Author

# Z. Czarnul

Bio: Z. Czarnul is an academic researcher from Oregon State University. The author has contributed to research in topics: Delta-sigma modulation & Noise shaping. The author has an hindex of 3, co-authored 5 publications receiving 30 citations.

##### Papers

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TL;DR: The concept of an N-path bandpass Delta Sigma A/D convertor with multibit sixth-order SC implementation and the new scheme appears to be very effective for the realization of the narrowband bandpass delta-sigma modulators needed for communication applications.

Abstract: The concept of an N-path bandpass Delta Sigma A/D convertor is introduced. A multibit sixth-order SC implementation is described. The new scheme appears to be very effective for the realization of the narrowband bandpass delta-sigma modulators needed for communication applications.

12 citations

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TL;DR: In this article, a pseudo-N-path (PNP) switched-capacitor (SC) integrator structure which avoids noise peaks in the main passband is described.

Abstract: Novel pseudo-N-path (PNP) switched-capacitor (SC) integrator structures which avoid noise peaks in the main passband are described. They combine the simplicity of the previously proposed RAM-type PNP SC circuits with the desirable properties of hybrid-type circuits. Simulation results are presented for filters employing these structures to verify their usefulness.

9 citations

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TL;DR: In this paper, a method for realising linear resistors and inductors based on a current inversion-type negative impedance convertor (NIC) using MOSFETs in the nonsaturation region is proposed.

Abstract: A novel method is proposed for realising linear resistors and inductors based on a current inversion-type negative impedance convertor (NIC) using MOSFETs in the nonsaturation region. Its application to continuous-time filters is also presented.

6 citations

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10 May 1992TL;DR: In this paper, two multiplexed delta-sigma modulator (Delta Sigma M) structures are described which achieve higher performance by increasing the oversampling frequency instead of increasing the over-sampling ratio.

Abstract: Two novel multiplexed delta-sigma modulator ( Delta Sigma M) structures are described which achieve higher performance by increasing the oversampling frequency. For a fixed amount of hardware, instead of increasing the oversampling ratio, it is preferable to use the multiplexing techniques to improve the obtainable signal-to-noise (SNR) performance of a delta-sigma modulator. Some of the resulting structures also offer the advantage of guaranteed stability for the same SNR performance which can also be provided by increasing the order of the modulator. This study illustrates an effective way of exchanging speed for higher conversion accuracy. >

2 citations

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TL;DR: In this paper, a new structure for realizing a multiplexed noise-shaping A/D convertor is proposed, which employs additional feedback paths for suppressing the quantizer error.

Abstract: A new structure for realizing a multiplexed noise-shaping A/D convertor is proposed. It improves the performance of first- or second-order Delta-Sigma modulators by employing additional feedback paths for suppressing the quantizer error. The structure, its theoretical analysis, and simulations confirming the improved resolution are presented.

1 citations

##### Cited by

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TL;DR: The architecture and performance of an interpolative bandpass A/D converter (ADC) and digital quadrature demodulator dedicated for digital narrowband transmission systems, like the cellular radio mobile receiver, are presented.

Abstract: The architecture and performance of an interpolative bandpass A/D converter (ADC) and digital quadrature demodulator dedicated for digital narrowband transmission systems, like the cellular radio mobile receiver, are presented. A prototype version has been implemented on a 1.2- mu m/7-GHz BiCMOS analog/digital array. A bandpass signal centered at 6.5 MHz with 200-kHz bandwidth is demodulated and converted with a 55-dB signal-to-noise ratio giving 9-b performance. >

67 citations

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General Electric

^{1}TL;DR: In this paper, an architecture for oversampled delta-sigma (Δ--Σ) analog-to-digital (A/D) conversion of high-frequency, narrow-band signals includes multistage Δ-Σ modulators that incorporate band-reject noise shaping centered at an arbitrary center frequency F bp.

Abstract: An architecture for oversampled delta-sigma (Δ--Σ) analog-to-digital (A/D) conversion of high-frequency, narrow-band signals includes multistage Δ--Σ modulators that incorporate band-reject noise shaping centered at an arbitrary center frequency F bp . These modulators cascaded with a bandpass digital filter centered at the arbitrary center frequency F bp perform A/D conversion for high-frequency, narrow-band signals having the same arbitrary frequency. The bandpass modulators are implemented by use of resonators which provide a substantially large gain at the arbitrary frequency.

59 citations

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General Electric

^{1}TL;DR: In this article, an architecture for oversampled delta-sigma (Δ-Σ) analog-to-digital (A/D) conversion of high-frequency, narrow-band signals includes multistage modulators that incorporate band-reject noise shaping centered at one fourth the clock frequency Fs.

Abstract: An architecture for oversampled delta-sigma (Δ-Σ) analog-to-digital (A/D) conversion of high-frequency, narrow-band signals includes multistage Δ-Σ modulators that incorporate band-reject noise shaping centered at one fourth the clock frequency Fs. These modulators cascaded with a bandpass digital filter also centered at a frequency of Fs/4 perform A/D conversion for high-frequency, narrow-band signals centered at the same frequency. The bandpass modulators are implemented by use of resonators in existing low-pass multistage modulators.

55 citations

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10 May 1992TL;DR: System-level simulations showed that this modulator promises a 94-dB SNR as long as the DAC (digital-to-analog converter) linearity is at least 8 b, and so a gain-compensated version of one of them is presented.

Abstract: Simulation results on two switched-capacitor circuits suitable for use in a multi bit bandpass sigma-delta modulator are presented. The circuits use the N-path technique to guarantee accurate placement of the noise-transfer-function zeros. A 6th-order multibit bandpass analog-to-digital converter with a sampling frequency which is four times the center frequency and with a 5.5% bandwidth relative to the center frequency (the oversampling ratio equals 36) is described as a design example. System-level simulations, reported earlier, showed that this modulator promises a 94-dB SNR as long as the DAC (digital-to-analog converter) linearity is at least 8 b. The simulation results presented show that, in order to achieve this level of performance, the integrator circuits require high op-amp gain, and so a gain-compensated version of one of them is presented. The improved circuit requires an op-amp gain of 54 dB to achieve a modulator SNR of 90 dB. >

41 citations

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30 May 1994TL;DR: This paper describes a method of digitizing a wide-band signal by performing subband decomposition via a bank of tuned bandpass sigma-delta modulators, increasing the effective oversampling ratio for the wide- band signal by the number of parallel modulators.

Abstract: This paper describes a method of digitizing a wide-band signal by performing subband decomposition via a bank of tuned bandpass sigma-delta modulators. Each modulator only converts a portion of the signal spectrum, increasing the effective oversampling ratio for the wide-band signal by the number of parallel modulators. A prototype bandpass /spl Sigma//spl Delta/ modulator with a programmable noise null was fabricated in a 2 /spl mu/m CMOS process and used to construct a four channel parallel A/D conversion system. >

34 citations