The Control System Analysis and Design Package (CSADP) is a computer-aided design package for applying classical control system analysis and design tools to experimental frequency response measurements. CSADP allows the user to analyze and manipulate measured frequency response data, design control systems using these measurements, and determine the operational amplifier hardware required to implement the design. To perform these tasks, CSADP provides tools that allow the user to define problems using both frequency response data files and transfer function descriptions; generate Bode, Nyquist, and root-locus plots; and curve-fit frequency response data. The curve-fitting program uses novel data-scanning techniques for conditioning the data, and for predicting the model form and starting parameters. CSADP also allows the user to design compensators interactively using Bode and root-locus methods, and aids the user in selecting the required resistor and capacitor values needed for implementing the compensator using op-amp circuits. In addition, CSADP provides coefficients required to implement the compensator using selected digital algorithms. CSADP was used in the design of a velocity loop compensator for a precision diamond turning machine. Open loop frequency response data gathered from the machine was used as the basis for compensator design using Bode methods. The required compensator coefficients generated by the program were programmed into the servo for testing. Results showed that the closed loop response predicted by the program accurately matched the measured response. Estimates of natural frequencies provided by the model prediction program were within 5 percent of the actual values. Errors in estimates of the damping ratios for very lightly damped complex poles ranged from only 10 percent to 30 percent. CSADP is written in FORTRAN 77 and provides Tektronix (TEK) 4010/4014 compatible graphics output.