Abstract: Multiple stage ranging circuitry for a measuring circuit includes a first ranging circuit that selectively amplifies an input signal by respective amounts according to the magnitude of the input signal thereto, and a second ranging circuit coupled to the output of the first ranging circuit selectively amplifies the output signal from the first ranging circuit by a respective amount according to the magnitude of that output signal to provide a measured output. The multiple stage ranging circuitry increases dynamic range and provides for high speed measurements over that dynamic range.

Abstract: A range selection circuit (13), including a logarithmic amplifier (23) and output circuitry (25) associated therewith, is configured to directly drive linear ranging circuitry for measurement circuitry (12) in an optical power meter (10) to measure signals that vary over a wide range of, for example, from about −7 dB to about −45 dB. This allows the optical power meter to change ranges as fast as one (1) times the hardware settling time. The range selection circuitry is in parallel with the measurement circuitry, which allows ranging to happen in real time.

Abstract: A range selection circuit (13), including a logarithmic amplifier (23) and output circuitry (25) associated therewith, is configured to directly drive linear ranging circuitry for measurement circuitry (12) in an optical power meter (10) to measure signals that vary over a wide range of, for example, from about -7dB to about -45dB. This allows the optical power meter to change ranges as fast as one (1) times the hardware settling time. The range selection circuitry is in parallel with the measurement circuitry, which allows ranging to happen in real time.