The mode ASCII is one of the traditional modes used by radio-amateurs as CW, RTTY et l'AMTOR. It is used by radio amateurs since 1980. On rappelle qu'en réception AMTOR, RTTY et ASCII , use two frequencies which are filtered, each one corresponding to a binary digit (1 or 0). These two frequencies, separated by a shift, modulate the RF when transmitted and the modulation is called Audio Frequency-Shift Keying (AFSK), otherwise the modulation can be done directly on the RF carrier and it is called Frequency-Shift Keying (FSK). In HF amateur radio, AFSK is used when you pass by the MIC input ot the transceiver but FSK can also used if you pass by the special input of the TX.
This mode is included into the software MULTIPSK by Patrick F6CTE, there is the description of this mode and its variants as well as the specifications coming from his software :
Click on the copy of the screen in order to listen to the corresponding audio signal .
Description :
Baud rate : 110. A character is composed of a « start » bit (1 « space »), 7 or 8 bits and a « stop » bit (2 « mark »)
Speed : 110 wpm (7 bits) or 100 wpm (8 bits)
Modulation : FSK two tones (« mark » and « space » , "mark" high) with a shift of 170 Hz (or, sometimes, 200 Hz),
Receive mode : USB
Character set : 7-bits ASCII (or 8-bit ASCII for some languages), no parity,
Shape of pulse : rectangular
Bandwidth : 700 Hz (due to rectangular shape),
Demodulation : non coherent,
Synchronization : asynchronous with start bit,
Correction code : no
Convolution code : no
Interleaving : no
Pmean/Ppeak : 1
Lowest S/N : -2 dB