Performance and qualification of a multi-rate DPSK modem

Abstract

Recently, we demonstrated a multi-rate DPSK modem with high-sensitivity over a wide dynamic range, which can significantly benefit performance and cost of NASA’s Laser Communication Relay Demonstration. This increased flexibility, combined with the need to verify robust operation under challenging free-space environmental conditions, results in a large number of operational states which must be accurately and thoroughly tested. To support this, we developed test and diagnostic capabilities that can be easily reconfigured to assess modem performance across a wide range of data rates and operational modes. These capabilities include internal self-test modes in which test waveforms can be directed from the transmitter into the receiver to determine modem communications performance. We used these self-test capabilities to demonstrate robust performance in realistic environments during thermal-vacuum, shock/vibration, and EMI/EMC testing.