Abstract—Volterra analysis and computer calculation of the wide-band diode bridge track and hold amplifier (THA) is proposed based on a high frequency Schottky diode model. Approximate expressions for the third-order harmonic distor-tion and the third-order intermodulation distortion are derived respectively. A computer program then calculates the distortion of weekly nonlinear THA based on the KCL and the nonlinear-current method. Simulations based on a commercially available 130 nm process technology are performed with the Spectre circuit simulator. Comparative SpectreRF simulated results for the diode bridge THA have shown good agreement with those of Volterra series analysis. It is also shown that results obtained by the program have a consistent match with those derived from Circuit simulator, whereas the overall computational efficiency has been improved in a special evaluation.