Keysight Technologies X-Series, Руководство по программированию

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360 Keysight CXG, EXG, and MXG X-Series Signal Generators Programming Guide
Creating and Downloading User–Data Files
FIR Filter Coefficient Downloads
FIR Filter Coefficient Downloads
The signal generator accepts finite impulse response (FIR) filter coefficient
downloads. After downloading the coefficients, these user–defined FIR filter
coefficient values can be selected as the filtering mechanism for the active
digital communications standard.
Data Requirements
There are two requirements for user–defined FIR filter coefficient files:
1. Data must be in ASCII format.
The signal generator processes FIR filter coefficients as floating point
numbers.
2. Data must be in List format.
FIR filter coefficient data is processed as a list by the signal generator’s
firmware. See Sample Command Line.
Data Limitations
The X-Series signal generators support both Real and Complex filters.
Complex filters can only be used with equalization filters. Refer to Table and to
Table . For more on equalization filters, refer to “Using the Equalization Filter”
on page 364 .
Filter lengths of up to 1024 taps are allowed. The oversample ratio (OSR) is the
number of filter taps per symbol. Oversample ratios from 1 through 32 are
possible.
If you encounter problems with this section, refer to “Data Transfer
Troubleshooting” on page 384 .
Modulation filters are real and have an oversample ratio (OSR) of two or
greater.
On the
N5166B,
N5172B, and N5182B with Options 653, 655, or 656, 657,
respectively, equalization filters are typically complex and must have an
OSR of one (refer to “Using the Equalization Filter” on page 364 and to the
User’s Guide).
Type of Filter Description
Real The I and Q samples are independently filtered by a single set of real coefficients.
Complex The samples are treated as complex (I + jQ) and convolved with the filter coefficients which are
specified as (I + jQ) in the time domain.