Airbus Defence and Space


Digital wideband pulse generator (DWPG)

Future radar instruments are characterised by their increased demands on bandwidth (e.g. 150 to 300MHz) and the introduction of complex modulation schemes with any phase coding and amplitude weighting. These upcoming challenges can efficiently only be met at the on-board waveform generation side by a highly flexible and modular design, having the capability to be easily adapted to the various applications with only minor modifications. With the memory readout technique the digital waveform samples are read from a Random Access Memory (RAM) section, converted from Digital-to-Analog and subsequently filtered to generate the desired analogue output signal. Reprogramming during the mission is performed by uploading of the updated waveform samples.

Features / technical details

Our preferred technical concept is based on the memory readout technique. This concept has proven to offer the highest possible degree on flexibility, since it allows any type of waveform sequences even with complex characteristics (i.e. any coding, amplitude weighting, pre-distortion to compensate for TX/RX waveform samples. The design and implementation of the DWPG has been guided by our long experience and profound knowledge on Digital Waveform Generation based on the memory readout concept, which Airbus Defence and Space GmbH has already proposed and successfully implemented in 1993 for ESA.

One of the key elements of the DWPG is an highly integrated Application Specific Integrated Circuit (ASIC) in radiation hardened technology with the following features:

• Radiation Tolerant MG2RT process (ATMEL)

• CMOS Sea-of-Gates 0.5µm, 3 metal layers

• Total Dose better than 100 krads

• Latch-up better than 100 MeV/mg/cm2

• SEU Threshold better than 25 MeV/mg/cm2

• 132 pins Multilayer Quad Flat Pack (MQFPL)

The fully programmable device provides all central functions of a Digital Chirp Generator using the memory readout concept:

• Sampling rate up to 400MHz with external MUX

• Memory storage capacity 256 kbit

• Programmable number of bits per sample: 8,16, 32bit

• Capability to switch between up to eight different pulses

• Standard microprocessor interface

• Pulse duration up to 80, 160, 320µs according the configuration

• Cyclic pulse generation capability

One of the most stringent constraints to achieve the nominal sampling rate of 400 MHz with one ASIC is the limited speed of the waveform memory. The introduction of a high speed multiplexing/interleaving scheme leads to overcome this technological constraint. 320 MHz bandwidth DWPG

For the High Bandwidth Option, the Single Channel Concept with a sampling clock of 800 Ms/s is implemented. For this solution at least two ASICs and a fast multiplexing stage is introduced. In order to expand the memory depth which is directly related to the maximum pulse length, four ASICs are used. The 8 to 1 High Speed Multiplexer (8 bit wide) operating at 800MHz is implemented in GaAs technology and is needed to read-out the eight DWPG ASIC output buses. All eight output buses are multiplexed into the high speed D/A-Converter operated at 800MHz.

150 MHz bandwidth DWPGLite

The single ASIC DWPG is implemented in a dual channel configuration, which is principally based on the generation of two baseband signal components (In-Phase and Quadrature-Phase). A subsequent analogue I/Q Modulator stage mixes and adds the In-Phase (I) and Quadrature Phase (Q) signals to IF in order to achieve the target chirp bandwidth of 150MHz. One advantage of the dual channel concept is that only one half of the sampling clock frequency must be implemented in the I- and Q channel.

DWPG Main Characteristics (High Bandwidth Option)
Generation Technique: Memory Read-Out
Waveform Modulation: Any Phase Coding and Amplitude Weighting
Sampling Clock Frequency: 800 MHz
Chirp Bandwidth: < 320 MHz
Waveform Memory Depth: 128k Samples (2 ASICs)
Pulse Duration: 0<TP<>
Pulse Switching: Between up to 8 Pulses
Pulse Repetition Frequency: < 20kHz
Number of Bits per Sample: 8Bits (cascadable to 8, 16...)
Output Signal Level: -5dBm ± 2dB @ 50 Ohm
Total Dose: > 100 krads
Latch-up: > 100 MeV/mg/cm2
SEU sensitivity: 25 MeV/mg/cm2
Size (PCB): Double Europe
Mass (PCB): 800 g
Power (ASIC): about 2 W
Power (PCB) < 15W



  • On-board chirp signal generator for pulsed radars (SAR, Altimeter)
  • Signal generator for navigation payloads
  • BPSK/QPSK signal generator/modulator for communication payloads