求翻译：模拟体制的信号源由于受模拟器件的局限性，产生信号的精度不高，温度及时间稳定性差，相位难以控制[6][7]；锁相式频率合成器以较高的频率精度、分辨率及频谱纯度得到广泛的应用，但是当需要窄频率步进时，环路带宽需要降低，致使锁定时间变长，不能满足要求是什么意思？

Analog system, the signal source due to the limitations of analog components, resulting in signal accuracy is not high, the temperature and time stability of the difference, the phase is difficult to control [6] [7]; PLL frequency synthesizer with high frequency accuracy, resolution rate and spectra

The signal source simulation system due to limitations of the simulator is a signal that the precision is not high, and the temperature difference between stability and time, phase is difficult to control [ 6] [ 7 ]; phase lock-frequency synthesiser with a greater frequency accuracy, resolution and

Because the simulation system supply oscillator is simulated the component the limitation, has the signal precision not to be high, the temperature and the time stability are bad, the phase controls (6)(7) with difficulty; The phase-lock type frequency synthesizer by the high frequency precision, th

Simulation system of signal sources due to limitations of the analog devices, signal accuracy is not high, temperature and time stability of difference, phase control [6][7], phase-locked frequency synthesizer at a higher frequency accuracy, resolution and spectral purity of a wide range of applicat

Imitating the signal source of the system is imitated the limitation of device, the precision of producing the signal is not high, temperature and time stability are bad, the phase place is difficult to control [6 ] [7 ]; T