Lazaro A Ramirez

US Patent:

6452372, Sep 17, 2002

Filed:

Sep 14, 2001

Appl. No.:

09/952701

Inventors:

Frederick K. Husher - Pembroke Pines FL
Gerard Schneider - Irvington NY
Lazaro Ramirez - Miramar FL

Assignee:

Coulter International Corp. - Miami FL

International Classification:

G01N 2700

US Classification:

324 711, 324 714, 324610, 324316

Abstract:

A junction field effect transistor (JFET) RF oscillator-detector circuit generates an RF signal for an apparatus for conducting electrical measurements of particles contained in a carrier fluid passing through an aperture in a cytometer flow cell. The JFET oscillator includes a plurality of parallel-coupled JFETs having respectively different V vs. I characteristics, that are biased to operate at square law detection regions of their respective V vs. I characteristics. One JFET operates in Class C mode, while the other operates in Class AB mode. An RF resonant circuit is electrically coupled to the JFETs and to the measurement cell, and is operative to establish the frequency of an RF field applied to the measurement cell. An RF load change detection circuit is coupled to the RF resonator circuit and is operative to detect an RF load change associated with a modification of the RF field as a result of a particle within the measurement cell aperture.

US Patent:

6323632, Nov 27, 2001

Filed:

Aug 13, 1999

Appl. No.:

9/374911

Inventors:

Frederick K. Husher - Pembroke Pines FL
Gerard Schneider - Irvington NY
Lazaro Ramirez - Miramar FL

Assignee:

Coulter International Corp. - Miami FL

International Classification:

G01N 2700
G01V 300
G01R 2702

US Classification:

324 711

Abstract:

A junction field effect transistor (JFET) RF oscillator-detector circuit generates an RF signal for an apparatus for conducting electrical measurements of particles contained in a carrier fluid passing through an aperture in a cytometer flow cell. The JFET oscillator includes a plurality of parallel-coupled JFETs having respectively different V. sub. DS vs. I. sub. DS characteristics, that are biased to operate at square law detection regions of their respective V. sub. DS vs. I. sub. DS characteristics. One JFET operates in Class C mode, while the other operates in Class AB mode. An RF resonant circuit is electrically coupled to the JFETs and to the measurement cell, and is operative to establish the frequency of an RF field applied to the measurement cell. An RF load change detection circuit is coupled to the RF resonator circuit and is operative to detect an RF load change associated with a modification of the RF field as a result of a particle within the measurement cell aperture.

Address:

9950 SW 156 Ter, Miami, FL 33157

VIN:

JN8AS5MT1BW563790

Make:

NISSAN

Model:

ROGUE

Year:

2011