David C Mackes

US Patent:

5124708, Jun 23, 1992

Filed:

Feb 25, 1991

Appl. No.:

7/661031

Inventors:

David C. Mackes - Catonsville MD
Franklin B. Jones - Catonsville MD

Assignee:

The United States of America as represented by the Secretary of the Air
Force - Washington DC

International Classification:

G01S 740

US Classification:

342174

Abstract:

The disclosed system comprises a testing system which measures the stability of a moving target indicator radar transmitter. It automatically measures the imperfections of its internal in-phase (I)/quadrature (Q) demodulator, and it consists of a control computer, a synchronizer, a frequency synthesizer, an IQ demodulator, a low noise amplifier and a waveform recorder. A unit under test is inserted across the test set for measurement and calibration. The system set has the following features: (a) An automatic calibration routine that requires a tunable RF source. This source provides the RF drive to the UUT. (b) A discontinuous analog to digital (A/D) sample clock that has a precise controllable relationship with the RF pulse. The A/D sample clock samples only during the presence of the RF. (c) A method for computing stability using a table of amplitude and phase weighting coefficients and pulse positions.