Targeted to meet the challenging requirements of wireless data (digital TV, CATV modulators, ISM transmitters, Wireless LAN, WLL) and two-way radio systems (APCO P25), the product’s I/Q architecture supports a wide range of modulation types. Various integrated, selectable functions are offered, to maintain performance across multiple modulations and bandwidths.
The quadrature modulator provides translation from baseband I/Q signals to a modulated RF signal. The wideband inputs can be driven single-ended or differentially for optimum performance. The device offers two integrated and matched double-balanced mixers, driven from a buffered quadrature split local oscillator. The ‘LO’ frequency is divided by either 2 or 4, with the mixers forming an I/Q vector modulator with programmable gain stages, offering 30dB of gain control in 2.5dB steps.
A digital control interface, C-BUS (SPI compatible interface), allows gain control as well as the power management of individual internal blocks for optimum system performance. The C-BUS interface operates from its own power supply, enabling the CMX993 to be interfaced to baseband devices of differing voltages.