N8UR PPS Logging System --
Switch Configuration
The PPS logging system uses two HP 59307A "VHF Switches" to route the various PPS signals to the time interval counter. The 59307A is GPIB controlled, and each unit has two independent 4-pole, single-throw switch units.
By cascading switches, two units can provide a total of 14 inputs and outputs, in practical configurations of 10 start and 4 stop channels or 7 start and 7 stop channels. I'm currently using the 10 and 4 configuration, with the routing shown as in the table below
| 1A common | To HP 5334A START | |
| 1A1 | To 1B common | |
| 1A2 | To 2A common | |
| 1A3 | From HP 5061A | PPS B2 |
| 1A4 | From HP 5065A | PPS C2 |
| 1B common | To 1A1 | |
| 1B1 | From CNS II | |
| 1B2 | From Spectracom 8170 | PPS D1 |
| 1B3 | From Z3805A | |
| 1B4 | Spare |
| 2A common | To 1A2 |
| 2A1 | From patch 01-8 |
| 2A2 | From patch 01-9 |
| 2A3 | From patch 01-10 |
| 2A4 | From patch 01-11 |
| 2B common | To HP 5334A STOP |
| 2B1 | From HP 5061A |
| 2B2 | From Z3805A |
| 2B3 | From CNS II |
| 2B4 | From patch 01-12 |
The cable from switch 2B to the HP 5334A STOP input is several feet longer than the cable to the START input. This provides enough delay that system noise tests can be performed by selecting the same source for both start and stop channels.