Analog Devices introduces a new direct digital frequency synthesizer

     Analog Devices announced that the company has increased the clock speed of its previous DDS integrated circuit (IC) by more than three times. ADI's AD9914 incorporates an on-chip high-speed 12-bit DAC with a sampling rate of 3.5 Gigabits per second (GSPS), while the AD9915 delivers 2.5 GSPS. Both device cores support advanced digital programmable technology capable of synthesizing frequency flexibility to simulate output sine waves at frequencies up to 1.4 GHz for a variety of communications applications, such as wireless base stations, military and commercial radars, and to protect communications systems.

     The new DDS device includes a 32-bit parallel port that allows for extremely rapid changes in the frequency, phase, and amplitude of the output signal, as well as programmable modular capabilities that expand the use of DDS ics for applications that require precise rational number relationships, such as signal generators and other laboratory equipment.

     Peter Real, vice president of Linear and RF products at Analog Devices, said: "By increasing the clock speed of the high-resolution DDS IC to 3.5 GSPS, our customers can generate higher output frequencies while improving dynamic performance. Analog Devices' new DDS products represent a significant advancement in technology, enabling better spury-free dynamic range (SFDR) over a much wider frequency band than previous generations. The AD9914 and AD9915 improve SFDR with fast frequency hopping and precision FM resolution, allowing designers to change frequencies in one clock cycle with ultra-precision FM.

     AD9914 and AD9915 take just a few nanoseconds to establish and have particle sizes well below 200 pHz. Other methods, including FPgas with built-in embedded DDS capabilities, are difficult to match the SFDR of Analog Devices DDS ics (better than -50 DBC) on output signals above 1 GHz, and require high operating power and discrete Dacs to synthesize sine waves.