A 6-GHz All-Digital Fractional- Frequency Synthesizer Using FIR-Embedded Noise Filtering Technique

摘要

A 6-GHz all-digital fractional-$N$ frequency synthesizer using an FIR-embedded noise filtering technique is presented. This noise filtering technique is realized in the digital domain without multiple matched analog components. This fractional-$N$ frequency synthesizer is fabricated in a 90-nm CMOS process, and it occupies 0.18 $hbox{mm}^{2}$. Its power is 28.8 mW with a supply of 1.2 V. The measured out-of-band phase noise at an offset of half the reference frequency is improved by more than 13 dB around 6 GHz considering cancellation variations for different output frequencies.