WO1993025006A1 - D/a converter and a/d converter - Google Patents
D/a converter and a/d converter Download PDFInfo
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- WO1993025006A1 WO1993025006A1 PCT/JP1993/000717 JP9300717W WO9325006A1 WO 1993025006 A1 WO1993025006 A1 WO 1993025006A1 JP 9300717 W JP9300717 W JP 9300717W WO 9325006 A1 WO9325006 A1 WO 9325006A1
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- dza
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Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/06—Continuously compensating for, or preventing, undesired influence of physical parameters
- H03M1/0617—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence
- H03M1/0634—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence by averaging out the errors, e.g. using sliding scale
- H03M1/0656—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence by averaging out the errors, e.g. using sliding scale in the time domain, e.g. using intended jitter as a dither signal
- H03M1/066—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence by averaging out the errors, e.g. using sliding scale in the time domain, e.g. using intended jitter as a dither signal by continuously permuting the elements used, i.e. dynamic element matching
- H03M1/0663—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence by averaging out the errors, e.g. using sliding scale in the time domain, e.g. using intended jitter as a dither signal by continuously permuting the elements used, i.e. dynamic element matching using clocked averaging
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/66—Digital/analogue converters
- H03M1/68—Digital/analogue converters with conversions of different sensitivity, i.e. one conversion relating to the more significant digital bits and another conversion to the less significant bits
- H03M1/682—Digital/analogue converters with conversions of different sensitivity, i.e. one conversion relating to the more significant digital bits and another conversion to the less significant bits both converters being of the unary decoded type
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/66—Digital/analogue converters
- H03M1/74—Simultaneous conversion
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M3/00—Conversion of analogue values to or from differential modulation
- H03M3/30—Delta-sigma modulation
- H03M3/458—Analogue/digital converters using delta-sigma modulation as an intermediate step
- H03M3/464—Details of the digital/analogue conversion in the feedback path
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M3/00—Conversion of analogue values to or from differential modulation
- H03M3/30—Delta-sigma modulation
- H03M3/50—Digital/analogue converters using delta-sigma modulation as an intermediate step
- H03M3/502—Details of the final digital/analogue conversion following the digital delta-sigma modulation
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M7/00—Conversion of a code where information is represented by a given sequence or number of digits to a code where the same, similar or subset of information is represented by a different sequence or number of digits
- H03M7/30—Compression; Expansion; Suppression of unnecessary data, e.g. redundancy reduction
- H03M7/3002—Conversion to or from differential modulation
- H03M7/3004—Digital delta-sigma modulation
- H03M7/3015—Structural details of digital delta-sigma modulators
- H03M7/302—Structural details of digital delta-sigma modulators characterised by the number of quantisers and their type and resolution
- H03M7/3022—Structural details of digital delta-sigma modulators characterised by the number of quantisers and their type and resolution having multiple quantisers arranged in cascaded loops, each of the second and further loops processing the quantisation error of the loop preceding it, i.e. multiple stage noise shaping [MASH] type
Definitions
- the present invention relates to a D / A (Digital / Analog) converter for converting a digital signal into an analog signal, and a digital / analog (D / A) converter for converting an analog signal into a digital signal.
- D / A Digital / Analog
- D / A digital / analog
- (Analog Digital) conversion device that converts the signal into a digital signal.
- the sampling frequency of the digital signal is higher than the sampling frequency of the digital signal.
- FIG. 24 is a block diagram showing an example of a conventional DZA converter.
- Numeral 10 is a digital fin- olator (DF), which multiplies the sampling frequency fs of the input digital signal by k times (k ⁇ 2). It is a thing.
- k 64.
- 11 is a noise shaper (NS) that limits the word length of the digital signal output from the DF 10 and also sets the frequency characteristics of the noise. Is changed to a predetermined characteristic.
- the noise shake of the tertiary characteristic, ' The output Y with respect to the input X is represented by the equation (1).
- the signal is converted to a 1-bit pulse signal and output as an analog signal.
- the A-converter shown in Fig. 24 uses the DF10 and NS11 to set the digital input signal to a sampling frequency of 64 fs and 11 levels.
- a so-called over-sampling D / A converter that converts a digital signal to an analog signal at a higher sampling frequency. What is it.
- Reference numeral 50 denotes a first-order delta-sigma modulator, which quantizes the input X, changes the frequency characteristics of noise, and outputs the result.
- the error component, one Vql is extracted and output to the next stage, where the output Y1 for the input X is expressed by equation (2).
- 5 1 is a second-order ⁇ modulator,
- a quantization error component Vql of the ⁇ modulator 50 is input, and the input Vql is quantized and noise frequency characteristics are changed and output.
- the output Y 2 with respect to one input V ql is expressed by equation (3).
- Vq2 quantization error
- Reference numeral 52 denotes a differentiator, which digitally differentiates the output Y 2 and outputs the result.
- the output Y 2 ′ of the differentiator 52 with respect to the input Y 2 is represented by Expression (4).
- V q2 (4)
- 53 is an adder which adds the outputs Y1 and Y2 'to obtain the output NS of NS11.
- FIG. 26 shows the results of obtaining the output signal spectrum by computer simulation. For simplicity, the signal is shown from 0 to 2 fs. Although only the 11-level digital signal was converted to an analog signal as described above, the signal was converted according to NS 11 as shown in FIG. 26. In a signal band of 0 to fs / 2, a dynamic range (D.) of 120 dB or more can be obtained.
- D. dynamic range
- the PWM 19 requires at least a clock of 704 fs.
- 704 fs 33.792 MHz.
- DA conversion When DA conversion is performed by a method other than PWM, it is possible to operate with lower power than in PWM.
- a DA conversion circuit using a resistor string may be used.
- this requires an extremely high relative accuracy of the resistor string. The reason is that the digital signal whose word length is limited by NS 11 is not affected by the small word length but is still in the original signal band (0 to fs / 2). This is because high accuracy of 120 dB or more is maintained as described above.
- the accuracy of the resistor string determines the DZA conversion accuracy.
- a high-precision resistor string For high-precision D / A conversion, a high-precision resistor string is required. There was a problem that the manufacture of the conversion circuit became difficult.
- Fig. 27 is a block diagram showing an example of a conventional AZD converter.
- reference numeral 70 denotes a subtractor, which outputs a difference between two input analog signals.
- An analog input from the outside is input to the addition terminal of the subtractor 70.
- 7 1 is an integrator which accumulates and outputs the analog signal output from the subtractor 70.
- Numeral 72 denotes a quantizer which converts an analog signal output from the integrator 71 into a digital signal and outputs the digital signal.
- the analog input is a ⁇ 1 signal.
- Reference numeral 79 denotes a DZA converter, which converts the output of the quantizer 72 into an analog signal.
- the output of the DZA converter 79 is input to the subtraction terminal of the subtractor 70.
- the AZD converter shown in Fig. 27 is known as a noise-sewing type AZD converter with primary characteristics, and the output Y with respect to the input X is expressed by the equation (5). It is represented by
- the sampling frequency (FS) is 64 fs
- the input signal frequency is about 0.02 fs
- the input signal level is O dB
- Figure 28 shows the results obtained by using a computer simulation to obtain the output signal spectrum for this case. For the sake of simplicity, the bandwidth from 0 to 2 fs is shown.
- a dynamic range (D.) of about 57 dB can be obtained in the signal band of 0 to fs / 2. .
- the DZA converter 79 is considered to require at least the accuracy of a digital signal to be obtained.
- the output of the DZA converter 79 has a 3% error as shown in Table 2.
- the present invention solves the above-mentioned conventional problems, and does not require a high-level power such as a PWM, and also requires a high accuracy in a DZA conversion circuit.
- the aim is to provide a DZA converter that does not require a high-precision device as well as an A / D converter that does not require a high-precision device for the DA converter 79. Target.
- the present invention has the following configuration. That is, (1) a digital filter for increasing the sampling frequency of the input digital signal by a factor of k (k ⁇ 2); A noise generator for receiving the output of the noise filter as input, changing the frequency characteristic of the noise to a predetermined characteristic together with the word length limitation, and the noise generator. A decoder for converting the output of the decoder into a 1-bit signal sequence corresponding to the value of the input, and a plurality of converters for converting the output of the decoder to an analog signal.
- a 1-bit DZA converter train composed of a plurality of 1-bit DZA converters, and an analog adder for integrating outputs of the 1-bit D / A converter trains,
- the output of the decoder is an output such that the number of 1-bit signals corresponding to the value of the output of the noise signal X-P is circulated.
- a multi-stage quantization type noise shaper that changes to a predetermined characteristic, and the output of each stage of the aforementioned noise system X — PA are input as inputs and correspond to the values of the inputs.
- a 1-bit DZA converter train composed of a plurality of 1-bit D / A converters for converting each output of the coder into an analog signal, and the 1-bit DZA converter
- An analog adder for synthesizing the output of the converter train, wherein the output of the decoder is a 1-bit number corresponding to the value of the output of the noise sweeper.
- a DA converter with an output that allows the signal to circulate.
- a subtractor that receives two analog signals and outputs the difference between the two, an integrator that integrates the analog output of the subtractor, and an output of the integrator.
- a quantizer for converting a digital signal into a digital signal; and a decoder for converting a digital output of the quantizer into a 1-bit signal sequence corresponding to the value of the signal.
- a 1-bit DZA converter train for converting the output of the decoder into an analog signal and an output of the 1-bit D / A converter train, respectively.
- An analog adder that outputs to the subtraction terminal of the subtractor, an analog input is input to the addition terminal of the subtractor, and a digital output is output from the quantizer.
- the number of 1-bit signals corresponding to the value of the output of the quantizer circulates through the output of the decoder.
- a Z D converter and be that o was the Do output Let 's that
- a first subtractor that receives two analog signals and outputs a difference between the two, and a first integrator that integrates an analog output of the first subtractor.
- a second subtractor that uses the analog output of the first integrator as an input to an addition terminal, and a second integration that integrates the analog output of the second subtractor And an output of the second integrator using a digitizer.
- a quantizer for converting a digital output of the quantizer into a one-bit signal sequence corresponding to the value of the signal; and a quantizer for converting the digital output of the quantizer into a one-bit signal sequence corresponding to the value of the signal.
- the 1-bit D / A converter train for converting the output of the decoder into an analog signal, respectively, and the output of the 1-bit D / A converter train are combined to obtain the first and second outputs.
- the analog input is inputted to the addition terminal of the first subtractor, and the digital output is provided.
- Output from the quantizer, and the output of the decoder is an output such that the number of 1-bit signals corresponding to the output value of the quantizer circulates.
- AZD converter is an output such that the number of 1-bit signals corresponding to the output value of the quantizer circulates.
- the present invention converts the output of a noise-synthesizer in a DA converter into a 1-bit signal train with a decoder, and then converts the output to a 1-bit signal sequence.
- the sampling frequency at the time of D / A conversion can be changed to the noise output digital output. It is possible to operate at much lower power than the PWM, which is the same as the sampling frequency of the above.
- the decoder is assigned so that the output of the noise sweeper is circulated to a plurality of 1-bit DZA converters. The correlation between the output value and the specific 1-bit DZA converter is eliminated. As a result, even if there is a relative error (variation) in the output between the 1-bit DZA converters, the occurrence of distortion and noise in the signal band is reduced. can do .
- FIG. 1 is a block diagram illustrating an embodiment of a DZA conversion device according to the present invention
- FIG. 2 is a circuit diagram illustrating an example of a DZA conversion circuit 15 in FIG.
- FIG. 3 is a block diagram showing an example of the decoder 12 of FIG. 1
- FIG. 4 is based on Table 5
- FIG. 1 is an output signal spectrum of the DZA converter of FIG. 1, and FIG.
- FIG. 6 is the DZA converter of FIG.
- FIG. 7 shows an output signal spectrum when the operation of the pointer 30 is such that signals 0 to 9 are repeatedly output in order without depending on the output of NS11. Is the output signal spectrum of the D / A converter of FIG.
- FIG. 8 is a block diagram showing another embodiment of the DZA converter according to the present invention.
- FIG. 9 is a block diagram showing an embodiment of the noise looper 41 of FIG. 8
- FIG. 10 is a circuit diagram showing an example of the D / A conversion circuit 47 of FIG. 1 1 is based on Table 9,
- the output signal spectrum of the D / A converter in FIG. 8 is based on Table 10
- the output signal spectrum of the DZA converter in FIG. 8 is based on Table 10
- FIG. 13 is based on Table 10.
- Table 11 the output signal spectrum of the DA converter of FIG. 8 is shown
- FIG. 14 is based on Table 12, the output signal spectrum of the A converter of FIG. 8 is shown.
- FIG. 14 is based on Table 12
- FIG. 15 is a block diagram showing an embodiment of the AZD conversion device according to the present invention
- FIG. 16 is a circuit diagram showing an example of the D / A conversion circuit 73 of FIG. 15
- FIG. 17 is the output signal spectrum of the AZD converter shown in FIG. 15 based on Table 15
- FIG. 18 is the A / D converter shown in FIG.
- the output signal spectrum when the operation is not repeated from the output of NS 11 and the signals 0 to 9 are repeatedly output in order
- FIG. 9 shows the AZD conversion according to the present invention.
- a lock diagram showing another embodiment of the device Fig. 20 is the spectrum of the output signal of the AZD converter of Fig. 19, and Fig. 21 is the output signal spectrum of the AZD converter of Fig. 19 based on Table 2.
- FIG. 19 shows the output signal spectrum of the AZD converter shown in FIG. 19, and FIG. 23 shows the AZD converter shown in FIG. 19, in which the operation of the pointer 30 is converted to the output of NS 11.
- Fig. 24 shows an example of a conventional 0/8 converter 25 is a block diagram showing an example of the noise shaper 11 shown in FIG. 24, and
- FIG. 26 is a block diagram showing the output signal of the DZA converter shown in FIG. 24.
- FIG. 27 is a block diagram showing an example of a conventional A / D converter
- FIG. 28 is an output signal spectrum of the A / D converter shown in FIG.
- FIG. 29 is an output signal spectrum of the AZD converter of FIG. 27 based on Table 2.
- FIG. 1 is a block diagram showing an embodiment of a D / A converter according to the present invention.
- 10 is a digital filter (DF)
- 11 is a noise filter, ° (NS), and both are shown in FIG. 24.
- It has the same configuration and functions as those of Reference numeral 12 denotes a decoder (DEC) that outputs m 1-bit signals corresponding to the digital signals output from the NS 11 1 .
- Reference numeral 13 denotes a 1-bit DZA converter train (DAC), from the first DA converter (DAC-1) to the m-th D / A converter (DAC-m). It consists of m uniform 1-bit D / A converters.
- Reference numeral 14 denotes an analog adder that sums m analog signals output from the DAC 13 and outputs the result as an analog signal.
- Reference numeral 15 denotes a DZA conversion circuit, which comprises a DAC 13 and an analog adder 14.
- the circuit 15 converts the analog signal to an analog signal, and converts the digital signal to an analog signal at a higher sampling frequency.
- FIG. 2 shows an example of the DZA conversion circuit 15 of FIG.
- reference numeral 13 denotes a 1-bit D / A converter array (DAC)
- 14 denotes an analog adder
- 15 denotes a DZA conversion circuit, each corresponding to FIG. ing .
- Reference numeral 20 denotes an impulse evening, which inverts and outputs a 1-bit input signal.
- 21 and 22 are resistors
- 23 is an operational amplifier (arithmetic amplifier). Explaining the operation of FIG. 2, first, the non-inverting input terminal of the operational amplifier 23 is grounded, and the inverting input terminal is a virtual ground point.
- All the 1-bit input signals are connected to the inverting input terminal of the operational amplifier 23 via the inverter 20 and the resistor 21, and the resistor 2 2 Is connected to the output terminal of the operational amplifier 23 via In other words, a current adding circuit composed of the resistors 21 and 22 is configured.
- the resistance of the resistor 21 of DAC-1 is Rl
- the resistance of the resistor 21 of DAC-2 is R2
- the resistance of the resistor 21 of DAC-m is Rm.
- the analog output voltage E o can be obtained by Expression (6).
- V is the output voltage of the inverter.
- the analog output is a voltage that is proportional to the number of signals that are "0" of the 1-bit input signal (in other words, the output of the inverter 20 is "1"). The value is to be output.
- Fig. 3 shows an example of DEC.12 in Fig. 1.
- reference numeral 30 denotes a pointer, which outputs the remainder of the accumulated value of the input signal.
- Reference numeral 31 denotes a ROM (read only memory), which is an m-bit data corresponding to an address in which an input signal is lower and an output of the pointer 30 is higher. It outputs the data.
- m 10 (p — 1).
- the pointer 30 accumulates 11-level signals (0 to: L0) output from the NS 11 in FIG. The remainder of 10 is found and output. Therefore, the output becomes 10 from 0 to 9.
- an address in which the input signal is lower and the output signal of the pointer 30 is higher is input to the ROM 31 to obtain 10-bit data.
- This 10-bit data represents 10 1-bit signals.
- Table 3 shows the relationship between the address (expressed in decimal notation for each of the upper and lower digits) and data (10 1-bit signals).
- Lower 0
- 1 2
- Lower 3 Upper data Upper data Upper data Upper data Upper data Upper data Upper data
- Table 3 Explaining in Table 3, the 10-bit data is "1" only as indicated by the numerical value of the input signal immediately below the address. The sum is now equal to the input signal. In addition, the lower part of the address, that is, the value of the output signal of the pointer 30 is shifted to the left as much as the value indicates, and the overflowing digits are circulated so as to appear from the right. Yes.
- ROM 31 As shown in Table 3, data is output as shown in Table 4, for example.
- Table 4 As can be seen from Table 4, only "1" indicated by the numerical value of the input signal is output so as to circulate through the 10-bit data. This indicates that there is no correlation between the input signal value and a specific bit of the 10-bit data. Therefore, even if there is a relative error between the outputs of the 1-bit DZA converter train 13 to which the 10-bit data is connected, the occurrence of distortion and noise in the signal band is reduced. It can be improved.
- the output of the 1-bit D / A converter array 13 is, for example, 1% relative error as shown in Table 5 (the error is distributed evenly in the range of ⁇ 1%).
- Figure 4 shows the results of a simulation in which the output signal spectrum was obtained under the same conditions as in Figure 26. For simplicity, the signal is shown from 0 to 2 fs.
- the output from NS11 provides a dynamic range of more than 120 dB in the signal band of 0 to fs / 2, but in Fig. 4, the dynamic range is approximately It is a dynamic range of 103 dB, and even if there is a relative error (difference from the average value) of as much as 1% at the output of the 1-bit DA converter train 13 Despite this, it can be seen that the performance degradation is slight.
- the output is such that data does not circulate, for example, the output signal spectrum when the output of the pointer 30 is fixed to 0 regardless of the input.
- Figure 5 shows the results obtained by simulation. As can be seen in Fig. 5, the noise increased compared to Fig. 4, harmonic distortion occurred, and the dynamic range deteriorated significantly to about 58 dB. You can see that it is.
- the operation of the pointer 30 is calculated by accumulating the 11-level signals (0 to: L0) output from the NS 11 in FIG. Although it is assumed that the remainder is obtained and output, as another embodiment of the present invention, the operation of the pointer 30 is performed in order of the signals 0 to 9 regardless of the output of the NS 11. It is also acceptable to output repeatedly.
- Figure 6 shows the simulation results of the spectrum of the output signal in this case. As shown in Fig. 6, although the noise is increased compared to Figs. 26 and 4, the harmonic distortion that occurred in Fig. 5 is seen. It has disappeared, and the dynamic range has been improved as compared with FIG. In particular, in this method, the operation of the pointer 30 only repeats and outputs the signals 0 to 9 in order, and the operation of accumulation and remainder is unnecessary. The circuit size of the pointer 30 can be reduced.
- Equation (8) The probability that the number of signals that become “1” in the output of DEC 12 in Fig. 1 becomes 1 is P If the probability of becoming 1 and 2 is P 2, and the probability of becoming m is P m, the effective value ⁇ rms of the relative error included in the analog output is Equation (8) is obtained.
- ⁇ rms 2 ⁇ 1 ⁇ ⁇ ra ⁇ i 2 + ⁇ 2 ⁇ ⁇ ⁇ (- ⁇ i10 ⁇ (i + 1) modlO) 2
- Equation (8) the first term on the right-hand side is due to the relative error of each DAC. Therefore, to reduce this term, the relative error between each DAC must be reduced. However, the second and subsequent terms on the right side are caused by the relative error between the combined DACs when combining and outputting the number of DACs corresponding to the output of DEC12. This term can be made smaller by the combination of DACs. As is clear from equation (4), reduce the second and subsequent terms on the right side For this purpose, the sum of the relative errors of adjacent DACs should be reduced, and for that purpose, the adjacent bits of the output signal sequence of DEC 12 are contradictory. It is sufficient to arrange the DACs so that the DACs that wait for a relative error (a negative error relative to the positive relative error, or vice versa) can be assigned. .
- the output of the 1-bit D / A converter array 13 has a relative error of 1% as shown in Table 6, for example, and the sign of the relative error. Are opposite (plus and minus are alternating) in adjacent DACs, the output signal spectrum is changed under the same conditions as in Figure 4.
- Figure 7 shows the results obtained in the simulation.
- the 1-bit DZA converters of DAC 13 are output to D 1, D 2, D 3, D 4,..., D m, respectively, in order of output level. -3, D m -2, D m-1, D m, the assignment of a 1-bit DZA converter to each bit of the DEC 12 output signal sequence
- D1, Dm-1, D3, Dm-3, ..., D4, Dm-2, D2, Dm may be arranged in this order. According to this array, the output of the 1-bit DZA conversion sequence 13 is as shown in Table 6.
- FIG. 8 is a block diagram showing an embodiment of the D / A converter according to the present invention.
- reference numeral 10 denotes a digital filter (DF), which has the same configuration and function as those shown in FIG.
- Numeral 41 denotes a multi-stage quantized noise sharpener (NS) having a configuration similar to that of NS11 in FIG. 25, but having outputs Y1 and Y as described later. 2 'is output as it is without addition.
- Reference numerals 42 and 43 denote decoders (DEC), and m and DEC 43 correspond to the digital signals output from the NS 41, respectively. Outputs n 1-bit signals.
- 4 4 and 4 5 are a series of A group of 1-bit D / A converters (DACs) in the 1-bit D / A converter train, and 44 are the first DZA converters (DAC-1) to the m-th DZA converters (DAC-1) Up to DAC — m) and 45 are all uniform (m + n) from the first DA converter (DAC-1) to the nth DZA converter (DAC-n). It consists of one 1-bit DZA converter.
- Reference numeral 46 denotes an analog adder which integrates the (m + n) analog signals output from the DACs 44 and 45, and outputs an analog signal. Is output.
- Reference numeral 47 denotes a D / A conversion circuit, which is composed of DACs 44 and 45 and an analog adder 46.
- Fig. 9 shows the configuration of NS41 in Fig. 8 in more detail.
- NS 41 in FIG. 8 has a similar configuration and function to NS 11 in FIG. 25, and includes a primary ⁇ modulator 50 and a secondary ⁇ modulator 5.
- the differentiator 52 is the same, and the description is omitted.
- NS11 in Fig.25 outputs the output Y1 of the primary ⁇ ⁇ modulator 50 and the output Y2 'of the differentiator 52 by the adder 53.
- Y1 and Y2 ' are respectively This is the point that the signals are output independently, and the DZA conversion circuit 47 adds Y1 and Y2 ', as described later.
- the adder 53 can be omitted, and the circuit scale can be reduced.
- FIG. 10 shows an example of the DZA conversion circuit 47 in FIG.
- reference numerals 44 and 45 denote 1-bit DZA converter groups (D AC :), and reference numeral 46 denotes an analog adder, which correspond to FIG. 8, respectively.
- Reference numeral 60 denotes an inverter which inverts and outputs a 1-bit input signal. 6
- a current adding circuit is constituted by the resistors 61 and 62.
- the resistance value of the resistor 61 of the DAC 1 of the DAC 4 4 is R ll
- the resistance value of the resistor 61 of the DAC 2 is R 12,...
- the resistor 6 1 of the DAC m The resistance value of the DAC 45 of DAC 45, the resistance value of the resistor 61 of R1 is R21, the resistance value of the resistor 61 of the DAC 2 is R2,.
- the analog output voltage Eo can be obtained by Expression (9).
- D AC 44 and 45 are all uniform.
- the output of the operational amplifier 63 or the analog output is "0" of the 1-bit input signal (in other words, the output of the inverter 30 is "1" ) That outputs a voltage value that is proportional to the number of signals that
- reference numeral 30 denotes a pointer, which outputs the remainder of the accumulated value of the input signal. It is something.
- Reference numeral 31 denotes a ROM (read-only memory) which has m bits corresponding to an address in which the input signal is at the lower level and the output of the pointer 30 is at the upper level. Outputs n bits of data.
- the difference between DEC 4 2 and 4 3 is due to the difference between m and n, and the principle of operation is basically the same. I will explain only.
- the DEC 4 2 receives 7 levels of signal Y1 (—3 to 13), but for simplicity, add 3 to the signal (0 to 6). I will proceed with the explanation.
- the pointer 30 accumulates the seven-level signal Yl (0 to 6) output from the NS 41 in FIG. Calculate and output the remainder of. Therefore, there are six outputs (0 to 5).
- an address in which the input signal is lower and the output signal of the pointer 30 is higher is input to the ROM 31 to obtain 6-bit data.
- This 6-bit data represents six 1-bit signals.
- Table 7 shows the relationship between the address (10-digit number) and data (6 1-bit signals) at this time.
- the 6-bit data is "1" only as indicated by the numerical value of the input signal at the lower address, and the sum of each bit is the input signal. Are equal to each other.
- the lower part of the address that is, the numerical value of the output signal of the pointer 30 is shifted to the left as much as shown, and the overflowing digits are circulated so as to appear from the right.
- Table 8 As can be seen from Table 8, "1" as indicated by the numerical value of the input signal is output so as to circulate through the 6-bit data. It shows that there is no correlation between the signal value and a specific bit out of the 6-bit data. For this reason, even if there is a relative error between the outputs of each 1-bit D / A converter of DAC 44 to which the 6-bit data is connected respectively, even if there is a relative error in the signal band, The generation of distortion and noise can be reduced.
- the DEC 42 is also described. Even in the case of the DEC 43, the input Y 2 ′ is 5 levels (12 to 12) and the output is 4 bits. Taking these differences into account, they are basically the same.
- the sampling frequency (FS) is 64 fs
- the input signal frequency is about 0.02fs
- the input signal level is OdB.
- the output signal spectrum when the output of 15 has a relative error of 1% as shown in Table 9 (the error is evenly distributed in the range of ⁇ 1%)
- Figure 11 shows the results obtained by simulation.
- Table 9 As shown in Fig. 26, a dynamic range of more than 120 dB can be obtained in the signal band of 0 to fs / 2 with the output from NS1. However, in Fig. 11, the dynamic range is about 104 dB, which is related to the fact that there is a relative error of 1% at the outputs of DACs 44 and 45. It is clear that the performance degradation is small.
- the 1-bit D / A converters in the 1-bit D / A converter array consisting of DACs 44, 45 are arranged in order of output level, and for example, as shown in Table 9. If they are assigned as DACs 44 and 45 in this order, the relative error of the 1-bit D / A converter group in each DAC can be reduced equivalently. Noise can be reduced. In other words, for example, in the case of Table 9, the relative error obtained by combining DACs 44 and 45 is 1%, but the relative error of DAC 44 alone is 0.6% and that of DAC 45 is not. 0.4%.
- NS 41 in FIG. 8 has a two-stage configuration as shown in FIG. 9, the arrangement of DACs 44 and 45 is as shown in Table 10 and each bit D is 1 bit.
- the phase of the noise due to the relative error of the 1-bit D / A converter group in each DAC is Since the probability that the phases become opposite to each other increases and the cases where the phases cancel each other increase, the generation of the noise can be further reduced.
- the sampling frequency (FS) is 64 fs
- the input signal frequency is about 0.02fs
- the input signal level is OdB.
- Figure 12 shows the simulation results of the output signal spectrum when the outputs of 4 and 45 are as shown in Table 10. Show. As shown in Fig. 12, the dynamic range is about 105 dB, and the ldB noise is smaller than in Fig. 11. ing .
- the 1-bit DZA converters of the 1-bit D / A converter array consisting of DACs 44 and 45 are arranged in the order of the output level, for example, as shown in Table 11. With DAC 44 at both ends and DAC 45 at the center If they are assigned, the difference between the average output levels of the DACs can be reduced, and the outputs Y1 and Y2 'of NS41 can be added to obtain the equation (2). Since the cancellation of the term of V ql in the equation (4) and the equation (4) can be realized with high precision, the generation of noise can be reduced.
- a D A C 1 3 1. 0 0 5 0.5
- the sampling frequency (FS) is 64 fs
- the input signal frequency is about 0.02 fs
- the input signal level is OdB.
- Figure 13 shows the simulation results of the output signal spectrum when the outputs of 4 and 45 are as shown in Table 11. Show. As shown in Fig. 13, the dynamic range is about 106 dB, and the noise is about 2 dB better than in Fig. 11. Is getting smaller.
- the sampling frequency (FS) is 64 fs
- the input signal frequency is about 0.02 fs
- the input signal level is OdB
- the DAC 44 Figure 14 shows the simulation results of the output signal spectrum when the output of 45 is as shown in Table 12.
- the dynamic range is about 106 dB
- the noise is about 2 dB smaller than in Fig. 11. ing .
- a D A C 1 3 1. 0 0 5 0.5
- the DZA converter is configured as described above.
- NS11 and NS41 used the ones represented by the formula (1), but if they function as noise shielders, they differ. It goes without saying that the degree and characteristics may be different.
- the configuration of DEC 12 shown in FIG. 3 and the ROM data in Table 1 are only examples for explanation, and are not limited to them.
- the number m of output bits of DEC 12 that is, the number m of 1-bit DZA converters 13
- m may be a larger number depending on the circuit configuration and the like. .
- FIG. 15 is a block diagram showing an embodiment of the A / D conversion device according to the present invention.
- reference numeral 70 denotes a subtracter
- 71 denotes an integrator
- 72 denotes a quantizer, each having the same configuration and function as those shown in FIG.
- Reference numeral 73 denotes a DZA converter, which converts the output of the quantizer 72 into an analog signal.
- the output of the D / A converter 73 is input to the subtraction terminal of the subtractor 70.
- Reference numeral 76 denotes an analog adder, which integrates the three analog signals output from the 1-bit D / A converter train 75 to form an analog signal. Output.
- the AZD converter in Fig. 15 is known as a noise-sharing AZD converter with primary characteristics, and the output Y for the input X is as shown in Fig. 27. Similarly, it is expressed by equation (5).
- FIG. 16 shows an example of a specific circuit of the DZA converter 73 in FIG.
- the D / A converter 73, the decoder 74, the 1-bit D / A converter train 75, and the analog adder 76 are shown in FIG. 15 respectively. Yes, it is.
- Reference numeral 80 denotes an inverter, which inverts and outputs a 1-bit input signal.
- Reference numerals 81 and 82 denote resistors, and reference numeral 83 denotes an operational amplifier (operational amplifier). To explain the operation of FIG. 16, first, the non-inverting input terminal of the operational amplifier 83 is grounded, and the inverting input terminal is a virtual ground point.
- All the 1-bit input signals are connected to the inverting input terminal of the operational amplifier 83 via an inverter 80 and a resistor 81, and further connected to a resistor 82 Is connected to the output terminal of the operational amplifier 23 through the terminal. That is, the current adding circuit is constituted by the resistors 81 and 82.
- the resistor value of resistor 81 of DAC-1 is R1
- the resistor value of resistor 81 of DAC-2 is R2
- the resistor value of resistor 81 of DAC-3 is R3.
- the analog output voltage Eo can be obtained by equation (10).
- the output of the analog output 3 is immediately “0" of the 1-bit signal output from the decoder 74 (the output of the inverter 20 is immediately “1"). ) to you output a voltage value proportional to the number of signals that have Tsu name that not even the name of the 0
- FIG. 3 shows an example of the decoder 74 shown in FIG.
- reference numeral 30 denotes a pointer, which outputs the remainder of the accumulated value of the input signal.
- 31 is R0M (read-only memory), which is a 3-bit address corresponding to an address in which the input signal is lower and the output of the pointer 30 is higher. It outputs data.
- the pointer 30 is an input signal, that is, a two-bit signal output from the quantizer 72 of FIG. 15.
- Table 13 To explain Table 13, the 3-bit data is lower than the address, that is, the number indicated by the numerical value of the input signal. Only “1" is set, and the sum of each bit is equal to the input signal. In addition, the lower part of the address, that is, the value of the output signal of the pointer 30 is shifted to the left as much as indicated, and the overflowing digits are circulated so as to appear from the right. Yes.
- ROM 31 As shown in Table 13, for example, data is output as shown in Table 14. Input signal Pointer 30 output signal RO M31 output signal Time
- Table 14 As can be seen from Table 14, only "1" indicated by the numerical value of the input signal is output so as to go around the 3-bit data. This indicates that there is no correlation between the numerical value of the input signal and a specific bit of the 3-bit data. For this reason, even if there is a relative error in the output of the 1-bit DZA converter 15 to which the 3-bit data is connected respectively, distortion and noise in the signal band can be obtained. Can be reduced.
- the sampling frequency (FS) is 64 fs
- the input signal frequency is about 0.02 fs
- the input signal level is 0 dB.
- Table 15 shows the output of DZA converter train 15
- Figure 17 shows the simulation result of the output signal spectrum when the relative error is 3% as shown in the figure. For simplicity, the signal is shown from 0 to 2 fs.
- the operation of the pointer 30 is described by accumulating the two-bit signals (“00” to “11”) output from the quantizer 72 in FIG. Although it is assumed that the remainder of the arithmetic operation 3 is obtained and output, as another embodiment of the present invention, the operation of the pointer 30 is performed independently of the output of the quantizer 72.
- the signal of 0 to 2 may be repeated and output in order.
- Figure 18 shows the results of a simulation of the output signal spectrum obtained in this case under the same conditions as in Figure 17. As shown in Fig. 18, although the noise increased compared to Fig. 17, the harmonic distortion that occurred in Fig. 29 was not seen. The dynamic range has also been improved to about 54 dB.
- the operation of the pointer 30 merely repeats and outputs the signals of 0 to 2 in order, and the operation of the accumulation and the remainder is unnecessary, so that the void operation is not required.
- the circuit scale of the data 30 can be reduced.
- FIG. 19 is a block diagram showing another embodiment of the AZD converter according to the present invention.
- 70 is a subtractor
- 71 is an integrator
- ⁇ 2 is a quantizer
- 73 is a DZA converter, which are the same as those shown in FIG. 15.
- Reference numeral 77 denotes a subtractor
- reference numeral 78 denotes an integrator, which have the same configuration and function as the subtractor 70 and the integrator 71, respectively.
- Fig. 19 an analog input from the outside is input to the addition terminal of the subtractor 77, and the analog signal output from the subtracter 77 is The output is accumulated by the integrator 78, and is further input to the addition terminal of the subtractor 70. Subsequently, the analog signal output from the subtractor 70 is accumulated by the integrator 71 and output, and the output is output from the analog signal by the quantizer 72. The digital signal is converted into a digital signal and becomes a digital output. The digital output is also input to the DA converter 73, converted into an analog signal, and input to the subtractor 77 and the subtraction terminal of the subtractor 70. It has been done.
- the AZD converter shown in Fig. 19 is known as a noise-swinging AZD converter with a quadratic characteristic, and the output Y with respect to the input X is expressed by the formula ( It is represented by 1 1).
- V q is the quantization error of the quantizer 7 2
- Fig. 20 shows the results obtained by computer simulation of the output signal spectrum in this case. For the sake of simplicity, the bandwidth from 0 to 2 fs is shown. As shown in Fig. 20, a dynamic range (D.R.) of about 83 dB can be obtained in the signal band of 0 to fs / 2.
- D.R. dynamic range
- the DZA converter 73 is equivalent to the DZA converter 73 of FIG. 15 and the input / output relationship of the ROM 31 of the decoder 74 is shown.
- Table 13 if the output of the 1-bit D / A converter train 75 has a relative error of 3% as shown in Table 15, the output signal spectrum is The room should look like Figure 22. For simplicity, signals from 0 to 2 fs are shown here. As shown in Figure 22, the dynamic range is about 83 dB, which is related to the fact that there is a relative error of 3% at the output of the DZA converter train 75. It can be seen that the performance degradation was slight.
- the DZA converter 73 of FIG. 19 is also similar to the D / A converter 73 of FIG.
- the operation of the interface 30 may be such that the signals of 0 to 2 are repeatedly output in order without depending on the output of the quantizer 72.
- Figure 23 shows the simulation results of the output signal spectrum in this case. As shown in Fig. 23, although the noise increased compared to Fig. 22, the harmonic distortion that occurred in Fig. 21 was observed. It has disappeared, and the dynamic range has been improved to about 56 dB.
- the AZD converter has been described in FIGS. 15 and 19, it may have a different configuration as long as it has the same functions and characteristics.
- a device that simultaneously performs the operations of the subtractor 70 and the integrator 71 may be used.
- the configuration of the decoder 74 shown in FIG. 3 and the ROM data in Table 13 are only examples for explanation, and are not limited to this. No.
- the output of the decoder 74 is connected to the p-th output of the quantizer 72.
- the number of bits that is, the number of 1-bit DZA converters 15
- P-1 the number of 1-bit DZA converters 15
- the circuit The number may be more than this depending on the configuration and the like.
- the sampling frequency at the time of DZA conversion is the sampling frequency of the digital output of the noise sweeper.
- the wave number it has an excellent feature that it can operate with much lower power than PWM.
- the decoder is assigned to circulate the output of the noise generator, 'to a plurality of 1-bit DZA converters. There is no correlation between the output value of the noise shaper and a specific 1-bit DZA converter, and even if there is a relative error in the output between each 1-bit DZA converter, the signal It has an excellent feature that it can reduce the occurrence of distortion and noise in the band.
- the DZA converter is the DZA converter of the present invention
- the output of the 1-bit DZA converter in the DZA converter has a relative error. Even in this case, the generation of distortion noise in the signal band can be reduced, and therefore, the DZA conversion circuit does not require a high-precision device and can be easily manufactured. It has the excellent feature that a high-precision AZD converter can be realized.
- the AZD conversion device of the present invention can further improve the AZD conversion accuracy by using a noise-shaping AD converter having a secondary characteristic.
- a noise-shaping AD converter having a secondary characteristic In this case, 1-bit DA converter 15 The effect of reducing the occurrence of distortion noise in the signal band with respect to the relative error existing at the output of the multiplexing device becomes even more remarkable.
- a lower sampling frequency is required in order to obtain AZD conversion accuracy equivalent to that of the first-order noise-single type AZD converter. It is possible to make a new device.
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP93910410A EP0597123A4 (en) | 1992-06-01 | 1993-05-28 | DIGITAL-ANALOG CONVERTER AND ANALOG-DIGITAL CONVERTER. |
US08/185,876 US5539403A (en) | 1992-06-01 | 1993-05-28 | D/A conversion apparatus and A/D conversion apparatus |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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JP4140223A JP2822776B2 (ja) | 1992-06-01 | 1992-06-01 | D/a変換装置 |
JP4/140223 | 1992-06-01 | ||
JP5/33051 | 1993-02-23 | ||
JP03305193A JP3151992B2 (ja) | 1993-02-23 | 1993-02-23 | A/d変換装置 |
Publications (1)
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WO1993025006A1 true WO1993025006A1 (en) | 1993-12-09 |
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PCT/JP1993/000717 WO1993025006A1 (en) | 1992-06-01 | 1993-05-28 | D/a converter and a/d converter |
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US (1) | US5539403A (ja) |
WO (1) | WO1993025006A1 (ja) |
Families Citing this family (23)
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US5786951A (en) * | 1996-06-05 | 1998-07-28 | Cirrus Logic, Inc. | Sampled amplitude read channel employing a discrete time noise generator for calibration |
US5933453A (en) * | 1997-04-29 | 1999-08-03 | Hewlett-Packard Company | Delta-sigma pulse width modulator control circuit |
US5901176A (en) * | 1997-04-29 | 1999-05-04 | Hewlett-Packard Company | Delta-sigma pulse width modulator control circuit |
JP3457517B2 (ja) | 1997-09-12 | 2003-10-20 | 松下電器産業株式会社 | D/a変換装置 |
US6204788B1 (en) * | 1998-08-25 | 2001-03-20 | Matsushita Electric Industrial Co., Ltd. | Digital/analog conversion apparatus |
US6150970A (en) * | 1999-03-01 | 2000-11-21 | Sony Corporation | Method and system for digital to analog conversion |
US6441761B1 (en) * | 1999-12-08 | 2002-08-27 | Texas Instruments Incorporated | High speed, high resolution digital-to-analog converter with off-line sigma delta conversion and storage |
DE19960560B4 (de) * | 1999-12-15 | 2006-12-14 | Siemens Ag | Verfahren und System zum Übertragen eines Meßwertes zu einer Steuereinrichtung, die mit einem Integral des Meßwertes arbeitet |
JP3725001B2 (ja) | 2000-03-28 | 2005-12-07 | 株式会社東芝 | 選択回路、d/a変換器及びa/d変換器 |
US6775529B1 (en) | 2000-07-31 | 2004-08-10 | Marvell International Ltd. | Active resistive summer for a transformer hybrid |
US7194037B1 (en) | 2000-05-23 | 2007-03-20 | Marvell International Ltd. | Active replica transformer hybrid |
USRE41831E1 (en) | 2000-05-23 | 2010-10-19 | Marvell International Ltd. | Class B driver |
US7433665B1 (en) | 2000-07-31 | 2008-10-07 | Marvell International Ltd. | Apparatus and method for converting single-ended signals to a differential signal, and transceiver employing same |
US7113121B1 (en) | 2000-05-23 | 2006-09-26 | Marvell International Ltd. | Communication driver |
US6462688B1 (en) | 2000-12-18 | 2002-10-08 | Marvell International, Ltd. | Direct drive programmable high speed power digital-to-analog converter |
US7312739B1 (en) | 2000-05-23 | 2007-12-25 | Marvell International Ltd. | Communication driver |
US7606547B1 (en) | 2000-07-31 | 2009-10-20 | Marvell International Ltd. | Active resistance summer for a transformer hybrid |
US6489908B2 (en) * | 2001-04-30 | 2002-12-03 | Texas Instruments Incorporated | Wireless local loop terminal and system having high speed, high resolution, digital-to-analog converter with off-line sigma-delta conversion and storage |
US6853325B2 (en) * | 2002-12-27 | 2005-02-08 | Renesas Technology Corp. | Pulse width modulation digital amplifier |
US7312662B1 (en) | 2005-08-09 | 2007-12-25 | Marvell International Ltd. | Cascode gain boosting system and method for a transmitter |
US7577892B1 (en) | 2005-08-25 | 2009-08-18 | Marvell International Ltd | High speed iterative decoder |
CN103828241B (zh) | 2011-09-20 | 2016-08-31 | 松下知识产权经营株式会社 | Da变换装置以及声音系统 |
JP6792137B2 (ja) * | 2016-03-03 | 2020-11-25 | ミツミ電機株式会社 | D/a変換器、及びa/d変換器 |
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JPH0319524A (ja) * | 1989-06-16 | 1991-01-28 | Matsushita Electric Ind Co Ltd | ディジタル・アナログ変換器 |
JPH03143026A (ja) * | 1989-10-27 | 1991-06-18 | Nec Corp | ディジタル―アナログ変換器 |
JPH0472820A (ja) * | 1990-07-12 | 1992-03-06 | Matsushita Electric Ind Co Ltd | 電流源回路 |
JPH04152715A (ja) * | 1990-10-16 | 1992-05-26 | Toshiba Corp | ディジタル・アナログ変換器 |
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US4414641A (en) * | 1981-06-01 | 1983-11-08 | The United States Of America As Represented By The Secretary Of The Navy | Digital m of n correlation device having increased bit rate |
JPH05347563A (ja) * | 1992-06-12 | 1993-12-27 | Sony Corp | D/a変換装置 |
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1993
- 1993-05-28 WO PCT/JP1993/000717 patent/WO1993025006A1/ja not_active Application Discontinuation
- 1993-05-28 US US08/185,876 patent/US5539403A/en not_active Expired - Lifetime
Patent Citations (4)
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JPH0319524A (ja) * | 1989-06-16 | 1991-01-28 | Matsushita Electric Ind Co Ltd | ディジタル・アナログ変換器 |
JPH03143026A (ja) * | 1989-10-27 | 1991-06-18 | Nec Corp | ディジタル―アナログ変換器 |
JPH0472820A (ja) * | 1990-07-12 | 1992-03-06 | Matsushita Electric Ind Co Ltd | 電流源回路 |
JPH04152715A (ja) * | 1990-10-16 | 1992-05-26 | Toshiba Corp | ディジタル・アナログ変換器 |
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