A novel type of mixer used for direct frequency synthesis

The frequency synthesizers are an essential part of any modern communications system. They generate clock and oscillator signals needed for up and down conversion. Today´s communication standards demand both high frequency accuracy and fast frequency settling. The fine frequency resolution is usually desired and low spurious signals, accuracy and stability are also most important for these devices. For some types of the frequency synthesizer the mixer is very significant part. In this paper, the frequency synthesizer architecture based on direct synthesis described. More over the new coincidence mixer used in this synthesizer is presented. The mathematic derivation and simulation results are also shown.