximum value of the analog signal is equal to or slightly smaller than the full-scale voltage can be satisfied by the full-scale voltage adjustment unit. At this time, the driving circuit unit does not need to be provided with a gain unit. .

Referring to FIG. 7 , it shows a schematic diagram of another embodiment of the fingerprint identification system of the present invention. The difference between the embodiment and the embodiment shown in FIG. 2 is that the drive circuit unit includes: a controller 201 , a sample hold circuit 202 , an analog-to-digital conversion unit 206 and a full-scale voltage adjustment unit 203 .

This embodiment is applicable to the condition that the discrete analog signal detected by the fingerprint sensor is relatively large, and the maximum value of the continuous analog signal is equal to or slightly lower than the full-scale voltage through the full-scale voltage adjustment unit, and the reference potential of the continuous analog signal In a lower case, the driving circuit unit does not need to set a gain unit and a compensation unit at this time.

In summary, the fingerprint recognition system provided by the present invention includes a full-scale voltage adjustment unit, which can adjust the full-scale voltage according to the maximum input voltage of the analog-to-digital conversion unit to obtain a high-resolution digital signal, The fingerprint information detected by the fingerprint identification system can more truly reflect the user's fingerprint pattern, thereby improving the performance of the fingerprint identification system.

Because the full-scale voltage adjustment unit expands the range of the input voltage of the analog-to-digital conversion unit, the fingerprint sensor detects that the signal is within the range of the input voltage of the analog-to-digital conversion unit. Or the analog signal detected by the fingerprint sensor is amplified by the gain unit and is located within the input voltage range of the analog-to-digital conversion unit, so that the fingerprint sensor in the prior art that is scrapped due to a small signal can obtain the load design requirements through the adjustment of the drive circuit unit The fingerprint recognition system improves the yield rate.

In addition, during the use of the fingerprint identification system, due to aging reasons, the analog signal detected by the fingerprint sensor will decrease. The full-scale voltage adjustment unit of the fingerprint identification system provided by the present invention can adjust the full-scale voltage to reduce the analog signal. The signal is still within the input voltage range of the analog-to-digital conversion unit, or the reduced analog signal is within the input voltage range of the analog-to-digital conversion unit after being amplified by the gain unit, thereby increasing the lifespan of the fingerprint identification system.

It should be understood that the examples and embodiments herein are illustrative only, and that various modifications and correct.

Claims (12)

1. A fingerprint recognition system, characterized in that, said fingerprint recognition system comprises: a fingerprint sensor for detecting a fingerprint pattern and converting said fingerprint pattern into a discrete analog signal of fingerprint information; The driving circuit unit is used to perform data processing on the discrete analog signal detected by the fingerprint sensor, and the driving circuit unit includes: a controller for driving the fingerprint sensor; The sampling and holding circuit is used to collect and maintain the instantaneous voltage of the discrete analog signal to form a continuous analog signal; an analog-to-digital conversion unit for converting a continuous analog signal into a digital signal; The full-scale voltage adjustment unit is used to adjust the full-scale voltage of the analog-to-digital conversion unit, and the full-scale voltage is the maximum input voltage for the analog-to-digital conversion unit to perform analog-to-digital conversion. 2. The fingerprint recognition system according to claim 1, wherein the full-scale voltage regulation unit comprises a first register and a regulator, wherein, The first register is used to set multiple sets of reference voltages and full-scale voltages corresponding to the reference voltages, the reference voltages include a first reference voltage and a second reference voltage; The regulator is used to select the first reference voltage and the second reference voltage from the first register according to the regulation command, and set the selected first reference voltage and the second reference voltage in the analog-to-digital conversion unit; The analog-to-digital conversion unit obtains a corresponding full-scale voltage based on the first reference voltage and the second reference voltage. 3. The fingerprint identification system according to claim 1, wherein the full-scale voltage is 1 to 1.1 times the maximum voltage of the continuous analog signal. 4. The fingerprint identification system according to claim 2, further comprising a compensating unit, which is used to shift the reference potential of the analog signal to reduce the reference potential according to the offset command before the analog-to-digital conversion. potential. 5. The fingerprint identification system as claimed in claim 4, wherein the compensation unit comprises a second register and a shifter, the second register is used to set multiple groups of offset voltage values, and the shifter uses Then, according to the offset command, the reference potential of the analog signal is decreased by an offset, and the offset is the offset voltage value in the second register. 6. The fingerprint recognition system according to claim 4, wherein the reference potential is less than 0.1 times of the full scale voltage. 7. The fingerprint identification system according to claim 4, further comprising a gain unit, configured to amplify the analog signal before the analog-to-digital conversion according to the gain command, and increase the voltage of the analog signal. 8. The fingerprint identification system as claimed in claim 7, wherein the gain unit includes a third register and an amplifier, and the third register is used to set multiple groups of gain multiples; the amplifier is used for gain according to the third register Multiplier to increase the voltage of the analog signal. 9. The fingerprint identification system according to any one of claims 4, 5, 7 or 8, wherein the analog signal is a continuous analog signal formed after processing by the sampling and holding circuit or detected by the fingerprint sensor Discrete analog signal about fingerprint information. 10. A test device comprising the fingerprint recognition system of claim 1, wherein the test device further comprises a measurer and a judger; The measuring device is used to measure the digital signal output by the analog-to-digital conversion unit, and send the measurement result to the judging device; The determiner is used to determine whether the maximum value of the digital signal measured by the measuring device is greater than or equal to the high threshold of the digital signal, and when the maximum value of the digital signal is less than the high threshold of the digital signal, the regulator of the full-scale voltage regulation unit Issue an adjustment command. 11. A test device comprising the fingerprint recognition system of claim 5, wherein the test device further comprises a measurer and a judger; The measuring device is used to measure the digital signal output by the analog-to-digital conversion unit, and send the measurement result to the judging device; The determiner is used to determine whether the maximum value of the digital signal measured by the measuring device is greater than or equal to the high threshold of the digital signal, and when the maximum value of the digital signal is less than the high threshold of the digital signal, the regulator of the full-scale voltage regulation unit issue adjustment orders; The determiner is also used to determine whether the minimum value of the digital signal measured by the measuring device is less than or equal to the low threshold of the digital signal, and when the minimum value of the digital signal is greater than the low threshold of the digital signal, send a message to the offset device of the compensation unit offset command. 12. A test device comprising the fingerprint identification system of claim 7, wherein the test device further comprises a measurer and a judger; The measuring device is used to measure the digital signal output by the analog-to-digital conversion unit, and send the measurement result to the judging device; The determiner is used to determine whether the maximum value of the digital signal measured by the measuring device is greater than or equal to the high threshold of the digital signal, and when the maximum value of the digital signal is less than the high threshold of the digital signal, the regulator of the full-scale voltage regulation unit issue adjustment orders; The determiner is also used to determine whether the minimum value of the digital signal measured by the measuring device is less than or equal to the low threshold of the digital signal, and when the minimum value of the digital signal is greater than the low threshold of the digital signal, send a message to the offset device of the compensation unit offset command; The judger is also used to judge whether the first reference voltage and the second reference voltage set by the regulator are equal to the first reference voltage and The minimum value of the second reference voltage, if it is the minimum value, a gain command is issued to the amplification phase.

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