SPICE-Simulation using LTspice IV

9.2. Two Stage Broadband Amplifier with Feedback
9.2.1. Task
Design a gainblock for a 75 communication system with the following specifications:
a) Input and output resistance are both 75. So a lot of 75 blocks can be connected in series using the
RG59 cable type.
b) The gain should be 6dB when loading the output by 75.
c) Use a power supply with +12V DC.
d) The gain must be constant in the frequency range from 1kHz to 10MHz.
e) Use an npn and a pnp transistor (BC547B and BC557B) with feedback.
f) Use a trimmer resistor in the base circuit of the first transistor to compensate all part tolerances.
9.2.2. Circuit Diagram for Simulation
Draw this circuit and take note:
The values of the resistors R1 and R2 must always be written as
14.8k and 2.2k
Never write 14,8k or 2,2k -- you will get wrong results without any warnings!!
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