Spectral Effects of Discrete-Time Amplitude Levels in Digital-Intensive Wideband Radio Transmitters
Martelius, Mikko; Stadius, Kari; Lemberg, Jerry; Roverato, Enrico; Kosunen, Marko; Ryynänen, Jussi; Anttila, Lauri; Valkama, Mikko (2018-04-26)
Martelius, Mikko
Stadius, Kari
Lemberg, Jerry
Roverato, Enrico
Kosunen, Marko
Ryynänen, Jussi
Anttila, Lauri
Valkama, Mikko
IEEE
26.04.2018
2018 IEEE International Symposium on Circuits and Systems, ISCAS 2018
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202002041829
https://urn.fi/URN:NBN:fi:tuni-202002041829
Kuvaus
Peer reviewed
Tiivistelmä
This paper examines one source of spectral degradation in polar and multilevel outphasing transmitters. The degradation is caused by the amplitude signal appearing at the transmitter output as a baseband component, in addition to the desired RF signal. This baseband component contains sampling images and quantization noise across the spectrum. Thus, it adds noise at the signal band where it cannot be filtered and limits the achievable ACLR, particularly in wideband LTE and 5G systems. We analyze the origin of this phenomenon and related effects of system and signal parameters, and propose three design solutions for eliminating or alleviating the problem. Our analysis and simulations demonstrate that using a voltage-subtracting power combiner cancels the described degradation, potentially leading to significant improvement in spectral performance.
Kokoelmat
- TUNICRIS-julkaisut [16944]