I am not sure of the origin of this circuit. This is an item thatcame from my files.
The lattice circuit can be used to mix two signals into one or splitone signal into two. There is complete isolation between the splitsignals (shown on the left in the diagram below). Shorting one inputwill not affect the other input.
This circuit is ideal for encoding and decoding matrix stereo signals.It is suitable for any application where a passive function is requiredand the resulting loss in signal level is not important.
editor, Radio magazine
This can be used as a passive mixer or splitter. Either way, thereis complete isolation between each input. Resistors should all be ofthe same value and will determine the input and output impedance. For a600 ohm circuit input and output impedance, use 600 ohm resistors. Fora 10k ohm impedance, use 10k ohm resistors. Loss through the device isalways 6dB.