UHF television tuner production - involves using prototype which is established by empirical adjustment of two-section earth plate for optimum coupling (NL070976)

摘要

A method for the production of HF circuits, is used especially for UHF television tuners. There is an HF resonant circuit connected at two different earth points to an earth foil (43) on a circuit board, and with a coupling circuit also connected to two different points on the earth foil, which is difficult to design theoretically. A model of the HF circuit is first built, and the degree of coupling between the resonant circuit and the coupling circuit is adjusted by making interruptions at different points of the earth foil. When satisfactory coupling is achieved the model is taken as a production prototype. The adjustment may be effected by using two sections to the earthfoil, bridged at several points, and breaking the bridges successively until those remaining provide the necessary degree of coupling.