Digital Modulation Settings and Limits

There are multiple methodologies for creating digital modulation formats in Siglent RF signal generators. There are built in modulation formats that enable pattern creation from the front panel, there are built in arbitrary or custom files that make it possible to access standard modulations that are more complex, and there is the SIgIQPro software that enables more fully customizable solutions that can be downloaded directly to the instrument.

Built in modulation types that can be customized from the front panel include:

· AWGN (Additive White Gaussian Noise)

· Multi-tone

· IoT signals (SSG5000X-V only)

· Stream file (SSG5000X-V only)

· Custom digital modes

· Arbitrary

AWGN or Additive White Gaussian Noise creates noise in the RF channel. The use can set the bandwidth of the noise which is centered around the center frequency like so:

AWGN noise can be generated up to the full bandwidth of the generator. 75 MHz or 150 MHz (with the option) for the SSG5000X-V models and 500 MHz or 1 GHz (with the option) for the SSG6082A-V.

Multi-tone signals are covered in the section titled: “Multi-tone Signal Generation”.

IoT signals include the ZigBee and Z-Wave. These waveforms include oversampling ratios, frames, length, marker, and trigger settings. Users can also customize PPDU and PSDU settings in the ZigBee format. These waveforms can also be produced in SigIQPro for either the SSG5000X-V or the SSG6082A-V. See the chapter titled: “SigIQPro Signal Generation Software” for more information.

sample clock (up to 5 MHz), modulation attenuation,
and a baseband offset frequency.

Many custom digital modes are built in with some configurability. These include:

There is also a user modulation type where the user can customize a constellation diagram and allocate symbol values in a table. Those are the custom modulation types. In addition to the modulation type, users can also set the data values. Data options look like:

Here, users can set the symbol rate up to the maximum based on the instrument bandwidth. Also, set the symbol length. Bits/Symbol are set by the modulation type. There are also front panel options for setting the filtering:

With front panel editing of the modulation type, filtering, and data these signals can be significantly customized for many applications.

The final category of IQ modulation available from the front panel is the ARB mode. Arbitrary mode enables users to load pre-saved files to the baseband generator. See all the files preloaded in the SSG5000X-V or SSG6082A-V in the preloaded data section. They include preloaded datafiles for 5G NR, Bluetooth, CDMA2000, GSM, LTE FDD, LTE TDD, WCDMA, and WLAN.

This is also the menu where users can access the multi-carrier capabilities by essentially loading a file separately to different channels. Alternatively, the waveform sequence tool can also be activated here. Instead of simultaneous IQ signal files across multiple channels you can sequence between files on a single carrier. This creates long data sequences for complex interoperation tests. Both the SSG5000X-V and the SSG6082A-V instruments can sequence up to 1024 wave segments and up to 65535 wave repetitions.

The SSG6082A-V has significantly more memory with a max playback capacity of 2048 MSa and a segment length of up to 2 GSa. The SSG5000X-V is limited to 200 MSa for both max length and total capacity.

Additional wave customization is possible using the SIGIQPro PC software.