The Design of a Wide-Band Transistor Telephone Repeater and its Distortion Performance

The design of a two-stage transistor amplifier having overall current feedback is considered. Allowance is made for variation of the transistor parameters, their noise figures and inherent non-linearities. The stability of the feedback loop of the amplifier is investigated, and its operation as a wide-band (60¿1300 kc/s) telephone line-repeater outlined. Finally a modified two-stage amplifier, utilizing a cascode output stage to improve its harmonic distortion, is described together with a method of estimating the distortion produced by such amplifiers.