Power Line Carrier
GARD 8000 SYS RFL Electronics
April 23, 2015 10-3 973.334.3100
10.2 FSK OPERATION
The PLC Module supports two FSK operational modes: 2F and 3F.
In 2F operation a guard tone is located a fixed deviation below or above the channel center frequency.
At the occurrence of a trip, the tone shifts to the opposite side of the channel center frequency. In 3F
operation a guard tone is located at the channel center frequency. One of two trips can occur. One trip
causes the tone to shift a fixed deviation below the channel center frequency. The other trip causes the
tone to shift a fixed deviation above the channel center frequency.
The performance of 2F and 3F operation is defined by the Maximum Trip Transport Delay,
Dependability and Security.
Maximum Trip Transport Delay is defined as the time between the following two events: 1) when the
Module transmitter is notified of a trip event through the Logic Bus, until 2) the Module receiver on
the other side of the link writes the trip event into the Logic Bus status registers. More specifically, it is
defined as the delay between the Logic Bus frame reception interrupt which contains the trip event
information until the status register is written in the receiver. The Maximum Trip Transport Delay for
2F operation is defined by the three operational configurations given in Table 10-1. The Maximum
Trip Transport Delay for 3F operation is defined by the three operational configurations given in Table
10-2. See also Figure 10-2. Minimum Channel Spacing (FSK).
Dependability is defined as the probability that a trip event will be successfully communicated to the
other end of the link within the Maximum Trip Transport Delay as a function of the signal to noise
ratio of the link.
Security is defined as the probability that a false trip event will be declared at the receive end of the
link as a function of the signal to noise ratio of the link.
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