Agilent Technologies Signal Analyzer N9030a - Manual (Page 541)

6 RLC Swept SA Measurement Front-Panel & SCPI Reference
AMPTD Y Scale
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Offsets are used when gain or loss occurs between a device under test and the analyzer input.
Thus, the signal level measured by the analyzer may be thought of as the level at the input of an
external amplitude conversion device. Entering an offset does not affect the trace position or
attenuation value, just the value of the top line of the display and the values represented by the
trace data. Thus, the values of exported trace data, queried trace data, marker amplitudes, trace
data used in calculations such as N dB points, trace math, peak threshold, and so forth, are all
affected by Ref Level Offset.
Changing the offset causes the analyzer to immediately stop the current sweep and prepare to begin a
new sweep, but the data will not change until the trace data updates, because the offset is applied to the
data as it is taken. If a trace is exported with a nonzero Ref Level Offset, the exported data will contain the
trace data with the offset applied.
The maximum reference level available is dependent on the reference level offset. That is, Ref
Level - Ref Level Offset must be in the range –170 to +30 dBm. For example, the reference level
value range can be initially set to values from –170 dBm to 30 dBm with no reference level offset.
If the reference level is first set to –20 dBm, then the reference level offset can be set to values of –
150 to +50 dB.
If the reference level offset is first set to –30 dB, then the reference level can be set to values of –
200 dBm to 0 dBm. In this case, the reference level is “clamped” at 0 dBm because the maximum
limit of +30 dBm is reached with a reference level setting of 0 dBm with an offset of –30 dB. If
instead, the reference level offset is first set to 30 dB, then the reference level can be set to values
of –140 to +60 dBm.
µW Path Control
The µW Path Control functions include the µW Preselector Bypass (Option MPB) and Low Noise Path
(Option LNP) controls in the High Band path circuits.
When the µW Preselector is bypassed, the user has better flatness, but will be subject to spurs
from out of band interfering signals. When the Low Noise Path is enabled, the analyzer
automatically switches around certain circuitry in the high frequency bands which can contribute
to noise, when it is appropriate based on other analyzer settings.
For most applications, the preset state is Standard Path, which gives the best remote-control
throughput, minimizes acoustic noise from switching and minimizes the risk of wear out in the
hardware switches. For applications that utilize the wideband IF paths, the preset state is the µW
Preselector Bypass path, if option MPB is present. This is because, when using a wideband IF
such as the 140 MHz IF, the µW Preselector’s bandwidth can be narrower than the available IF
bandwidth, causing degraded amplitude flatness and phase linearity, so it is desirable to bypass
the preselector in the default case.
Remote Language Compatibility Measurement Application Reference 541