"A Dither-Less All Digital PLL for Cellular Transmitters,"

An all-digital frequency synthesizer for cellular
transmitter is presented. Low phase-noise is achieved both
in-band and out-of-band exploiting a 2-dimensional Vernier
time-to-digital converter and a dither-less digitally controlled
oscillator. These building blocks heavily rely on digital calibration
techniques to precisely and efficiently implement two-point modulation
and spur cancellation in the presence of implementation
impairments. The presented prototype shows an in-band phase
noise of 108 dBc/Hz, an out-of-band phase noise of 160 dBc/Hz
@20 MHz and in-band fractional spurs below 50 dBc. These
results are obtained for an output carrier of 1.8 GHz, a reference
clock of 26 MHz, with a power consumption of 41.6 mW.