54 results about "Crystal oscillator frequencies" patented technology

System for filtering an input frequency to produce an output frequency having low phase noise. A first PLL includes, in the feedback path, a frequency translation circuit which translates a frequency from a VCO in the first PLL by an offset frequency provided by the second PLL to provide either a sum or difference frequency. The first PLL locks its VCO to a crystal oscillator input frequency translated by the offset frequency due to the frequency translation circuit. A second PLL compares the input frequency to be filtered to the output of the first PLL VCO. The second PLL causes the first PLL VCO to lock to the input frequency by varying the offset frequency it provides to the frequency translation circuit. The bandwidth of the second PLL is significantly smaller than the bandwidth of the first PLL. The filtered output frequency is available from the first PLL VCO.

The present invention provides a method and a device for adjusting a carrier frequency of a multiple-input multiple-output microwave device. The method includes: obtaining, by an indoor unit IDU, a frequency of a radio frequency-reference crystal oscillator and a first frequency multiplication factor of each outdoor unit ODU; selecting, by the indoor unit IDU, one of the frequencies of the radio frequency-reference crystal oscillator as a reference frequency; adjusting, by the indoor unit IDU, a carrier frequency of the multiple-input multiple-output microwave device according to the first frequency multiplication factor and a radio frequency offset between the reference frequency and the frequency of the radio frequency-reference crystal oscillator of each ODU. In the method and the device for adjusting the carrier frequency of the multiple-input multiple-output microwave device according to the present invention, each ODU sends information of the frequency of the radio frequency-reference crystal oscillator to the IDU, and the IDU adjusts an intermediate frequency according to an offset of the frequency of the radio frequency-reference crystal oscillator, thereby achieving the objective of adjusting a carrier frequency of the multiple-input multiple-output microwave device.