Data Regeneration With Fsk Modems - ABB ETL600 Instruction Manual

ABB Switzerland Ltd
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Datarates: ≤ 100, ≤ 200, ≤ 300, ≤ 600 and ≤ 1'200 bps with FSK;
2'400, 4'800 and 9'600 bps with DAPSK. The FSK modems with
datarates of ≤ 200 and ≤ 1'200 bps are available in two versions
with different bandwidths.
•
Compatibility with the following ITU-T standards for
telecommunication:
- R.37 (100 Bd)
- R.38a (200 Bd within 480 Hz bandwidth)
- R.38b (200 Bd within 360 Hz bandwidth)
- V.23 (1'200 Bd within 1700 Hz bandwidth)
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Receive data regenerator (only for FSK)
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Half-duplex mode
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Signal quality supervision (SNR)
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Standard data interface : ITU-T V.24, TIA/EIA RS-232
The NSK600 can be used in many applications that require multiple or
single data transmission channels over power line carrier. Carrier
keying allows the modem to be used in a point to point link or in a
multipoint network.
Similar to the teleoperation ports described in section 3.4.2.1, each
NSK600 modem can be configured for disconnectable or non-
disconnectable operation:
•
In mode 'disconnectable', the modem signal is suppressed during
the transmission of teleprotection command signals. This allows to
assign more power to the teleprotection signal during command
transmission.
•
In mode 'non-disconnectable', the modem signal is not
suppressed during the transmission of teleprotection command
signals. This mode has to be chosen when the short signal
interruptions (typically less than 100 ms) caused by teleprotection
command transmission in mode 'disconnectable' cannot be
tolerated. However, due to transients at the beginning and at the
end of command signals, bit errors may occur at these instants. As
a consequence of choosing the mode non-disconnectable, the
available power for teleprotection command signals is reduced
accordingly.
When commissioning an NSK600 modem, two different methods for
channel equalization are available: allpass filters and an equalizer.
Refer to document 1KHW001494 "APLC Channel equalization" in the
Annex for details.
3.5.1.1.

Data Regeneration with FSK Modems

The NSK600 modems using FSK modulation provide transparent
transmission of a binary anisochronous data signal. Ideally, the
received data signal is an exact delayed replica of the transmitted data
signal. In reality, the received data signal shows isochronous distortion
due to
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1KHW001489-EN
November 2005
ETL600
Structure and Function