Setting up a MB-OFDM Measurement
This topic provides information for connecting your signal to an 89600 VSA for successful demodulation of MB- signals. A typical measurement
includes the following measurement setup process (each step is discussed
in the following text):
- Connect
your signal
- Configure
the Center Frequency and Span
- Configure
the Input Range
- Configure
Triggering (if required)
- Verify
input signal capture and initial parameter settings
- Configuring
the demodulator for MB-OFDM measurements
- Select
the MB-OFDM demodulator
- Select
the
- Select
the
- Set
- Set
the
- Run
the measurement
MB-OFDM Measurement Setup Information
-
Connecting
Your Signal: If your input hardware has a second input channel, the raw I (In-phase) and Q (Quadrature-phase) signals can be connected (). With this configuration, the VSA
removes the quadrature mixer from the demodulator's signal flow, which
connects the I-component of your signal to Channel 1, and the
Q-component to Channel 2.
Notes for I+jQ input:
- Selecting an
configuration enables DC coupling.
- Use User Correction to correct for any offset or gain imbalance between the
I and Q signals.
- Range
is set independently for the I and Q inputs, but can be coupled by selecting the Couple Paired Channels parameter.
- Configuring
the and :
- Setting
the Center Frequency: The VSA's center frequency must be set within
approximately ±300 of the carrier frequency of the MB-OFDM Band
Group signal, otherwise the VSA may not be able to lock onto your
signal. To review the Band Group carrier frequencies, see Band
Group and Band Frequencies.
- Setting
the Frequency Span: When selecting a frequency span, select the narrowest
span that includes all of your signal components, a nominal 528 for
non-hopping and 1584 MHz for hopping.
Using Preset to Standard or setting the Band Group measurement parameter will automatically set Center Frequency and Span according to the standard.
Set before setting and when using a non-standard center frequency or span for a certain Band Group.
- Configuring
the Input : The input
range must be set correctly to obtain accurate measurements. Input
ranges that are too low overload the VSA's Analog-to-Digital Converter
(). Input ranges that are too high increase noise, which increases
errors reported in error summary data, such as Error Vector Magnitude
().
- Set
up triggering (if required): The default triggering mode is set to "FreeRun".
However, if a different trigger mode is preferred, now is the time
to configure the triggering ().
- Verify
the input signal and initial parameter settings: View your signal in the
frequency domain to verify the parameter settings set in the previous
steps.
- Configuring
the demodulator for MB-OFDM measurements: Configure the demodulator
parameters manually or use the Preset
to Standard parameter.
is preset by the first and then by the Time-Frequency
Code ().
- Set
the demodulator to MB-OFDM (). This enables the MB-OFDM demodulator
properties and measurement parameters.
- Set
the Time-Frequency Code (
- Select Data Rate (
- Set Preamble Type to Auto ().
- Set
the Result Length ( where determines the
signal capture length in terms of the number of OFDM symbol-times, making
sure that the result length is long enough to capture at least one MB-OFDM
packet. For more information, see Lengths,
Intervals, and Offsets.
- Run
the Measurement
See Also
Selecting the
MB-OFDM Demodulator
Using
Standard Setups/Presets (MB-OFDM)
MB-OFDM Demod Properties Dialog Box
2024
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