Velocity Sorting Detection in Backward Wave Autodyne Reception (Correspondence)

An electronically tunable microwave receiver which uses an oscillating backward wave amplifier driving a crystal detector has been described previously. This receiver has the advantages of large dynamic range and good rejection of unwanted signals, but has the disadvantage that its frequency response can be no better than that of its crystal detector. Since a variation in sensitivity of greater than 3 db over the tuning range of 8 to 12 kmc would seriously lower its usefulness as a spectrum display device, the restrictions on the crystal detector performance are quite severe.