Musical Instrument User Manual

APPENDIX P P - 1
Appendix P
CHANNELS SIMULTANEOUSLY SAMPLED AT 100 MS/s
The scope has two 8-bit flash analog-to-digital converters (ADCs), each with a
maximum sample rate of 100 MS/s. This allows two channels to be captured
simultaneously in single shot mode, with sample rates of up to 100 MS/s for each
channel. The horizontal resolution is then 10 ns (i.e., 1/100 MS/s).
DOUBLE SAMPLING MODE FOR 200 MS/s SINGLE CHANNEL ACQUISITIONS
Input stage switching expands the capability of both ADCs so they can be
interleaved, allowing a maximum sample rate of 200 MS/s on a single channel.
The entire acquisition memory can be used so that the record length for a single
channel acquisition is can be equal to the full memory of the instrument (i.e., 8K
for the standard instrument, and 32 K for an instrument equipped with Memory
Expansion). The interleaving is done by feeding the input signal of a single
channel to both ADCs that are sampling at a phase difference of 5 ns.
GLITCH DETECTION
The sampling rate of a DSO decreases when you lower the timebase setting. As
long as the glitch capture feature is activated, the ADCs continue to sample at
their maximum speed. A fast digital circuit analyzes all of these samples at real-
time speed (100-MHz signal processing).
Only the maximum and minimum values (i.e., an envelope of min/max pairs) are
stored in memory. Such a glitch detection circuit allows very narrow glitches to be
captured even at low timebase settings and even if they occur only once.
The glitch capture circuit can also be used to avoid aliasing. The upper curve and
the lower curve of an AM modulated signal appear on screen as an envelope of
min/max pairs, and the area in between is shaded.
In the two-channel mode, glitches down to 10 ns (i.e., 1/100 Ms) can be captured.
In single-channel mode, even glitches down to down to 5 ns can be captured.
GLITCH CAPTURE IN FOUR CHANNEL MODE
If more than two channels are activated and the glitch detector is switched on, the
scope automatically selects the alternating mode. Since the alternate mode
allows each ADC to run at full speed, 10 ns glitch detection is now possible on all
four channels.
Single-shot acquisition with glitch detection is possible only in one- and two-
channel modes.