Resistance Compensated Band-Pass Crystal Filters for Use in Unbalanced Circuits

I N a recent paper 1 a description is given of a number of wave filters employing quartz crystals as elements. Most of these filters were of the lattice type and hence were inherently balanced. For some purposes, however, such as connecting together unbalanced tubes, it is desirable to obtain a filter in an unbalanced form and it is the purpose of this paper to show several forms for constructing resistance compensated band-pass crystal filters which will give results similar to those described previously. Another purpose is to give a numerical comparison between the characteristics obtainable with resistance compensated crystal and electrical filters. I I . A COMPARISON OF THE P E R F O R M A N C E CHARACTERISTICS CRYSTAL VS. C O I L AND C O N D E N S E R F I L T E R S OF In order to show the properties of resistance compensated crystal filters it is instructive to give a comparison between the types of characteristics which can be obtained by using crystal and coil and 1 "Electrical Wave Filters Employing Quartz'Crystals as Elements," W. P. Mason, B. S. T. J., July, 1934, p. 405.