Miniaturization Microwave Frequencies This Vibration Module Study More

Frequency synthesizer is a key component of any test and measurement system, communication and monitoring system. It is playing more and more important part in modern military, defense and wireless communications technology. The appeal of a low cost, high performance frequency synthesizer is recognized throughout the microwave industry. Ultra broadband, low phase noise, small frequency step, fast tuning speed are becoming hotspot of frequency synthesizer.Firstly, this paper introduces the concept and fundamental indexes of frequency synthesizer. Then several basic frequency synthesizer methods have been discussed with their advantages and disadvantages. On the basis of that and targets for the project, this paper presents the scheme of S、X band and K band frequency synthesizer. After that, all of their indexes have been analyzed in theory to prove the feasibility of the scheme. The frequency synthesizer module is divided into two parts:X band PLL and K band PLL. As the signal sampling clock, S band spot is produced by the VCO of X band PLL because its requirements is relatively low. K band frequency synthesizer has thirteen spots switching by an external TTL serial control signal. In order to suppress the dividing signal of VCO feedback loop, two microstrip coupling band-pass filters have been used after two PLL output ports. Besides the spurious and harmonic of two PLL outputs can be improved.The test results have reached the expected goals basically. The phase noise of S band spot is better than-90dBc/Hz@10kHz, spurious suppression is lower than requirement, harmonic suppression is greater than20dBc, output power10dBm. When it comes to the X band spot, the phase noise is also better than-90dBc/Hz@10kHz, spurious suppression is superior to-70dBc, harmonic suppression is greater than20dBc, output power7dBm. The K band PLL has thirteen output frequency spots, the phase noise of all the spots is better than-80dBc/Hz@10kHz, spurious suppression is superior to-60dBc, harmonic suppression is greater than20dBc, output power range from4to7dBm, hopping time is less than100us. Consequently, the feasibility of the frequency synthesizer module has been proved.