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FSK Analyzer
- under construction
GA-082 is an analyzer for
telegraphy signals (telex),
developed around 1983 by Rohde & Schwarz in München (Germany).
The microprocessor-controlled device can be used to determine the data
rate (baud) as well as the data format of an intercepted
Frequency-shift Keying (FSK) signal,
but is also capable of decoding a wide range of encoding and protocols,
such as ASCII,
Baudot,
ARQ-28 and SITOR.
The range of codes can be expanded with the optional
GA-082/B1 Protocol Extender.
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In practice, most telegraphic communications via the HF and VHF radio bands
use some kind of frequency shift keying (FSK), such as F1B or F7B.
Although most radio networks use a standard method for this, such as CCITT,
specific methods were used for diplomatic and military networks.
In radio intercept
stations it is common practice to analyse such signals,
determine the exact data format and speed, and monitor any traffic that is
sent through the ether. The R&S GA-082 allows fully automatic analysis of such
FSK radio signals with the highest possible accuracy.
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Furthermore, the FS-082 can be used for automatic identification of a given
signal, by measuring the equipment-specific deviations of all parameters of
the signal data. This technique is known as 'fingerprinting'. In combination
with Radio Direction Finding (RDF),
this technique is used to recognise transmitters and detect and profile
entire radio networks.
Whenever the code is known, the FS-082 can directly show the demodulated
text on its LED display or send it to a computer.
Even if the text is scrambled or encrypted, the GA-082 can be a valuable tool
for traffic analysis.
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The GA-082 contains software for the analisys of the following codes
(data protocols). Please note that code 11 to 19 require the optional
user 10 program package to be installed. In addition it was possible to
have the firmware extended by Rohde & Schwarz for 15 to 25
special codes.
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No
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Code
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Desciption
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*
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00
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STOP-MOD
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Permanent start or stop polarity
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01
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IDLE 1:1
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Idle signal, 1 mark and 1 space sent alternately
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02
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IDLE 1:6
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Idle signal, 1 mark and 6 spaces sent alternately
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03
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-
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-
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04
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IDLE 1:4
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-
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05
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IDLE 28
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-
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06
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IDLE 56
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Idle signals, periods of 14, 28 and 56 bits are repeated
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Programs for CCITT codes No. 2, 3 and 5
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07
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BAUDOT
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CCITT No. 2, Asynchronous 7.5 bits (1 start, 5 data, 1.5 stop)
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123
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08
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ARQ-28
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CCITT No. 3, Synchronous 7 bits (3 mark, 4 space, 4th char inv)
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1
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09
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ARQ-56
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Same as N08, but every 8th character inverted
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1
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10
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ASY-ASCI
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CCITT No. 5, Asynchronous 10 bits (1 start, 7 data, 1 paraity, 1 stop)
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1
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User 10 program package
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11
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CODE 3:4
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-
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12
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SITOR
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-
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1
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13
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SIFEC
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-
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1
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14
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PARITY 14
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-
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15
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ARQ-1A
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-
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1
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16
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SIEM-FEC
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-
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1
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17
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BAUER 10
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-
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1
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18
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SPREAD 21
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-
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1
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19
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SPREAD 51
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-
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1
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Test prorams
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78
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PERIOD
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Periodic check (aa bbb)
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79
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M/S L BIT
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Code statistics
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Decode program present.
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Measure stop-bit.
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Cyrillic letters possible.
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- Main input, 110-120V AC or 220-240V AC
- Input for demodulated signal (single current)
- Floating input for two demodulated channels (single or double current)
- IF/AF input (IF frequency internally programmable)
- IEC 625-1 interface (IEEE 488)
- V.24/V.28 serial interface (RS232)
- Reference frequency input (1, 5 or 10 MHz)
- Optional Program Unit GA-082/A1 or GA-082/B1
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© Crypto Museum. Last changed: Sunday, 10 May 2020 - 08:37 CET.
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