has additional sample rates of 100 and 200 MS/s available. See the Spike Software manual for
further information on using Zero Span analysis.
2.6.3.1 Triggering in Zero Span
You can specify an immediate, video, external, or frequency mask trigger (FMT) in zero-span
mode.
Immediate triggering causes the measurement to occur immediately and can be thought of a ‘no-
trigger’.
Video triggering allow you to begin the measurement only after a signal exceeds a specific
amplitude on the RF input. This is useful when you need to analyze a periodic transmission.
External triggering triggers a measurement after a hardware trigger occurs on the trigger SMA
port. If your transmitter has a trigger output, you can route this to the trigger in SMA. You can
trigger on the rising edge or falling edge of a signal. A 3.3V CMOS trigger with 50 ohm output
impedance is ideal, but 5V logic with 50 ohm output impedance is acceptable. Higher or lower
output impedance may work with a short BNC cable, but longer cables may cause issues with
reflection.
FMT triggering triggers a measurement after a spectrum amplitude exceeds a customer defined
spectrum mask. Spectrums are calculated by performing 50% overlapping FFTs on the time
domain data.
2.6.4 I/Q Sweep List
I/Q sweep lists allow customers to sweep a list of frequencies and collect a custom number of I/Q
samples at each frequency. In this measurement, the SM device can sweep frequencies up to its
maximum sweep rate of 120us per frequency (~8333 frequencies per second). Data is sampled
at the device’s native sample rate, 50MS/s for the USB SM devices, and 200MS/s for the
networked SM devices.
Triggering is not available for this measurement. I/Q timestamping is performed at each
frequency.
This functionality is only available through the API. See the API manual for more information.
2.6.5 Segmented I/Q Capture (SM200B/SM435B only)
The SM200B and SM435B includes 2 GB of DDR memory for capturing I/Q data at the full 250
MS/s sample rate (160 MHz bandwidth). This memory may be used as a single, contiguous, two
second capture, or as multiple smaller (segmented) captures. Trigger modes for these captures
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