A 1.55 GHz to 2.45 GHz center frequency continuous-time bandpass delta-sigma modulator for frequency agile transmitters
A 1.55 GHz to 2.45 GHz center frequency continuous-time bandpass delta-sigma modulator for frequency agile transmitters
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DOI：
10.1109/rfic.2009.5135511
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发表时间：
2009-06
期刊：
影响因子：
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通讯作者：
Martin Schmidt;M. Grozing;S. Heck;I. Dettmann;M. Berroth;D. Wiegner;W. Templ;A. Pascht
中科院分区：
文献类型：
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作者：
Martin Schmidt;M. Grozing;S. Heck;I. Dettmann;M. Berroth;D. Wiegner;W. Templ;A. Pascht
提出了一种中心频率在1.55 ~ 2.45 GHz范围内可编程的四阶连续时间带通Δ-Σ调制器（CT-BPDSM）。该调制器适用于多种标准的S类功率放大器。该电路采用多反馈架构，具有归零（RZ）和半归零（HRZ）脉冲。环路滤波器由发射极简并输入跨导体LC谐振器和Q增强电路组成。配置寄存器允许以5位分辨率对谐振器输入跨导体、Q增强电路和谐振器电容进行编程。谐振器中心频率的微调是用变容二极管实现的。该电路采用200 GHz-fT SiGe双极技术实现。在20 MHz带宽下，中心频率为2.2 GHz时的实测信噪比为45.5 dB。在1.55 GHz处，SNR降低到40.7 dB。测量的调制器输出的上行UMTS-FDD ACLR（相邻信道泄漏功率比）在第一相邻信道中为48.4dB。
This paper presents a 4th order continuous-time bandpass delta-sigma modulator (CT-BPDSM) with a programmable center frequency ranging from 1.55 GHz to 2.45 GHz. The modulator is suited to be applied in multi-standard class-S power amplifiers. The circuit features a multi-feedback architecture with return-to-zero (RZ) and half-return-to-zero (HRZ) pulses. The loop filters consist of LC-resonators with emitter degenerated input transconductors and Q-enhancement circuits. A configuration register allows to program the resonator input transconductors, the Q-enhancement circuits and the resonator capacitances with 5 bit resolution. Fine tuning of the resonator center frequency is achieved with varactors. The circuit is implemented in a 200 GHz-fT SiGe-bipolar technology. The measured SNR at 2.2 GHz center frequency is 45.5 dB in a bandwidth of 20 MHz. At 1.55 GHz the SNR decreases to 40.7 dB. The measured uplink UMTS-FDD ACLR (adjacent channel leakage power ratio) of the modulator output is 48.4 dB in the first adjacent channel.