LeCroy LSA1000, Operator'S Manual

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About the LSA1000
Channels
The LSA1000 offers two channels for signal input. There are four
additional BNC connectors for an external trigger channel, external
reference clock in, external reference clock out and acquisition status
output. The LSA1000 can be “stacked” to provide more channels
and parallel processing with multiple units. And multiple units can be
synchronized using external reference clock connections.
Triggering
Trigger rates of up to 1 GHz are possible with the LSA1000. Single
Edge triggers are described by a source, coupling, slope, and level
condition.
➢
Source is selected from:
➢
CH1, CH2: the acquisition channel signal conditioned for the
overall voltage gain, coupling, and bandwidth
➢
EXT: the signal applied to the EXT TRIG IN BNC connector.
It can be used to trigger the LSA1000 with an ECL signal
level. The input impedance is 50

, terminated to
–2V.
Optionally, this input can be configured to accept a TTL level
signal. This configuration must be specified at time of
purchase.
➢
Coupling refers to the type of signal coupling at the input of the
trigger circuit. LSA1000 supports DC coupling on all sources,
where all the signal's frequency components are allowed to pass
through to the trigger circuit. This coupling mode is used for
high-frequency bursts.
➢
Slope selects the direction of the trigger voltage transition that
generates a trigger event. In addition to the two traditional
choices of
Positive and Negative , the Window mode is also
included. In Window mode two trigger levels (one upper, one
lower) are defined with the window region in between. Triggering
occurs when the signal leaves the window region in either
direction,
as shown in the diagram on the next page .
➢
Level defines the source voltage at which the trigger circuit will
generate an event (a change in the input signal that satisfies the
trigger conditions). The selected level is associated with a trigger
source in the same way as the coupling. Note that the trigger
level is specified in volts and is normally unchanged when the
vertical gain or offset is modified.