A 16bit sigma-delta audio analog-to-digital converter is developed.It consists of an analog modulator and a digital decimator.A standard 2-order single-loop architecture is employed in the modulator.Chopper stabilizat...A 16bit sigma-delta audio analog-to-digital converter is developed.It consists of an analog modulator and a digital decimator.A standard 2-order single-loop architecture is employed in the modulator.Chopper stabilization is applied to the first integrator to eliminate the 1/f noise.A low-power,area-efficient decimator is used,which includes a poly-phase comb-filter and a wave-digital-filter.The converter achieves a 92dB dynamic range over the 96kHz audio band.This single chip occupies 2.68mm2 in a 0.18μm six-metal CMOS process and dissipates only 15.5mW power.展开更多
A new modulation format in optical fiber communication system, the eight differential phase shift keying (8DPSK) of multi-phase modulation technology based on carrier-suppressed return-to-zero (CSRZ) is proposed in th...A new modulation format in optical fiber communication system, the eight differential phase shift keying (8DPSK) of multi-phase modulation technology based on carrier-suppressed return-to-zero (CSRZ) is proposed in this paper. The formulae of CSRZ-8DPSK modem methods are derived theoretically and the methods are demonstrated. Spectra based on CSRZ and CSRZ-8DPSK modulation methods and their eye diagrams by simulation with MATLAB are obtained. The results show that the CSRZ-8DPSK modulation methods have narrower spectra with higher efficiency. The performance of eye diagrams is also much satisfactory after demodulation, suggesting some possible applications of the methods in the next generation of optical fiber communications.展开更多
文摘A 16bit sigma-delta audio analog-to-digital converter is developed.It consists of an analog modulator and a digital decimator.A standard 2-order single-loop architecture is employed in the modulator.Chopper stabilization is applied to the first integrator to eliminate the 1/f noise.A low-power,area-efficient decimator is used,which includes a poly-phase comb-filter and a wave-digital-filter.The converter achieves a 92dB dynamic range over the 96kHz audio band.This single chip occupies 2.68mm2 in a 0.18μm six-metal CMOS process and dissipates only 15.5mW power.
文摘A new modulation format in optical fiber communication system, the eight differential phase shift keying (8DPSK) of multi-phase modulation technology based on carrier-suppressed return-to-zero (CSRZ) is proposed in this paper. The formulae of CSRZ-8DPSK modem methods are derived theoretically and the methods are demonstrated. Spectra based on CSRZ and CSRZ-8DPSK modulation methods and their eye diagrams by simulation with MATLAB are obtained. The results show that the CSRZ-8DPSK modulation methods have narrower spectra with higher efficiency. The performance of eye diagrams is also much satisfactory after demodulation, suggesting some possible applications of the methods in the next generation of optical fiber communications.
