MENU_HP:  Time signal processing:  HBG Time-Code (CH)
In these 3 frames you can see:
A)    one 10 s window of a generic HBG Time-Code, from Newchatel (CH), recorded during this seismic recording (Apulia, South Italy, 1972), sampled at 100 Hz; if you 'read' it carefully, you could see the 3-spikes hour mark, pointed out by the arrow;
B)    the results of the two stacking algorithm, regarding the first and last 30 s of the Time-Code signal; in this case the routine TSTAC was set in 'AUTO' mode (and it worked properly: see the correct 'X' positions on the beginning of the big slope);
C)    a 13 s length signal window (from sec 7 to 20) of the VR channel; note the offset and the amplitude levels.

The Time-Code, here, was the HBG; but many others do exist in Europe, and more complete, for example the DCF (from Mainflingen, Germany)

MENU_HP: Time-Code processing