A 20Mb/s phase modulator based on a 3.6GHz digital PLL with −36dB EVM at 5mW power

Abstract

This paper introduces a digital-intensive phase modulator circuit, which is able to enforce an arbitrary carrier phase change (up to ±π radians) in one clock sample. For a clock frequency of 40MHz, the modulation error, expressed in terms of error vector magnitude (EVM), is below -36dB for a 20Mb/s QPSK-modulated or a 10Mb/s GMSK-modulated carrier at 3.6GHz.