VCO based multi-stage noise shaping ADC Articles uri icon

publication date

  • February 2012

start page

  • 206

end page

  • 208

issue

  • 4

volume

  • 48

International Standard Serial Number (ISSN)

  • 0013-5194

Electronic International Standard Serial Number (EISSN)

  • 1350-911X

abstract

  • 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.