Speaker info: Mark Elo, Jon Netzer, Joan Mercade (please add everyone’s Bio)
Abstract:
The need for faster and faster data rates in cellular systems creates a number of design challenges for analog RF engineers, especial those designing amplifiers or transmitter output stages. The underlying dominant cellular transmission technology is Orthogonal Frequency Division Multiplex (OFDM), and while it has excellent multipath resilience, things become more problematic as you increase the throughput of the transmission. Wider bandwidths mean more modulated carriers and this will inevitably increase the peak to average ratio of the signal. High peak signals will cause intermodulation distortion, which then generates spectral regrowth, adjacent channel interference, and a deterioration of the EVM performance.
In this session we will talk about various amplifier stimulus signals that will help you get the most insight into how your amplifier is going to perform. Stating with fundamentals of a two-tone stimulus through to the use of multi-tones with various phase relationships that allow you to stress the amplifier deterministically. Then we will look at the OFDM signal and how different test signals for 4G, 5G, and WiFi are employed to create peak signals causing different types of spectral regrowth. We will also discuss how to reduce spectral regrowth with techniques such as waveform clipping and envelope tracking.
We’ll discuss some theory, some practical aspects and have a number of measurement demonstrations, using analog signal generators and arbitrary waveform generators. You will gain some great insights and come away with some solid techniques on how to make effective measurements and fully understand how to get the most performance out of your amplifier and output stage.