Wavecom W-SPECTRA (Automatic Monitoring System) V1.1.0 - Manual (Page 162)

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Transmission Modes WAVECOM Monitoring System W-SPECTRA, W-SPEED Manual V1.1.0
Digit Hz Digit Hz
3 1160 B 886
4 1270 C 2600
5 1400 D 856
6 1530 E 2400
7 1670 F 680
Tone duration: 70 ms.
PICCOLO-MK6 and PICCOLO-MK12
PICCOLO-MK6 and PICCOLO-MK12 are MFSK (multi frequency shift keying) systems. The earlier PICCOLO
versions MK1, MK2 and MK3 used 34 or 40 tones, each tone representing one character of the ITA-2 or
ITA-5 alphabet respectively.
Parameter Value
Frequency range HF
Operation modes Simplex
Modulation MFSK-6, MFSK-12
Speed 50 ms, 25 ms
Receiver settings DATA, CW, LSB or USB
Input format(s) AF, IF
Additional Info ITA-2 for MK6, ITA-5 for MK12
The tone duration was 100 ms and the tone spacing 10 Hz.
Recent systems operate with two sequential tones. The combination of the two tones defines the transmit-
ted character. An increase in the signal-to-noise ratio is achieved by this method.
PICCOLO-MK6 is based on the ITA-2 Baudot alphabet. 6 tones are used which results in a total of 36 com-
binations. The tone duration is 2 x 50 ms for one character which corresponds to 75 Baud Baudot with 7.5
bit code words.
PICCOLO-MK12 transmits ITA-5 characters. To transfer 7 bit ASCII characters, twelve tones are required.
This produces 144 bit combinations of which 128 are used. The transmission speed is equivalent to an
asynchronous data rate of 110 Baud.
The WAVECOM software displays four windows on the screen: Normal T1/T2, Inverse T1/T2, Normal
T2/T1 and Inverse T2/T1. This way of organizing the display is due to the fact that it is not possible for
the operator to decide from the monitored tone sequence, whether the first received tone constitutes tone
1 or tone 2 of a character. In addition, reception may occur using either the upper or the lower sideband
giving a total of four decoding possibilities. Decoding of data is done simultaneously in all four windows.
Tone Assignment of PICCOLO-MK6 and PICCOLO-MK12