gtps3m0tSystem Performance and Measurement Reference

Details of Message Collection

Time Stamp - High-Speed Input Message

 Environment: 
High-Speed input messages are time stamped when the ECB is created; this four-byte time stamp is still in the ECB when intercepted by CDC1.

 Effect: 
It is not necessary, therefore, for CDC1 to time stamp an input message before recording it on the RTC tape.

Time Stamp - High Speed Output Message

 Environment: 
There is no time stamp in an output message block when intercepted by CDC1.

 Effect: 
After intercepting the output message block, CDC1 time stamps it. The time stamp is four bytes long because CDC1 records bits 20 through 51 of the 64-bit time-of-day (TOD) clock.