A boxcar averager implemented with digital technology enables data acquisition and processing without gaps as there is no integrator that needs to be discharged. In this way, the speed limitation affecting analog boxcars no longer applies. It is possible to average pulse after pulse without dead times up to repetition rates of 600 MHz. Thanks to this capability, some applications will benefit from a measurement time reduction by a factor of up to 1000 when compared to what is achieved with conventional analog instruments. The granularity of the gating window is determined by the inverse of the 1.8 GSa/s sampling rate, that is, by multiples of 556 ps.
Baseline Suppression and Arithmetic Operations
Each boxcar unit is equipped with a baseline gate to perform a measurement with baseline suppression (subtraction of the background noise, measured in regions of the period without signal, from the boxcar measurement) or other advanced measurements such as fully differential signal path analysis. This flexibility is essential to give access to more applications than is possible with conventional analog boxcars.
The Arithmetic Unit, included in all UHFLI Lock-in Amplifiers, provides the capability to perform arithmetic operations using the results from the two boxcar units as operands and outputting the result; this opens up even more advanced measurement possibilities.
Periodic Waveform Analyzer
Pressing one button is all it takes to display the periodic waveform of a signal of interest, for instance the transients of a decay process. The real shape of the pulse is reconstructed through efficient time binning, a process that does not require any external equipment. Therefore, users can define the boxcar settings from within the user interface without the need for an additional sampling scope.
Measurements with Two Timebases
An experiment with two timebases can involve a slower modulation superimposed on a fast pulsed laser. Traditionally, the measurement of such signals involves complex sweeping of trigger points and post-processing of data. The multi-channel boxcar solves this issue elegantly by performing the data deconvolution in real time, associating the measurement result of the fast timebase to the time bins according to the slow timebase. This process provides immediate feedback on the amplitudes in a graphical display.