|WiNRADiO Universal FSK Decoder|
The WiNRADiO Universal FSK Decoder is an extremely versatile signal decoding utility for WiNRADiO receivers 1000/1500 or 3000 series, as well as G3 series. Using WiNRADiO models with in-built DSP (for example WR-G313i) will provide the best decoding quality; however, the Decoder will also work well with a sound card.
The Decoder contains several powerful analysis tools, making it possible to determine transmission characteristics of an unknown signal automatically.
Looking at the decoder's main control panel on the right, you will see a drop-down list at the top, labelled Protocol. Here you can select the type of coding protocol used. Using the Add or Edit buttons, new protocols can be added, either created entirely from scratch (the number of variable parameters makes the number of usable protocols almost unlimited), or by deriving new protocols from existing ones by modifying some of their parameters.
A "protocol" consists of all the various settings and parameters which are needed to be able to decode a signal, including the type of coding, mark/space frequencies, baud rate, character format, translation table, etc.
The first stage of the signal decoding chain is the level detector, visible at top-left of the main control panel above.
This detector allows the user to determine whether an adequate audio signal level exists at the decoder input. This facility is available only when a sound card is used; in such case the level should be adjusted either using the receiver or sound card volume settings. With WiNRADiO DSP receivers, the level control is automatic.
The first is the Time Estimations module which attempts to determine the bit length and the baud rate. The estimated value is displayed for reference, and it can be either used for further processing, or ignored by the user if a manually entered or preset value is preferred.
Universal Decoder - Data Output Window
The Data Output window shows the result of the entire demodulation and decoding process. It uses the data provided by the processes described above, as well as several additional user-adjustable parameters. Sometimes the transmitted characters are passed through a bit inversion mask; the decoder can easily handle this situation and special protocols can be defined when the correct mask has been identified. Also, certain protocols are polarity-dependent while others require automatic mode for correct functionality. These parameters can be set on the main control panel in the Bit Inversion Mask and Polarity groups of buttons.
Universal FSK Decoder - Character Translation Table
Before the decoded characters are displayed, they are passed through the Translator which relies upon a set of character translation tables to provide translation of the raw characters to national alphabets. These tables can be selected also in the main control panel of the Decoder, as one of the parameters which form the entire "protocol".
Universal FSK Decoder - Character Statistics
The "icing on the cake" of this multi-featured decoder is the Character Statistics display which creates a character histogram of the received text. The number of displayed bars (each corresponding to a different character) depends on the currently selected protocol. The bars are ordered by the character hex code. The displayed information is always normalized to the largest value. The statistics for each bar can be seen by simply moving the mouse over it. This is a very useful facility for signal intelligence activities.
The WiNRADiO Universal FSK Decoder comes with the following basic protocols pre-installed: ARQ1000D, ARQ-E, ARQ-N, ARQ-6, ARQ6-70, ARQ6-90, ARQ6-98, ARQ-E3, Baudot, IRA (ASCII), Packet Radio, POL-ARQ, SITOR-A, SITOR-B, NAVTEX, Raw Bits, SI-ARQ and SWED-ARQ. Many other protocols can be added by modifying the numerous decoding and demodulation parameters the Universal FSK Decoder offers.