Ultra-broadband, high resolution frequency synthesizer for LTE Radio Channel Emulator

This paper proposes a high performance frequency synthesizer system featured by ultra-broadband, low phase noise, high resolution and tunable phase for LTE Radio Channel Emulator. The system makes use of both the direct digital synthesis and the indirect synthesis techniques and includes a 1.2 GHz frequency synthesizer, a 2 GHz frequency synthesizer and a 1.5 GHz~6 GHz broadband frequency synthesizer with a high theoretical frequency resolution which is better than 107 μHz when the DDS is used as the reference. Experimental results show that, at 10 kHz offset from the carrier, the phase noises are -114.59 dBc/Hz at 1.2 GHz, -114.09 dBc/H at 2 GHz and better than -95 dBc/Hz over 1.5 GHz~6 GHz frequency band, and the output power level ranges from -13.87 dBm to -11.01 dBm.