Two-frequency impedance plethysmograph: real and imaginary parts

Albert Lozano-Nieto, J. Rosell, R. Pallás-Areny

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


A four-channel impedance plethysmograph has been designed. Impedance signals are obtained at two frequencies by measuring both real and imaginary parts. Particular attention has been paid to the sine wave generation circuits that provide system versatility. The required phase-sensitive demodulation is achieved by means of analogue multiplexers. Results show that there are significant variations in the thoracic equivalent capacitance related to respiration and that there is an increased sensitivity to cardiac activity at low frequencies.

Original languageEnglish (US)
Pages (from-to)38-42
Number of pages5
JournalMedical & Biological Engineering & Computing
Issue number1
StatePublished - Jan 1 1990

All Science Journal Classification (ASJC) codes

  • Biomedical Engineering
  • Computer Science Applications


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