Abstract
Radio transmitters capable of transforming variable envelope signals into constant envelope signals can be associated with high-efficiency switched mode power amplifiers. One of the techniques providing this conversion is Polar Sigma-Delta (ΣΔ) architecture. This approach provides efficient solution for high-dynamic signals, and, moreover, it offers flexibility in amultiradio environment. The overall concept of the polar ΣΔ transmitter is presented here along with novel modifications and improvements. Namely, when recombining the envelope and the phase signals, it is suggested to replace the analog mixing by a digital mixing. The impact of a frequency synthesizer with a switched loop bandwidth and its imperfections on the overall polar ΣΔ architecture is investigated as well. The Mobile WiMAX standard has been chosen for validation due to very high requirements in terms of power dynamics and the variable channel bandwidth. Simulation results are presented in this paper, and advantages and drawbacks of this novel approach are pointed here as well.
Highlights
Recent years have seen a considerable development of wireless communication systems such as cellular communications, Personal Area Networks (PANs), Local Area Networks (LANs), and Metropolitan Area Networks (MANs), and they keep evolving at a rapid pace
We have presented a polar ΣΔ transmitter as a suitable candidate for multi-radio applications, and, we have proposed novel modifications and improvements to this architecture
It has been shown that proposed modifications can significantly decrease the overall circuit complexity compared to the previously proposed polar architectures
Summary
Recent years have seen a considerable development of wireless communication systems such as cellular communications, Personal Area Networks (PANs), Local Area Networks (LANs), and Metropolitan Area Networks (MANs), and they keep evolving at a rapid pace. A multiradio transceiver that combines low power and low costs by sharing reconfigurable components and that is capable of generating any arbitrary waveform becomes the ultimate goal This concept is known as a multi-radio transceiver. A multi-radio transmitter should be able to support the most diffused wireless communication standards in the radio band of 800 MHz to 6 GHz and be able to adapt its operating parameters to required specifications [1]. It has to cope with variable signal dynamics, which in turn requires high linearity and low-noise performance of the whole transmission chain.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
