Real Time

Waveform Files

This topic is only for those signals where the software creates a waveform file that is downloaded to an instrument for playback. The real-time signal is generated by configuring instrument settings (no file is downloaded) and requires the Signal Studio software Wxx real-time license option. The real-time signal settings along with any instrument attributes such as amplitude and frequency are captured in the SCPI commands. These commands can be viewed in the SCPI Log Viewer.

Understanding Waveform File Generation

The number of signals required by the tests vary. Some require one signal while most require multiple signals. For some tests, when the test requires multiple signals, the software provides the ability to either create a single waveform file or multiple waveform files. For other tests, such as for LTE Clause 8 tests,the use of multiple instruments is required.

For tests where the PXB is supported, the use of the PXB is typically viewed as using multiple instruments. This is because of the PXB"s multiple baseband generator (BBG) capability and its need to use signal generators as RF upconvertors. But there are some tests such as for LTE Clause 7 where the PXB can imitate the single instrument behavior by using the single channel configuration (single BBG). For these tests, within the test settings window, the Signal Generator field selection enables the use of the same PXB BBG for all signals.

A single waveform file is created when the same instrument is selected (a user selection in the test settings window) for the signals. When different instruments are selected for each signal, the software creates multiple waveform files, one for each signal. For the tests that use a CW Interferer, some tests provide the capability to either combine it with other the test signals into a single waveform file, or have the CW Interferer instrument settings downloaded to a separate signal generator. For the tests that do not offer this capability, the CW Interferer must use it own signal generator.

The following figure illustrates using a separate signal generator for each signal. The software shows three different connected signal generators (shown in the top upper left side under the Hardware Connection and Settings node) and in the selected 7.8 Receiver Intermodulation test settings window, each test signal is using a different instrument (one of the connected instruments).


Based on the instrument selection shown in the figure, the software, upon clicking Execute, builds and downloads two separate waveform files. One for the Wanted Signal and another for the E-UTRA Interferer signal. Because the CW Interferer is also using a different instrument than the other two signals, the software for this signal just downloads the instrument settings to the instrument identified as Signal Generator (2:Connected).

If only one of the instruments was selected for all three signals (shown in the figure below), then the software would build and download one waveform file to the selected instrument that includes all three signals.


Other instrument to signal combinations for the above figures include:

To determine whether combining signals is supported for your tests, see the Test Case Manager Software topic.

Waveform File Generation and the Offline Mode Feature

This feature is not available for the PXB.

The software places the waveform file on the PC hard-drive regardless of the Offline Mode setting. Offline Mode determines whether the waveform is downloaded to the instrument:

This setting is located in the Signal Generator (n:<connection status>) node, Closed Signal Generator Settings window.

The Offline Mode feature is not available for the PXB.

Waveform File Naming and File Location

The software uses the following file names for its waveform files:

There is also a unique name that the software creates for the LTE test case 8.2.3 when the wanted signal uses FRC A3-1. For more information, see the LTE FDD and LTE TDD Tests topic.

There is no way to name or rename a waveform file using the software user interface. These names are used for both the file on the PC hard drive and the file downloaded to an instrument. The only way to change the waveform file name is to access the file and manually change the file name.

To change the name for waveforms downloaded to an instrument, refer to that instruments User's Guide for information on renaming a waveform file.

To change the name for files on the PC hard drive, access the waveform file in the following directory based on operating system:

Windows® 7 waveform file location

W-CDMA GMSK Interferer

All Other Waveforms

Windows XP waveform file location

W-CDMA GMSK Interferer

All Other Waveforms


When using the PXB, the software stores waveform files in the standard PXB waveform file locations:

The software determines the n value based on the PXB selection and test.

LTE and W-CDMA Clause 7 Tests

Whether the Wanted or Interferer waveform is stored in Channel1 or Channel2 depends on the PXB selection in the Signal Generator selection field. The PXB (BBG2) selection cannot be used without one of the signals using the PXB (BBG1) selection.

LTE and W-CDMA Clause 8 Tests

For these tests, the PXB waveform file locations are fixed for each signal as shown below (not all tests use all signals):