This example is from a design on the web site of Michael G. Ellis N4BCU. His design has five All Pass filters in each path and exhibits a wider frequency response and a much reduced phase error. It should work well from 50 Hz up to 5 kHz. By changing the resistors to single values that are available the response will probably be degraded but the opposite sideband suppression can, in theory, be maintained better than 45 dB. Even choosing resistors as series or parallel pairs it would probably be very difficult to get close to the ideal calculated result of better than 60 dB. The additional filter stages have produced a wider frequency response than that of the KK7B design and this could be useful.

If you have any other design that you would like me to include then please contact me by e-mail with the details.

73, Lawrence GJ3RAX

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