Tunable HF detector probe for HF transmission line - achieves self-cancellation of interference signals using screened double coupling line

摘要

The detector probe has a Hf input (10) and a LF or DC output (12) to which a resistor (14e is coupled for receiving the LF or DC measuring signal. A transformer (58) has a primary winding (16) coupled in earth-symmetry to the HF input via a variable choke coil (18) and associated turning capacitor with its secondary winding (20) coupled via a screened line with a rectifier and filter chain. The secondary winding of the transformer is earth-free and the screened line coupling it to the rectifier and filter chain comprises a symmetrical double line (22), so that received interference signals appear simultaneously between the screening (24) and both lines for self-cancellation. The detector can be used for a wide frequency range.