Flip-Flop Circuits

Determine the output states for this J-K flip-flop, given the pulse inputs shown:

Flip-flops often come equipped with asynchronous input lines as well as synchronous input lines. This J-K flip-flop, for example, has both “preset” and “clear” asynchronous inputs:

Describe the functions of these inputs. Why would we ever want to use them in a circuit? Explain what the “synchronous” inputs are, and why they are designated by that term.

Also, note that both of the asynchronous inputs are active-low. As a rule, asynchronous inputs are almost always active-low rather than active-high, even if all the other inputs on the flip-flop are active-high. Why do you suppose this is?

A scientist is using a microprocessor system to monitor the boolean (“high” or “low”) status of a particle sensor in her high-speed nuclear experiment. The problem is, the nuclear events detected by the sensor come and go much faster than the microprocessor is able to sample them. Simply put, the pulses output by the sensor are too brief to be “caught” by the microprocessor every time:

She asks several technicians to try and fix the problem. One tries altering the microprocessor’s program to achieve a faster sampling rater, to no avail. Another recalibrates the particle sensor to react slower, but this only results in missed data (because the real world data does not slow down accordingly!). No solution tried so far works, because the fundamental problem is that the microprocessor is just too slow to “catch” the extremely short pulse events coming from the particle sensor. What is required is some kind of external circuit to “read” the sensor’s state at the leading edge of a sample pulse, and then hold that digital state long enough for the microprocessor to reliably register it.

Finally, another electronics technician comes along and proposes this solution, but then goes on vacation, leaving you to implement it:

Explain how this D-type flip-flop works to solve the problem, and what action the microprocessor has to take on the output pin to make the flip-flop function as a detector for multiple pulses.