Title :
Analysis of VCO based noise shaping ADCs linearized by PWM modulation
Author :
Hernandez, L. ; Prefasi, E. ; Paton, Susana ; Rombouts, P.
Author_Institution :
Electron. Technol. Dept., Carlos III Univ. of Madrid, Leganes, Spain
Abstract :
Nonlinearity is one of the main problems associated with VCO based noise shaping ADCs. Their open loop architecture does not permit correction of the nonlinear voltage to frequency response of the VCO by feedback. Recently, linearization of a VCO ADC by Pulse Width Modulation (PWM) precoding has been proposed. Here, the input signal is encoded by a PWM modulator to drive the VCO with a 2-level signal, thus eliminating the nonlinearity of the VCO. This paper analyzes the remaining inherent distortion in such modulators which originates from subsampling the PWM sidebands.
Keywords :
analogue-digital conversion; frequency response; precoding; pulse width modulation; voltage-controlled oscillators; 2-level signal; PWM modulation precoding; PWM sideband subsampling; VCO nonlinearity; VCO-based noise shaping ADC linearization; frequency response; nonlinear voltage; open loop architecture; pulse width modulation precoding; Amplitude modulation; Frequency modulation; Noise; Noise shaping; Pulse width modulation; Voltage-controlled oscillators;
Conference_Titel :
Electronics, Circuits and Systems (ICECS), 2012 19th IEEE International Conference on
Conference_Location :
Seville
Print_ISBN :
978-1-4673-1261-5
Electronic_ISBN :
978-1-4673-1259-2
DOI :
10.1109/ICECS.2012.6463729
