Abstract: Disclosed is a low noise microwave frequency synthesizer having a plurality of rapidly switchable output frequencies. Two banks of oscillators are selectively mixed to yield a range of output signals of low phase noise and low spurious noise. The first bank of oscillators comprises low noise, highly stable oscillators of a frequency range below the desired synthesized output signal. The second bank of oscillators comprises low noise, highly stable oscillators of a frequency range lower than the first bank. The signal from the second bank of oscillators is frequency multiplied to a desired frequency range by a low multiplication factor and then mixed with the signal from the first bank of oscillators. Multiplied phase noise is reduced by using a low multiplication factor. The upper sideband of the mixed signals is output as the synthesized output signal. Rapid switching between oscillators in both banks provides a frequency range of synthesized output signals which may be rapidly stepped through as desired.

Abstract: A logarithmetic sidelobe blanking system operable in a pulse compression radar system in which the dynamic range of the blanking system is not limited by the compression dynamic range. A sidelobe blanking receiver is provided to process the sidelobe signals in a manner identical to the processing in the radar receiver. The uncompressed IF pulses in both the sidelobe receiver and the main lobe receiver are sampled prior to their being amplitude limited, and are applied through logarithmetic amplifiers whose dynamic range capability is at least equal to the dynamic range of the preceding circuits. The output signals of the logarithmetic amplifiers are then compared and if the sidelobe signal is larger than the main lobe signal the compressed pulse at the output of the pulse compressor is located and used for blanking to ensure that only the time interval of the compressed pulse width is removed.