MATLAB® provides an ideal environment for mixed-signal analysis, providing you with much greater analysis and visualization functionality than spreadsheets or traditional programming languages like C/C++. However, you don’t have to abandon your existing investments; MATLAB will work with Microsoft® Excel® and with C/C++.
At the highest level of mixed-signal analysis, MATLAB is used to create basic system architectures; for example, which is better: a second or third order sigma-delta modulator? What type of PLL is best? What do the Bode plots say about system stability? In industry, MATLAB is used to figure out the best starting point for design.
MATLAB is also used for detailed mixed-signal analysis in subsystems. For example, MATLAB's curve fitting, statistics, and visualization features are used to calculate a digital function that corrects for amplifier non-linearity in digital predistortion. In ADCs, MATLAB is used extensively for filter design. In both examples, you can build a solution and visualize the results as you go.