2) seeker decoy system. More complex design consisting of a clock, a counter and a decoder (working as output). You need at least 8 MM launchers to make it work reliably. Advantages are self-targeting properties and missile spread on launch. The main disadvantage is that you can't control which enemy the system will aim at. Works best in close combat since decoys are quite slow.
1) simple MC decoy system (reload 1 s, 1 projectile/shot) is a capable long-range one, and it is incredibly simple to make it fire each 0,5 seconds (just link a clock to a flipflop, flipflop to NOT and a missile computer, NOT to a second missile computer). Works best for suppressing a certain ship's PD since missiles fly straight ahead
The decoy system is not about launching a missile or two with the main one. It is about contantly spamming missiles at a rate enemy PD can't overcome (I was satisfyed only when my decoy launcher was capable of launching 10 missiles per second). Some ion missiles won't defend main missile payload from PDs