A direct digital synthesizer with 100-MHz output capability

A bipolar direct digital synthesizer with 5-kHz to 100-MHz output capability is described. Channel spacing is 5 kHz with a 'hop' time between discrete output frequencies of less than 17 ns. Spurious output rejection is better than -32 dBc, and close-to-carrier measurements indicate a noise floor lower than -138 dBc at +or-25 kHz.<
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