SPACE-BASED HIGH-SPEED DIRECT DIGITAL SYNTHESIZER MULTICHIP-MODULE USING LOW-TEMPERATURE COFIRED CERAMIC

The Mid-Course Space Experiment S-Band Beacon Receiver, a space-based radar system, required a programmable radio frequency source to genera te local oscillator signals to down-convert the target signals. The Ap plied Physics Laboratory developed a high-speed direct digital synthes izer system to function as the programmable radio-frequency source. It operates at a clocking frequency of 600 MHz and can output frequencie s up to 240 MHz in 35-Hz steps. The packaging considerations were unus ual because of the weight, size, and clock rate requirements specific to this application. To accommodate circuit performance at high speeds , the Laboratory used a low-temperature co-fired ''green tape'' cerami c substrate material with a low dielectric constant.