An all-digital phase-frequency tunable clock generator for wireless OFDM communications systems

An all-digital clock generator is designed to enable the clock phase and frequency tuning dynamically during the wireless communications system is in operation. This phase-frequency tunable clock generator (PFTCG) provides 8 clock phases for selection and enables the ADC circuits sampling signals with lower frequency and better sampling phase, resulting in lower power consumption. The PFTCG provides the frequency tuning range ±150ppm centered at 5MHz, resulting in high performance due to smaller sampling clock offset. This PFTCG is simulated under the wireless body area network system, and shows a 6.3dB SNR improvement at BER=1e⁻³, and the hardware is simulated with power 77.56μW in the standard process 90nm CMOS technology.