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 generate local oscillator signals to down-convert the target signals. The Applied Physics Laboratory developed a high-speed direct digital synthesizer system to function as the programmable radio-frequency source. It operates at a clocking frequency of 600 MHz and can output frequencies up to 240 MHz in 35-Hz steps. The packaging considerations were unusual 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'' ceramic substrate material with a low dielectric constant.