David Keith Sherman

US Patent:

55022979, Mar 26, 1996

Filed:

Dec 12, 1994

Appl. No.:

8/354274

Inventors:

David M. Sherman - Everett WA

Assignee:

Intermec Corporation - Everett WA

International Classification:

G06K 710

US Classification:

235472

Abstract:

A method and apparatus for detecting the presence of a surface which may bear a bar code symbol. The apparatus generates a series of pulses having a duty cycle which depends upon whether light reflected from a surface bearing a bar code symbol has been detected recently. If such a surface has been detected, the duty cycle is maintained at a high rate. Otherwise, the duty cycle is reduced substantially until such a surface is again detected to save battery power.

US Patent:

45104549, Apr 9, 1985

Filed:

Nov 14, 1983

Appl. No.:

6/551713

Inventors:

David M. Sherman - Everett WA

Assignee:

John Fluke Mfg. Co., Inc. - Everett WA

International Classification:

G01R 2300

US Classification:

330 2

Abstract:

A system for tailoring the frequency response of the amplifier of an AC volt meter during calibration, comprising an adjustable filter consisting of a primary resistor and a number of differently valued capacitors connected together through a corresponding number of switches within an array. During a calibration mode, a test voltage is applied to the input of the amplifier, and the microprocessor switches different values of the capacitors in circuit with the amplifier. The combination of capacitors that causes the frequency response of the amplifier to match most closely with a predetermined response is selected for calibration.

US Patent:

51071401, Apr 21, 1992

Filed:

Oct 31, 1989

Appl. No.:

7/430502

Inventors:

David M. Sherman - Everett WA

Assignee:

Intermec Corporation - Lynnwood WA

International Classification:

H03K 508
H03K 502
H03G 330

US Classification:

307358

Abstract:

An apparatus for automatically adjusting the gain of amplifiers receiving the detected light signal from a bar code scanner. The apparatus causes all signals input to the signal processing circuitry to have the same gain. The anticipatory automatic gain control circuit determines the gain from a maximization of the amplitude of an input signal and a time-delayed copy of the input signal. The gain control signal thus developed is used to identically control the gains of both a first variable-gain amplifier circuit which receives the maximized amplitude signal and a second variable-gain amplifier circuit which receives only the time-delayed copy of the input signal.

US Patent:

55503624, Aug 27, 1996

Filed:

Jan 3, 1995

Appl. No.:

8/367749

Inventors:

David M. Sherman - Everett WA

Assignee:

Intermec Corporation - Everett WA

International Classification:

G06K 710

US Classification:

235455

Abstract:

A method and apparatus for calibrating a bar code scanner. The bar code scanner contains circuitry including a programmable read-only memory (PROM) which stores data affecting the operation of other circuitry in the bar code scanner. The operation of the bar code scanner can be optimized by being monitored by an adjustment circuit under the control of a computer, the adjustment circuit producing signals which change the data stored in the PROM. Among the aspects of the bar code scanner which can be affected are optimization of the output signal, optimization of the signal which causes the bar code symbol to be illuminated, and response of the bar code scanner to the lack of a bar code symbol to read.