Pulse descriptor word streaming with the R&S®SMW200A

The R&S®SMW200A vector signal generator can take on the role of a powerful and flexible signal generation source for the most realistic and agile radar scenarios in highly integrated radar scenario simulators. With the R&S®SMW-K503 option, the R&S®SMW200A can generate the most modern I/Q modulated radar signals from streamed pulse descriptor words (PDW) received via LAN. It supports a PDW execution rate of up to 1 MPDW/s.

Your task

Radar engineers often use software tools such as the R&S®Pulse Sequencer software to calculate radar scenarios. This is a good solution for research and development and during verification of radar equipment. Users can change parameters quickly and have a lot of flexibility when designing the radar scenario. For operational tests, radar engineers often need to generate ultra-long radar scenarios that contain demanding electronic warfare (EW) environments with high pulse density. Scenarios can originate from earlier simulations or live recordings. They are often stored as lists of pulse descriptor words (PDW) on a recorder. The PDWs contain the radar signal parameters for each pulse together with a timestamp that defines the pulse start time. A solution for regenerating the radar scenario is to stream the stored PDWs to a signal source. As an alternative, radar engineers can simulate the scenario and stream the PDWs directly to a signal source without previously storing the PDWs.

For both approaches, radar engineers need a signal source that can receive the streamed PDWs, e.g. over LAN, interpret them and regenerate the radar signal from the PDWs.

T&M solution

The R&S®SMW200A takes on the role of an agile signal source that generates demanding EW environments within its baseband bandwidth of 2 GHz. It generates I/Q modulated pulsed signals, agile signals with fast switching and classical pulsed signals from streamed PDWs. The R&S®SMW200A receives the streamed PDWs from the radar signal simulator via LAN. The powerful baseband hardware interprets the PDWs and generates the RF signal based on the pulse descriptions at the required point in time as defined in the PDWs. The R&S®SMW200A can execute and generate pulses from the streamed PDWs with a maximum execution rate of up to 1 Mpulse/s or 1 MPDW/s respectively.

Rohde & Schwarz proprietary PDW format

A single PDW representing one pulse has a fixed length and contains data with information such as time of arrival (ToA), frequency offset, amplitude offset, pulse duration and modulation parameters and the I/Q waveform segment ID.

The flexibility of this format makes it possible to define traditional pulsed signals such as unmodulated pulses and pulses with linear frequency modulation (LFM). In addition, streamed PDWs can contain a reference to an I/Q waveform segment stored in the ARB memory of the R&S®SMW200A.

Rohde&Schwarz proprietary PDW format
Rohde&Schwarz proprietary PDW format

Streaming classical PDWs

For PDWs that only contain traditional pulsed signals, users benefit from the realtime signal generation capability of the wideband baseband hardware. Unmodulated pulses, Barker coded pulses, LFM pulses (chirps) together with frequency offsets or amplitude offsets are generated in realtime based on the parameters defined in the PDW. The pulse start time is defined by the ToA timestamp included in the PDW.

Streaming I/Q modulated signals

The R&S®SMW200A vector signal generator can also generate any I/Q modulated pulsed signal from streamed PDWs. As a unique feature, the PDW can contain a reference to a predefined waveform segment that is stored in the memory of the digital baseband. This solution enables the user to mix PDWs defining classical pulsed signals with modern radar signals that are often I/Q modulated and require a vector source to generate the signal. ToA information defines the start of signal generation. Frequency offsets and amplitude offsets are also applied in realtime as defined by the PDW.

Streaming control PDWs

Control PDWs give the user direct control over the RF hardware of the R&S®SMW200A without stopping the stream. Control PDWs make it possible to change the absolute RF frequency (e.g. from X-band to C-band to simulate different radar bands) or RF level (e.g. from 0 dBm to –20 dBm to simulate different EIRPs of emitters) of the instrument without have to send an extra remote command.

The user can use the full RF frequency range and dynamic range of the RF hardware and, for example, switch the RF frequency to cover different radar bands. By embedding these control commands in the stream, the start of the change can be exactly determined by a ToA time stamp. The signal can be changed in a predictable and stable manner after a very short time.

Key performance parameters for realtime signals
Minimum PRI 1 μs
Maximum PDW execution rate 1 MPDW/s

Ready for HIL applications

The R&S®SMW200A produces only a very low delay from the Ethernet input on the R&S®SMW200A to the RF output port on the vector signal generator. It is therefore suitable for low latency applications.

Two-path concept

Since an R&S®SMW200A can be equipped with two RF paths up to 20 GHz with two independent R&S®SMW-B9 wideband baseband boards, the R&S®SMW200A can accept two independent PDW streams. Multichannel setups become compact, simpler and have a smaller footprint.

Single-box solution for PDW streaming

The R&S®SMW200A equipped with the R&S®SMW-K503 option is a compact, single-box solution for generating the most demanding and realistic radar scenarios for any I/Q modulated signal. PDWs are streamed via a LAN interface to the wideband baseband hardware.

Key facts

  • Execution rate with R&S®SMW-K503 up to 1 MPDW/s
  • Single-box solution for PDW streaming applications with any I/Q modulated complex pulsed waveforms
  • Ultralong signal playtime with minimum memory requirements
  • Outstanding signal quality
  • Two independent RF paths with wideband baseband in a single box
Concept of PDW streaming with the R&S®SMW200A
Concept of PDW streaming with the R&S®SMW200A