Electronics Letters · 2012 · 16 citations · 3 references
EngineeringElectrical EngineeringAnalog ElectronicsLow-power DesignMicroelectronicsAnalog Integrated CircuitsCmos Circuit DesignDigital Integrated Circuit DesignDigital Integrated CircuitsLow-power Digital Circuit DesignPulse-width ModulationAnalog-digital ConversionAnalog-to-digital ConversionAnalog-to-digital Converter DesignAnalog-to-digital ConvertersCmos Analog Integrated CircuitsCmos Digital Circuit DesignNonlinearityVoltage-controlled Oscillators
A way to combine several analogue-to-digital converters (ADCs) based on voltage-controlled oscillators (VCOs) to implement a multi-stage noise shaper (MASH) is proposed. By means of a simple digital circuit, the phase quantisation error in one stage is extracted as a pulsed signal. Then, this pulsed signal modulates the VCO in the next stage. First, the equations that describe the system are discussed and then a hardware implementation suitable for low power applications is proposed. The proposed implementation circuit also desensitises the ADC from the VCO nonlinearity by precoding the input signal using a pulse width modulation modulator.
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