出版社：The Institute of Image Information and Television Engineers
摘要：Orthogonal frequency division multiplexing (OFDM) is a suitable digital modulation method for terrestrial digital broadcasting systems. However, the phase noise in an OFDM receiver must be reduced, because the phase noise disturbs the orthogonality among the OFDM sub-carriers. This report describes the design of a wideband tunable local oscillator with low phase noise characteristics for OFDM receivers. We have developed a balanced oscillator with an L-C parallel resonance circuit between the transistor emitter ports, which has a wide band frequency range of 1.15-2.2 GHz and low phase noise performances of-66 dBc/Hz (1-kHz offset) or less. We also calculated the SNR at the output of the tuner of OFDM sub-carriers by using this balanced oscillator, and the results show that the SNRs of 33dB or more are achievable even for the 1-kHz sub-carrier spacing system.
