The Design and Testing of Multirange Receivers

The principal difficulties in the design of high-frequency receivers reside in the complexity of the multirange circuits. Several ctrcuits and a unit assembly arrangement are described which improve the frequency calibration and simplify the design. Testing is facilitated by the use of simplified signal generators having "piston" attenuators. The attenuator comprises a pair of coplanar coils, coaxial coils, or condenser plates, one fixed and one movable axially in a moderately long cylindrical copper shield. The attenuation in decibels is directly proportional to the displacement of the movable element, and the calibration can be comnputed.