WaveExpert 100H LeCroy Equivalent Time Sampling Oscilloscope System

The Teledyne / LeCroy WaveExpert 100H Equivalent Time Sampling Oscilloscope System consisting of a mainframe and up to four plug-in acquisition pods or modules. Different modules allow the connection of either optical or electrical signals to the instrument with bandwidths up to 100 GHz. In addition to the acquisition modules, PPG (pulse pattern generator) and CDR (clock and data recovery) modules are also manufactured.

The heart of Wave Expert is the timebase which is housed in the mainframe. The timebase controls the acquisition heads by supplying a sampling pulse or strobe to the modules and digitizers which convert the stored charge in the modules into a numerical voltage value for display. Unlike more common DSO's, the timebase in Wave Expert samples only in the equivalent-time mode, that is, it samples at a rate much lower than its bandwidth but synchronous to the signal under test. This type of sampling requires that the signal under test be periodic and the timebase samples the signal at least once per period. The displayed waveform is built-up from multiple acquisitions of a single period of the signal with each acquisition being at a progressively longer delay from the previous one relative to the phase of the signal under test. This acquisition method is known as sequential sampling. Sequential sampling utilizes a trigger signal to determine the phase of the signal under test and the sampling strobe is generated by the timebase after a delay from the trigger. One sample is taken per trigger and the delay is slightly increased on each subsequent trigger. The sampling rate in this acquisition mode is determined by the trigger rate but is no faster than 500 kS/s.

Wave Expert 100H also features a powerful new sampling technique called High stability Coherent Interleaved Sampling (HCIS).This optional timebase (WE-HCIS) enables samples to be acquired at the rate of 10 MS/s independent of the trigger rate. HCIS does this by generating a sampling strobe that is phase-locked to the clock of the signal under test. An internal phase locked loop generates a 10 MHz strobe that is precisely offset from an integer sub-multiple of the signal clock so that the sampling point moves relative to the phase of the signal from sample to sample. The signal is constructed in much the same way as the sequential timebase except that the sampling rate is fixed at 10 MHz.