The voltage divider phase shift filter (VDPSF) has been used in the past to construct inductorless narrowband filters with moderately high Q values, for example, Q = 50. This work reports a new configuration of this filter that can achieve extremely high Q values over a range of frequencies from very low to very high values. A typical value is Q = 2500, but can be even higher. These high values of Q can be obtained at very low frequencies, solving a long-standing problem for LC tank circuits. The new configuration consists of one voltage divider phase shift filter nested within a second such filter. A simulation is done to verify the accuracy of the theory and demonstrate the stability of Q with respect to circuit element value changes. One significant application of such a filter is in the creation of a tunable oscillator with a very high degree of spectral purity.
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