Marcus Q Pendergrass

US Patent:

6671310, Dec 30, 2003

Filed:

Jun 12, 2000

Appl. No.:

09/591690

Inventors:

James L. Richards - Fayetteville TN
Mark D. Roberts - Huntsville AL
Marcus H. Pendergrass - Huntsville AL
Larry W. Fullerton - Brownsboro AL

Assignee:

Time Domain Corporation - Huntsville AL

International Classification:

H04B 169

US Classification:

375138

Abstract:

A method for positioning pulses over time (via a time layout) applies time-hopping codes having pre-defined characteristics. The time layout can be sequentially subdivided into at least first and second time components that have the same or different sizes. The method applies a first time-hopping code having first pre-defined properties to the first time component and a second time-hopping code having second pre-defined properties to the second time component. The pre-defined properties may relate to the auto-correlation property, the cross-correlation property, and spectral properties, as examples. The codes can be used to specify subcomponents within a frame, and positions (range-based, or discrete) within the subcomponents, where the pulses are positioned.

US Patent:

6677796, Jan 13, 2004

Filed:

Sep 20, 2001

Appl. No.:

09/957646

Inventors:

Vernon R. Brethour - Owens Cross Roads AL
Marcus H. Pendergrass - Huntsville AL
Ryan N. Confer - Huntsville AL

Assignee:

Time Domain Corp. - Huntsville AL

International Classification:

H03K 300

US Classification:

327237, 327238, 327248, 327255

Abstract:

A system and method of implementing precision time delays that provides important and novel improvements over prior techniques of implementing time delays by utilizing a new strategy for selecting the values in the sine and cosine lookup tables. Sine and cosine values which result in non-uniform amplitudes enable increased overall accuracy with fewer bits communicated from the look-up tables to the analogue portion of the system. Further, herein is provided the addition of a variable amplitude threshold crossing capability following the combining of the sine and cosine signals. The time delay accuracy of the resulting phase and amplitude hybrid system can be improved either by increasing the number of bits in the sine/cosine phase management section or by increasing the number of bits in the amplitude section. There is provided herein an optimum strategy for choosing the number of bits used in the phase and amplitude sections for the best overall delay accuracy with the fewest overall control bits.

US Patent:

6778603, Aug 17, 2004

Filed:

Nov 8, 2000

Appl. No.:

09/708025

Inventors:

Larry W. Fullerton - Brownsboro AL
Mark D. Roberts - Huntsville AL
James L. Richards - Fayetteville TN
Marcus H. Pendergrass - Huntsville AL

Assignee:

Time Domain Corporation - Huntsville AL

International Classification:

H03K 708

US Classification:

375238

Abstract:

A system and method for shaping the energy spectrum of a pulse train used by a pulse transmission system. The initial temporal and non-temporal characteristics of pulses comprising the pulse train are established using a designed code or a pseudorandom code and the spectral properties of the pulse train are determined. At least one characteristic of at least one pulse of the plurality of pulses that make up the pulse train are modified or at least one pulse is added or deleted to the pulse train and the spectral properties of the modified pulse train are determined. Whether or not the modification to the pulse train improved the energy spectrum relative to acceptance criteria is determined. The pulse train having the most desirable energy spectrum is selected. The optimization process can also iterate and may employ a variety of search algorithms.

US Patent:

6788730, Sep 7, 2004

Filed:

Aug 15, 2000

Appl. No.:

09/638046

Inventors:

James L. Richards - Fayetteville TN
Mark D. Roberts - Huntsville AL
Marcus H. Pendergrass - Huntsville AL
Larry W. Fullerton - Brownsboro AL

Assignee:

Time Domain Corporation - Huntsville AL

International Classification:

H04B 169

US Classification:

375138

Abstract:

A method for specifying pulse characteristics applies codes having pre-defined characteristics to a layout. The layout can be sequentially subdivided into at least first and second components that have the same or different sizes. The method applies a first code having first pre-defined properties to the first component and a second code having second pre-defined properties to the second component. The pre-defined properties may relate to the auto-correlation property, the cross-correlation property, and spectral properties, as examples. The codes can be used to specify subcomponents within a frame, and characteristic values (range-based, or discrete) within the subcomponents.

US Patent:

6912240, Jun 28, 2005

Filed:

Nov 26, 2001

Appl. No.:

09/991607

Inventors:

P. Vijay Kumar - Rancho Palos Verdes CA, US
Marcus H. Pendergrass - Huntsville AL, US

Assignee:

Time Domain Corporation - Huntsville AL

International Classification:

H04B001/69

US Classification:

375130, 375150

Abstract:

The present invention relates to a method for generating and apparatus for employing code families having desirable correlation properties. Regardless of code length, maximum autocorrelation of the codes is 4 for any nonzero offset and maximum cross-correlation of any two codes from a code family is 4 for any offset. The codes can be used in impulse radio systems and non-impulse radio systems including CDMA, TDMA, FDMA, OFDM and various other frequency hopping and direct sequence systems. The codes can be used to specify various impulse radio and non-impulse radio signal characteristics including pulse position in time, amplitude, width, type, phase, phase difference, frequency, spreading code, etc. The codes have the unique property that they can specify as many as two components in which a signal is not present. A method of code compression is provided.

US Patent:

6937639, Aug 30, 2005

Filed:

Apr 16, 2001

Appl. No.:

09/835184

Inventors:

Marcus H. Pendergrass - Huntsville AL, US
Mark D. Roberts - Huntsville AL, US

Assignee:

Time Domain Corporation - Huntsville AL

International Classification:

H04L027/30

US Classification:

375135, 375138, 375149, 375239, 375256, 342 18, 342 44, 342386

Abstract:

A system, method and computer program product for positioning pulses, including positioning pulses within a specified time layout according to one or more codes to produce a pulse train having one or more predefined spectral characteristics where a difference in time position between adjacent pulses positioned to produce a spectral characteristic differs from another difference in time position between other adjacent pulses positioned to produce the spectral characteristic. The present invention may include shaping a code spectrum according to a spectral template in order to preserve a pre-defined code characteristic. A pre-defined code characteristic can include desirable correlation, or spectral properties. A transmitter incorporating the present invention can avoid transmitting at a particular frequency. Similarly, a receiver can avoid interference with a signal transmitting at a particular frequency.

US Patent:

6959032, Oct 25, 2005

Filed:

Aug 15, 2000

Appl. No.:

09/638150

Inventors:

James L. Richards - Fayetteville TN, US
Mark D. Roberts - Huntsville AL, US
Marcus H. Pendergrass - Huntsville AL, US

Assignee:

Time Domain Corporation - Huntsville AL

International Classification:

H04B001/69
H03K007/04
H03K009/04

US Classification:

375138, 375239

Abstract:

A coding method specifies pulse positioning over time according to a time layout about a time reference where a pulse can be placed at any location within the time layout. The method generates time-hopping codes having predefined properties, and a coded pulse train based on the time-hopping codes and the time layout. The time reference may be fixed or non-fixed and can be a time position of a preceding or a succeeding pulse. In addition, the predefined properties can be autocorrelation, cross-correlation, or spectral properties.

US Patent:

7145954, Dec 5, 2006

Filed:

Aug 15, 2000

Appl. No.:

09/638151

Inventors:

Marcus H. Pendergrass - Huntsville AL, US
Mark D. Roberts - Huntsville AL, US
James L. Richards - Fayetteville TN, US

Assignee:

Time Domain Corporation - Huntsville AL

International Classification:

H04B 14/06

US Classification:

375247, 375239, 375242

Abstract:

A coding method, specifies temporal and/or non-temporal pulse characteristics, where pulse characteristic values are relative to one or more non-fixed reference characteristic values within at least one delta value range or discrete delta value layout. The method allocates allowable and non-allowable regions relative to the one ore more non-fixed references. The method applies a delta code relative to the allowable and non-allowable regions. The allowable and non-allowable regions are relative to one or more definable characteristic values within a characteristic value layout. The one or more definable characteristic values are relative to one or more characteristic value references. In addition, the one or more characteristic value references can be a characteristic value of a given pulse such as a preceding pulse or a succeeding pulse.