244 Keysight E8357D/67D & E8663D PSG User’s Guide
GPS Modulation (Option 409)
Real Time GPS
Figure 8-3
GPS Signal Generation Diagram
Data Modes and Subframe Structures
You can select one of the three following data modes for use with the C/A or
C/A+P ranging code:
— Raw - The Raw data mode enables the continuous transmission of 300 bits
of data per subframe without incorporating parity bits. Use this mode for
BER and low-level demodulation testing.
— Enc - The encoded (Enc) data mode enables the continuous transmission of
10 words per subframe, with each word containing 24 bits of raw data and 6
trailing parity bits (computed from the selected data by the PSG).
— TLM - The telemetry (TLM) mode enables the continuous transmission of a
formatted TLM word, a handover word (HOW), and default navigation data
as outlined in the
Global Positioning System Standard Positioning Service
Signal Specification
, 2nd Edition, June 2, 1995. Use this mode for receiver
testing.
shows the subframe structures for each data mode.
