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Pulser amplitude feedback amplifier (view source)
Revision as of 16:37, 20 June 2014
, 16:37, 20 June 2014→Output pulses
Figure 4. Oscilloscope traces of pulses from the pulser amplitude feedback circuit, showing several pulses superimposed (left panel) and a single pulse (right panel). The upper trace (blue) is the NIM trigger signal from the pulse generator. The lower trace (yellow) is the photodiode signal, as shaped and amplified by the feedback circuit. The high frequency oscillations at the beginning of the photodiode pulse are the result of pickup from the large instantaneous pulse currents flowing on the laser diode pins during the intense 1ns pulse. The amplifier stretched the feedback pulse so that it reaches a maximum after these transients have died away.
Figure 4. Oscilloscope traces of pulses from the pulser amplitude feedback circuit, showing several pulses superimposed (left panel) and a single pulse (right panel). The upper trace (blue) is the NIM trigger signal from the pulse generator. The lower trace (yellow) is the photodiode signal, as shaped and amplified by the feedback circuit. The high frequency oscillations at the beginning of the photodiode pulse are the result of pickup from the large instantaneous pulse currents flowing on the laser diode pins during the intense 1ns pulse. The amplifier stretched the feedback pulse so that it reaches a maximum after these transients have died away.
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[[image:laserDiode_pd_amp_pulse(3).png|400px|center]]
Figure 5. Raw data recorded by the FADC250 on the pulser amplitude feedback channel. Pulse-to-pulse shape variation is very slight apart from overall magnitude fluctuations, which are at the level of 1%.