In this paper, a complete high-speed Continuous-Time Bandpass Delta-Sigma modulator for digital receiver applications is modeled, using VHDL-AMS. The main Continuous-Time DeltaSigma modulator’s nonidealities such as excess loop delay, clock jitter and multi-bit feedback DAC element mismatch in the modulator loop are also modeled and their effects evaluated. An accurate understanding of these no...

Higher order delta-sigma (∆Σ) modulator with one bit quantizer is known as one of the easiest method to gain a high resolution A/D converter without the need of accurately matched components. However, stability of higher order ∆Σ modulator is still a problem during the design and implementation process. Stabilizing higher order modulator requires the proper choice of integrator gains. In this p...

Mats Høvin1, Alf Olsen2, Tor Sverre Lande1 and Chris Toumazou3 1Dept. of Informatics, University of Oslo, Blindern, N-0316 Oslo, Norway 2Schlumberger Geco-Prackla, Jongsåsveien 4, N-1300 Sandvika, Norway 3Dept. of Electrical & Electronic Engineering, Imperial College, Exhibition Road, London SW7 2BT, UK Abstract— This paper describes a new first and secondorder delta-sigma modulator (DSM) conce...

In this paper, a alternative structure method for continuous time sigma delta modulator is presented. In this modulator for implementation of integrators in loop filter second generation current conveyors are employed. The modulator is designed in CMOS technology and features low power consumption (<2.8mW), low supply voltage (±1.65), wide dynamic range (>65db), and with 180khZ bandwidth. Simul...

This paper presents the design of a second-order Sigma-Delta modulator for digital audio. This modulator has been designed at 3 V power supply with oversampling ratio of 256 and simulated in a 0.6 μm CMOS technology. The simulated results give SNDR of 96 dB for a 24 KHz signal bandwidth. The sampling frequency is 12.288 MHz and the Nyquist rate of the modulator is 48 KHz.

An efficient means for constructing a narrow bandpass filter for an analogto-digital converter based on a bandpass sigma-delta modulator is presented. It is shown that the filter can be made with very simple hardware, comparable to that required by an analog-to-digital converter using standard lowpass sigma-delta modulation. Introduction Bandpass sigma-delta modulation [1] is a variant of the m...

Abstract This paper presents a design of a switched-capacitor discrete time 1st order Delta-Sigma modulator used for a resolution of 8 bits Sigma-Delta analog to digital converter. For lower power consumption, the use of operational transconductance amplifier is necessary in order to provide wide output voltage swing and moderate DC gain. Simulation results showed that with 0.35um CMOS technolo...

An adaptive delta-sigma modulator of 1st order with one-bit quantization is presented. Adaptation is instantaneous and based on an exponential law. The feedback signal is a multibit discrete-level signal generated by a digital-to-analog converter (DAC). Compared to a nonadaptive delta-sigma modulator of 1st order, the input dynamic range is significantly enhanced. The gain in dynamic range is 6...

This paper discusses issues concerning the design of cascade sigma-delta modulators intended for multistandard wireless receivers. Four standards are covered: GSM, Bluetooth, UMTS, and WLAN. A top-down design methodology is proposed to find out the optimum modulator topology in terms of circuit complexity and reconfiguration parameters. Several reconfiguration strategies are adopted at both arc...

This work proposes a novel structure for adaptive sigma delta modulation that leads to considerable improvement in the dynamic range of the modulator. The quantizer step-size is adapted based on estimates of the input signal to the quantizer block rather than on estimates of the input signal to the modulator itself, as is common in current schemes. The proposed structure can be implemented rath...