A customized IQ modulator driven by equal-amplitude binary signals for generating offset-free 16-quadrature amplitude modulation (QAM) is proposed and validated through simulations. The incorporation of tunable splitters demonstrates the feasibility of the transmitter and enables more efficient constellations such as hexagonal 16-QAM.

A simple but rigorous analysis of the important sources of noise in homodyne detection is presented. Output noise and signal-to-noise ratios are compared for direct detection, conventional (one-port) homodyning, and two-port homodyning, in which one monitors both output ports of a 50-50 beam splitter. It is shown that two-port homodyning is insensitive to local-oscillator quadrature-phase noise...

Here, a self-oscillating mixer is experimentally demonstrated employing both the fundamental and harmonic signals generated by the oscillator sub-circuit in the mixing process. The resulting circuit is a dual-band down-converting mixer that can operate in the C-band, or in the X-band. The oscillator uses the active super harmonic coupling to enforce the quadrature relationship of the fundamenta...

This paper presents a general ring oscillator circuit topology for high speed operation, multiphase output and wide range tuning. The topology use sub-feedback inverters to construct fast loop for long chain ring oscillator to achieve high speed. The operating frequency of the ring oscillator is directly proportional to the transconductance (G,) of subfeedback inverters which can be controlled ...

A direct downconversion receiver implemented in 0.13 μm 1P8M process is presented. The circuit is formed by a single-end LNA, an active balun for conversion into balanced mode, a quadrature double-balanced passive switch mixer and a quadrature voltage-controlled oscillator. The receiver operates in the 2.4 GHz ISM band and complies with IEEE 802.15.4 (ZigBee) specifications. The circuit exhibit...

We experimentally investigate quadrature correlations between pump, signal, and idler fields in an above-threshold optical parametric oscillator. We observe new quantum correlations among the pump and signal or idler beams, as well as among the pump and a combined quadrature of signal and idler beams. A further investigation of unforeseen classical noise observed in this system is presented, wh...

This paper presents a low power 2.4-GHz fully integrated 1 MHz resolution IEEE 802.15.4 frequency synthesizer designed using 0.18um CMOS technology. An integer-N fully programmable divider employs a novel Truesingle-phase-clock (TSPC) 47/48 prescaler and a 6 bit P and S counters to provide the 1 MHz output with nearly 45% duty cycle. The PLL uses a series quadrature voltage controlled oscillato...