The circuit in Figure 1 uses current-feedback amplifiers to implement a wideband full-wave rectifier for applications such as a control/AGC system reference or as an amplitude indicator. Putting the full-wave-rectifier diodes in the feedback loop of an op amp works better than does using simple diode-based rectifiers. The op amp’s loop gain decreases the distortion and offset voltage that the diodes introduce. Simple diode rectifiers also require large signals and are temperature-sensitive. The op-amp technique works well for signal frequencies to about 500 kHz,…Link