100pps

1. The GPS receiver engine can output PP1S or 100PPS. If I use it as the input of PD, which one is better? What's the difference?

2. The time accuracy of PP1S is 200ns. Is that mean that the PP1S has 200ns jitter or wander?

1. What's a PD?

2. Probably yes, but depends on the receiver. Maybe you will enjoy these papers:

"Low-cost, High Accuracy GPS Timing"
ftp://www.gpstime.com/pub/ION-GPS2000/ion-time.pdf

"GPS and Precision Timing Applications"
http://metrologyforum.tm.agilent.com/pdf/AN1272.pdf

Depend on what you have to do.

For example, for frequency comparition by timing techniques, as long is the period as the Number of significative digits increase, so periods 1 sec. long are usually considered "long enough".

The 100pps (=100 Hz), once multiplied (or Phase locked) up to 10 MHz may be used as very stable external clock for instruments like SA or VNA or frequency meters.