In this design the values that have been entered are those used in the R2/T2 design by KK7B. Three All Pass filters have been used in each path. Over the frequency range from 300 Hz to 3 kHz it can be seen that the opposite sideband suppression should exceed 45 dB and is over 50 dB in the middle of the range. There is quite a slope on the phase response curve that shows that changing some values could improve the performance still further. Presumably practical compromise values were chosen.

The R2 appeared in QST January 1993. It has also been published in copies of the ARRL Handbook and in the ARRL book called QRP Power.

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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