A 50-Mb/s CMOS QPSK/O-QPSK Transmitter Employing Injection Locking for Direct Modulation
A 50-Mb/s CMOS QPSK/O-QPSK Transmitter Employing Injection Locking for Direct Modulation
复制标题
采用注入锁定进行直接调制的 50 Mb/s CMOS QPSK/O-QPSK 发送器
DOI：
10.1109/tmtt.2011.2174377
复制
发表时间：
2012
影响因子：
4.3
通讯作者：
C. Heng
中科院分区：
文献类型：
--
作者：
Shengxi Diao;Yuanjin Zheng;Yuan Gao;San;X. Yuan;M. Je;C. Heng
介绍了一种适用于生物医学高质量成像的50 Mb/S正交相移键控/偏移相移键控发射机。以915 MHz为中心，通过电容器组切换直接改变LC压控振荡器的自谐振频率，实现了调相。通过消除传统QPSK/O-QPSK发射机中的许多不必要的构建块，实现了显著的功率和面积节约。该芯片采用0.18-μMcmos工艺实现，其有源核心面积为0.28mm2。该发射机的注入频率为305 MHz，1.4V电源下功耗为5.6 mW，O-QPSK/QPSK调制的误差矢量值为11.4%/5.97%，在50Mb/S下的输出功率为-3dBm。通过将注入频率降低到101.67 MHz，在相同的电源电压下功耗为5.88 mW，输出功率为-3.3dBm。在50 Mb/S的QPSK调制下，发射机的EVM值达到了6.4%。
A 50-Mb/s quadrature phase-shift keying (QPSK)/offset quadrature phase-shift keying (O-QPSK) transmitter suitable for biomedical high-quality imaging application is presented. Centered at 915 MHz, the phase modulation is achieved by directly modifying the self-resonant frequency of an LC voltage-controlled oscillator through capacitor bank switching. By eliminating many unnecessary building blocks in the conventional QPSK/O-QPSK transmitter, significant power and area savings are achieved. Implemented in 0.18- μm CMOS technology, it occupies an active core area of 0.28 mm2. With 305-MHz injection frequency and consuming 5.6 mW under 1.4-V supply, the transmitter achieves error vector magnitude (EVM) of 11.4%/5.97% for O-QPSK/QPSK modulation while delivering output power of -3 dBm at 50 Mb/s. By lowering the injection frequency to 101.67 MHz, it consumes 5.88 mW under the same supply voltages while delivering an output power of -3.3 dBm. The transmitter achieves measured EVM of 6.4% at 50 Mb/s under QPSK modulation.