Transmitting System Using Alias Harmonic Components of Output Signal of DAC

Abstract

A novel transmitter, which does not require the up-converter at the baseband stage, is presented. The main difference between proposed system and conventional one is the use of an alias harmonic component as high-IF (Intermediate Frequency) signal.In this paper, each alias harmonic components are examined by EVM (Error Vector Magnitude) and, the RF (Radio Frequency) front-end using the 3rd order alias harmonic component at 180 MHz as IF is demonstrated. The EVM performance of RF output at 2150 MHz resulted in less than 4 % in the case of 200 ksps (symbol per second).

Transmitting System Using Alias Harmonic Components of Output Signal of DAC

“…The power level of IMD does not depend on frequency, so that the ratio of IMD to the desired signal becomes large in high frequency. Every alias harmonic components cause the 3rd IMDs at various frequencies, IMD 3 KZ Ai Cos oit2 n =-oo 33 =*-+A3cos3St*-+ 2 * 3Ai2A cos2 wVtcos w1t+ + * 3AiA2 cos Wit Cos 2w t + + | 6AiAiAk cos Cit cosw1t cos Ckt+ (5) where Ai cos-it represents i-th order alias harmonic component and i < j < k is assumed.…”

“…The authors have reported the possibility of the use of alias harmonic components [3] [4] [5]. This paper investigates the relationship between the oversampling rate of the DAC and the frequency of alias harmonic components satisfying low EVM characteristics for practical use, and the EVM characteristics on SNR (Signal-to-Noise Ratio).…”

Classification for synthesis of high spectral purity current-steering mixing-DAC architectures

“…M [ 1 in (1). Using M [ 1 does not result in better linearity while the signal power and Signal to Noise Ratio (SNR) is worse [10,24]. Therefore, for high spectral purity, the output signal in the first Nyquist band should be used as the primary output of the Mixing-DAC.…”