[evlatests] hittite samplers on ea03.

[Vivek Dhawan]

A bit more on comparing the Hittite pair with the best Teledyne samplers:

* Histograms look much better (yesterday's plot).

* Stability of amplitude, delay, phase, bandpass look just as good. Longer tests
   (with more samplers) are in the works.

* RL crosstalk just as good.

* Calibration (switched power) nonlinearity is closer to theoretical,
* and there is less variation across the subbands within a sampler baseband.

* Noise on the visibilities: 0-10% (+_3%) better than the teledyne samplers.
   Various single baselines and combinations were compared. This data had no
   8-bit channels in parallel, that will be done ASAP.

* NO birdies in the autocorrelations.

So far so good!