Marconi Selenia 25-Tone Modem

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Marconi Selenia 25-Tone Modem
Marconi25.jpg
Frequencies 3 MHz,30 MHz
Frequency Range 3 MHz - 30 MHz
Mode USB
Modulation PSK,OFDM
ACF
Bandwidth 1.6 kHz
Location Worldwide
Short Description The Marconi Selenia 25-Tone Modem is a military modem developed sometime around 2003 by Marconi Selenia Communications (Now Finmeccanica). It supports ECCM capability and transmits at a datarate of 2400bps.
I/Q Raw Recording
Audio Sample

The Marconi Selenia 25-Tone Modem is a military modem developed sometime around 2003 by Marconi Selenia Communications (Now Finmeccanica). It supports ECCMElectronic Counter-CounterMeasures (ECCM) is a part of electronic warfare which includes a variety of practices which attempt to reduce or eliminate the effect of electronic countermeasures (ECM) such as jamming. ECCM is also known as electronic protective measures (EPM), chiefly in Europe. capability and transmits at a datarate of 2400bps.

Characteristics[edit]

The 25-Tone Modem employs OFDMOrthogonal Frequency-Division Multiplexing across a bandwidth of ~1600 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).. There are 25 total QPSKQuadrature Phase-Shift Keying (2 bits per symbol) subcarriers. On the lower half there are 12 subcarriers, and on the upper half there are 13. Each subcarrier is spaced ~60 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). from each other, and each subcarrier transmits at ~48 BdBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second. for a total bit rate of 2400 bpsBits per second (bps).


Standard[edit]

The standard Non-ECMAn Electronic CounterMeasure (ECM) is an electrical or electronic device designed to trick or deceive radar, sonar or jam communication links. It may be used both offensively and defensively to deny information to an enemy. mode has a ~510 msmilliseconds (.001 of a second) preamble made of two main parts. The first part is a quick 3 + pilot tone preamble lasting ~260 msmilliseconds (.001 of a second). The One of the three tones is a continuous tone and the other two are FSKFrequency-Shift Keying with a shift of ~485 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). at ~50 BdBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second.. The second part is a preamble in the data transmission lasting ~250 msmilliseconds (.001 of a second).


ECCMElectronic Counter-CounterMeasures (ECCM) is a part of electronic warfare which includes a variety of practices which attempt to reduce or eliminate the effect of electronic countermeasures (ECM) such as jamming. ECCM is also known as electronic protective measures (EPM), chiefly in Europe.[edit]

The ECCMElectronic Counter-CounterMeasures (ECCM) is a part of electronic warfare which includes a variety of practices which attempt to reduce or eliminate the effect of electronic countermeasures (ECM) such as jamming. ECCM is also known as electronic protective measures (EPM), chiefly in Europe. mode is designed to mitigate ECMAn Electronic CounterMeasure (ECM) is an electrical or electronic device designed to trick or deceive radar, sonar or jam communication links. It may be used both offensively and defensively to deny information to an enemy. efforts such as jamming. This mode uses a ~450 msmilliseconds (.001 of a second) long 3-tone preamble made up of one unmodulated tone and two FSKFrequency-Shift Keying tones of ~485 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). shift at ~50 BdBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second.. There is no pilot tone and no further preamble, and these transmissions are shorter in duration than Non-ECMAn Electronic CounterMeasure (ECM) is an electrical or electronic device designed to trick or deceive radar, sonar or jam communication links. It may be used both offensively and defensively to deny information to an enemy..

Samples[edit]

Standard ECCMElectronic Counter-CounterMeasures (ECCM) is a part of electronic warfare which includes a variety of practices which attempt to reduce or eliminate the effect of electronic countermeasures (ECM) such as jamming. ECCM is also known as electronic protective measures (EPM), chiefly in Europe.
Marconi25.jpg
Marconi ECCM.jpg

Frequencies[edit]

Additional Links[edit]


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