| 摘要 |
PURPOSE:To attain broad band and high gain and to improve the stability, by receiving an output of a magnetic head at two cascode amplifiers differentially, applying a balanced negative feedback to the differential section, and receiving and outputting the outputs of the cascode amplifiers at field effect transistors (TRs) for buffer repectively. CONSTITUTION:TRsQ4, Q6 constitute the differential amplifier DA, each collector is connected to each emitter of common-base TRsQ3, Q7 respectively to form the cascode amplifiers CA1, CA2 respectively. Each collector of the TRsQ3, Q7 is connected to each gate of field effect TRsQ2, Q8 for buffer respectively, each source of the TRsQ2, Q8 is connected to each base of emitter follower TRsQ1, Q9, and the emitter is connected to output terinals t21, t22. A signal at the output terminals is returned to the differential amplifier DA via feedback resistors R3, R17. |
