Description

The AD9957 functions as a universal I/Q modulator and agileupconverter for communications systems where cost, size, powerconsumption, and dynamic performance are critical. TheAD9957 integrates a high speed, direct digital synthesizer(DDS), a high performance, high speed, 14-bit digital-to-analogconverter (DAC), clock multiplier circuitry, digital filters, andother DSP functions onto a single chip. It provides basebandupconversion for data transmission in a wired or wirelesscommunications system.The AD9957 is the third offering in a family of quadraturedigital upconverters (QDUCs) that includes the AD9857 andAD9856. It offers performance gains in operating speed, powerconsumption, and spectral performance. Unlike its predecessors,it supports a 16-bit serial input mode for I/Q baseband data.The device can alternatively be programmed to operate either asa single tone, sinusoidal source or as an interpolating DAC.The reference clock input circuitry includes a crystal oscillator,a high speed, divide-by-two input, and a low noise PLL formultiplication of the reference clock frequency.The user interface to the control functions includes a serial porteasily configured to interface to the SPORT of the Blackfin®DSP and profile pins to enable fast and easy shift keying of anysignal parameter (phase, frequency, or amplitude).Applications HFC data, telephony, and video modems Wireless base station transmissions Broadband communications transmissions Internet telephony