APPENDIX E 



Certification Specifications for 

 International DCPRS 



1. RF Power Output 



The Effective Isotropic Radiated Power (EIRP) of a DCPRS 

 and antenna shall not exceed 52 dBm under any combination 

 of service conditions. 



2. Frequency Characteristics 



The DCPRS transmitted RF shall be in the 402. 002 57 7- MHz to 

 402.098582-MHz band. (See Table 1.) 



3. Stability 



A. Temperature and Long Term 



The transmitted carrier frequency stability shall be 

 better than 1.5 parts per million against temperature 

 variations and aging altogether. This specification 

 applies typically over the temperature range of -20°C 

 to +50°C and over 1 year, unless specified differently 

 by the DCP operator. 



B. Short Term 



The phase jitter on the transmit carrier shall be less 

 than 3" RMS when measured through a phase lock loop 

 two-sided noise bandwidth (2BL) of 20 Hz and within 

 + 2 KHz. (See Fig. 1. ) 



4. Electromagnetic Interference 



Any transmitter spurious emissions, when measured with 

 modulation and with antenna and diplexer connected, shall be 

 down from the unmodulated carrier level by 60 dB, (referred 

 to a measurement bandwidth of 500 Hz). International ship- 

 board EMI specification should also be included. 



5. Transmit Data 



After 5 seconds of unmodulated carrier, the carrier shall be 

 modulated with the bit and message synchronization data 

 patterns which are 2.5 seconds of alternate 1,0 data bits, and 

 the 46-bit preamble consisting of the 15-bit MLS synch word 

 (100010011010111) followed by the 31-bit BCH address word 

 (different for each platform), and a message proper consisting 

 of 8-bit data words. The binary data shall be Manchester 

 encoded and shall modulate the carrier in the following manner: 



A data "0" shall consist of +60° carrier phase shift for 5 

 milliseconds followed by -60° carrier phase shift for 5 

 milliseconds, and a data "1" shall consist of -60° carrier 

 phase shift for 5 milliseconds followed by +60° carrier 

 phase shift for 5 milliseconds. (See Fig. 2.) The phase of 

 the 5 seconds unmodulated carrier shall correspond to the 

 phase of the modulated carrier. 



75 



