Patent ID: 7221916

Claim:
A reference signal enhancement device for phase lock loop oscillators (PLO), comprising: a band pass filtering unit coupled to a reference signal to filter high frequency noise, low frequency noise, and harmonic components of the reference signal or components with frequency exceeded a predetermined frequency in the reference signal, wherein the reference signal has the predetermined frequency; and a signal amplification device coupled to the band pass filter to convert the filtered reference signal, wherein the band pass filtering unit comprises: a first low pass filter coupled to the reference signal to filter a high frequency component in the reference signal so as to eliminate the high frequency noise; a second low pass filter coupled to the first low pass filter to filter harmonic components of the reference signal or components with frequency higher than the predetermined frequency in the reference signal; and a band pass filter coupled to the second low pass filter to filter a low frequency component in the reference signal so as to eliminate the low frequency noise.