A frequency counter ________ a signal.

In the digital clock project, the 60 Hz signal is sent through a Schmitt-trigger circuit to produce square pulses at the rate of ________.

The interface of the stepper motor needs to operate in one of ________ mode(s).

In the keypad encoder, the ________ must hold in its current state until a key is released.

In the digital clock project, the 1 pps signal is used as a synchronous clock for all of the counter stages, which are ________.