Digital tranponder 11/14 GHz, 120 Mbit/sec. Phase 2: Transponder test equipment and system measurements

Test equipment which generates a 14 GHz carrier, 4 phase modulated with a time division multiplex access (TDMA) signal is described. The four phase shift keying (PSK) carrier, generated in the digital transponder, is converted to an intermediate frequency and demodulated in the test equipment. The received digital data are compared with the originally transmitted data in a TDMA test equipment for evaluating the bit error rate. The test equipment itself is checked by a test loop via a test converter from 14 GHz to 11 GHz, incorporated in the test equipment. Results show an uplink degradation of 0,9 dB and a downlink degradation of 1,7 dB, with 0.001 bit error rate (nominal levels and room temperature) for transponder and test equipment together.