A simple, non-invasive probe for reconstructing signals inside a DSP

A simple, non-invasive probe is proposed that extracts digital samples of a signal of interest from a DSP and reconstructs the samples into an equivalent analog signal. The probe is useful for software design and debugging as well as troubleshooting and verification of DSP systems in the field. A sample buffering system ensures that the digital samples are reconstructed into analog samples at substantially constant intervals, even if the DSP generates the digital samples at varying intervals. The buffering system uses a control loop to generate the analog samples at a sample rate that is equivalent to the mean sample rate of the digital samples. Consequently, the reconstructed analog signal accurately represents the digital signal found within the DSP. This signal may then be sent to conventional test equipment suited for analysis of analog signals