Abstract:
An optical spectrum analyzer (FIG. 2) is provided with a user selectable sensitivity (160). Required operating parameters are set in response to user selection of sensitivity (162) to permit measurement of an input light beam (12) at the selected sensitivity. Setting the required parameters includes setting a required gain of a video channel (48, 90, 92, 94, 96) to permit measurement of a specified maximum input signal and to provide the selected sensitivity, setting a required video bandwidth of the video channel (48, 90, 92, 94, 96) to provide the selected sensitivity at the required gain of the video channel (48, 90, 92, 94, 96) and setting a sweep rate to provide the selected sensitivity at the required video bandwidth. When the normal bandwidth of the video channel (48, 90, 92, 94, 96) is not adequate to provide the selected sensitivity, the electrical signal is passed through a digital filter having a filter coefficient (FILTER COEFFICIENT) set to provide the required video bandwidth. A peak detector (90) is incorporated in the video channel (48, 90, 92, 94, 96) to accurately measure signal amplitudes in a fast scanning condition.
Abstract:
An optical spectrum analyzer (FIG. 2) is provided with a user selectable sensitivity (160). Required operating parameters (172, 174, 176) are set in response to user selection of sensitivity (162) to permit measurement of an input light beam (12) at the selected sensitivity (160). Setting the required parameters (172, 174, 176) includes setting a required gain (172) of a video channel (48, 90, 92, 94, 96) to permit measurement of a specified maximum input signal and to provide the selected sensitivity (160), setting a required video bandwidth (174) of the video channel (48, 90, 92, 94, 96) to provide the selected sensitivity (160) at the required gain (172) of the video channel (48, 90, 92, 94, 96) and setting a sweep rate (176) to provide the selected sensitivity (160) at the required video bandwidth (174). When the normal bandwidth of the video channel (48, 90, 92, 94, 96) is not adequate to provide the selected sensitivity (160), the electrical signal is passed through a digital filter (100) having a filter coefficient (FILTER COEFFICIENT) set to provide the required video bandwidth (174). A peak detector (90) is incorporated in the video channel (48, 90, 92, 94, 96) to accurately measure signal amplitudes in a fast scanning condition.