ABB ETL600, Инструкция по эксплуатации, Страница: 148 / 382

ABB Switzerland Ltd
1KHW001489-EN ETL600
where P
PE
(x) is given by equation (3).
5.2.3.4. Absolute voltage level
The absolute voltage level defines by how many dB the RMS voltage
U of a signal x is greater or smaller than the reference voltage of
775 mV:
[ ]
,
775
) (
log 20
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
∗ =
mV
x U
dBu L
RMS
u
(10)
where U
RMS
(x) is given by equation (4).
5.2.3.5. Absolute peak voltage level
The absolute peak voltage level defines by how many dB the peak
voltage U of a signal x is greater or smaller than the reference voltage
of 775 mV:
[ ]
,
775
) (
log 20
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
∗ =
mV
x U
peak dBu L
peak
u
(11)
where U
peak
(x) is given by equation (5).
5.2.3.6. Absolute peak envelope voltage level
The absolute peak envelope voltage level defines by how many dB the
peak envelope voltage U of a signal x is greater or smaller than the
reference voltage of 775 mV:
[ ]
,
775
) (
log 20
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
∗ =
mV
x U
PE dBu L
PE
u
(12)
where U
PE
(x) is given by equation (6).
5.2.4. Absolute level definitions - digital signal processing
Within ETL600, most signal processing operations are executed by
digital signal processors (DSPs). Continuous analog signals are
represented by time sequences of sampling values. Each sampling
value X(n) is a dimensionless digit in fixed or floating point
representation.
In analogy to analog signals, we define the following levels for digital
signals:
5-4 November 2005 Configuration and Set-up