Quad-band EDGE Transceiver
Analog Devices, Inc. announces its single-chip radio transceiver for the EDGE (Enhanced Data Rates for GSM Evolution) cellular standard. Based on the company’s direct conversion Othello® radio architecture, the new Othello-E transceiver integrates virtually all the necessary components, including voltage-controlled oscillators (VCOs), PLL loop filters and power management, for a complete quad-band EDGE radio design. The device can operate in the 850, 900, 1800, and 1900 MHz frequency bands, enabling worldwide coverage. To achieve the increased linearity necessary for the signals that support EDGE data rates, the Othello-E radio leverages a logarithmic RF power detector to enable a closed-loop polar modulation transmitter design, which also contributes to better manufacturability and reduced design complexity. Closed-loop polar modulation is an improvement over open-loop polar designs which require close matching of the transceiver and power amplifier. Analog Devices Othello-E transceiver (part number AD6546) includes separate low-noise amplifiers (LNA) for all four GSM bands (850, 900, 1800 and 1900 MHz) and a fractional-N PLL synthesizer with integrated VCO and loop filter for local oscillator (LO) generation.