PPSsignaal

PPSsignaal, short for pulse-per-second, is a precise timing signal that marks the start of each second with a sharp electrical pulse. It is produced by time-distribution sources such as Global Navigation Satellite System (GNSS) receivers, including GPS, GLONASS, Galileo and BeiDou, as well as by dedicated time servers. The pulse is aligned to a reference time scale (typically GPS time or UTC minus any disclosed offset) and serves as an exact time anchor for other equipment.

The signal characteristics of a PPS signaal are a short, high-contrast pulse, usually lasting a fraction of a microsecond to a few microseconds. The rising edge is used as the exact time marker. Output levels are commonly TTL or CMOS, and the signal is often provided via a BNC connector or similar interface. The temporal precision of the PPS signaal depends on the source; GNSS-based PPS can achieve timing accuracy on the order of tens of nanoseconds relative to the reference time, with stability improving as the system disciplines a local oscillator.

Applications of the PPS signaal include disciplining local oscillators in timekeeping equipment, providing a precise time reference for network time servers (such as NTP and PTP), and timestamping events in data acquisition and telecommunications networks. It is not a full time code by itself but a time-edge marker that enables precise synchronization when combined with a time-of-day reference and appropriate processing.

Implementation considerations include managing jitter, propagation delay, and cable quality, as well as ensuring proper grounding and isolation. When the reference time is UTC-based, leap seconds and time-offset information must be accounted for to maintain accurate time labeling.