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EEPW首頁 > 模擬技術(shù) > 設(shè)計(jì)應(yīng)用 > 利用MAXQ7667確定超聲傳感器的諧振頻率和阻尼特性

利用MAXQ7667確定超聲傳感器的諧振頻率和阻尼特性

作者: 時(shí)間:2012-09-14 來源:網(wǎng)絡(luò) 收藏
UND-COLOR: rgb(255,255,255); orphans: 2; widows: 2; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px">  // Find the center frequency based on the average of the two frequencies that have a

  // LPFD reading that is 70% of the peak reading.

  for (i = 0; i number_of_steps; i++)

  {

  if (lpfdata[i] > peak*0.7)

  {

  first70 = i;

  i = number_of_steps;

  }

  }

  for (i = number_of_steps; i >0; i--)

  {

  if (lpfdata[i] > peak*0.7)

  {

  second70 = i;

  i= 1;

  }

  }

  i = (first70 + second70)/2; // i = the loop value at the center frequency.

  center_pllf = i*step_size; // Set PLLF_bit.PLLF to this value for the resonant frequency.

  //Remeasure damping using the center frequency.

  damp_time = damping_half_time(center_pllf, 75);

  // At this point there are three valuable pieces of information about the transducer.

  // Peak = the peak value from the frequency sweep.

  // center_pllf = the PLLF setting at the resonant frequency.

  // damp_time = time for the resonance to decay to 1/2 the peak value.

  center_burst_frequency = 16000000/Burst_Clock_Divider*(center_pllf+768)/1024;

  SendData();

  } // While(1)

  } // End Main


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