The problem can be detected by looking at the packet sequence. Sorting by packet count gives a time-tag inversion, sorting by SDF packet time, gives a line count inversion. Figure 42.3 is an excerpt from a listing of packet headers. The time column is in seconds, the delta is the delta-time from the previous packet. Packet 4112 comes before 4111, and the delta-time is 0.000977 seconds, which is exactly 1000 clock ticks at 1.024 MHz.
Figure 42.3: Listing of Packet Headers
pkx obs owner pfc spp wpp ppf fcount lcount time delta
1 39 HSP 0140 1 34 52941 19 4099 90919501.904297 0.000000
2 39 HSP 0140 1 34 52941 19 4100 90919501.913086 0.008789
3 39 HSP 0140 1 34 52941 19 4101 90919501.921143 0.008057
4 39 HSP 0140 1 34 52941 19 4102 90919501.929932 0.008789
5 39 HSP 0140 1 34 52941 19 4103 90919501.938232 0.008301
6 39 HSP 0140 1 34 52941 19 4104 90919501.947144 0.008911
7 39 HSP 0140 1 34 52941 19 4105 90919501.955200 0.008057
8 39 HSP 0140 1 34 52941 19 4106 90919501.964111 0.008911
9 39 HSP 0140 1 34 52941 19 4107 90919501.972168 0.008057
10 39 HSP 0140 1 34 52941 19 4108 90919501.981201 0.009033
11 39 HSP 0140 1 34 52941 19 4109 90919501.989258 0.008057
12 39 HSP 0140 1 34 52941 19 4110 90919501.998901 0.009644
13 39 HSP 0140 1 34 52941 19 4112 90919502.005371 0.006470
14 39 HSP 0140 1 34 52941 19 4111 90919502.006348 0.000977
15 39 HSP 0140 1 34 52941 19 4113 90919502.013672 0.007324
16 39 HSP 0140 1 34 52941 19 4114 90919502.023315 0.009644
17 39 HSP 0140 1 34 52941 19 4115 90919502.030762 0.007446
18 39 HSP 0140 1 34 52941 19 4116 90919502.039307 0.008545
19 39 HSP 0140 1 34 52941 19 4117 90919502.047852 0.008545
20 39 HSP 0140 1 34 52941 19 4118 90919502.056396 0.008545
21
There is no conclusive proof as to the frequency or randomness of these signatures. The HSP team has requested a change in the sort order to specify lines first and time second when processing the data.