3
System performance characteristics
This data sheet offers two types of performance numbers
to describe the merit of any measurement system:
specifications and supplemental characteristics.
Specifications describe the instrument’s warranted
performance over the temperature range of 23 ˚C ± 3 ˚C.
Supplemental characteristics are typical but non-warranted performance parameters. These are denoted as
“typical,” “nominal,” or “approximate.”
To specify the performance of an 8510 system, the data
sheet lists each system’s dynamic range, measurement
uncertainty and measurement port characteristics. The
glossary below explains the major terms used in the
System Performance section of this data sheet.
DYNAMIC RANGE has two descriptions: receiver
dynamic range and system dynamic range. In either case,
the noise floor (which affects P
min
as defined below) is
measured with full two-port error-correction and 1024
averages.
System dynamic range = P
ref–Pmin
, where P
ref
is the
nominal or reference power out of port 1 with maximum
power delivered from the source and P
min
is the minimum
power into port 2 that can be measured above the peaks of
the system’s noise floor (10 dB above the average noise
floor). System dynamic range is the amount of attenuation
that can be measured from a 0 dB reference.
Receiver dynamic range = P
max–Pmin
, where P
max
is
the maximum power that can be input to port 2 before
0.1 dB compression of the test set and P
min
is the minimum power into port 2 that can be measured above the
peaks of the system’s noise floor (10 dB above the average noise floor). Receiver dynamic range is the system’s
full usable dynamic range if the system is considered a
receiver. An active device, such as an amplifier, may be
required to realize the receiver dynamic range.
Calibration is the process of measuring standards which
have fully defined models (and are thus called “known”
standards) in order to quantify a network analyzer’s
systematic errors based on an error model.
Calibration must be performed within the operating temperature specified for the calibration kit. For all calibration kits the operating temperature is 23˚ C ±3˚ C. For a
calibration to remain fully verifiable, the temperature of
the network analyzer must remain within ±1˚ C around the
initial measurement calibration temperature.
Error correction is the process of mathematically
removing from the measurement those systematic errors
determined by calibration.
MEASUREMENT UNCERTAINTY curves show the
worst case uncertainty in reflection and transmission
measurements using full two-port error correction with a
specified calibration kit. This includes residual systematic
errors, as well as system dynamic accuracy, connector
repeatability, noise and detector errors. Cable stability and
system drift are not included. All measurements assume
step sweep mode with 1024 averages unless otherwise
specified.
Furthermore, the graphs for reflection measurement
uncertainty apply to a one-port device. The graphs for
transmission measurement uncertainty assume a wellmatched device (S
11
= S22= 0). In the phase uncertainty
curves, the phase detector accuracy is better than 0.02
degrees, useful for measurements where only phase
changes.
Using the 8510 specification and performance verification
software, uncertainty curves can be calculated for nonidealized devices, and specifications can be edited
for custom setups.
MEASUREMENT PORT CHARACTERISTICS indicate the RF performance of test set port leakages, mismatches, and frequency response. The specification for
the test set’s crosstalk does not include noise.
“Raw” port characteristics refer to the test set’s intrinsic,
uncorrected performance. “Residual” port characteristics give the test set’s performance after error correction.