1993 IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM DISCRETE SPURIOUS SIGNALS AND BACKGROUND NOISE IN DIRECT DIGITAL FREQUENCY SYNTHESIZERS

In the present paper we shall discuss some sources of output spurious signals in direct digital frequency synthesizers (DDFS). First, we provide a closed form solution for spurious signals generated by the phase truncation. Then we pay attention to the accuracy of sine look-up tables and arrive at an estimated level of background spurious signals generated this way. Further, we investigate the behaviour of digital to analog convertors (DAC), their bit resolution, nonlinearity, and clock signal leakage. Finally we will investigate the eventual phase noise level.

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