Bi-level Quadrature-modulation low-pass EPWM transmitter using half side of tri-level ΔΣ modulator

Abstract

This paper presents a bi-level quadraturemodulation (QM) low-pass (LP) envelope-pulse-widthmodulation (EPWM) transmitter using a half side of tri-level EPWM. Simulation including digital signal processing with the QM LP-EPWM and microwave circuit simulation with a class-D power amplifier (PA) using n-MOSFETs shows an excellent error vector magnitude (EVM) of 36 dB at 1 GHz. The transmitter with a class-D PA for bi-level EPWM signal shows much better EVM performance than the one for trilevel signal.Index Terms -transmitterpower amplifierclass-D envelope pulse-width modulationquadrature modulation, error vector magnitudepower-added efficiency

Optimization of DSM Sampling Frequency and Interleaving Frequency for Bilevel Quadrature-Modulation EPWM Transmitter

“…To meet these requirements, the envelope pulse-width modulation (EPWM) technique [1]- [12] has been intensively investigated owing to its potential high power efficiency and linearity. Among the EPWM transmitter architectures the quadraturemodulation-type (QM) EPWM transmitter [2], [4]- [6], [8]- [12] is promising. First, QM EPWM enables a lower sampling rate for pulse-width modulators such as  modulators (DSMs).…”

“…However, in this configuration the chip area and power loss are large owing to the existence of a transformer [13] which must be connected with a single-ended device such as a microstrip antenna. To solve this problem, we previously proposed a bilevel QM EPWM transmitter using a half side of a trilevel QM EPWM architecture [11]- [12]. This transmitter can achieve high efficiency because the trilevel DSM used in the transmitter represents the "off" state which stops a burst RF signal [11].…”

“…This transmitter can achieve high efficiency because the trilevel DSM used in the transmitter represents the "off" state which stops a burst RF signal [11]. In addition, this transmitter enables the bilevel operation of a PA and only one PA is needed [12]. Therefore, the chip area and power loss are small owing to the omission of the transformer necessary for combining positive and negative signals in a trilevel transmitter [12].…”

“…In addition, this transmitter enables the bilevel operation of a PA and only one PA is needed [12]. Therefore, the chip area and power loss are small owing to the omission of the transformer necessary for combining positive and negative signals in a trilevel transmitter [12]. However, the optimum relationship between the DSM sampling frequency (fs), the interleaving frequency (f i ) and the carrier frequency (f c ) for a bilevel QM EPWM transmitter has not been investigated [11]- [12].…”

“…Therefore, the chip area and power loss are small owing to the omission of the transformer necessary for combining positive and negative signals in a trilevel transmitter [12]. However, the optimum relationship between the DSM sampling frequency (fs), the interleaving frequency (f i ) and the carrier frequency (f c ) for a bilevel QM EPWM transmitter has not been investigated [11]- [12]. This paper presents this optimum relationship, with the error vector magnitude (EVM) and the coding efficiency (CE) as figures of merit (FOMs).…”