Chapter 7 251
Digital Signal Interface Module
Operating the N5102A Module in Input Mode
6. Press the More (1 of 2) softkey.
From this softkey menu, select the bit order, swap I and Q, the polarity of the data, and access menus that
provides data negation, scaling, and filtering parameters.
7. Press the
Data Negation softkey.
Negation differs from changing the I and Q polarity. Applied to a sample, negation changes the affected
sample by expressing it in the two's complement form, multiplying it by negative one, and converting the
sample back to the selected numeric format. This can be done for I samples, Q samples, or both.
The choice to use negation is dependent on the device being tested.
8. To access I/Q scaling and filter parameters, press
Return > N5102A Off On to On. This will invoke the
real time Custom format in the ESG baseband generator. This is needed to set the filter parameters when
Pre-FIR Samples is selected as the data type.
9. Press the
Baseband Setup softkey.
Use this softkey menu to adjust the I/Q scaling and access filter parameters. If the selected data type is
Samples, the
Filter softkey is grayed out (inactive). For more information on user-defined filtering, refer
to the “Using Finite Impulse Response (FIR) Filters” on page 173 and “Modifying a FIR Filter Using
the FIR Table Editor” on page 178.
Digital Data
If the N5102A digital module is not on, press Return > Return > N5102A Off On to On.
Digital data is now being transferred through the N5102A module to the ESG. The green status light should
be blinking. This indicates that the data lines are active. If the status light is solidly illuminated (not
blinking), all the data lines are inactive. The status light comes on and stays on (blinking or solid) after the
first time the N5102A module is turned on (
N5102A Off On to On). The status light will stay on until the
module is disconnected from its power supply.
NOTE If changes are made to the baseband data parameters, it is recommended that you first
disable the digital output (
N5102A Off On softkey to Off) to avoid exposing the device and
the N5102A module to the signal variations that may occur during the parameter changes.
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