Fractional-N Direct Digital Frequency Synthesis with a 1-Bit Output

A novel digital frequency synthesis (DDS) architecture with a 1-bit output is proposed, simulated, and demonstrated. A new noise shaping quantization algorithm is also evaluated and used within the proposed DDS system. Large tuning ranges and rapid (open loop) response characteristics are achieved with only a static reference frequency input, without the use of analog components, allowing easy integration in digital CMOS processes. Across a tuning range of 10% f
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, a noise floor of -80 dBc/Hz and spurious tones lower than -50 dBc are possible with this system