Digital-to-analog conversion apparatus and method with signal calibration mechanism

Abstract

The present disclosure relates to a digital-to-analog conversion device and method with signal calibration mechanism. A digital-to-analog conversion method with signal calibration mechanism, comprising: generating an output analog signal by a digital-to-analog conversion circuit according to an input code word of an input digital signal to control the operating state of each current source; generating an echo signal by an echo transmission circuit according to the output analog signal; generating a deviation signal by a calibration circuit according to the input code word from a code word deviation table mapping; generating an echo cancellation signal by an echo cancellation circuit according to the deviation signal processed by an echo cancellation coefficient; generating a deviation amount by a calibration parameter operation circuit according to the difference between the echo signal and the echo cancellation signal, performing statistical operation according to the operating state of each current source, and calculating the current deviation value of the target current source according to the operation between the groups, converting the current deviation value of the current source into the code word deviation value to update the code word deviation table.

Description

Technical Field

[0001] This invention relates to digital-to-analog conversion technology, and more particularly to a digital-to-analog conversion device and method with a signal calibration mechanism. Background Technology

[0002] A digital-to-analog converter (DTC) is a crucial component that converts signals from digital to analog form. DTCs can generate analog signals of varying magnitudes by multiplying different digital codes by corresponding conversion gain values.

[0003] However, for current-output digital-to-analog converters, process drift will cause non-ideal deviations in the amplitude and shape of the output. Among these, the amplitude deviation will severely affect system performance. Summary of the Invention

[0004] In view of the problems of the prior art, one of the objectives of the present invention is to provide a digital-to-analog conversion device and method with a signal calibration mechanism to improve the prior art.

[0005] This invention includes a digital-to-analog converter with a signal calibration mechanism, comprising: a digital-to-analog conversion circuit, an echo transmission circuit, a calibration circuit, an echo cancellation circuit, and a calibration parameter calculation circuit. The digital-to-analog conversion circuit includes multiple current sources, each with a current deviation value. Based on the input codeword contained in the input digital signal, the circuit controls the operation state of each current source to either a first current output state or a second current output state, and generates an output analog signal based on the total current of the current sources. In the first current output state and the second current output state, the current sources output currents of opposite polarities but equal magnitudes. The echo transmission circuit processes the output analog signal to generate an echo signal. The calibration circuit receives the input digital signal and generates a deviation signal based on a codeword deviation table mapped from the input codeword. The codeword deviation table contains a one-to-one correspondence between multiple codewords and multiple codeword deviation values. The echo cancellation circuit processes the deviation signal according to a set of echo cancellation coefficients to generate an echo cancellation signal. The calibration parameter calculation circuit generates an offset based on the difference between the echo signal and the echo cancellation signal; the offsets corresponding to different input codewords are divided into multiple groups according to the operating state of each current source and statistical calculations are performed; each current source is set as the target current source and the current deviation values ​​of each current source other than the target current source are mutually canceled according to the calculation between the groups, thereby calculating the current deviation value of the target current source; and the current deviation value of the current source is converted into the codeword deviation value to update the codeword deviation value in the codeword deviation table.

[0006] This invention further includes a digital-to-analog conversion method with a signal calibration mechanism, comprising: a digital-to-analog conversion circuit comprising multiple current sources, each having a current deviation value; controlling the operation state of each current source to one of a first current output state and a second current output state according to the input codeword contained in the input digital signal; and generating an output analog signal according to the total current of the current sources, wherein the current sources output currents of opposite positive and negative values ​​but equal magnitude in the first current output state and the second current output state, respectively; processing the output analog signal by an echo transmission circuit to generate an echo signal; and receiving the input digital signal by a calibration circuit and generating a deviation signal by mapping the input codeword to a codeword deviation table, wherein the codeword deviation table contains multiple codewords and multiple codes. The system establishes a one-to-one correspondence between word deviation values; the echo cancellation circuit processes the deviation signal based on a set of echo cancellation coefficients to generate an echo cancellation signal; the calibration parameter calculation circuit generates an offset based on the difference between the echo signal and the echo cancellation signal; the calibration parameter calculation circuit performs statistical calculations on the offsets corresponding to different input codewords, grouping them into multiple groups according to the operating state of each current source; the calibration parameter calculation circuit sets each current source as the target current source and, based on the calculations between groups, cancels out the current deviation values ​​of current sources other than the target current source, thereby calculating the current deviation value of the target current source; and the calibration parameter calculation circuit converts the current deviation value of the current source into a codeword deviation value to update the codeword deviation value in the codeword deviation table.

[0007] The features, implementation, and effects of this case will be described in detail below with reference to the accompanying drawings as a preferred embodiment. Attached Figure Description

[0008] Figure 1 A block diagram showing a digital-to-analog converter with a signal calibration mechanism in one embodiment of the present invention is shown.

[0009] Figure 2 This diagram shows a circuit diagram of a digital-to-analog conversion circuit in one embodiment of the present invention;

[0010] Figure 3 This diagram illustrates a grouping of offsets based on the operating states of each current source, according to one embodiment of the present invention.

[0011] Figure 4 A more detailed schematic diagram of a group is shown in one embodiment of the present invention; and

[0012] Figure 5 This invention illustrates a flowchart of a digital-to-analog conversion method with a signal calibration mechanism, according to one embodiment of the present invention. Detailed Implementation

[0013] One of the objectives of this invention is to provide a digital-to-analog converter with a signal calibration mechanism to calibrate for deviations in different codewords, thereby avoiding errors caused by output signal level offset.

[0014] Please refer to Figure 1 . Figure 1 The block diagram shown in one embodiment of the present invention is a digital-to-analog converter 100 with a signal calibration mechanism. The digital-to-analog converter 100 includes: a digital-to-analog conversion circuit 110, an echo transmission circuit 120, a calibration circuit 130, an echo cancellation circuit 140, an error calculation circuit 150, an inversion error calculation circuit 160, a calibration parameter calculation circuit 170, and an auxiliary digital-to-analog conversion circuit 180.

[0015] The digital-to-analog converter 110 receives an input digital signal IS with an input codeword from a signal source SS and performs digital-to-analog conversion to generate an output analog signal OAS. The signal source SS is, for example, but not limited to, a transmission circuit (TX) in a communication system.

[0016] Please refer to the following at the same time Figure 2 . Figure 2 The circuit diagram of digital-to-analog conversion circuit 110 is shown in one embodiment of the present invention.

[0017] The digital-to-analog converter circuit 110 includes multiple current sources CA to CS. The input codeword of the input digital signal IS controls the operating state of each current source CA to CS to either a first current output state or a second current output state, and generates an output analog signal OAS based on the total current of the current sources CA to CS. The first current output state and the second current output state output currents of opposite polarities but equal magnitudes.

[0018] In one embodiment, the input codeword of the input digital signal IS includes multiple thermometer codes TC, used to control current sources CA to CO implemented as thermometer-controlled current sources, with each current source CA to CO corresponding to an output of one unit current. In one embodiment, the thermometer code TC controls the switching circuit 200 corresponding to the current sources CA to CO, so that the current sources CA to CO are electrically coupled to different current output paths through the switching circuit 200, for example... Figure 2 The solid line path and the dashed line path shown are used to operate in one of the first current output states and the second current output states.

[0019] A thermometer code will be 2 A Each combination corresponds to 2 control numbers. A-1 thermometer-controlled current source. In this embodiment, A is 4. Therefore, 4 thermometer codes TC will control 15 thermometer-controlled current sources CA~CO in 16 combinations.

[0020] In operation, when the thermometer code changes sequentially from (0000), (0001), ... (1111), the current sources CA to CO switch their operating states sequentially like a thermometer, from all being in the second current output state to sequentially switching the current sources CA to CN to the first current output state, until all current sources CA to CO are in the first current output state.

[0021] In one embodiment, the input codeword of the input digital signal IS further includes multiple binary codes BC to control current sources CP to CS implemented using binary-controlled current sources, with each current source CP to CS corresponding to output current of 1 / 2 unit, 1 / 4 unit, 1 / 8 unit, and 1 / 16 unit, respectively. In one embodiment, the binary code BC controls the switching circuit 210 corresponding to the current sources CP to CS, so that the current sources CP to CS are electrically coupled to different current output paths through the switching circuit 210, for example... Figure 2 The solid line path and the dashed line path shown are used to operate in one of the first current output states and the second current output states.

[0022] B binary codes BC will be used in 2 B Each combination corresponds to a binary controlled current source with a control number of B. In this embodiment, B is 4. Therefore, the four binary codes BC will control the four binary controlled current sources CP to CS in 16 combinations.

[0023] In operation, when the binary code is switched sequentially from (0000), (0001), ... (1111), the current source CP is in the second and first current output states respectively when the highest bit is 0 and 1, the current source CQ is in the second and first current output states respectively when the second highest bit is 0 and 1, the current source CR is in the second and first current output states respectively when the second lowest bit is 0 and 1, and the current source CS is in the second and first current output states respectively when the lowest bit is 0 and 1.

[0024] Therefore, by means of the control implemented by the thermometer code TC on the switching circuit 200 and the control implemented by the binary code BC on the switching circuit 210, the digital-to-analog conversion circuit 110 can generate an output analog signal OAS from the total current of the current sources CA to CS.

[0025] Due to process deviations, the current sources CA to CS will exhibit current deviation values. 2 A -1 thermometer-controlled current source will generate 2 A-1 current deviation value and B binary controlled current sources will generate B current deviation values. All current sources cause a total of 2 A -1+B current deviation values.

[0026] These current deviation values, depending on the different input codewords, will combine to produce different codeword deviation values. In the aforementioned numerical example, 15 thermometer-controlled current sources and 4 binary-controlled current sources will generate a total of 19 current deviation values, and these 19 current sources are controlled by 256 combinations generated from 8-bit input codewords (4 bits for the thermometer code and 4 bits for the binary code). Therefore, the 19 current deviation values ​​will correspond to 256 codeword deviation values.

[0027] The echo transmission circuit 120 processes the output analog signal OAS to generate the echo signal ES.

[0028] In one embodiment, the echo transmission circuit 120 includes an echo response circuit 190 and an analog-to-digital converter circuit 195. The echo response circuit 190 performs echo response processing on the output analog signal OAS, and the analog-to-digital converter circuit 195 further performs analog-to-digital conversion processing to generate an echo signal ES. In one embodiment, the echo transmission circuit 120 may more selectively include, for example, but not limited to, a low-pass filter or other digital signal processing circuitry (not shown), to perform further digital processing on the echo signal ES.

[0029] The calibration circuit 130 receives the input digital signal IS and generates a deviation signal DS by mapping the input codeword of the input digital signal IS to the codeword deviation table TB. The codeword deviation table TB contains a one-to-one correspondence between multiple codewords and multiple codeword deviation values, and the input codeword will be one of these codewords. Taking the above 8-bit form as an example, the codeword deviation table TB will have 256 correspondences, so that 256 codewords are respectively matched with 256 deviation values. In one embodiment, in the initial state, the deviation value corresponding to all codewords is preset to 0.

[0030] The echo cancellation circuit 140 processes the deviation signal DS according to a set of echo cancellation coefficients CEC to generate an echo cancellation signal ECS. It should be noted that, in one embodiment, the echo cancellation circuit 140 may be shared with the receiving circuit (RX) in a communication system to cancel echoes fed into the receiving circuit from the transmitting circuit.

[0031] The calibration parameter calculation circuit 170 generates an offset DA based on the difference between the echo signal ES and the echo cancellation signal ECS. The echo signal ES and the echo cancellation signal ECS can be selectively processed by the error calculation circuit 150 and the inversion error calculation circuit 160 before being calculated by the calibration parameter calculation circuit 170.

[0032] Error calculation circuit 150 subtracts echo cancellation signal ECS from echo signal ES to generate error signal DIS. In the initial state, echo cancellation circuit 140 trains echo cancellation coefficient CEC based on error signal DIS to achieve convergence of CEC, and then applies response processing to deviation signal DS based on the converged echo cancellation coefficient CEC. This response processing approximates the path response of input digital signal IS from signal source SS via digital-to-analog conversion circuit 110 and echo response circuit 190.

[0033] Next, the inversion error calculation circuit 160 performs a one-dimensional inversion of the echo cancellation coefficient CEC, multiplies it by the value of the error signal DIS, and then accumulates the results to generate the inversion error value FD. The calibration parameter calculation circuit 170 can use the inversion error value FD as the offset DA corresponding to the input codeword based on the path delay DL of the echo cancellation circuit 140 and the inversion error calculation circuit 160.

[0034] It should be noted that the above-described method of generating the offset is only one example. In other embodiments, the calibration parameter calculation circuit 170 may also generate the offset DA in other ways.

[0035] Furthermore, the calibration parameter calculation circuit 170 divides the offset DA corresponding to different input codewords into multiple groups according to the operating states of each current source CA to CO, and performs statistical calculations. The calibration parameter calculation circuit 170 assigns the offset DA corresponding to different input codewords to one of these groups, corresponding to a combination of thermometer codes, and generates an average value for each group. These groups are arranged sequentially, with each pair of adjacent groups causing one of the thermometer-controlled current sources to operate in a first current output state and a second current output state, respectively.

[0036] Please refer to Figure 3 . Figure 3 The diagram shows a group of G01 to G16, which are distinguished according to the operating states of each current source CA to CO, in one embodiment of the present invention.

[0037] In one embodiment, the current deviation values ​​of current sources CA to CO are ΔA to ΔO, respectively. When current sources CA to CO are in a first current output state, they are represented by +ΔA to +ΔO; when current sources CA to CO are in a second current output state, they are represented by -ΔA to -ΔO.

[0038] Group G01 corresponds to the thermometer code (0000) that puts current sources CA to CO in the second current output state, while the binary code can be any value (0000 to 1111). Therefore, a total of 16 input codewords (00000000 to 00001111) will be classified into group G01. After averaging the offsets DA of multiple entries classified into group G01, the current deviation values ​​of current sources CP to CS (current sources controlled by binary codes) will cancel each other out, making the average value approach the sum of the current deviation values ​​of current sources CA to CO -ΔA -ΔB -ΔC - ... –ΔO.

[0039] Similarly, the average values ​​of groups G02 to G16 corresponding to each thermometer code (0001 to 1111) can be obtained from the above derivation process. The detailed derivation process will not be repeated here.

[0040] The calibration parameter calculation circuit 170 sets each current source CA to CO as the target current source and calculates the current deviation value of the current sources other than the target current source by performing calculations between groups G01 to G16.

[0041] More specifically, the calibration parameter calculation circuit 170 generates one of a plurality of thermometer-controlled current deviation values ​​based on the difference between the average values ​​of every two adjacent groups. For example, the difference between the average values ​​of group G02 and group G01 can be expressed by the following formula:

[0042] (+ΔA-ΔB-ΔC-...-ΔO)-(-ΔA-ΔB-ΔC-...–ΔO)=+2ΔA

[0043] Therefore, the calibration parameter calculation circuit 170 can generate the current deviation value ΔA of the current source CA according to the above calculation.

[0044] Similarly, the calibration parameter calculation circuit 170 can generate current deviation values ​​ΔB to ΔO corresponding to each current source CB to CO based on the difference between the average values ​​of group G03 and group G02, the difference between the average values ​​of group G04 and group G03, ..., the difference between the average values ​​of group G16 and group G15.

[0045] In one embodiment, the calibration parameter calculation circuit 170 may first set the average value of group G01 and group G16 to 0 as an anchor point before performing calculations between groups, thus avoiding system interaction.

[0046] Please refer to Figure 4 . Figure 4 A more detailed schematic diagram of groups G01 and G16 is shown in one embodiment of the present invention.

[0047] The offset DA assigned to each group includes not only the current deviation value of the thermometer-controlled current source, but also a combination of the current deviation values ​​of 16 binary-controlled current sources.

[0048] Taking groups G01 and G16 as examples, the current deviation values ​​of the current sources CP to CS corresponding to the binary controlled current sources are ΔP to +ΔS, respectively. Here, when the current sources CP to CS are in the first current output state, it is represented by +ΔP to +ΔS; when the current sources CP to CS are in the second current output state, it is represented by -ΔP to -ΔS. Therefore, depending on the operating state of the current sources CP to CS, the current deviation values ​​of each group will be as follows: Figure 4 The 16 combinations shown. Figure 4 In the diagram, the 16 combinations corresponding to group G01 are labeled as P01 to P16, and the 16 combinations corresponding to group G16 are labeled as N01 to N16.

[0049] The calibration parameter calculation circuit 170 selects a first group and a second group from groups G01 to G16, wherein the thermometer codes corresponding to the first group and the second group respectively completely reverse the operating states of each thermometer-controlled current source. Further, the calibration parameter calculation circuit 170 divides the offset DA that makes each binary controlled current source in the first group and the second group into groups and averages them to generate one of the binary controlled current deviation values.

[0050] Taking groups G01 and G16 as examples, the thermometer code (0000) corresponding to group G01 causes all current sources CA to CO to operate in the second output current state, while the thermometer code (1111) corresponding to group G16 causes all current sources CA to CO to operate in the completely opposite first output current state.

[0051] Taking the current source CP as an example, the calibration parameter calculation circuit 170 divides the offset DA that makes the current source CP in the first current output state into groups G01 and G16 and averages them. Figure 4 As shown, the offset DA that makes current source P in the first current output state corresponds to combinations N09~N16 and P09~P16, and is marked with a white dot. After averaging, the current deviation values ​​ΔQ~ΔS of these combinations cancel each other out, leaving the current deviation value ΔP of current source CP.

[0052] The current deviation values ​​ΔQ to ΔS can be generated in the same way. For example, the current deviation value ΔQ can be generated based on the average of the groups marked with black dots, the current deviation value ΔR can be generated based on the average of the groups marked with white square dots, and the current deviation value ΔS can be generated based on the average of the groups marked with black square dots. The detailed calculation process will not be elaborated further here. It should be noted that the selection of groups G01 and G16 is only an example. In other embodiments, the calibration parameter calculation circuit 170 may also select two other groups that completely reverse the operation of the thermometer-controlled current source.

[0053] The calibration parameter calculation circuit 170 then converts the current deviation values ​​ΔA to ΔS into codeword deviation values ​​to adjust the calibration parameters. Figure 1 The codeword deviation values ​​in the codeword deviation table TB are updated. In one embodiment, the calibration parameter calculation circuit 170 can accumulate multiple offsets DA at regular intervals and then calculate the current deviation value to continuously update the codeword deviation table TB.

[0054] After the codeword deviation value is updated to a stable level, the auxiliary digital-to-analog converter 180 receives the input digital signal IS and generates a deviation calibration analog signal CAS based on the updated codeword deviation table TB according to the input codeword. The absolute value of the deviation calibration analog signal CAS is equivalent to the absolute value of the deviation corresponding to the input codeword. The digital-to-analog converter 100 may further include a superposition circuit 185 to superimpose the deviation calibration analog signal CAS with the output analog signal OAS to cancel out the deviation value corresponding to the input codeword and output the actual output analog signal AAS.

[0055] It should be noted that the deviation value can be positive or negative. When the deviation value is positive, the deviation calibration analog signal CAS can be negative. When the deviation value is negative, the deviation calibration analog signal CAS can be positive.

[0056] Therefore, the digital-to-analog converter in this case can convert the current deviation values ​​of a small number of current sources into the deviation values ​​of a large number of codewords, and calibrate for the deviations of different codewords. Not only can the output signal level offset be calibrated, but the enormous amount of computation required to directly calculate the deviation values ​​of each codeword can also be avoided.

[0057] Please refer to the following at the same time Figure 5 . Figure 5 The flowchart shown is of a digital-to-analog conversion method 500 with a signal calibration mechanism in one embodiment of the present invention.

[0058] In addition to the aforementioned apparatus, the present invention also discloses a digital-to-analog conversion method 500, applicable to, for example, but not limited to, [other applications]. Figure 1In the digital-to-analog conversion device 100. The implementation of the digital-to-analog conversion method 500 is as follows: Figure 5 As shown, it includes the following steps.

[0059] In step S510: The digital-to-analog converter circuit 110, which includes multiple current sources CA to CS each with a current deviation value, controls the operation state of each current source CA to CS to one of a first current output state and a second current output state according to the input code word contained in the input digital signal IS, and generates an output analog signal OAS according to the total current of the current sources CA to CS, wherein the first current output state and the second current output state output currents that are opposite in sign and the same in magnitude.

[0060] In step S520: the echo transmission circuit 120 processes the output analog signal OAS to generate the echo signal ES.

[0061] In step S530: the calibration circuit 130 receives the input digital signal IS and generates a deviation signal DS based on the input codeword mapping from the codeword deviation table TB, wherein the codeword deviation table TB contains a one-to-one correspondence between multiple codewords and multiple codeword deviation values.

[0062] In step S540: the echo cancellation circuit 140 processes the deviation signal DS according to a set of echo cancellation coefficients CEC to generate the echo cancellation signal ECS.

[0063] In step S550: the calibration parameter calculation circuit 170 generates an offset DA based on the difference between the echo signal ES and the echo cancellation signal ECS.

[0064] In step S560: The calibration parameter calculation circuit 170 performs statistical calculations on the offset DA corresponding to different input codewords, which are divided into multiple groups according to the operating states of each current source CA to CS.

[0065] In step S570: The calibration parameter calculation circuit 170 sets each current source CA to CS as the target current source and calculates the current deviation values ​​of each current source CA to CS other than the target current source by performing calculations between groups, thereby calculating the current deviation value of the target current source.

[0066] In step S580: the calibration parameter calculation circuit 170 converts the current deviation value of the current source into a codeword deviation value to update the codeword deviation value in the codeword deviation table TB.

[0067] It should be noted that the above-described implementation is merely an example. In other embodiments, those skilled in the art can make modifications without departing from the spirit of the invention.

[0068] In summary, the digital-to-analog converter and method with a signal calibration mechanism of the present invention can convert the current deviation values ​​of a small number of current sources into the deviation values ​​of a large number of codewords, and then calibrate the deviations of different codewords. Not only can the output signal level offset be calibrated, but the enormous amount of computation required to directly calculate the deviation values ​​of each codeword can also be avoided.

[0069] Although the embodiments of this case are described above, these embodiments are not intended to limit this case. Those skilled in the art can make changes to the technical features of this case based on the express or implied content of this case. All such changes may fall within the scope of patent protection sought in this case. In other words, the scope of patent protection of this case shall be determined by the scope of the patent application in this specification.

[0070] [Symbol Explanation]

[0071] 100: Digital-to-analog converter

[0072] 110: Digital-to-Analog Conversion Circuit

[0073] 120: Echo transmission circuit

[0074] 130: Calibration Circuit

[0075] 140: Echo cancellation circuit

[0076] 150: Error Calculation Circuit

[0077] 160: Reversal Error Calculation Circuit

[0078] 170: Calibration parameter calculation circuit

[0079] 180: Auxiliary digital-to-analog converter circuit

[0080] 185: Superposition Circuit

[0081] 190: Echo Response Circuit

[0082] 195: Analog-to-digital conversion circuit

[0083] 200, 210: Switching circuit

[0084] 500: Digital-to-Analog Conversion Methods

[0085] S510~S580: Steps

[0086] AAS: Actual output analog signal

[0087] BC: binary code

[0088] CAS: Deviation Calibration Analog Signal

[0089] CC: Echo cancellation coefficient

[0090] DA: Offset

[0091] DL: Path Delay

[0092] DIS: Error Signal

[0093] DS: Deviation signal

[0094] ECS: Echo Cancellation Signal

[0095] ES: Echo signal

[0096] FD: Reversal Error Value

[0097] G01~G16: Groups

[0098] IS: Input digital signal

[0099] N01~N16: Combinations

[0100] OAS: Output analog signal

[0101] P01~P16: Combinations

[0102] TB: Codeword Deviation Table

[0103] TC: Thermometer Code

[0104] ΔA~ΔS: Current deviation value

Claims

1. A digital-to-analog converter with a signal calibration mechanism, comprising: A digital-to-analog converter circuit includes multiple current sources, each with a current deviation value, and controls the operation state of each current source to one of a first current output state and a second current output state according to the input codeword contained in the input digital signal. The circuit generates an output analog signal according to the total current of the current sources, wherein the current sources output currents of opposite positive and negative values ​​but the same magnitude in the first current output state and the second current output state, respectively. The echo transmission circuit processes the output analog signal to generate an echo signal; The calibration circuit receives the input digital signal and generates a deviation signal based on the input codeword mapping from the codeword deviation table, wherein the codeword deviation table contains a one-to-one correspondence between multiple codewords and multiple codeword deviation values. The echo cancellation circuit processes the deviation signal according to a set of echo cancellation coefficients to generate an echo cancellation signal. as well as The calibration parameter calculation circuit is configured as follows: The offset is generated based on the difference between the echo signal and the echo cancellation signal; The offset corresponding to different input codewords is divided into multiple groups according to the operating state of each current source and statistical calculation is performed. Each of the current sources is set as a target current source, and the current deviation values ​​of the current sources other than the target current source are canceled out by the inter-group operation, and then the current deviation value of the target current source is calculated. as well as The current deviation value of the current source is converted into the codeword deviation value to update the codeword deviation value in the codeword deviation table.

2. The digital-to-analog converter as claimed in claim 1 further includes an auxiliary digital-to-analog converter circuit, which receives the input digital signal, generates a deviation calibration analog signal based on the input codeword mapped from the codeword deviation table, and then superimposes the deviation calibration analog signal with the output analog signal to cancel the codeword deviation value corresponding to the input codeword, and outputs it as an actual output analog signal.

3. The digital-to-analog converter of claim 1, wherein the input codeword includes a plurality of thermometer codes for controlling a plurality of thermometer-controlled current sources in the current source, and the calibration parameter calculation circuit is further configured to: The offset corresponding to different input codewords is grouped into one of the groups corresponding to a combination of thermometer codes, and the average value of the offset is generated for each group. The groups are arranged sequentially, and every two adjacent groups cause one of the thermometer-controlled current sources to operate in the first current output state and the second current output state, respectively. The current deviation value of one of the thermometer-controlled current sources is generated based on the difference between the average values ​​of every two adjacent groups.

4. The digital-to-analog converter of claim 3, wherein the input codeword further comprises a plurality of binary codes for controlling a plurality of binary controlled current sources in the current source, and the calibration parameter calculation circuit is further configured to: Selecting a first group and a second group from the groups, wherein the thermometer codes corresponding to the first group and the second group respectively completely reverse the operating state of each thermometer-controlled current source; and The offset of each binary controlled current source in the first group and the second group at the first current output state is averaged to generate the current deviation value of one of the binary controlled current sources.

5. The digital-to-analog converter as described in claim 4, wherein the number of thermometer codes is A, and the number of thermometer-controlled current sources is 2. A -1, and the number of said groups is 2. A The number of binary codes is B, the number of binary controlled current sources is B, and the number of combinations of the offset included in each group is 2. B The number of current deviation values ​​is 2. A -1+B items.

6. The digital-to-analog conversion device of claim 4, wherein the calibration parameter calculation circuit sets the average value of the first group and the second group to 0, and generates one of the thermometer-controlled current deviation values ​​based on the difference between the average values ​​of every two adjacent groups.

7. A digital-to-analog conversion method with a signal calibration mechanism, comprising: A digital-to-analog converter circuit comprising multiple current sources, each with a current deviation value, controls the operation state of each current source to one of a first current output state and a second current output state according to the input codeword contained in the input digital signal, and generates an output analog signal according to the total current of the current sources, wherein the current sources output currents of opposite positive and negative values ​​but the same magnitude in the first current output state and the second current output state, respectively. The echo transmission circuit processes the output analog signal to generate an echo signal; The calibration circuit receives the input digital signal and generates a deviation signal based on the input codeword and the codeword deviation table, wherein the codeword deviation table contains a one-to-one correspondence between multiple codewords and multiple codeword deviation values. The echo cancellation circuit processes the deviation signal according to a set of echo cancellation coefficients to generate an echo cancellation signal. The calibration parameter calculation circuit generates an offset based on the difference between the echo signal and the echo cancellation signal; The calibration parameter calculation circuit performs statistical calculations on the offset corresponding to different input codewords, which are divided into multiple groups according to the operating state of each current source. The calibration parameter calculation circuit sets each current source as a target current source and calculates the current deviation value of each current source other than the target current source by performing calculations between groups to cancel each other out. Then, the current deviation value of the target current source is calculated. as well as The calibration parameter calculation circuit converts the current deviation value of the current source into the codeword deviation value to update the codeword deviation value in the codeword deviation table.

8. The digital-to-analog conversion method as described in claim 7, further comprising: The auxiliary digital-to-analog converter receives the input digital signal and generates a deviation calibration analog signal based on the input codeword mapping from the codeword deviation table. The deviation calibration analog signal is then superimposed on the output analog signal to cancel the codeword deviation value corresponding to the input codeword, and the output is the actual output analog signal.

9. The digital-to-analog conversion method of claim 7, wherein the input codeword includes a plurality of thermometer codes for controlling a plurality of thermometer-controlled current sources in the current source, and the digital-to-analog conversion method further includes: The calibration parameter calculation circuit divides the offset corresponding to different input codewords into one of the groups corresponding to a combination of thermometer codes, and generates an average value of the offset for each group. The groups are arranged sequentially, and for every two adjacent groups, the operating state of one of the thermometer-controlled current sources is respectively the first current output state and the second current output state; and The calibration parameter calculation circuit generates the current deviation value of one of the thermometer-controlled current sources based on the difference between the average values ​​of every two adjacent groups.

10. The digital-to-analog conversion method of claim 9, wherein the input codeword further comprises a plurality of binary codes for controlling a plurality of binary-controlled current sources in the current source, and the digital-to-analog conversion method further comprises: The calibration parameter calculation circuit selects a first group and a second group from the groups, wherein the thermometer codes corresponding to the first group and the second group respectively completely reverse the operating state of each thermometer-controlled current source; and The calibration parameter calculation circuit averages the offset of each of the binary controlled current sources in the first group and the second group that makes them the first current output state, to generate the current deviation value of one of the binary controlled current sources.

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