STEMlab measurement board is a universal tool for the acquisition, processing, and generation of radiofrequency signals. Due to hardware limitations, acquisition and generation of signals are limited to a range of ±1 V. This master's thesis presents attenuator and amplifier extension boards, which extend the input and output voltage range to values comparable with low-budget oscilloscopes and function generators.
Attenuator extension board follows the architecture and principles of oscilloscope input stage design. Each subsection of the attenuator was developed using analytical and numerical simulation methods, which were further verified by measuring the prototype printed circuit board. The prototype circuit of the attenuator allows the setting of the attenuation level with an extended 1-2-5 sequence, typically used in oscilloscopes, between ±400 V and ±2 V (with 10x probe attenuation) over a wide bandwidth. Measured rise time of the attenuator is 2.3 ns.
Amplifier extension board increases the power of measurement board output signals. Necessary amplification level is achieved using a current-feedback amplifier built with discrete semiconductor components. An existing amplifier from accessible literature was upgraded with a class AB output power stage. The amplifier's operation was evaluated using simulation and the construction of a prototype printed circuit board. The constructed amplifier, with an output impedance of 50 Ω and voltage gain equal to 10 V/V, achieves a 34 MHz small signal bandwidth. With a large amplitude output signal of ±10 V driving a 50 Ω load, the amplifier achieves a 26 MHz large signal bandwidth.
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