Instructions

Page 58
Setting the channel bandwidth and turning the measurement function on causes two yellow
markers to be positioned at the channel limits, equidistant from the centre frequency. The
Channel Power is shown in dBm.
7.12.2 Adjacent Channel Power Ratio (ACPR)
This measures the relative power, in dBm, of a main channel to its higher and lower adjacent
channels.
Setting the channel bandwidth, channel spacing and turning the measurement function on
causes two yellow markers to be positioned at the channel limits of the central channel, and two
pairs of light blue markers to be positioned at the limits of the upper and lower channels.
The main channel power is shown in dBm, followed by the ACPR of the lower and upper
channels in dB.
7.12.3 Occupied Bandwidth (OBW)
This measurement determines the channel bandwidth necessary to achieve a user specified
percentage of the total power found across the span. The measurement is made relative to the
start and stop frequencies of the span.
Setting the required percentage of total power and turning the measurement function on causes
two yellow markers to be positioned at the frequency points that contain that power. These will
not necessarily be symmetrically placed around the centre frequency.
The bandwidth between the markers (OBW) is displayed in MHz along with the centre
frequency calculated from the mid-point of the markers and the error between this and the
chosen centre frequency.