Crystal Phase Conpensation Network and Its Application on Linear Phase-Shift Crystal Filter
Huang Xian-he · Piezoelectrics and Acoustooptics · 2005
A crystal phase compensation network is introduced in this paper.On magnitude-frequency characteristic,it is an all-pass network.But it can provide phase compensation within crystal filter bandwidth.Then we can get a linear phase crystal fileter composed of a common crystal filter and a crystal phase compensation network.So,the designed bandwidth of linear phase crystal filter is increased and the design is more flexible.As an example,a 21.85 MHz linear phase crystal filter is presented.Its 3 dB bandwidth is 70 kHz and group delay ripple is =±0.6 μs.As description,this method provides a novel and flexible compromised solution for resolving conflict between filter′s magnitude-frequency characteristic and phase-frequency characteristic.