Quadrature direct digital frequency synthesizers using interpolation-based angle rotation

Abstract

This paper describes a quadrature direct digital frequency synthesizer (QDDFS) architecture based on a new phase-to-sine conversion technique. The proposed technique uses polynomial interpolation and rotational transformation in a fine/coarse approach, achieving high-resolution output with a wide spurious-free dynamic range (SFDR). The QDDFS with this technique requires small-sized lookup tables and a simple computational engine. The fine/coarse decomposition significantly reduces the size of required lookup tables, and the polynomial interpolation enables accurate approximation of cosine and sine values. Two prototype QDDFS ICs were fabricated in 0.35-m CMOS. The final prototype IC produces 16-b cosine and sine outputs with a spectral purity greater than 100-dB. It has a frequency tuning resolution of 0.03-Hz at a 150-MHz sampling rate and consumes 350-mW with a 3.0-V power supply.Index Terms-CMOS digital integrated circuits, direct digital synthesis, digital signal processing (DSP) chips, frequency synthesizers, interpolation.

Design and analysis of dual-mode numerically controlled oscillators based controlled oscillator frequency modulation

“…The digital world is controlled based on the convenient measures. The studies [4], [5] introduce the concept of digital synthesis frequency. But in 1974 it was came up.…”