---
res:
  bibo_abstract:
  - Simultaneous transmitting and receiving (STaR) enhances the utilization of single
    transducer ultrasound measurement systems. In distance measurement applications
    the dead zone can be reduced to nearly zero, independent of the transmitted signal.
    So it is possible to transmit codedsignals to identify different sensors without
    increasing the minimum distance. The electrical transducer signal consists of
    the electrical transmitted and received signal. A separation of these two signals
    can be done with a mathematical model of the electrical system. For this purpose
    it is necessary to digitize the electrical transducer signal. Due to the relative
    small amplitude of the received signal compared to the transmitted signal amplitude,
    a high resolution analog to digital converter (ADC) is needed. This leads to high
    requirements for the ADC. The necessary resolution limits the sample rate of the
    ADC. By down mixing the transducer signal using a coherent quadrature demodulation
    (CQD), as used in many high frequency ultrasound applications, the sample rate
    of the ADC can be reduced. In this contribution an airborne ultrasound distance
    measurement system with reduced dead zone is used to analyze the effects of this
    concept to the signal conditioning, system identification and system performance.
    The approach is compared with a system without CQD and an ADC with a lower resolution
    but a higher sample rate. By analyzing the pros and cons of both systems the usability
    of a CQD based system for a STaR application is evaluated. The distance measurement
    system used for the experiments is based on a 40 kHz airborne ultrasonic transducer.
    A gyrator based transmit amplifier delivers a system bandwidth of about 10 kHz.
    In the experiments, coded transmitted signals are used to measure the distance
    to a metal reflector. The main objectives are short distances between 0 mm and
    200 mm. Here a separation of transmitted and received signal is necessary. The
    reflector distance is calculated by a cross correlation between transmitted and
    received signal.@eng
  bibo_authorlist:
  - foaf_Person:
      foaf_givenName: Andreas
      foaf_name: Schröder, Andreas
      foaf_surname: Schröder
  - foaf_Person:
      foaf_givenName: Bernd
      foaf_name: Henning, Bernd
      foaf_surname: Henning
  dct_date: 2011^xs_gYear
  dct_language: eng
  dct_title: Model based separation of transmitted and received signal for single
    transducer distance measurement applications@
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