She stood up and began to pace to and fro.她站起身，开始来回踱步。The boat was rocking gently to and fro in the water.小船在水中轻轻地来回摇荡。They travel to and fro between London and Paris.他们奔走于伦敦和巴黎之间....
Two phase - shift - networks of frequency discriminator are given circuit and layout examples.本文较详细地分析了鉴频器用移相网络的特性和集成化难易点.Quartz crystal, crystal oscillator, ceramic resonator, ceramic filter, saw filter, ceramic discrim...