CN118138050A - Direct quantization analog front-end interface circuit based on delta modulator - Google Patents

Abstract

The invention relates to a direct quantization analog front end interface circuit based on a delta modulator, which comprises an embedded high gain amplifier, a coarse quantization analog-to-digital converter, a digital circuit, a digital-to-analog converter, a unit gain amplifier and a fine quantization analog-to-digital converter; the output signal of the embedded high-gain amplifier is quantized by the coarse quantization analog-to-digital converter to output a preprocessed coarse quantization result, the preprocessed coarse quantization result is given to the digital circuit to be processed to obtain a coarse quantization result, the coarse quantization result is converted into an analog signal by the digital-to-analog converter, and the analog signal is subtracted from the analog input signal to be input into the embedded high-gain amplifier; after the output signal of the embedded high-gain amplifier is driven by the unit gain amplifier, the output signal is input into the fine quantization analog-to-digital converter to quantize and output a fine quantization result; the final input analog signal is directly quantized into a digital output signal consisting of two parts, a coarse quantization result and a fine quantization result. The beneficial effects are low power consumption, high accuracy, simple design, and direct quantization.

Description

Direct quantization analog front-end interface circuit based on delta modulator

[ Field of technology ]

The invention relates to the technical field of electronic circuits, in particular to a direct quantization analog front-end interface circuit based on a delta modulator.

[ Background Art ]

Conventional analog front-end interface circuits typically include front-end amplifiers, anti-aliasing filters, programmable gain amplifiers, analog-to-digital converters, and the like, which can process an input analog signal and output a quantized result. In practical application, the driving capability of the signal source may be weak (e.g., bioelectric signal), so the analog front-end interface circuit must have a high input impedance, so as to reduce the requirement for the driving capability of the signal source, and meanwhile, the high input impedance can also improve the common mode rejection ratio of the whole analog front-end interface circuit, and effectively suppress the power frequency interference (50/60 Hz) in the test process. Fig. 1 is a schematic diagram of an analog front end interface circuit architecture based on a high gain amplifier cascaded gain control amplifier. As shown in fig. 1, the amplitude of the input signal is also unpredictable, if the amplitude of the input signal is small, the interface circuit needs to have a larger gain to fully amplify the input signal for quantization processing of the subsequent analog-to-digital converter or the subsequent analog-to-digital converter needs to have a high precision, but in the case of a large amplitude of the input signal, the high gain of the interface circuit can cause circuit saturation to cause signal loss, so that the gain needs to be adjusted in time, which additionally introduces a control circuit (such as an automatic gain control circuit) to increase hardware cost. Fig. 2 is a schematic diagram of an analog front end interface circuit architecture based on a low gain amplifier cascaded high resolution analog to digital converter. As shown in fig. 2, another solution to this problem is to cascade high-resolution analog-to-digital converters using low-gain amplifiers, which can avoid saturation of the output signal, but because of the small amplification factor, the resolution requirement for the subsequent cascaded analog-to-digital converters is high, which increases the design difficulty of analog-to-digital conversion and increases the hardware cost.

Fig. 3 is a schematic diagram of an analog front end interface circuit architecture based on a conventional delta modulator. As shown in fig. 3, the delta modulator introduces an integrator in the feedback loop whose output signal is the derivative of the input signal, which makes the delta modulator insensitive to voltage amplitude signals and less prone to saturation of the output signal; however, conventional delta modulators also require a decimation filter in series at the output to integrate the derivative result of the output for reconstruction of the input signal, which increases the hardware overhead of the circuit.

The invention aims at the technical problems that the prior art needs to connect a decimation filter in series at the output to integrate the derivative result of the output and increase the hardware cost of a circuit and the resolution of the prior delta modulator is lower, and improves the analog front-end interface circuit.

[ Invention ]

The invention aims to provide an analog front-end interface circuit which has low power consumption, high precision, simple design and direct quantification.

In order to achieve the above purpose, the technical scheme adopted by the invention is that the direct quantization analog front end interface circuit based on the delta modulator comprises an embedded high gain amplifier, a coarse quantization analog-to-digital converter, a digital circuit, a digital-to-analog converter, a unit gain amplifier and a fine quantization analog-to-digital converter; the output signal of the embedded high-gain amplifier is quantized by the coarse quantization analog-to-digital converter to output a preprocessed coarse quantization result, the preprocessed coarse quantization result is processed by the digital circuit to obtain a coarse quantization result, the coarse quantization result is converted into an analog signal by the digital-to-analog converter and subtracted from the analog input signal to be input into the embedded high-gain amplifier, so that the output amplifier signal output by the embedded high-gain amplifier is not saturated; after the output signal of the embedded high-gain amplifier is driven by the unit gain amplifier, the output signal is input into the fine quantization analog-to-digital converter to quantize and output a fine quantization result; the final input analog signal is directly quantized into a digital output signal consisting of two parts, a coarse quantization result and a fine quantization result.

Preferably, the digital circuit comprises an integrator circuit and a slope detection circuit; the input signal of the integrator circuit is an L-bit binary digital signal for preprocessing a coarse quantization result, the output signal is an M-bit binary digital signal, the integration step length of each time of the integrator circuit is variable, each time of the integration step length is + -i, wherein i is an integer, and the value is related to the slope of an analog input signal; the slope detection circuit is used for carrying out difference between the current integrator circuit output and the previous integrator circuit output to obtain the slope information of the analog input signal and control the value of i, and the slope detection circuit is smaller in absolute value of the difference result, smaller in slope of the analog input signal and smaller in value of i, larger in absolute value of the difference result, larger in slope of the analog input signal and larger in value of i, zero in the difference result, no change of the analog input signal, 0 in value of i, positive in the difference result, ascending in the analog input signal, negative in the difference result, descending in the analog input signal, 0 in the difference result, unchanged in sign of i, and unchanged in sign.

Preferably, the embedded high gain amplifier is configured to amplify an input amplifier signal in amplitude, let the amplitude of the analog input signal be Va, and the amplitude of the output signal of the digital-to-analog converter be Vb, and then the amplitude of the input amplifier signal be Va-Vb, and after the amplification of the embedded high gain amplifier, the output amplifier signal be a×a (Va-Vb), where a represents the amplification factor of the embedded high gain amplifier.

Preferably, the output signal of the embedded high gain amplifier is converted into an L-bit binary digital signal, i.e. a coarse quantization result is preprocessed; the digital circuit is used for carrying out operation processing on the L-bit binary digital signal and respectively outputting an M-bit binary digital signal and a 2^M-bit thermometer code digital signal; the M-bit binary digital signal is used as a coarse quantization result, and the 2^M-bit thermometer code digital signal is used for driving an M-bit binary digital-to-analog converter; the output signal of the digital-to-analog converter is directly subtracted from the analog input signal at the input to form an input amplifier signal to be input into the embedded high-gain amplifier.

Preferably, the embedded high gain amplifier output signal is simultaneously used as an input signal of a unit gain amplifier; the unit gain amplifier is used for driving the fine quantization analog-to-digital converter, and the amplitude of the output signal of the unit gain amplifier is the same as the amplitude of the input unit gain amplifier signal; the fine quantization analog-to-digital converter converts the unity gain amplifier output signal to an N-bit binary digital signal.

Preferably, the digital output signal is composed of a coarse quantization result, that is, an M-bit binary digital signal output by digital circuit processing and an N-bit binary digital signal output by fine quantization analog-to-digital converter, and is represented by a digital code of a+β+n, where α and β represent weights of the coarse quantization analog-to-digital converter and the fine quantization analog-to-digital converter, respectively.

Preferably, the digital circuit further comprises a decoder circuit and a dynamic weight averaging circuit; the decoder circuit is used for converting the M-bit binary digital signal output by the integrator circuit into 2^M-bit thermometer codes, and the input signal and the output signal of the dynamic weight average circuit are 2^M-bit thermometer codes and are used for realizing dynamic matching of devices in the digital-to-analog converter.

Preferably, the coarse quantization analog-to-digital converter and the fine quantization analog-to-digital converter may be constituted by a successive approximation analog-to-digital converter, a full flash analog-to-digital converter, a sigma-delta analog-to-digital converter, or the like.

Preferably, the digital-to-analog converter may be constituted by a capacitive digital-to-analog converter, a resistive digital-to-analog converter, a current type digital-to-analog converter, or the like.

Preferably, the analog input signal is a differential analog input signal or a single-ended analog input signal.

The direct quantization analog front-end interface circuit based on the delta modulator has the following beneficial effects: the coarse quantization analog-to-digital converter is matched with the digital circuit to cascade the fine quantization analog-to-digital converter, so that the aim of improving the resolution of the whole circuit is fulfilled; 1. compared with the traditional amplifier, the delta modulator with the embedded high-gain amplifier is used as an input stage, has a better anti-saturation function under the same gain, the input amplitude can reach the rail-to-rail, and meanwhile, the coarse quantization analog-to-digital converter in the delta modulator can realize the coarse quantization function of M bits in cooperation with a digital circuit; 2. the introduction of the high-gain amplifier reduces the performance requirement on the fine quantization analog-to-digital converter, thereby reducing the power consumption and the design difficulty of the whole circuit, and the resolution of the direct quantization analog front-end interface circuit is approximately equal to M+N, so that the high resolution is realized; 3. the traditional high-resolution analog-to-digital converter can work only by needing low-noise amplifier driving, and the direct quantization analog front end interface circuit has the characteristic of high input impedance and can be directly applied to the field of weak signal detection under the complex interference condition.

[ Description of the drawings ]

Fig. 1 is a schematic diagram of an analog front end interface circuit architecture based on a high gain amplifier cascaded gain control amplifier.

Fig. 2 is a schematic diagram of an analog front end interface circuit architecture based on a low gain amplifier cascaded high resolution analog to digital converter.

Fig. 3 is a schematic diagram of an analog front end interface circuit architecture based on a conventional delta modulator.

Fig. 4 is a schematic diagram of a delta modulator-based direct quantization analog front end interface circuit architecture.

Fig. 5 is a schematic diagram of the internal components of a delta modulator-based digital circuit of a direct quantization analog front end interface circuit.

Reference numerals and components referred to in the drawings are as follows: 1. the embedded high gain amplifier, 2, coarse quantization analog-to-digital converter, 3, digital circuit, 31, integrator circuit, 32, slope detection circuit, 33, decoder circuit, 34, dynamic weight average circuit, 4, digital-to-analog converter, 5, unity gain amplifier, 6, fine quantization analog-to-digital converter, 11, analog input signal, 12, signal of input amplifier, 13, signal of output amplifier, 14, L bit binary digital signal, 151, 2^M bit thermometer code digital signal, 152, M bit binary digital signal, 153, 2^M bit thermometer code, 16, digital-to-analog converter output signal, 17, unity gain amplifier output signal, 18, N bit binary digital signal, 19, digital output signal.

[ Detailed description ] of the invention

Features and exemplary embodiments of various aspects of the invention are described in detail below. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the invention by showing examples of the invention. The present invention is in no way limited to any particular configuration and algorithm set forth below, but covers any modification, substitution, and improvement of elements, components, and algorithms without departing from the spirit of the invention. In the drawings and the following description, well-known structures and techniques have not been shown in order to avoid unnecessarily obscuring the present invention.

Examples

The embodiment realizes a direct quantization analog front-end interface circuit based on a delta modulator.

The direct quantization analog front end interface circuit based on the variable step length of the delta modulator has the characteristics of high input impedance and high gain, and can effectively inhibit the saturation condition when the traditional analog front end interface circuit is saturated under the conditions of large-amplitude input signals and high gain, and the performance requirement of the cascaded analog-to-digital converter is reduced because the direct quantization analog front end interface circuit based on the variable step length of the delta modulator has the characteristics of high gain when the amplitude of the input signals is smaller. Compared with the traditional delta modulator, the integrator in the feedback loop in the design of the embodiment is realized by using the digital integrator, and meanwhile, the function of a decimation filter required by the output of the traditional delta modulator can be realized, so that the hardware cost is reduced, and meanwhile, the embedded high-gain amplifier is added, so that the digital delta modulator can be used for further fine quantization, and the resolution of the whole circuit is improved.

Fig. 4 is a schematic diagram of a delta modulator-based direct quantization analog front end interface circuit architecture. As shown in fig. 4, the principle is as follows: the difference between the analog input signal and the output signal of the digital-to-analog converter is amplified by the embedded high gain, the amplified signal is quantized by a coarse quantization analog-to-digital converter to output a preprocessed coarse quantization result, the preprocessed coarse quantization result is processed by a digital circuit to obtain a coarse quantization result, the coarse quantization result is converted into the analog signal by the digital-to-analog converter and subtracted from the analog input signal to be input into the embedded high gain amplifier, so that the aim that the signal amplified by the embedded high gain amplifier is not saturated is fulfilled, the output signal of the embedded high gain amplifier is also driven by a unit gain amplifier and is used as the input of a fine quantization analog-to-digital converter, and the fine quantization analog-to-digital converter continuously quantizes the signal to finally realize the function of directly quantizing the input analog signal. The output result of the direct quantization analog front-end interface circuit with variable step length based on the delta modulator consists of a coarse quantization result and a fine quantization result, and the two results are multiplied by the weights respectively and then added to reconstruct the input signal.

The direct quantization analog front end interface circuit based on the variable step length of the delta modulator mainly comprises an embedded high-gain amplifier 1, a coarse quantization analog-to-digital converter 2, a digital circuit 3, a digital-to-analog converter 4, a unit gain amplifier 5 and a fine quantization analog-to-digital converter 6, and can be applied to the scene of weak signal detection under the complex interference environment. The embedded high gain amplifier 1 is configured to amplify a signal 12 of an input amplifier in amplitude, where an amplification factor is determined by a feedback coefficient in an amplifier feedback network, and herein, assuming that an analog input signal 11 has an amplitude Va and a digital-to-analog converter output signal 16 has an amplitude Vb, the amplitude of the signal 12 of the input amplifier is Va-Vb, and the signal 13 of the output amplifier is a x (Va-Vb) after the amplification process of the embedded high gain amplifier 1, where a represents an amplification factor of the embedded high gain amplifier 1; the coarse quantization analog-to-digital converter 2 may convert the signal 13 of the output amplifier into a corresponding L-bit binary digital signal 14, i.e. a pre-processed coarse quantization signal; the digital circuit 3 performs operation processing on the L-bit binary pre-processed coarse quantized digital signal 14, and outputs an M-bit binary digital signal 152, i.e., a coarse quantized signal and a 2^M-bit thermometer code digital signal 151, respectively; the M-bit binary digital signal 152 is used as a coarse quantized output digital signal, and the 2^M-bit thermometer coded digital signal 151 is used to drive an M-bit binary digital-to-analog converter 4; the output analog signal 16 of the M-bit binary digital analog converter is directly subtracted from the analog signal 11 input into the delta modulator at the input position, and the signal 12 forming the input amplifier is input into the embedded high gain amplifier 1; the embedded high gain amplifier output signal 13 is also used as the input signal of the unit gain amplifier 5; the unity gain amplifier 5 is used to drive the fine quantization analog-to-digital converter 6, the unity gain amplifier output signal 17 having the same amplitude as the output amplifier signal 13; the fine quantization analog-to-digital converter 6 can convert the unity gain amplifier output signal 17 into a corresponding N-bit binary digital signal 18, i.e. a fine quantization signal; the digital output signal 19 of the analog front end interface circuit is composed of an M-bit binary digital signal 152 processed by the digital circuit 3 and an N-bit binary digital signal 18 output by the fine quantization analog-to-digital converter 6; the input analog signal 11 of the analog front-end interface circuit can be finally represented by a digital code (digital output signal 19) of α×m+β×n, and the input signal is reconstructed; the above-mentioned α and β represent weights of the coarse quantization analog-to-digital converter 2 and the fine quantization analog-to-digital converter 6, respectively.

The direct quantization analog front end interface circuit analog input signal 11 based on the delta modulator step size is differential, and the digital output signal 19 is the quantization result of the input signal difference; or the analog input signal 11 is single ended and the output signal 19 is the quantized result of the input signal.

The coarse quantization analog-to-digital converter 2 and the fine quantization analog-to-digital converter 6 can convert the input analog signals into corresponding digital signals, and the conversion accuracy is determined by the quantization bit number of the analog-to-digital converter; the coarse quantization analog-to-digital converter 2 has L quantization digits, and can quantize an input analog signal into a corresponding L digit code; the fine quantization analog-to-digital converter 6 has N quantization bits, and can quantize the input analog signal into a corresponding N digital code; the coarse quantization ADC 2 and the fine quantization ADC 6 may be implemented by analog-to-digital converter circuits such as a successive approximation ADC (Successive Approximation ADC), a full Flash ADC (Flash ADC), or a sigma-delta ADC (SIGMA DELTA ADC), respectively.

Fig. 5 is a schematic diagram of the internal components of a delta modulator-based digital circuit of a direct quantization analog front end interface circuit. As shown in fig. 5, the digital circuit 3 includes four circuits including an integrator circuit 31, an input signal slope detection circuit 32, a decoder circuit 33, and a dynamic weight average circuit 34 (DYNAMIC WEIGHT AVERAGE, DWA); the input signal of the integrator circuit 31 is an L-bit binary digital signal 14, and the output signal is an M-bit binary digital signal 152; the integrating step length of the integrator circuit 31 is variable each time, and each time the integrating step length can be + -i, wherein i is an integer, and the value of i is related to the slope of the analog input signal 11; the input signal slope detection circuit 32 obtains slope information of the analog input signal 11 by making a difference between the current integrator output and the previous integrator output, so as to control the value of i; the input signal slope detection circuit 32, in each comparison time interval, indicates that the smaller the absolute value of the difference result is, the smaller the slope of the input signal (i is a slow change of the input signal 11), the smaller the value of i is (e.g., 1), the larger the absolute value of the difference result is, the larger the slope of the input signal is (e.g., a fast change of the input signal 11), the larger the value of i is (e.g., 10), and in particular, if the difference result is zero (i is a no change of the input signal 11), the value of i is 0 at this time; the input signal slope detection circuit 32 determines the sign of the integration step by making a positive or negative difference in each comparison time interval, if the difference is positive, it indicates that the input signal 11 is rising, the sign should be taken, if the difference is negative, it indicates that the input signal 11 is falling, the sign should be taken, and in particular, when the difference is 0 (indicating that the input signal 11 has not changed), the sign remains consistent with the last time the result was not 0; the input signal slope detection circuit 32 has an erroneous judgment preventing function, i.e. the slope judgment of the whole signal is not affected by the individual erroneous result; the decoder circuit 33 is responsible for converting the M-bit binary digital signal 152 of the integrator circuit into 2^M-bit thermometer code 153; the 2^M-bit thermometer code 153 is used as an input of a dynamic weight average circuit, and an output result of the dynamic weight average circuit is a 2^M-bit thermometer code digital signal 151.

The digital-to-analog converter 4 can convert the input digital signal into corresponding analog signal, and the conversion accuracy is determined by the effective bit number of the digital-to-analog converter 4; the digital-to-analog converter 4 has M-bit binary significant digits, and can convert 2^M-bit input thermometer codes into analog signals and output the analog signals; the digital-to-analog converter 4 may be a capacitive digital-to-analog converter (Capacitor DAC), a resistive digital-to-analog converter (Resistor DAC), a Current digital-to-analog converter (Current DAC), or the like; the digital-to-analog converter 4 described above may also be used to determine the feedback coefficients in the feedback network of the embedded high gain amplifier.

The unit gain amplifier 5 is used for driving the fine quantization analog-to-digital converter 6, and the gain of the unit gain amplifier 5 is one; the input signal of the unity gain amplifier 5 is a differential input, and the output signal is a differential output; or the input signal is single-ended input, and the output signal is single-ended output.

It will be appreciated by those of ordinary skill in the art that all or part of the steps of implementing the above embodiments may be implemented by hardware, or may be implemented by a program for instructing related hardware, where the program may be stored in a computer readable storage medium, where the storage medium may be a magnetic disk, an optical disc, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), or the like.

The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and additions to the present invention may be made by those skilled in the art without departing from the principles of the present invention and such modifications and additions are to be considered as well as within the scope of the present invention.

Claims (10)

1. A delta modulator based direct quantization analog front end interface circuit, characterized by: the digital-to-analog converter comprises an embedded high-gain amplifier, a coarse quantization analog-to-digital converter, a digital circuit, a digital-to-analog converter, a unit gain amplifier and a fine quantization analog-to-digital converter; the output signal of the embedded high-gain amplifier is quantized by the coarse quantization analog-to-digital converter to output a preprocessed coarse quantization result, the preprocessed coarse quantization result is processed by the digital circuit to obtain a coarse quantization result, the coarse quantization result is converted into an analog signal by the digital-to-analog converter and subtracted from the analog input signal to be input into the embedded high-gain amplifier, so that the output amplifier signal output by the embedded high-gain amplifier is not saturated; after the output signal of the embedded high-gain amplifier is driven by the unit gain amplifier, the output signal is input into the fine quantization analog-to-digital converter to quantize and output a fine quantization result; the final input analog signal is directly quantized into a digital output signal consisting of two parts, a coarse quantization result and a fine quantization result.

2. The delta modulator-based direct quantization analog front end interface circuit of claim 1, wherein: the digital circuit comprises an integrator circuit and a slope detection circuit; the input signal of the integrator circuit is an L-bit binary digital signal for preprocessing a coarse quantization result, the output signal is an M-bit binary digital signal, the integration step length of each time of the integrator circuit is variable, each time of the integration step length is + -i, wherein i is an integer, and the value is related to the slope of an analog input signal; the slope detection circuit is used for carrying out difference between the current integrator circuit output and the previous integrator circuit output to obtain the slope information of the analog input signal and control the value of i, and the slope detection circuit is smaller in absolute value of the difference result, smaller in slope of the analog input signal and smaller in value of i, larger in absolute value of the difference result, larger in slope of the analog input signal and larger in value of i, zero in the difference result, no change of the analog input signal, 0 in value of i, positive in the difference result, ascending in the analog input signal, negative in the difference result, descending in the analog input signal, 0 in the difference result, unchanged in sign of i, and unchanged in sign.

3. The delta modulator-based direct quantization analog front end interface circuit of claim 2, wherein: the embedded high-gain amplifier is used for carrying out amplification processing on the amplitude of an input amplifier signal, setting the amplitude of an analog input signal as Va and the amplitude of an output signal of the digital-to-analog converter as Vb, and carrying out amplification processing on the input amplifier signal as Va-Vb, wherein the output amplifier signal is A (Va-Vb), and A represents the amplification factor of the embedded high-gain amplifier.

4. A delta modulator-based direct quantization analog front end interface circuit as claimed in claim 3, characterized in that: the coarse quantization analog-to-digital converter is used for converting the output signal of the embedded high-gain amplifier into an L-bit binary digital signal, namely preprocessing a coarse quantization result; the digital circuit is used for carrying out operation processing on the L-bit binary digital signal and respectively outputting an M-bit binary digital signal and a 2^M-bit thermometer code digital signal; the M-bit binary digital signal is used as a coarse quantization result, and the 2^M-bit thermometer code digital signal is used for driving an M-bit binary digital-to-analog converter; the output signal of the digital-to-analog converter is directly subtracted from the analog input signal at the input to form an input amplifier signal to be input into the embedded high-gain amplifier.

5. The delta modulator-based direct quantization analog front end interface circuit of claim 4, wherein: the embedded high-gain amplifier output signal is simultaneously used as an input signal of the unit gain amplifier; the unit gain amplifier is used for driving the fine quantization analog-to-digital converter, and the amplitude of the output signal of the unit gain amplifier is the same as the amplitude of the input unit gain amplifier signal; the fine quantization analog-to-digital converter converts the unity gain amplifier output signal to an N-bit binary digital signal.

6. The delta modulator-based direct quantization analog front end interface circuit of claim 5, wherein: the digital output signal is composed of a coarse quantization result, namely an M-bit binary digital signal which is processed and output by a digital circuit and an N-bit binary digital signal which is output by a fine quantization analog-to-digital converter, and is represented by a digital code of alpha, M and beta, wherein alpha and beta respectively represent weights of the coarse quantization analog-to-digital converter and the fine quantization analog-to-digital converter.

7. The delta modulator-based direct quantization analog front end interface circuit of claim 6, wherein: the digital circuit further comprises a decoder circuit and a dynamic weight average circuit; the decoder circuit is used for converting the M-bit binary digital signal output by the integrator circuit into 2^M-bit thermometer codes, and the input signal and the output signal of the dynamic weight average circuit are 2^M-bit thermometer codes and are used for realizing dynamic matching of devices in the digital-to-analog converter.

8. The delta modulator-based direct quantization analog front end interface circuit of claim 7, wherein: the coarse quantization analog-to-digital converter and the fine quantization analog-to-digital converter are composed of a successive approximation analog-to-digital converter, a full flash analog-to-digital converter or a sigma-delta analog-to-digital converter.

9. The delta modulator-based direct quantization analog front end interface circuit of claim 8, wherein: the digital-to-analog converter is composed of a capacitance type digital-to-analog converter, a resistance type digital-to-analog converter or a current type digital-to-analog converter.

10. The delta modulator-based direct quantization analog front end interface circuit of claim 9, wherein: the analog input signal is a differential analog input signal or a single-ended analog input signal.