General description
The MFSK16 is based on multi-tone FSK modulation and also utilizes the most modern FEC (Forward Error Correction) techniques as well as interleaving. The MFSK16 provides 31 WPM text throughput with FEC and 62 WPM with no FEC. SkySweeper supports also 2MFSK16 (63 WPM) and 4MFSK16 (125WPM) modes.
With the ‘Config’ button you can configure the transmission magnitude & frequency. With ‘Load’ you can load the text to be transmitted from a file. ‘Start/Stop’ starts and stops the transmission. When the characters have been transmitted, the Red text ‘Transmitting’ is shown in the dialog. If the Yellow text ‘Ready to Transmit’ is shown, you should press the Green button in the Configuration Editor to start the transmission. With ‘Reset’ you can reset the transmitter. The MFSK16 transmitter shows the currently transmitted character as inverted. Transmission is always started from the cursor position.
Configuration
Pressing the ‘Config’ button opens the following Configuration dialog box.
Parameters:
Mode
The used mode is selected here. MFSK16 is a standard MFSK16 transmission. 2MFSK16 is double speed version and 4MFSK16 is four times faster version of the standard mode.
Magnitude
With this you can set the magnitude (maximum amplitude) of the transmitted signal. The amplitude value is set as an absolute value. When 16-bit processing is used, the maximum magnitude will be 32767. If 8-bit processing is used the maximum is 127.
Carrier Frequency
This sets the carrier frequency. Note, that if the transmission is connected directly to one of SkySweeper’s own decoders, the FFT resolution is limited, which might cause the situation when the decoder does not lock exactly to the transmitted frequency. This effect has no influence on the performance of the decoder.
FEC
If FEC is selected then Forward Error Correction is used. This means that interleaving and convolution coding is used to protect the data. When FEC is selected the text throughput will be dropped by 50%.
Sum to RX
If this switch is selected, the TX signal is added to the block’s input signal. Otherwise, the input signal is muted.
Repeat
With this switch you can set the transmitter dialog text to be repeated when the last character has been sent. The repeated block starts from the cursor position.
Macro
The ‘Macro’ button opens or closes the TX macro panel
Load
The ‘Load’ button opens the transmitter load data control Dialog, which is used to read text from a file, or a socket, into the transmission text window.
Start
The ‘Start’ button starts transmission from the cursor position. If there is text selected in the transmission window, only the selected text is sent. It is not possible to edit the transmission window when transmission is on. Transmission can be stopped at any time by pressing the ‘Stop’ button. If the TX control signal is enabled the Start and Stop buttons turn the signal on and off.
Reset
The ‘Reset’ button clears the transmission window and resets the transmitter.
