New dual-loop 900MHz and 1800MHz frequency band digital tuning system

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New dual-loop 900MHz and 1800MHz frequency band digital tuning system [Copy link]

Abstract: A new digital tuning system composed of DDS+ dual PLL is studied : A loop generates the clock signal required by DDS , and B loop generates high-frequency output. B loop makes the tuner output frequency f0 change greatly , and A loop and DDS make f0 change slightly. The system operates at 850MHz~925MHz and 1700MHz~1850MHz, and the frequency resolution can reach 25kHz . Under the control of a single-chip microcomputer , frequency hopping can be realized.