Dennis L Fredrickson

US Patent:

44345046, Feb 28, 1984

Filed:

Jun 10, 1982

Appl. No.:

6/387234

Inventors:

Dennis L. Fredrickson - Leawood KS

Assignee:

Frederickson Communications, Inc. - Lenexa KS

International Classification:

H04B 100
H04B 700
H04Q 700

US Classification:

455 32

Abstract:

An airborne radio-telephone transceiver is provided having improved channeling and decode circuitry compatible with the selective signalling call-up system prescribed by the Federal Communications Commission. The decode circuitry includes a filter and detector dependent only on reception of a single selected frequency transmitted as a call-up signal by a ground station. A retriggerable, resettable, monostable multivibrator, configured as a pulse swallower, provides the necessary counter offset for proper call-up signal decoding. The invention includes scanning circuitry for rapid operator selection of active transmit-receive channels in the operator's geographic area.

US Patent:

D2744279, Jun 26, 1984

Filed:

Sep 14, 1981

Appl. No.:

6/301529

Inventors:

Dennis L. Fredrickson - Leawood KS

Assignee:

Fredrickson Communications, Inc. - Lenexa KS

US Classification:

D14 53

US Patent:

43203574, Mar 16, 1982

Filed:

Jul 1, 1980

Appl. No.:

6/165026

Inventors:

Paul G. Wulfsberg - Overland Park KS
Dennis L. Fredrickson - Leawood KS
Gregory L. Triplett - Olathe KS
Ralph J. Crumrine - Olathe KS
Cole E. Cunningham - Dallas TX

International Classification:

H03L 718
H03C 309

US Classification:

331 16

Abstract:

A frequency synthesizer employing direct FM, as opposed to phase modulation, so subaudible tones may be transmitted, in the form of a 10 KHz increment, direct synthesizer with a skewed frequency standard deriving four intermediate 2. 5 KHz tuning steps. Fast settling time of frequency change accommodates semi duplex operation, and a shaping network provides the amount of skewing changes required between band ends for substantially perfect tracking. A low division ratio programmed divider in the system maximizes transmitter signal to noise ratio, and a low pass filter in the synthesizer phase locked loop allows voice band moduation.