Ikegami HTM monitors convert analogue RGB input to YUV for signal processing, only putting the signals back into RGB at the end of the pipeline. What's interesting about this is that while other common analogue RGB -> YUV conversion circuits use a complex combination of op-amps and resistors, or in some cases specialized ICs, Ikegami's conversion is essentially done with nothing but a matrix of common-value resistors. The only catch is that the signals need to be buffered first.
Here is the relevant section of the schematic. If anyone wants the whole service manual in order to see all the surrounding circuitry, just PM me. If this winds up being applicable for something, cool. If not, well, at least it's interesting.
(Note that there are actually two sets of matrices: one for HD and one for SD. ICs 102/302/502 toggle between them.)
