APPENDIX C 



DCPRS Certification Standards 

 (Interrogated & Self -Timed) 



•1 . RF Power Output . The Effective Isotropic Radiated Power 

 (EIRP) of a DCPRS and antenna shall not exceed 50dBm 

 under any combination of service conditions. 



2. Frequency Characteristics . DCPRS received radio frequency 

 (RF) shall be 468.825 MHz^ . The transmitter RF shall be 

 in the 401.85 MHz to 402 MHz band. (See Table 1.) 



3. Stability . 



A. Temperature . The transmitter carrier frequency 

 shall change by less than 0.5 parts per million 

 over the temperature range of -20°C to +50°C. 



B. Long-Term . The long-term stability (including 

 temperature variations) shall be better than one 

 part per million per year. 



C. Short-Term . The phase jitter on the transmit 

 carrier shall be less than 3 degrees RMS. 



4. Electromagnetic Interference (EMI) . All transmitter 

 spurious emissions, when measured with modulation and with 

 antenna and diplexer connected, shall be down from the 

 unmodulated carrier level by 50dB. 



5. Transmission Format . After a minimum of 4.9 seconds of 

 unmodulated carrier, the carrier shall be modulated with 

 the bit and message synchronization patterns which are at 

 least 2.4 seconds of alternate 1, data bits, and the 46- 

 bit preamble consisting of the 15-bit MLS sync word 

 followed by the 31-bit BCH command word. Transmission of 

 the address shall be complete within 11 seconds after receipt 

 of an interrogation. The binary data shall be Manchester- 

 encoded 8-bit ASCII, odd parity and shall modulate the 

 carrier in the following manner: a data "0" shall consist of 

 +60° (+5°) carrier phase shift for 5 milliseconds followed by 

 -60° (+5°) carrier phase shift for 5 milliseconds, and a data 

 "1" shall consist of -60° (+5°) carrier phase shift for 5 

 milliseconds followed by +60° (+5°) carrier phase shift for 



5 milliseconds. Data rate shall be 100 BPS +.1 BPS . (See 

 Figure 1 . ) 



6. End of Transmission . Immediately after sending the sensor data, 

 the DCPRS shall transmit three 8-bit ASCII, odd parity, 



End of Transmission (EOT) characters contiguously with the 

 ASCII sensor data characters (no break) and return to the 

 standby condition. 



'For the West Satellite. DCPRS assigned to the East Satellite 

 will be required to receive on 468.8375 MHz. 



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