BS EN IEC 61280 discusses standards for fibre optic communication subsystem test procedures. Fibre-optic communication is a method of transmitting information from one place to another by sending pulses of infrared light. BS EN IEC 61280‑2‑8 specifies two main methods for the determination of low bit error ratio (BER) values by making accelerated measurements. These include the variable decision threshold method (Clause 5) and the variable optical threshold method (Clause 6). In addition, a third method, the sinusoidal interference method, is described in Annex B. These methods are applicable to the determination of the error performance in respect of amplitude-based impairments.
BS EN IEC 61280‑2‑8 specifies the mean bit error ratio, which is well in excess of practical performance requirements for digital signals, it gives the advantage of concatenating many links over long distances without the need to employ error correction techniques.
The error performance in BS EN IEC 61280‑2‑8 are measured for various levels of impairment, and the results are then extrapolated to a level of zero impairment using computational or graphical methods according to theoretical or empirical regression algorithms.
BS EN IEC 61280‑2‑8 on fibre optic communication subsystem test procedures is useful for:
Fibre-optic communication systems and subsystems are inherently capable of providing good error performance at very high bit rates. BS EN IEC 61280‑2‑8 provides you with two measurement methods, the variable decision threshold method and the variable optical threshold method, for the determination of low bit error ratio values by making accelerated measurements.
The variable decision threshold method mentioned in BS EN IEC 61280‑2‑8 is the procedure that can most accurately measure the Q-factor and the bit error ratio for optical systems with unknown or unpredictable noise statistics. A key limitation, however, to the use of the variable threshold method to measure Q-factor and bit error ratio is the need to have access to the receiver electronics in order to manipulate the decision threshold.
Variable optical threshold method from BS EN IEC 61280‑2‑8 consists of the optical addition of an interfering pre-set bias light to the received optical signal in order to increase the measured bit error ratio. Measurements taken at several values of bias light are extrapolated to zero bias, to evaluate the bit error ratio value for normal operation. This method is applicable to DC-coupled receivers only.
The sinusoidal interference method as described in BS EN IEC 61280‑2‑8 optically or electrically, adds an interfering sinusoidal signal to the digital signal at a point before the receiver decision circuit in order to increase the measured bit error ratio. The measurements, taken at several values of reducing sinusoidal amplitude, are extrapolated to zero amplitude, thereby giving the system bit error ratio.
BS EN IEC 61280‑2‑8:2021 supersedes BS EN 61280‑2‑8:2003. BS EN IEC 61280‑2‑8:2021 includes some technical changes with respect to BS EN 61280‑2‑8:2003. These include:
EN 61280-2-8 Ed.2.0
IEC 61280-2-8 Ed.2.0