We propose and experimentally verify a novel approach to achieve phase-coherence orthogonally polarized optical single sideband (OSSB) modulation with a tunable optically carrier-to-sideband ratio (OCSR). In our scheme, the orthogonally polarized OSSB signal is achieved using a dual-polarization quadrature phase shift keying (DP-QPSK) modulator without an optical band-pass filter (OBPF). Theref...

A silicon electro-optic modulator based on coupled microring resonators is proposed. The dual-ring modulator has wide optical bandwidth, high extinction ratio and low insertion loss. A simple integrated circuit connecting the two rings allows for fast modulation speed of >40 Gbit/s. This device has both improved optical and electrical performance over a single-ring modulator. The dual-ring modu...

The paper proposes a novel structure for a MASH digital delta-sigma modulator (DDSM) in order to achieve a long sequence length. The expression for the sequence length is derived. The condition to produce the maximum sequence length is also stated. It is proved that the modulator output only depends on the structure of the first-order error feedback modulator (EFM1) which is the first stage of ...

Stable equilibrium study cascaded one bit sigma-delta modulator In the paper defines a boundary of stability zone for sigma-delta modulator. The boundary depends from inner sigma-delta modulator coefficients. For designing purposes such result could use to find or compare some appropriate schemes with each other. It's proved some statements and showed that boundary could be found theoretically ...

There is two main parts of Sigma-delta ADC: analog modulator and digital filter, the performance of modulator determines the performance of sigma-delta ADC, so the design of modulator is very important. This paper introduces the principle of sigma-delta ADC modulator with high accuracy and the applied over sampling technique, noise shaping technique and multi-bit quantize technique. This paper ...

This paper proposes a continuous-time bandpass ∆ΣAD modulator architecture which performs high-accuracy AD conversion of high frequency analog signals and can be used for next-generation radio systems. We use an RF DAC inside the modulator to enable subsampling and also to make the SNDR of the continuous-time modulator insensitive to DAC sampling clock jitter. We have confirmed that this is the...

A new continuous-time multi-stage noise-shaping delta-sigma modulator has been designed. This modulator provides high resolution and robust stability characteristics which are the primary advantages of the conventional multi-stage noise-shaping architecture. At the same time, previous critical challenges that degraded the overall performance of multi-stage noise-shaping delta-sigma modulators a...

In a previous study [1], we proposed an adaptive sigma delta modulator with improved dynamic range. The modulator adapts the step size of the quantizer from estimates of the quantizer input instead of the modulator input. In this study, we conduct an error variance analysis of the new modulator and derive expression for the SNR. The derived expression shows that the SNR is independent of the in...

A methodology for the design of Continuous-Time (CT) Sigma-Delta (Σ∆) modulators with VCO-based quantizer is proposed. The coefficients of the CT Σ∆ modulator are accurately calculated such that the noise transfer function of the modulator is exactly the same as a Discrete-Time (DT) Σ∆ modulator of the same order. Several design examples for different modulator orders and feedback DAC signal sh...

RF Vector Modulator enables independent control of a narrowband RF signal amplitude and phase. Unfortunately practical realization of an analog vector modulator suffers from misbalances and imperfections in the I and Q signal paths. Use of a feed-forward based calibration can compensate for them and significantly improve RF performance and control accuracy of a real vector modulator. Achieved i...