
Chapter 4
Input circuitry
The input circuitry of any oscilloscope, whether an analog- or a
digital storage- type, is critical to overall performance. However,
the design principles are well understood and design practice
long since stabilised, with the result that the input circuitry of a
digital storage oscilloscope is identical to that of an analog scope
with the same effective bandwidth. An oscilloscope is usually
used to examine voltage waveforms. These may exist in a low
impedance circuit, such as a power supply or the output stage on
a hi-fi amplifier, but they may also be encountered