Assume the following interrogation arrives at the ATCRBS transponder.
Assume all pulses are the same amplitude (above MTL threshold) and width
(0.8 microseconds).  The first arriving pulse will be here called P1.  The next in
time sequence will be called P2, and the time from its rising edge to the rising
edge of the previous pulse, in microseconds, will be stated.  Same for following
pulses, if any, reference its immediately preceding pulse.

Assume there is just the one interrogation, as stated, "all by itself".

Because peoples lives are at stake, this test is open book and untimed.  Conduct
whatever you want to test, consult any reference text, do NOT consult another
person, while completing this test.  Turn in for grading only when you are
completely sure.

Remember to explain your answers
(for selection A or B or C, not necessary for D).
 

1.   P1            then
      P2 @ 2us then
      P3 @ 6us
          A) reply squawk     B) reply altitude     C) suppress     D) don't know

2.   P1            then
      P2 @ 8us
          A) reply squawk     B) reply altitude     C) suppress     D) don't know

3.   P1            then
      P2 @ 2us then
      P3 @ 19us
          A) reply squawk     B) reply altitude     C) suppress     D) don't know

4.   P1              then
      P2 @ 21us
          A) reply squawk     B) reply altitude     C) suppress     D) don't know

5.   P1            then
      P2 @ 2us then
      P3 @ 6us then
      P4 @ 2us
          A) reply squawk     B) reply altitude     C) suppress     D) don't know

6.   P1            then
      P2 @ 8us then
      P3 @ 2us
          A) reply squawk     B) reply altitude     C) suppress     D) don't know

7.   P1              then
      P2 @ 2us   then
      P3 @ 19us then
      P4 @ 2us
          A) reply squawk     B) reply altitude     C) suppress     D) don't know

8.   P1              then
      P2 @ 21us then
      P3 @ 2us
          A) reply squawk     B) reply altitude     C) suppress     D) don't know

9.   P1            then
      P2 @ 5us then
      P3 @ 2us then
      P4 @ 6us
          A) reply squawk     B) reply altitude     C) suppress     D) don't know

10. P1            then
      P2 @ 5us then
      P3 @ 8us
          A) reply squawk     B) reply altitude     C) suppress     D) don't know

11. P1            then
      P2 @ 5us then
      P3 @ 2us then
      P4 @ 19us
          A) reply squawk     B) reply altitude     C) suppress     D) don't know

12. P1            then
      P2 @ 5us then
      P3 @ 21us
          A) reply squawk     B) reply altitude     C) suppress     D) don't know

13. P1            then
      P2 @ 5us then
      P3 @ 2us then
      P4 @ 6us then
      P5 @ 2us
          A) reply squawk     B) reply altitude     C) suppress     D) don't know

14. P1            then
      P2 @ 5us then
      P3 @ 8us then
      P4 @ 2us
          A) reply squawk     B) reply altitude     C) suppress     D) don't know

15. P1              then
      P2 @ 5us   then
      P3 @ 2us   then
      P4 @ 19us then
      P5 @ 2us
          A) reply squawk     B) reply altitude     C) suppress     D) don't know

16. P1              then
      P2 @ 5us   then
      P3 @ 21us then
      P4 @ 2us
          A) reply squawk     B) reply altitude     C) suppress     D) don't know

17. Your occupation (check all that apply, not graded)
      A) FAA
      B) avionics repair technician
      C) DER
      D) pilot
      E) degreed electrical or electronics engineer
      F) university faculty

The answers, that the FAA Air Traffic Control Association realizes are correct, but are afraid to publish: