Oscilloscopes and other instruments that so precisely measure voltage are ill-suited to handling time-based communications signals, for their preoccupation with amplitude compromises timing accuracy, wastes memory, and complicates timing analysis. A measurement technique is presented, called phase digitizing, that remedies the situation by continuously counting a signal's zero-crossings and recording exactly when they occur. The deficiencies of previous approaches are examined for the case of spread-spectrum measurements. The principles and characteristics of the approach are described.