Linear transmitter architecture using a 1-bit /spl Sigma//spl Delta/

Linearity of transmitter is a difficult point to achieve with non constant envelope modulation. The simplest solution is to use a class A power amplifier with sufficient back off, so that sufficient linearity can be obtained but to the detriment of the efficiency. In this paper we present a development of the classical EER architecture where the non constant modulated signal is transformed into a constant one. The envelope variation is restored after an efficient power amplifier with a simple bandpass filter. The key point of this architecture is a full digital 1-bit sigma-delta modulator used to transform the envelope signal into a series of pulses working at frequencies up to 1 GHz