Ken Stone's homepage
The dome filter is a 90Â° phase difference network, as used in frequency shifters. It is not a project in itself, and will be of no use to most people. I designed this board simply because I needed some dome filters for my own experimentation. The boards I am selling are simply left over from this run.
The circuit is based on the work of, and Copyright by Bernie Hutchins. It was presented in Electronotes 83, in Nov 1977. The implementation is very similar to that of JÃ¼rgen Haible for his frequency shifter. Do not expect either of these people to help you with the construction of this PCB.
Component values are selected using the formula printed on the PCB itself.
I will be giving no more details on this project at this stage, and suggest you purchase Electronotes if you need more information.