•  Fully tunable 70 MHz IF input for satellite monitoring with no external receivers.
• High performance wideband analog front end.
• High-speed DSP.
• Fully reconfigurable (inputs, FPGA, DSP, bandwidth, IF frequency ).
• Half-size PCI card with SMA input connectors.
• Highly reconfigurable front end:
  • Three wideband AF/IF inputs (50 Hz – 25 MHz).
  • One wideband IF input (52.5 MHz – 87.5 MHz) with SAW filter.
  • 14 bit/92.16 MSps analog to digital converter (ADC).
  • Automatic level control and overrun protection.
  • 60 dB input dynamic range
• Digital Down Conversion (DDC):
  • 96 dB dynamic range (16 bits)
  • Bandwidth configurable from 5 kHz to 500 kHz
  •  Automatic gain setting to achieve maximum dynamic range.

• Digital Signal Processing:
  • TMS320C6414 DSP (5760 MIPS)
  • External 128 Mb SDRAM and 1 Mb FLASH RAM.
• TCP/IP, XML remote control interface.
• powerful 0.5, 1, 2, 4, 24, 48 and 96 kHz wideband FFT.
• I/Q data stream interface (XML/TCP/IP).
• Optional classifier with automatic code check.
• BitViewer Tool.
• Digital receiver interface .
• Single channel INMARSAT B/M/mM mode for data, fax and voice (B, M)  (optional)
• EasySatSystem Multi channel INMARSAT B/M/mM monitoring system (optional).
• Optional classifier with 4 and 8 kHz bandwidth.

• Local use in a PC with standard W61PC application software.
• Remote use over a LAN with standard W61PC application software.
• Remote control from other applications using third party software, e.g. Radio Monitoring Tools, Alarm Monitor.

This allows the system to be adapted to the client's need and applications.

Using an audio or IF input signal, the W61PC decodes a variety of text and graphical transmission modes. The determination of signal characteristics is assisted by a large number of analysis and measurement functions operating over a wide range of signal parameters. The W61PC is the advanced next-generation decoder in the well known WAVECOM® line of decoders. The W61PC is equipped with powerful DSP software and hardware to allow the realization of real-time demodulators and filters. The large onboard memory provides sufficient space for data buffering. Additionally, the whole computing power of the host PC is also available for data processing.
 

The W61PC software is a 32-bit Microsoft Windows application providing a familiar user interface and system functions. The availability of sophisticated software development tools allows rapid implementation of new functionality.

All of the integrated analysis tools contain many different methods and viewing options. It assists the operator in analyzing the important signal parameters. Exact measurements are easily made using adjustable cursors with associated numerical displays. Dynamic zoom functions allow magnification of details in any selected window. The scroll buffering feature makes it possible to move back and forward in signal history. Real-time FFT functions with a fast display refresh rate are implemented. Additional powerful functions provide the tools for analyzing unknown signals. A wide range of system default settings can be configured, e.g. input signal level, sampling rate, measuring interval, centre frequency and demodulator type. Additionally a variety of international alphabets can be selected.
More than 150 modes are currently implemented.

• Additional customer specific modes.
• Software source code and the complete development environment. This allows for implementing additional codes or adapting the user interface to specific requirements.
• Training.

For this reason an equalizer is generally required in the demodulation to compensate such interference before the data can be further processed. Because the channel or the distortion may change with time (time-variant), such equalizer must be adaptive. There are many kinds of equalizers: optimum equalizer estimates the maximal likelihood data sequence according to the channel knowledge. Such equalizer has usually very high computational complexity and is impractical or infeasible for time-variant channel.

Many kinds of low complexity equalizer are proposed. They include linear equalizer, which operates with different criteria e.g. peak distortion, minimum mean square error (MMSE), etc. Decision feedback equalizer (DFE) is a very popular nonlinear equalization scheme. In most case it is a combination of a linear equalizer and a nonlinear decision part, both parts can be implemented with different algorithms. Most recently, iterative equalizers (Turbo equalizers) are researched where channel estimation and channel decoding are considered as well.

There are several kinds of adaptive equalizers in WAVECOM decoders: decision feedback equalizer based on Kalman algorithm, equalization based on estimated channel matrix and Turbo equalizer. These equalizers are used in most HF-ACARS, MIL and STANAG modes, because most of them employ a bandwidth efficient single carrier 8-PSK modulation scheme for high speed data transmission (up to ca. 10k bps).

The improvement of bit error rate with equalizer is usually big, this depends on the signal quality and quality of the equalizer. The following two phase constellation diagrams show the demodulation with and without the decision feedback equalizer used in WAVECOM decoder. A real-time recorded signal from an HF-antenna is used. The phase constellation of the demodulation without the equalizer is almost equally distributed on the phase plane, whereas the one with the equalizer shows a quite concentrated distribution around the 8 possible phase points. The error rate of demodulation with an equalizer is usually small, in this example it is about 2%, the one without using an equalizer is about 60%, this makes the demodulated bits totally useless.

Equalizer Off

• Manual or automated monitoring of radio data communications in the HF/VHF/UHF/SHF (satellite) bands.
• Signal intelligence.
• Signal analysis and classification.