Inventors:
Mark A. Koehnke - Attleboro MA
W. Roger Melick - Sudbury MA
Raoul E. Plutchak - Boxborough MA
Stephen Rego - Franklin MA
Steve B. Santangelo - Cumberland RI
Assignee:
Raytheon Company - Lexington MA
International Classification:
G01S 7292
G01S 740
Abstract:
A radar transmitter for producing a radar signal in response to a radar trigger signal fed thereto. The transmitter includes a radio frequency oscillator for producing a signal having a radio frequency carrier to be used in each transmitted radar signal. The signal produced by the oscillator is amplified by a radio frequency amplifier. In response to the system trigger signal, the transmitter is configured in a normal operating mode to operate with three noise cancellation loops; i. e. , an automatic level control loop (ALC); an amplitude modulation noise cancellation loop (AM noise cancellation loop); and a phase modulation noise (PM noise cancellation loop). In response to the system trigger signal, the normal operating mode is preceded with two calibration modes: an AM noise calibration mode used to determine a nominal operating point for the AM noise calibration mode; and a subsequent phase modulation (PM) noise calibration mode used to establish a nominal operating point for the PM noise calibration mode. During the AM noise calibration mode, a nominal operating level is determined which places the TWT amplifier slightly below saturation.