Abstract: This paper presents a method which combines the design of the freguency synthesizer with the design of a receiver, in order to receive all frequency band of meteorological satellite, for obtainning a optimum performance to cost ratio. For the purpose of automatic designing of receiver, there are computer interface circuits in frequency synthesizer. This means that computer may be connected directly to frequency synthesizer. Therefore the digital phase-locked technigues are used in meterological satllite reception equipment. In this paper we analys noise performance of phase-locked loop. The task in the design of a digital phase-locked frequency synthesizer, therefore, is to try to decrease the amplitude of interference spectrum.