×

Sensing device and method for measuring emission time delay during irradiation of targeted samples

  • US 6,157,037 A
  • Filed: 12/04/1998
  • Issued: 12/05/2000
  • Est. Priority Date: 12/04/1998
  • Status: Expired due to Term
First Claim
Patent Images

1. An apparatus to measure emission time delay during irradiation of targeted samples by utilizing digital signal processing to determine the emission phase shift caused by the sample, said apparatus comprising:

  • a source of electromagnetic radiation adapted to irradiate a target sample;

    means for generating first and second digital input signals of known frequencies with a known phase relationship;

    means for converting said first and second digital input signals to analog sinusoidal signals;

    means for directing said first analog input signal to said electromagnetic radiation source to modulate said electromagnetic radiation source by the frequency thereof to irradiate said target sample and generate a target sample emission;

    means for detecting said target sample emission and producing a corresponding first analog output signal having a phase shift relative to the phase of said first analog input signal, said phase shift being caused by the emission time delay in said sample;

    means for producing a known phase shift in said second analog input signal to create a second analog output signal;

    means for converting said first and second analog output signals to first and second digital output signals respectively;

    a mixer for receiving said first and second digital output signals and comparing the signal phase relationship therebetween to produce a signal indicative of the change in phase relationship between said first and second digital output signals caused by said target sample emission; and

    feedback means to simultaneously alter the frequencies of said first and second digital input signals while substantially continuously vary the phase offset between said first and second digital input signals based on said mixer signal to ultimately place said first and second digital output signals in quadrature while compressing the frequency range therebetween.

View all claims
  • 3 Assignments
Timeline View
Assignment View
    ×
    ×