Abstract: Methods of design in wideband, low phase noise frequency synthesizers were analyzed. A scheme of synthesizer design is proposed, in which a mixing-PLL frequency synthesis technique is used, thus realizing wide-range PLL frequency synthesizer applying the chip Q3236. The scheme has a frequency range of 1 000～2 160 MHz, with a frequency step of 20 MHz, phase noise≥ -95 dB/Hz (offset 1 kHz from carrier), spurious free dynamic range 60 dB, P m≥8 dB. All test results proved that it is an effective method to expand the bandwidth and that it achieves successfully ultra-low phase noise.