7. Fail-Safe Design . The DCPRS shall incorporate a "fail-safe" design 

 feature such that malfunctioning of the equipment shall in no way 

 cause continuous transmission. Further, provision shall be made 



to retrigger the fail-safe via the interrogation link in 90-second 

 intervals without interruption of data transmission by addressing 

 the radio set. 



8. Receive Signal . The DCPRS shall continuously receive and demodulate 

 the standard GOES Data Collection System interrogation signal over 

 an input signal level range of -100 dBm maximum to -130 dBm minimum 

 centered at 468.825 MHz^ and modulated +60°PSK with 100-bit/second 

 Manchester-coded data. The DCPRS shall be capable of simultaneous 

 reception and transmission and meet all performance requirements 



of the DCPRS in this mode. The DCPRS shall be capable of auto- 

 matically locking to the interrogation signal at an input signal 

 level as low as -135 dBm (total signal power with the following data 

 present: 15-bit Maximal Linear Sequence (MLS) sync word 

 (100010011010111) followed by the 31-bit Bose-Chaudhuri-Hocquenqhem 

 (BCH) command word (0011010010000101011101100011111)). 



9. Acquisition Time . The receiver shall acquire lock on the interroga- 

 tion signal in 2 minutes or less from standby condition, when the 

 carrier is within _100 Hz of 468.825 MHz^ . 



10. Spurious Emissions . Reradiated local oscillator and mixing frequency 

 signals shall be less than 50 microvolts at the antenna or primary 

 power in-out terminal. 



11. Antenna Polarization . Polarization shall be right-hand circular, 

 according to IEEE Standard 65.34.159. 



12 . Data Formatting Restrictions . 



The following ASCII control characters must not appear in the 



DCPRS message: DLE , NAK , SYN , ETB , CAN, GS , RS , SOH , STX, 



ETX, ENQ, and ACK. EOT characters may appear only at the end 

 of transmission. 



^For the West satellite. DCPRS assigned to the East satellite 

 will be required to receive on 468.8375 MHz. 



38 



