Results 1  10
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16
Spectral Shaping of Circuit Errors in DigitaltoAnalog Converters
, 1997
"... Recently, various multibit noiseshaping digitaltoanalog converters (DAC's) have been proposed that use digital signal processing techniques to cause the DAC noise arising from analog component mismatches to be spectrally shaped. Such DAC's have the potential to significantly increase the present p ..."
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Cited by 43 (19 self)
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Recently, various multibit noiseshaping digitaltoanalog converters (DAC's) have been proposed that use digital signal processing techniques to cause the DAC noise arising from analog component mismatches to be spectrally shaped. Such DAC's have the potential to significantly increase the present precision limits of 16 data converters by eliminating the need for onebit quantization in deltasigma modulators. This paper extends the practicality of the noiseshaping DAC approach by presenting a general noiseshaping DAC architecture along with two specialcase configurations that achieve first and secondorder noiseshaping, respectively. The secondorder DAC configuration, in particular, is the least complex of those currently known to the author. Additionally, the paper provides a rigorous explanation of the apparent paradox of how the DAC noise can be spectrally shaped even though the sources of the DAC noisethe errors introduced by the analog circuitryare not known to the ...
A 12mW ADC DeltaSigma Modulator with 80 dB of Dynamic Range Integrated in a SingleChip Bluetooth Transceiver
, 2002
"... This paper presents a switchedcapacitor multibit ADC deltasigma modulator for baseband demodulation integrated in a singlechip Bluetooth radiomodem transceiver that achieves 77 dB of signaltonoiseplusdistortion ratio (SINAD) and 80 dB of dynamic range over a 500kHz bandwidth with a 32MHz ..."
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Cited by 11 (6 self)
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This paper presents a switchedcapacitor multibit ADC deltasigma modulator for baseband demodulation integrated in a singlechip Bluetooth radiomodem transceiver that achieves 77 dB of signaltonoiseplusdistortion ratio (SINAD) and 80 dB of dynamic range over a 500kHz bandwidth with a 32MHz sample rate. The 1mm 2 circuit is implemented in a 0.35 m BiCMOS SOI process and consumes 4.4 mA of current from a 2.7V supply.
An approach to tackle quantization noise folding in doublesampling 61 modulation A/D converters
 IEEE Trans. Circuits Syst. II
, 2003
"... Abstract—61modulation is a proven method to realize high and very highresolution analogtodigital converters. A particularly efficient way to implement such a modulator uses doublesampling where the circuit operates during both clock phases of the masterclock. Hence, the sampling frequency is ..."
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Cited by 5 (4 self)
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Abstract—61modulation is a proven method to realize high and very highresolution analogtodigital converters. A particularly efficient way to implement such a modulator uses doublesampling where the circuit operates during both clock phases of the masterclock. Hence, the sampling frequency is twice the masterclock frequency. Unfortunately, path mismatch between both sampling branches causes a part of the quantization noise to fold from the Nyquist frequency back in the signal band. Therefore, the performance is severely degraded. In this paper, we show that the problem is reduced but not eliminated by employing multibit quantization. Next, we present an indepth solution for the problem. The approach consists of modifying the quantization noise transfer function of the overall modulator to have one or several zeros at the Nyquist frequency. This way the effect of noise folding can nearly be eliminated. It is shown that this can be implemented by a simple modification of one of the integrators of the overall modulator circuit. Finally, several design examples of singlebit and multibit modulators are discussed. Index Terms—Analogtodigital conversion, doublesampling, spectral shaping.
Quadrature Mismatch Shaping for DigitaltoAnalog Converters
"... Abstract—Quadrature sigma–delta analogtodigital converters require a feedback path for both the I and the Q parts of the complex feedback signal. If two separate multibit feedback digitaltoanalog converters (DACs) are used, mismatch among the unit DAC elements leads to additional mismatch noise i ..."
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Cited by 3 (0 self)
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Abstract—Quadrature sigma–delta analogtodigital converters require a feedback path for both the I and the Q parts of the complex feedback signal. If two separate multibit feedback digitaltoanalog converters (DACs) are used, mismatch among the unit DAC elements leads to additional mismatch noise in the output spectrum as well as an I/Q imbalance. This paper proposes new quadrature bandpass (QBP) mismatch shaping techniques. In our approach, the I and Q DACs are merged into one complex DAC, which leads to nearperfect I/Q balance. To select the unit DAC elements of the complex multibit DAC, the wellknown butterfly shuffler and tree structure are generalized towards a complex structure, and necessary constraints for their correct functioning are derived. Next, a very efficient firstorder QBP shaper implementation is proposed. Finally, the newly presented complex structures are simulated to prove their effectiveness and are compared with each other with respect to performance. Index Terms—Butterfly shuffler, mismatch shaping, quadrature bandpass (QBP), treestructured, 61 analogtodigital converters (ADCs). I.
0 Systematic Approach for Scaling Coefficients of DiscreteTime and ContinuousTime SigmaDelta Modulators
"... —In this paper we present a systematic method to scale the integrators output swings of modulator. It is shown that this scaling method preserves both the Noise Transfer Function and the Signal Transfer Function of the modulator. Examples are given to illustrate the effectiveness of the proposed met ..."
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Cited by 3 (3 self)
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—In this paper we present a systematic method to scale the integrators output swings of modulator. It is shown that this scaling method preserves both the Noise Transfer Function and the Signal Transfer Function of the modulator. Examples are given to illustrate the effectiveness of the proposed method to alleviate circuit nonidealities.
Design of doublesampling 61 modulation A/D converters with bilinear integrators
 IEEE Trans. Circuits Syst. I, Reg. Papers
, 2005
"... Abstract—Doublesampling techniques allow to double the sampling frequency of a switched capacitor 61 analogtodigital convertors without increasing the clock frequency. Unfortunately, path mismatch between the double sampling branches may cause noise folding, which could ruin the modulator’s perfo ..."
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Cited by 2 (2 self)
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Abstract—Doublesampling techniques allow to double the sampling frequency of a switched capacitor 61 analogtodigital convertors without increasing the clock frequency. Unfortunately, path mismatch between the double sampling branches may cause noise folding, which could ruin the modulator’s performance. The fully floating doublesampling integrator is an interesting building block to be used in such a double sampling 61 modulator because its operation is tolerant to path mismatch. However, this circuit exhibits an undesired bilinear filter effect. This effectively increases the order of the modulator by one. Due to this, previously presented structures don’t have enough freedom to fully control the modulator pole positions. In this paper, we introduce modified topologies for doublesampling 61 modulators built with bilinear integrators. We show that these architectures provide full control of the modulator pole positions and hence can be used to implement any noise transfer function. Additionally, analytical expressions are obtained for the residual folded noise. Index Terms—Analogtodigital convertors, double sampling, 61 modulation. I.
Systematic design of doublesampling 61 A/D converters with a modified noise transfer function
 IEEE Trans. Circuits Syst. II, Exp. Briefs
, 2004
"... (ADCs) are sensitive to path mismatch which causes quantization noise to fold into the signal band. A recent solution for this problem consists of modifying the noise transfer function (NTF) of the modulator such that it has one or several zeros at the Nyquist frequency, next to those in the baseban ..."
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Cited by 2 (2 self)
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(ADCs) are sensitive to path mismatch which causes quantization noise to fold into the signal band. A recent solution for this problem consists of modifying the noise transfer function (NTF) of the modulator such that it has one or several zeros at the Nyquist frequency, next to those in the baseband. In this brief, we present a systematic design strategy for such ADCs. It consists of finding optimal pole positions for the modified NTF. This can be combined with optimizing the zeros as well. Next, we introduce several efficient structures that have enough degrees of freedom to realize the optimized pole positions. Index Terms—Analog–digital (A/D) conversion, double sampling, sigma–delta 61 modulation. I.
Stable HighOrder DeltaSigma DACs
, 2003
"... Stability analysis of highorder deltasigma loops is a challenge. In this brief, a sufficient design criterion is presented for highorder multibit errorfeedback DACs which are especially suitable for highspeed operation. This analytical criterion might be too conservative, but it allows the desig ..."
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Cited by 1 (1 self)
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Stability analysis of highorder deltasigma loops is a challenge. In this brief, a sufficient design criterion is presented for highorder multibit errorfeedback DACs which are especially suitable for highspeed operation. This analytical criterion might be too conservative, but it allows the design of stable, robust, and highresolution deltasigma DACs. Both analytical and numerical analysis are performed for verification. Also, experimental results of a discretecomponent multiplierfree prototype demonstrate 10bit operation at a very low oversampling ratio of 4.
Mismatch Insensitive DoubleSampling Quadrature Bandpass 61 Modulation
"... Abstract—In a doublesampling quadrature bandpass sigma– delta modulator, path mismatch between the doublesampling branches and between the I/Q paths occurs. In this paper, an analytical study is presented which shows that this causes quantization noise and input signals to fold from the image band ..."
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Cited by 1 (1 self)
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Abstract—In a doublesampling quadrature bandpass sigma– delta modulator, path mismatch between the doublesampling branches and between the I/Q paths occurs. In this paper, an analytical study is presented which shows that this causes quantization noise and input signals to fold from the image band into the signal band and that this also results in a selfimage component. To reduce the folding from the image band, a novel resonator is presented. This resonator has a bilinear input circuit so that noise and signals exhibits firstorder shaping before folding in the band of interest. Next, three different modulator architectures based on the novel resonator are introduced. Finally, the remaining problem of selfimage is tackled with a simple, yet efficient offline calibration strategy. Various design examples are shown and simulated to illustrate and prove the effectiveness of the proposed architectures and methods. Index Terms—Analogtodigital (A/D) conversion, bilinear circuits, double sampling, sigma–delta (61 modulation. I.
Design Guide of HighOrder DeltaSigma Modulators  an Empirical Study
, 2002
"... Highorder deltasigma ADCs suffer from stability problems for large input signals. On the other hand, they provide potential solutions for a large range of applications. Here, their design is revisited in a tutorial manner in order to identify the best achievable signaltonoise ratio for a given l ..."
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Highorder deltasigma ADCs suffer from stability problems for large input signals. On the other hand, they provide potential solutions for a large range of applications. Here, their design is revisited in a tutorial manner in order to identify the best achievable signaltonoise ratio for a given loopfilter order, internalquantizer resolution, and oversampling ratio.