ABSTRACT

The single most important specification affecting the final system cost is often the transmitter saturated power, which is intimately linked to the transmitter linearity requirements. The transmitter average and peak output powers are usually determined from link/margin analysis for the overall system. A signal is generated by the frequency synthesizer and amplified by the transmitter, after which it is fed to the antenna for transmission. The transmitter may include frequency conversion or multiplication to the actual transmit band. The need for high linearity is dependent on the maximum acceptable adjacent channel power in adjacent channels or bands. Since most of the signal processing is performed at the modulation frequencies, the majority of the circuit is available for application-specific integrated circuit implementation. The in quadrature modulator is a basic building block used in numerous applications, and is an essential element of many linearization methods.