Increasable and decreasable signal strengths

Solution 1:

This is probably the most compact circuit of this type; it additionally can accept pulses on any length on both inputs and provides symmetrical signals, x and 15-x on the two sides. The only downside is that you need 18 stacks of any 64-stackable item, to completely fill the droppers under the repeaters - the other droppers are to be left empty. Both repeaters should be set to 2 ticks.

This circuit should also work on Bedrock Edition, with the small modification - add solid blocks on top of the empty droppers to power them through these blocks - on JE they can be powered through quasi-connectivity.