Method and apparatus for performing analog mode operations when transmitting audio and data in a wireless tdma system

Abstract

A method and apparatus are provided for use in a transceiver of a wireless system that enable analog mode operations to be performed using in-phase (I) and quadrature (Q) values. The apparatus comprises a processor that performs FM modulation to generate I, Q pairs when operating in the analog mode. When transmitting in the analog mode, the processor encodes a digital representation of the signal to be transmitted into I, Q pairs and outputs the I, Q pairs to a digital-to-analog converter (DAC) comprised by the apparatus. The DAC converts the digital I, Q pairs into analog signals and outputs the analog signals to a cosine wave generator, which generates an in-phase cosine wave and an out-of-phase cosine wave having amplitudes that are proportional to the I and Q values, respectively. The cosine waves are summed for transmission over air. When receiving in the analog mode, a digital down converter converts the received signal into digital I and Q values. The processor then demodulates the I and Q values into a digital representation of the received signal to extract the signal content. When transitioning from transmitting data to transmitting audio, and vice versa, the processor ensures that abrupt changes in the phases of the I, Q pairs do not occur.