Pulse per second

A pulse per second (PPS, or 1PPS ) (also called pulses per second) is an electrical signal, which lasts less than a second, has a sharp rising or falling edge, and the repeated precise once per second. PPS signals output from the radio - beacon, frequency standards, or other types of oscillators, and some precision GPS receivers. Precision watches are sometimes manufactured so that they generate a PPS signal and passed to a processing unit, where the PPS signal is aligned to the UTC second and is converted to a usable format for the display. Atomic clocks have an external PPS output usually, although they could work internally with 9,192,631,770 Hz (see definition of a second). PPS signals have an accuracy of 12 picoseconds, which can extend to a few microseconds, or 2.0 nanoseconds to several milliseconds per day.

Use

PPS signals are used for precise timekeeping. An increasingly spreading application is the computer-based time tracking, taking into account the NTP protocol. Because GPS is assumed to be a Stratum 0 source, a common application is the connection of the PPS signal to the PC via a connection with low latency and low jitter that the program allows to synchronize it. This turns the PC into a stratum 1 time source. It is noted that because the PPS signal is not defined as the time, but the start of the second, must be combined with another function, the PPS time source that provides the full date and time. In this way, the time can be found both accurate and precise.