Inventors:
Ruy L. Brandao - Ft. Lauderdale FL
Henri Baran - Coral Springs FL
Arezki Manseur - Boca Raton FL
Steven R. Sweet - Margate FL
Assignee:
Allied-Signal Inc. - Morris Township NJ
International Classification:
H03B 910
G01S 702
G01S 742
Abstract:
The invention comprises a weather radar system in which a magnetron transmitter is controlled in frequency by injecting therein a low power locking signal from a stable frequency source. Frequency lock between the source and the magnetron is maintained without requiring injection signals of excessive power by an automatic frequency control (AFC). The AFC determines the frequency and phase error between the injection signal and the magnetron output and adjusts the frequency of the source so as always to be within a narrow band of frequencies centered about the natural frequency of the magnetron. Over the long term, therefore, the frequency of the source will vary by an amount equal to the change in the natural frequency of the magnetron occurring during that time. Over the short term, however, the difference in frequency between the injection signal and the magnetron output is zero, while the phase difference is less than 90. degree. The frequency source controlling the magnetron also serves as a frequency source for generating the several local oscillator frequencies required by the system receiver.
