Millimeter-Wave Modulated-Signal and Error-Vector-Magnitude Measurement With Uncertainty

Abstract

We provide techniques to generate and characterize precision wideband millimeter-wave modulated signals. We use predistortion to obtain a significant improvement in signal quality and an associated reduction in the error vector magnitude (EVM) of the signals generated by an arbitrary-waveform-generator-based source. We adapt a recently developed microwave uncertainty framework to the problem and use it to estimate the uncertainties in the modulated-signal measurements. Models of uncertainties related to all calibration and measurement procedures within the traceability path are included in a sensitivity analysis and Monte Carlo simulations that maintain correlations between time-and frequency-domain errors. We demonstrate EVM values of approximately 1.6% 0.5% for a 1-GSymbol/s 64-state quadrature-amplitude-modulated signal at 44 GHz.Index Terms-Digitally modulated signal, error vector magnitude (EVM), measurement uncertainty, microwave measurement, millimeter-wave wireless communications, oscilloscope, wireless system.

Comparison of timebase interpolation methods for traceable, wideband mm-wave communication signals

“…However, the time base corrections seen experimentally for our system, show that the interpolation choice has a relatively small effect on EVM for our typical 2.5 ps time step. Although the EVM values, as shown in Table 1, are small, the uncertainty analysis in [3] yielded an average EVM of approximately 1.5%. Thus, although we can minimize EVM of our precision source, the effect is not significant.…”

“…First, there is intense interest in expanding the available wireless spectrum to these high frequencies [2]. Second, we have developed at NIST a method using predistortion for generating a precise, calibrated communication signal at these frequencies that allows a rigorous estimate of uncertainties [3].…”

“…Prior work [5]- [8], including our own [3] has allowed accurate uncertainty estimates for this metric. Thus, the EVM provides an ideal measurement with which to compare the choice of an interpolation method in reconstructing a modulated signal.…”

“…PREDISTORTION While the method for creating a broadband, modulated signal with minimized EVM has been discussed previously [3], a brief summary will be presented here. This method will work for a modulated signal in any protocol.…”

Co-Simulation for Systematic and Statistical Correction of Multi-Digital-to-Analog-Convertor Systems

“…To realize the deployment of 5G systems, methods to calibrate signal generators with wide bandwidths are being studied [1,2]. The high-speed signals required for 5G systems are generally synthesized by incorporating medium-speed digital-toanalog converters (DACs) as if the overall speed reaches multiple times the speed of an individual DAC [3].…”