Research/Patents/US 5374903
US 5374903Tier 1 — UAP Program Assignee

GENERATION OF WIDEBAND LINEAR FREQUENCY MODULATION SIGNALS

Assignee

Hughes Aircraft

Filed as: HUGHES AIRCRAFT COMPANY, A DE CORP.

Filed

Apr 22, 1988

Granted

Dec 20, 1994

Location

CULVER CITY CA US

Abstract

A low-frequency low bandwidth Linear Frequency Modulation (LFM) waveform, nominally a 1 MHz to 10 Mz swept frequency analog sinusoid or digital square wave, is produced by direct digital synthesis. This waveform is upconverted in frequency and expanded in bandwidth, nominally to microwave frequencies with bandwidths of nominally 160-360 MHz, in a multiplying offset phase locked loop. The phase locked loop also linearly frequency modulates a X-band carrier with the microwave frequency LFM waveform to produce an output signal suitable for Synthetic Aperture Radar. The phase locked loop induces low phase error, and may be closed around the radar transmitter to remove phase errors induced by that unit.

Source: Google Patents

35 USC §181 Secrecy Order

Imposed

Dec 12, 1988

Rescinded

May 23, 1994

Duration

5 years, 5 months

Inventor

  • 1JAMES L. BLANTON

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Back to patent indexSource: USPTO 35 USC §181 secrecy order records