This paper proposes a new stable design strategy for 1bit high order digital ∆Σ modulator for multistandard fractionalN frequency synthesizer. The proposed digital ∆Σ modulator presents simplicity, low power consumption and controls a dualmodulus divider instead of multi-modulus one as in existing ∆Σ fractional-N frequency synthesizer. Simulation results illustrate the ∆Σ modulator good perform...

There is significant current interest in spintronic devices fashioned after a spin analog of the electro-optic modulator proposed by Datta and Das [Appl. Phys. Lett., 56, 665 (1990)]. In their modulator, the “modulation” of the spin polarized current is carried out by tuning the Rashba spin-orbit interaction with a gate voltage. Here, we propose an analogous modulator where the modulation is ca...

In this paper, a new approach to optimize a sigma-delta modulator has been presented. This last became the most popular tools in analog-to-digital conversion application. Sigma delta modulator will be the most suitable choice for multistandard system reception. We proposed to add dither before the quantizer of sigma-delta modulator in order to eliminate any distortions introduced by the quantiz...

In current scenario highresolutionADC architecture based on a resetting modulator required high gain operational Transcoductace Amplifier (OTA)and quanitizerin low-voltage nanometer-scale CMOSprocesses because of good speed and calibration-free response are becoming more popular in communication system. Proposed work achieves such high resolution, despite poor component matching using Folded ca...

A third-order single-bit delta-sigma modulator is presented in this paper. An op-amp dynamic current biasing technique is used to improve the power-efficiency of the modulator. The voltage reference block is integrated with the delta-sigma modulator core to avoid the use of large off-chip bypass capacitors and to minimize pin numbers. It achieves 89.2 dB dynamic range over 10 kHz signal bandwid...

Silicon modulators are promising devices for future optical networks to realize large capacity transmission with a low cost and a small footprint. In this paper, a silicon modulator for quadrature phase-shift-keying format is designed, fabricated and characterized. The fabricated modulator chip has short length of 3.5 mm, which is approximately one tenth of a widely used lithium niobate modulat...

This paper presents the design of a monobit 6 order delta-sigma modulator in a GaAs 0.2 μm technology. The central frequency is 750 MHz and the sampling frequency is 3 GHz. The reached resolution is 10.5 bits over a 10 MHz bandwith. The modulator operates from ± 5 V power supplies and consumes 5.7 W. Each block of the modulator is presented at transistor level. Two drawbacks are pointed out: lo...

This paper explains the design of two stage operational amplifier, single bit comparator and D flipflop best suited for the fifth order continuous-time sigma-delta modulator. A fifth order continuous time sigma delta modulator is chosen for 40MHz Signal Bandwidth with an nyquist frequency of 150MHz. Two stage opamp is used to provide the high gain to the modulator. A single quantizer is used to...

We propose a silicon Fabry–Perot planar waveguide modulator structure consisting of two Bragg reflectors to form the cavity. The Bragg reflectors are nanoscale trenches in the waveguide fabricated using electron beam lithography and reactive ion etching. Compared to conventional waveguide modulator designs, large modulation depth can be achieved with much smaller modulator length using high-fin...

Single-bit second-order delta-sigma modulators are commonly used in high-resolution ADCs. Testing this type of modulator requires a high-resolution test stimulus, which is difficult to generate. This paper proposes a novel and robust technique to determine the performance of the modulator, which incorporates simple design-for-testability circuitry. This technique requires only digital stimulus ...