Stephen A Roth

US Patent:

7068725, Jun 27, 2006

Filed:

Jun 26, 2001

Appl. No.:

09/892166

Inventors:

Stephen A. Roth - Aumsville OR, US
Thomas L. Mosher - Salem OR, US

Assignee:

Garmin AT, Inc. - Salem OR

International Classification:

H04L 25/34
H04L 27/10
H03D 3/00

US Classification:

375272, 375334

Abstract:

A method is disclosed for optimally adjusting the received bit detection threshold in a digital communication system, such as a TDMA system that is characterized by very short duration burst transmissions. In one embodiment of the invention, a half-duplex radio modem is used for transmission and receipt of messages for airborne and ground-based Automatic Dependent Surveillance-Broadcast (ADS-B) service. A feedback path is provided for in the transmission/receiver unit to provide the transmission signal to the receiver path. A bit detection threshold adjustment circuit receives the transmission signal. The circuit digitizes the analog baseband signal, detects the positive and negative peak values and calculates a peak-to-peak deviation value to define the bit detection threshold value.

US Patent:

48454460, Jul 4, 1989

Filed:

Dec 19, 1986

Appl. No.:

6/945216

Inventors:

Stephen A. Roth - Aumsville OR

Assignee:

II Morrow, Inc. - Salem OR

International Classification:

H03H 1124

US Classification:

333 81R

Abstract:

A variable attenuator comprises a plurality of attenuator stages connected in series along a transmission line signal path. Each attenuator stage comprises a resstive pi-section attenuating pad which may be selectively inserted into the signal path to increase attenuation along the path. Each series element of the pad is selectively inserted or removed from the signal path by opening or closing a parallel connected switching device, while each shunt element of the pad is selectively connected to or disconnected from ground by closing or opening a corresponding series connected switching device. The switching devices each comprise an NPN bipolar transistor and a PNP bipolar transistor, the emitter of each transistor being coupled to the emitter of the other and the collector or each transistor being connected to the collector of the other, to provide a low impedance AC signal path from collector to emitter when the transistors are active.

US Patent:

52451720, Sep 14, 1993

Filed:

May 12, 1992

Appl. No.:

7/882170

Inventors:

Robert Esslinger - Wilton CT
Joseph Mulligan - Fairfield CT
Lance Garland - Wilsonville OR
Stephen Roth - Aumsville OR
Paul Roth - Aumsville OR

Assignee:

United Parcel Service of America, Inc. - Atlanta GA

International Classification:

G01J 120

US Classification:

2502012

Abstract:

An apparatus for focusing an image onto an image receptor is disclosed. The apparatus includes a stationary lens, a rotatable frame that is rigidly connected to the image receptor, and a base. The base is pivotally connected to the rotatable frame about a rotational axis. The image is focused by the stationary lens onto the image receptor by pivoting the rotatable frame about the rotational axis. In an alternate embodiment, an apparatus for focusing an image onto an image receptor includes a stationary lens, a voice coil actuator, a servo loop for driving the voice coil actuator, and an electromechanical transducer for measuring the position of the image receptor. The electromechanical transducer is electrically connected to the servo loop. Connecting means for rigidly connecting the image receptor to the voice coil actuator are also provided. The image is focused by the stationary lens onto the image receptor by driving the voice coil actuator.

US Patent:

50916971, Feb 25, 1992

Filed:

Jul 31, 1989

Appl. No.:

7/388579

Inventors:

Stephen A. Roth - Aumsville OR
Roar Berg-Johansen - Salem OR

Assignee:

II Morrow, Inc. - Portland OR

International Classification:

G01R 3304
G01C 1728

US Classification:

324253

Abstract:

A magnetometer and method for measuring magnetic field strength particularly adapted for use in an electronic flux gate compass. A core of magnetic material in the shape of a toroid is coupled to a drive coil and to two sense coils oriented along orthogonal axes. A current limited, current source coupled to the drive coil periodically saturates the core, drives the core out of saturation at an intermediate current level, and saturates the core again. Each sense coil is coupled to a sense circuit which measures the current in the sense coil induced by the periodically changing flux density in the coil resulting from an external magnetic field coupled to the sense coil, produces a dc feedback signal to cancel out the external magnetic field, and provides the dc signal as an output representative of the external magnetic field strength along the axis of the sense coil. The dc signal is produced by synchronously detecting the amplified ac current in the sense coil. Low pass filters are provided to eliminate ac components from the magnetometer output.

US Patent:

51704935, Dec 8, 1992

Filed:

Jul 25, 1988

Appl. No.:

7/223911

Inventors:

Stephen A. Roth - Aumsville OR

Assignee:

IIMorrow, Inc. - Salem OR

International Classification:

H04B 146
H04B 118

US Classification:

455 82

Abstract:

A dual function antenna system and method. A system is provided for using a single antenna for both the reception of low frequency navigational signals, such as LORAN-C, and high frequency communications signals in the VHF region. The antenna is at a remote location from a low frequency receiver and a high frequency transceiver. Both the low frequency and the high frequency signals are coupled to the receiver and transceiver, respectively, over the same transmission line at one end thereof. A preamplifier is provided at the location of the antenna to increase the strength of the low frequency signal applied to the transmission line. A high pass filter is provided to couple the antenna and the transmission line and prevent feedback from the output of the preamplifier from reaching its input. The other end of the transmission line is coupled to the high frequency transceiver by a high pass filter, and to the low frequency receiver by a low pass filter. The preamplifier is supplied with DC power over the transmission line, and includes a current regulator so that the preamplifier may be used with a wide range of supply voltages.

US Patent:

40841871, Apr 11, 1978

Filed:

Sep 7, 1976

Appl. No.:

5/720854

Inventors:

Kenneth George Schlotzhauer - Beaverton OR
Stephen Anthony Roth - Beaverton OR

Assignee:

Tektronix, Inc. - Beaverton OR

International Classification:

H04N 508

US Classification:

358153

Abstract:

A circuit for accurately extracting the synchronization information contained within a composite video waveform includes a means for establishing the back porch level of the waveform to a first voltage through a first feedback loop, a means for establishing the sync tip level of the waveform to a second voltage through a second feedback loop, a means for providing the extracted synchronization information at a time determined midway between the first and second voltages, and a system which achieves these ends. An automatic gain control amplifier is included as a portion of the circuit within the system and whose gain is linearly proportional to the logarithm of the AGC voltage and wherein changes in AGC voltage do not interrupt the DC potentials within the amplifier nor do DC changes change the gain of the amplifier.