Method and means for parallel frequency acquisition in frequency domain fluorometry
First Claim
1. A digital frequency domain system for measuring the light emitted by a sample when excited by a light source having harmonic content, said system comprising:
- (a) means for exciting said sample to emit a light signal, said means including a light source having a harmonic content and a predetermined fundamental frequency thereof;
(b) a first means for detecting the light emitted by the sample to generate a first electrical signal containing information representative of the response of said sample at said fundamental and harmonic frequencies;
(c) a second means for generating a second electrical signal representative of said fundamental frequency and a predetermined correlation frequency;
(d) cross-correlation means for mixing said first and second electrical signals to generate a third electrical signal having a response at the fundamental and harmonic frequencies imposed on said correlation frequency;
(e) means for digitizing said third electrical signal to obtain a plurality of data values for each period of the correlation frequency;
(f) a data processing means for simultaneously calculating from said plurality of data values the phase and modulation values of the response of the sample at the fundamental and a predetermined number of said harmonic frequencies.
2 Assignments
0 Petitions
Accused Products
Abstract
A digital frequency domain fluorometer utilizing a computer-controlled digital data acquisition system is use for the study of fluorescence and phosphorescence phenomena in the bio-chemical, biological and bio-physics arts. The computer is used for the direct collection of data, as well as for the filtering and calculation of the phase and modulation values of the sample under study. From these values, fluorescence lifetimes and anisotropy decay times can determined. The digital data acquisition system provides for the simultaneous collection and processing of several modulation frequencies. In addition, the digital frequency domain fluorometer can utilize an array detector for detecting the modulated light from the various samples under study. The use of the array detector provides a means for independently collecting data over a large number of pixels. This configuration allows for a time resolved image to be collected at once.
-
Citations
65 Claims
-
1. A digital frequency domain system for measuring the light emitted by a sample when excited by a light source having harmonic content, said system comprising:
-
(a) means for exciting said sample to emit a light signal, said means including a light source having a harmonic content and a predetermined fundamental frequency thereof; (b) a first means for detecting the light emitted by the sample to generate a first electrical signal containing information representative of the response of said sample at said fundamental and harmonic frequencies; (c) a second means for generating a second electrical signal representative of said fundamental frequency and a predetermined correlation frequency; (d) cross-correlation means for mixing said first and second electrical signals to generate a third electrical signal having a response at the fundamental and harmonic frequencies imposed on said correlation frequency;
(e) means for digitizing said third electrical signal to obtain a plurality of data values for each period of the correlation frequency;(f) a data processing means for simultaneously calculating from said plurality of data values the phase and modulation values of the response of the sample at the fundamental and a predetermined number of said harmonic frequencies. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A digital frequency domain fluorometer for measuring the fluorescent response of a sample when excited by a pulsed light source, said fluorometer comprising:
-
(a) means for exciting said sample to emit fluorescent light, said means including a pulsed light source of a predetermined fundamental frequency, said fundamental frequency intrinsically defining a plurality of harmonic frequencies; (b) a first means for measuring the fluorescent light emitted by the sample to generate a first electrical signal containing phase and modulation information representative of the response of said sample at said fundamental and harmonic frequencies; (c) a second means for generating a second electrical signal representative of said fundamental frequency and a predetermined correlation frequency; (d) cross-correlation means for mixing said first and second electrical signals to generate a third electrical signal having the phase and modulation response at the fundamental and harmonic frequencies imposed on said correlation frequency; (e) means for digitizing said third electrical signal to obtain a plurality of data values for each period of the correlation frequency; (f) a first filter means for removing any non-harmonic or non-synchrous frequencies from said plurality of data values; (g) a data processing means for calculating a fast fourier transform on said plurality of data and modulation values to obtain the phase values of the response of the sample at the fundamental and a predetermined number of said harmonic frequencies; - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
-
-
20. A method of measuring the response of a sample having a harmonic content when excited by a light source, said method comprising:
-
(a) exciting said sample to emit a light signal with a light source at a predetermined fundamental frequency, said light source having a harmonic content; (b) detecting the light emitted by the sample to generate a first electrical signal containing information representative of the response of said sample at said fundamental and harmonic frequencies; (c) generating a second electrical signal representative of said fundamental frequency and a predetermined correlation frequency; (d) mixing said first and second electrical signals to generate a third electrical signal having a response at the fundamental and harmonic frequencies imposed on said correlation frequency; (e) digitizing said third electrical signal to obtain a plurality of data values for each period of the correlation frequency; (f) simultaneously calculating from said plurality of data values, the phase and modulation values of the response of the sample at the fundamental and a predetermined number of said harmonic frequencies. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29)
-
-
30. A digital frequency domain fluorometer for measuring the response of a sample when excited by a light source, said fluorometer comprising:
-
(a) first means for exciting said sample to emit a light signal, said means including a light source having a harmonic content and a predetermined fundamental frequency, said light signal containing phase and modulation information representative of the response of the sample at said fundamental and harmonic frequencies; (b) second means for generating a second signal representative of said fundamental frequency and a predetermined correlation frequency; (c) third means for mixing said light signal and said second signal to generate a third signal representative of the phase and modulation information imposed on the correlation frequency; (d) fourth means for converting third signal to an electrical signal and digitizing said electrical signal to obtain a plurality of data values for each period of the correlation frequency; (e) a data processing means for simultaneously calculating from said plurality of data values phase and modulation values of the response of the sample at the fundamental and a predetermined number of said harmonic frequencies. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39)
-
-
40. An improved array detector for detecting the emissions of an excited sample, said array detector
(a) means for exciting a sample said means exciting said sample at a predetermined frequency f1 ; -
(b) an array detector for receiving and recording the level of emissions received from sample; (c) an image intensifier positioned between said sample and said detector; (d) means for selectively biasing said image intensifier to effectively gate the emissions received by said detector at a frequency of f1 and fc ; (e) means for reading the recorded levels of emissions at the array detector at a frequency greater than fc
-
-
41. A system for measuring the light emitted by a sample when excited by a light source, said system having an array detector for detecting the modulated light emissions of an excited sample, said array detector comprising:
-
(a) a semiconductor array, for receiving and recording the level of modulated light emissions received from said sample; (b) an image intensifier positioned between the sample and said semiconductor array, said image intensifier modulating the gain of the modulated light emissions received from said sample and translating said emissions from a first frequency range to a second frequency range; (c) means for selectively biasing said image intensifier to effectively pass to said array detector emissions having frequencies of f1 and fc ; and (d) means for reading at a frequency than fc, the recorded levels of modulated light emissions of said array detector. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48, 49, 50)
-
-
51. A system for measuring the light emitted by a sample when excited by a light source, said system having an array detector for detecting the modulated light emissions of an excited sample, said array detector comprising:
-
(a) a semiconductor array for receiving and recording the level of modulated light emissions received from said sample; (b) an image intensifier positioned between said sample and said semiconductor array, said image intensifier modulating the gain of the modulated light emissions from a first frequency range to a second frequency range; (c) means for selectively biasing said image intensifier to effectively pass to said array detector emissions having frequencies of f1 and fc ; (d) a modulator means for further modulating said modulated light emissions from said sample at said frequency fc ; and (e) means for reading at a frequency other than fc, the recorded levels of modulated light emissions of said array detector. - View Dependent Claims (52, 53, 54, 55, 56, 57, 58, 59, 60, 61)
-
-
62. An array detector for detecting the modulated light emissions of an excited sample, said array detector comprising:
-
(a) a semiconductor array for receiving and recording the level of modulated light emission received from said sample; (b) an image intensifier positioned between said sample and said semiconductor array, said image intensifier modulating the gain of the modulated light emissions from a first frequency range to a second frequency range; (c) means for selectively biasing said image intensifier to effectively pass to said array detector emissions having frequencies of f1 and fc ; (d) a modulator means for further modulating said modulated light emissions from said sample at said frequency fc ; and (e) means for reading at a frequency other than fc, the recorded levels of modulated light emissions of said array detector. - View Dependent Claims (63, 64, 65)
-
Specification