Four-to-one symmetric-asymmetric impedance transformer - for push-pull amplifiers output in TV receiver has three pairs of coils

摘要

The 4:1 impedance transformer transforms an H.F. push-pull amplifier output (in e.g. a television receiver) into an asymmetric output for connecting via e.g. a coaxial cable to the next amplifier stage. The first of the transformers two symmetric input terminals is connected over a first coil to earth and over a fourth and sixth coils to an earthed asymmetric output terminal. The second symmetric input is connected over a third coil to earth and over a second and fifth coils to the second asymmetric output terminal. The first and second, the third and fourth, and the fifth and sixth coils each form a pair of coils, giving three pairs. The first two pairs have opposite winding senses and the third pair of coils have double the number of turns in the first two pairs coils.