George L Heiter, 893 Cape Isle Dr, South Yarmouth, MA 02664

4122399, Oct 24, 1978

Dec 7, 1977

5/858118

George Ludwig Heiter - Andover MA
Hotze Miedema - Boxford MA
Edwin Charles Moore - Windham NH

Bell Telephone Laboratories, Incorporated - Murray Hill NJ

H03F 132

330149

The problems of high cost, high loss and incomplete distortion compensation are resolved in a distortion generating circuit which employs a nonlinear phase modulator (70, FIG. 7) and a linear phase shifter (71) as a means of generating selected distortion signal components. The circuit includes an output coupler (30) and an output coupler (31) interconnected by means of a pair of wavepaths (32, 33). The nonlinear phase modulator (70), which includes a nonlinear reactive element (37), is disposed in one of the wavepaths (32). The linear phase shifter (71) is included in the other wavepath (33). By the appropriate adjustment of the linear phase shift in wavepath (33) the entire gamut of distortion characteristics can be compensated. Distortion generating circuits of the type disclosed can be employed as either predistorters or as postdistorters to compensate for the nonlinearities in electromagnetic signal devices, such as amplifiers.

5933770, Aug 3, 1999

Nov 27, 1995

8/563154

George Ludwig Heiter - Andover MA

Lucent Technologies Inc. - Murray Hill NJ

H04B 110

455307

A receiver system and method of operation are used to tune a selected channel from an input spectrum. The receiver includes an up-converter which responds to a selection setting for up-converting the input spectrum, including the selected channel and an unwanted spectrum; a first diplexer for dissipating the energy of the unwanted spectrum in a manner to reduce distortion effects on the up-converter; a down-converter for down-converting the up-converted selected channel having associated upper and lower sidebands and an intermediate frequency component; and a second diplexer for dissipating the energy of the upper and lower sidebands of the down-converted selected channel in a manner to improve intermodulation of the down-converter.

4232399, Nov 4, 1980

Oct 5, 1978

5/948889

George L. Heiter - Andover MA

Bell Telephone Laboratories, Incorporated - Murray Hill NJ

H04B 708
H03H 1120

455276

Continuously variable phase shift is obtained by means of two variable phase shifters (20,21) located in two separate, switchable parallel wavepaths (18, 19). The first phase shifter (20) is variable over, at least, the range between zero and 180 degrees. The second phase shifter (21) is variable over, at least, the range between 180 degrees and 360 degrees. Switching means (22, 23) are provided for switching the signal to one or the other phase shifter. A control circuit (16) simultaneously causing the phase shift through the two phase shifters to vary in the opposite sense. When maximum phase shift is reached, the control circuit switches the signal from one phase shifter to the other, thereby providing continuously variable phase shift through the network.

4621244, Nov 4, 1986

May 17, 1984

6/611331

George L. Heiter - Andover MA

AT&T Bell Laboratories - Murray Hill NJ

H03H 725
H01P 122

333 81A

The present invention relates to a broadband variable attenuator comprising a two- or three-section transmission line with a separate PIN diode bridging each of the two gaps between the adjacent ends of the transmission line sections. The two PIN diodes are disposed in series opposition and the first, second and third transmission line sections are connected to a diode variable biasing source to cause (a) substantially a total reflection of an input signal to the attenuator for a bias below a first value, (b) substantially a total transmission of an input signal through the diodes for a bias above a second value, and (c) a selected amount of both partial reflection and partial transmission of an input signal for a bias value between the first and second values. The broadband variable attenuator can be implemented using microstrip, stripline or coaxial technology without the need of d-c isolation capacitors or applique resistors while providing a maximum insertion loss under zero bias conditions.

4109212, Aug 22, 1978

Oct 29, 1976

5/736995

John Robinson Donnell - Exeter NH
George Ludwig Heiter - Andover MA
Hotze Miedema - Boxford MA

Bell Telephone Laboratories, Incorporated - Murray Hill NJ

H03B 104

328163

A complementary distortion circuit for reducing the level of IM products in the output of a TWT amplifier. One embodiment of the invention includes a 3 db, 90. degree. coupler to divide the input signal into two components of equal amplitude but differing phase with an IM generator positioned in the path of each component. The IM generator may comprise non-linear phase modulators or non-linear amplitude modulators. The two components are then re-combined in a second, 3 db, 90. degree. coupler. The non-linear phase-modulators may comprise varactors and the non-linear amplitude modulators may comprise varistors. The unit is intended to operate in the microwave region.