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US 2003/0165009 A1Published application
Measurement system for wide dynamic range optical power meter
AssigneeEXFO Electro-Optical Engineering Inc.
InventorChristian Olivier
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AssigneeEXFO Electro-Optical Engineering Inc.
InventorChristian Olivier
Estimating the term…
A measurement system for wide dynamic range operation in optical power measurement applications is disclosed. The system provides amplification over a wide dynamic range without glitch, signal loss or transient effect during range switch. This is achieved by combining first and second multi-gain photodiode amplifiers (10/1,10/2), with their input ports connected in common to receive the input signal from a photodiode, and by switching their gain settings to get continuous readings of a photodiode signal. More specifically, the gain setting of the first amplifier is changed only when the signal from the other amplifier is being output, and vice versa. Such an amplification system ensures a smooth transition within a wide dynamic range while monitoring various signal levels, e.g., monitoring processes with substantial variations of optical power from very high levels to very low levels.
A measurement system for providing an output signal proportional to an input signal (Ip) over a wide dynamic range comprises a first amplifier unit (10/1) having a first gain (G1) and a second amplifier unit (10/2) having a second gain (G2) that is different from the first gain, both amplifiers being connected to receive the input signal in common and, in operation, to provide a first signal (V1) and a second signal (V2), respectively, each proportional to the input signal, and a control unit (16/1,16/2,18/1,18/2,20) for selecting the first and second output signals alternatively as an output signal of the measurement system and in dependence upon the amplitude of the input signal.
A photodiode amplifier arrangement for operation over a wide dynamic range comprising a photodiode (24) having an anode and cathode, a first amplifier unit (10/1) having a first plurality of gain settings and a second amplifier unit (10/2) having a second plurality of gain settings, the first plurality of gain settings alternating with the second plurality of gain settings, the first and second amplifier units having their respective inputs connected to the anode and cathode, respectively, of the photodiode, a first gain selection unit (16/1) for selecting the plurality of gain settings of the first amplifier unit, individually, a second gain selection unit (16/2) for selecting the plurality of gain settings of the second amplifier unit individually, and a processor unit (20) for selecting the first and second amplifier units selectively and alternatively for output from the amplifier, and for changing the gain setting selection for the second amplifier unit while outputting the first signal and changing the gain setting of the first amplifier unit while outputting the signal from the second amplifier unit.
Dependencies are inferred from the claim text.