Digital frequency synthesizer for use in radar to deliver direct output signal, has direct digital synthesis unit delivering intermediate signal that serves to elaborate transposition signal, and possessing wide instantaneous frequency band

摘要

The synthesizer (SYNT) has a phase lock loop (PLL) including a return chain (CRT) with a frequency transposition unit i.e. mixer (MEL1), that receives a signal based on a phase lock loop output signal, and a frequency transposition signal (ftranspo). A direct digital synthesis unit (DDS2) delivers an intermediate signal (SI) that serves to elaborate the transposition signal. An instantaneous frequency band associated to the synthesis unit is wider than that of another direct digital synthesis unit (DDS1) coupled in upstream of the loop.