A keyboard can be comprised of a plurality of alphabetic keys that are disposed in an evenly-spaced grid pattern with respect to one another. A pulse transmission receiver includes: a front-end amplificationprocessing circuit; a synchronization circuit coupled to the front-end amplificationprocessing circuit; a clock coupled to the synchronization circuit; a trigger signal generator coupled to the clock; and at least one higher-order time derivative pulse generator coupled to the trigger signal generator. The illustrative embodiment further includes a third resistor connected between the first node and ground and a fourth resistor connected between the second node and ground.